Oral Cancer An update Strenocleidomastoid myocutaneous flap in the reconstruction of mandibular defect Flexible Denture For partially edentulous mouth -A review A systematic review concerning orthodontic treatment efficiency Early vs late treatment for class-2 mal occlusion Minimally Invasive Prosthodontics A review 3D Dimension diagnostic aid -CBCTIN Orthodontics Porcelain Laminates- a problem based treatment approach Gene therapy in oral diseases -An over view Keratocystic Odontogenic Tumor Of the mandible A case report Minimal Invasive Dentistry -A new perspective
Prosthodontic considerations in periodontally compromised dentition A systematic approach Public Recognition of Our Speciality A study Antioxidants and itâ€™s role in Oral Cancer - A review
IDA -MARTHANDAM BRANCH OFFICE BEARERS-2013 President:Dr.G.Sathish Kumar Imm.Past President: Dr.S.KarthigaKannan President-Elect:Dr. J.D. Dias Vice Presidents:Dr.SelvaLibin ,Dr.Indra Kumar Hon. Branch Secretary:Dr.Subramonian.S Hon. Jt. Secretary: Dr.Sherin Leon Hon. Asst. Secretary:Dr.Sudha Rani Hon. Treasurer: Dr.LeonDurai Rep to C.D.E:Dr.Farakath Khan Rep to C.D.H:Dr.Beyanso.C.P.Daniel Rep to State: Dr.J.D.Dias ,Dr.Subramonian ,Dr. V. Manoj Executive Committee: Dr.SankarPandian ,Dr.JeslinBeyanso Dr. Harry NihilNayagam Journal Editor: Dr.R.Sambhu Journal Co-Editor:Dr. Krishna Prasad Website & Event:Dr. Merlin Raja Singh ,Dr.Jithin.G.Nelson Greeting Committee :Dr. Shine Manoj.D.J Student Membership:Dr.Anuroopa Membership Committee:Dr.Priya.M.S ,Dr.Manoj.J.R ,Dr.Dhano Legal Cell:Adv.Rtn. Mohanan Nair ,Dr. B. Krishna Prasad Advisory Committee: Dr.J.D.Dias ,Dr.M.IrwinAnand ,Dr.AnithaJeslin Dr.Jain.R.S Care and Concern:Dr.Selva Kumar
Vol-1 issue-3 june-2013
Knowledge is progressing by geometrical ratio and not by arithmetical. It is important that we too become a part of this fast pace of progress. Not only assimilating but also disseminating is an important way in propagating knowledge. Realization of the maxim ' Publish or perish' in the world of science has inspired and encouraged many organizations to start their own journals. At present information is only a click away. It is important to have electronic versions of the journal so that the information reaches worldwide through the encompassing net. The number of patients we see is enormous in comparison with the rest of the world. But unfortunately we were not very keen to document. If at all we had proper documentation we would have been the leaders in the profession. It is gladdening that the younger generation is more enthusiastic, proactive and computer savvy. I am really delighted to write the Foreword for this issue of JOMIDA. The quality of the journal is impressive and the articles are informative and noteworthy. I take this opportunity to congratulate the editor, president, secretary and other office bearers for this noble venture. With best wishes
Prof. Dr. Varghese Mani Oral and Maxillo Facial Surgeon
Dean,Mar Baselios Dental College
Vol-1 issue-3 May-2013
Authorship criteria All persons designated as authors should qualify for authorship, and all those who qualify should be listed. Each author should have participated sufficiently in the work to take public responsibility for appropriate portions of the content. One or more authors should take responsibility for the integrity of the work as a whole, from inception to published article. Authorship credit should be based only on 1.Substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2.Drafting the article or revising it critically for important intellectual content; and 3.Final approval of the version to be published. Conditions 1, 2, and 3 must all be met. Acquisition of funding, the collection of data, or general supervision of the research group, by themselves, do not justify authorship. The order of authorship on the byline should be a joint decision of the co-authors. Authors should be prepared to explain the order in which authors are listed. Once submitted the order cannot be changed without written consent of all the authors. For a study carried out in a single institute, the number of authors should not exceed six. For a case-report and for a review article, the number of authors should not exceed four. For short communication, the number of authors should not be more than three. A justification should be included, if the number of authors exceeds these limits. Only those who have done substantial work in a particular field can write a review article. A short summary of the work done by the authors (s) in the field of review should accompany the manuscript. The journal expects the authors to give post-publication updates on the subject of review. The update should be brief, covering the advances in the field after the publication of article and should be sent as letter to editor, as and when major development occur in the field. Sending the Manuscript to the Journal Articles can be submitted to: email@example.com, firstname.lastname@example.org 1.First Page File: Prepare the title page, covering letter, acknowledgement, etc., using a word processor program. All information which can reveal your identity should be here. Do not zip the files.
Vol-1 issue-3 May-2013
Vol-1 issue-3 May-2013
Dear Friends, It gives me immense pleasure to meet you all through yet another edition of scientific journal of Marthandam IDA (JOMIDA).I would like to take this opportunity to inform all that we have moved a step forward by going online. JOMIDA is now available online at the link www.jomida.idamarthandam . I hope this small step holds much importance in this technologically sound, fast moving world which will help all the dental fraternity to access our journal from any part of this world. I strongly believe that the time is not that far for us to get this journal indexed. At this juncture I extend my sincere thanks to the advisory panel and the editorial team, the president and hon. secretary of IDA Marthandam and IDA Tamilnadu state and also each and every members of the IDA Marthandam family whose support and encouragement has played a significant role in the successful journey of JOMIDA. The editorial board is eager to know the feedback from the readers. Any suggestions, critics are always welcome which will help us to improve the quality of our journal and
help us to setup a standard that is equivalent to many national journals. Ignorance is the curse of god;Knowledge is the wing wherewith we fly to heaven - William Shakespeare Hope this edition of JOMIDA will add few feathers on the wing of knowledge and enlighten all the readers and fulfil their expectations. Thanking you, Yours Sincerely Dr.R.Sambhu Editor in Chief
Vol-1 issue-3 May-2013
Contents Oral Cancer - An update
Strenocleidomastoid myocutaneous flap in the reconstruction of mandibular defect
Dr. J. Pratheep,Dr. S. Subramonian, Dr. V. Vasanthakumar
Flexible denture for partially edentulous mouth -A review
Dr.Aravind Krishnan, Dr.Sreelal T, Dr.Anuroopa.A
A systematic review concerning orthodontic treatment efficiency Early vs late treatment for class-2 mal occlusion
Dr.Ruby Mathew,Dr.RamachandraPrabhakar,Dr.M.K.Karthikeyan, Dr.SaravananR., Dr.RajvikramN., Dr.C.Vishnu Chandran
Minimally Invasive Prosthodontics - A review Dr.Anjana.S, Dr. Sreelal.T, Dr. Shibu.A,Dr. Anuroopa.A, Dr. Aparna Mohan
3D Dimension diagnostic aid -CBCT in Orthodontics Dr. Sathya Chandran,Dr.Ramachandra Prabakar, Dr.Saravanan, Dr.Karthikeyan,Dr.Raj Vikram,Dr. Eshwara prasath
Porcelain laminates- a problem based treatment approach A. Leoney , P. S.Manoharan
Gene therapy in oral diseases -An over view
24 28 32
Dr.Gajendra.V, Dr.Hema.G, Dr.Kathiga Kannan,
Keratocystic odontogenic tumor of the mandible -A case report
Dr. Thomas Varghese, Dr.KarthigaKannan, Dr. Jassim K A, Dr. Merin George,
Minimal invasive dentistry -A new perspective Dr. Santhini G. Nair, Dr. S Rajesh
Prosthodontic considerations in periodontally compromised dentition - A systematic approach
Dr,Aparna Mohan, Dr,Anuroopa A., Dr ,James Rex
Public Recognition of Our Speciality - A study Dr. Ramandeep Singh Bhullar, Dr. S.Ram Kumar, Dr .Nanda Kumar, Prof. C. Ravindarn
Antioxidants and itâ€™s role in Oral Cancer - A review A. Sri Kennath J Arul ,A. Sri Sennath J Arul ,Sonika Verma ,Rashmika Verma
56 58 Vol-1 issue-3 May-2013
STATE PRESIDENT'S MESSAGE
I feel extremely happy to be communicating with you all through the medium of this issue.It is our privilege and responsibility as Dental Health Science professional to promote good and healthy practice by exchanging information and ideas on our experience and skills . Continuous learning is mandatory for the growth and success of the dental practice.So I believe this journal of yours gives the general dental practitioners the necessary scientific data both clinically and academically to enhance their skills to deliver better dental care to their patients. My best wishes for Team IDA Marthandam. Vazhga Bharatham, Valarga IDA. Dr. D. Senthil Kumar President IDA Tamil Nadu State Branch email@example.com.
STATE SECRETARYâ€™S MESSAGE
Dear Members, WARM GREETINGS!!! In this juncture I appreciate the office bearers for this humanity service to the peoples and our Dental fraternity. Our dental technologies are nowadays money minting factory. We are earning more from this field. We can get the knowledge from CDE Programs. Attend More Programs and Get more knowledge. Motivate your friends to attend more programs and also get knowledge. The great opportunity is coming to your country. FDI 2014 (DELHI). Register more. Our Tamilnadu State Dental Conference will be held on November 2013 at Pondicherry. We seek your participation. Through this journal once again I wish you all. Best of Luckâ€Ś. Dr.C.Sivakumar Hon. State Secretary IDA Tamilnadu State Branch CDH Chairman IDA - HO Ph: 9443395351 Vol-1 issue-3 May-2013
Dear members, It is a great honour to share my views with you all as the Marthandam branch president. During my presidential speech in December 2012,I stressed upon continuing dental education programme for our members. So keeping in mind, my goal, scientific lectures are being held by the eminent speakers of our area. I would like to appreciate the editor and the team of editorial board for working hard to bring out 3 issues of our scientific journal, which was appreciated by the IDA Tamilnadu state branch. I have to specially mention our secretary Dr. Subromonian, Dr. Dias and Dr .S. Karthiga Kannan for their dedication to our association. With warm regards Dr. G. Sathish Kumar President IDA Marthandam
Dear friends, I feel elated to reach you through the 3rd issue of JOMIDA. We the team MIDA,marching with pride and prosperity to reach the summit of success by commitment, dedication and encouraging support from all seniors and friends. I look forward to get the same in future, for successful running of MIDA and JOMIDA. Restless hard work, missionary thinking and unselfish effort is rd materialized by the 3 issue of JOMIDA from the editor and his team. I thank the authors for their faith and belief on us. I thank the editorial board, Dr. Sujan and the printers, the review committee for their remarkable rd work to publish the 3 issue successfully. I thank the well wishers and other friends for their comments for the success of our journal. Jaihind. Thanking you, Yours sincerely Dr.Subramonian Hon.Secretary IDA Marthandam
Vol-1 issue-3 May-2013
PROF J G KANNAPPAN (Late) Born: Dec 26, 1934 Died: Dec 30, 2010
Born on Dec 26, 1934, near Coimbatore, Tamilnadu, South India, he had received his basic schooling and education before graduating from St Joseph's College, Trichy. The first dentist from his family, he graduated from the Madras Medical College before pursuing his Master's in Dental Surgery (Orthodontics &Pedodontics), from the Nair Dental College in Mumbai. He went on to secure his Fellowship on the same in London by the Govt. of India five year schemes, before returning to an Academic career at various institutions in Tamilnadu and retired as the Principal of the Madras Dental College, Chennai. In realization of this generosity of the Govt. of India, Prof Kannappan has devoted his services to the poor and needy of the nation. As a token of gratitude to Govt of India, Dr Kannappan has established many endowments in the universities, schools and colleges for the benefit of youngsters. He was instrumental in shaping numerous individuals, institutions and organizations and founder of various professional societies including the Forensic Odontological Society of India, Indian Society of Dental Research etc. He was the president of the Tamilnadu Dental Association, Indian Orthodontic Society, Forensic Odontological Society and the Indian Society of Dental Research in addition to leadership roles in numerous dental and societal institutions.He was the recipient of the Leverhulme Fellowship in the United Kingdom, innumerable awards from Indian Government, and honors from various literary, religious, philosophical, and community-based organizations. He has authored articles and books on dental health and education in many languages and in International Journals.His contribution to ISDR (Indian Society for Dental Research) as one of the founder members and to its growth to the present status has been witnessed by many dental professionals.He is associated with IAFO in India, right from its inception. He has nurtured this institution of Forensic Odontology and has proposed to medical universities to implement Forensic Odontology as a separate subject in BDS curriculum and as a master degree. Dr J.G.Kannappan is the Professor Emeritus of the TN Dr MGR. Medical University, Chennai. He has been teaching dental and medical students for the last 51 years. He has taught, BDS, MBBS, MDS, and MSc Forensic Odontology students. He has guided MPhil candidates too. He has authored and edited 32 books in medical and dental subjects in English, Tamil and Hindi and they are in the world libraries. During the first TN Govt service, he has served rendering dental relief in all villages of Tamil nadu, thro" the mobile dental van, which was donated to the Govt of TN by then Vice President of India, Dr Sir Radhakrishnan. His research in leprosy is unique and that he has declared that leprosy is preventable and curable. His second research is about oral nutritional deficiency ulcers and symptoms are due to GIT worms. He has done the autopsy of the head at the site of Rajiv Gandhi assassination in 1990. He has formulated classification of dental appliances for the cleft palate patients and many more.He has been conferred prestigious DSc (Hon Casua) degree of the TN Dr.MGR. Medical University, by His Excellency Shree Surjit Singh Barnala, Governor of Tamil Nadu.
Vol-1 issue-3 May-2013
Sanjiv Nair MDS Facio Maxillary Surgeon Editor in chiefJMOSI Journal of maxillofacial &oral surgery of India
Cancer of the oral cavity predominantly are those arising from the epithelium lining the upper aero digestive tract which is referred to as Oral Squamous Cell Carcinoma(SCC). These cancers because of its location are easily identified and if diagnosed in its early stages are near curable with minimal functional and aesthetic morbidity. The epidemiologic studies on Oral cancer have thrown up a list of environmental factors directly or indirectly being responsible for its cause. The primary risk factor with a strong link are tobacco related products, both in its smoked and smoke less forms ,alcohol, ultra violet light , radiation , genetic factors ,Human Papilloma Virus (HPV) and malnourishment. Tobacco predisposes to change in the oral mucosa making it susceptible to alterations in cellular morphology. This can trigger genetic changes leading to alteration in cell devision.The exposure of the precursor cells of the oral mucosa to more than one factors may either have synergistic or additive effects in the development of oral SCC.
Vol-1 issue-3 May-2013
Biology of Oral SCC : - Multiple exposures over a long period of time causes sequential Deoxy ribose nucleic acid (DNA) Damage . When the DNA damage exceeds the Cell's DNA repair capability it leads to a permanently altered gene referred to as mutation. Survival of the DNA damaged Cell ( mutant cell) is however important to allow its accumulation and progression to carcinoma. Initiation of Carcinoma is a complex process facilitated indigenously by break down of the body's immune mechanism as well. Accessory factors such as angiogenesis allows recruitment of blood vessels to the mutant cells allowing it to sustain its division and growth . Oral Squamous cell carcinoma has ability to spread or metastasize due to its access to structures within the connective tissue. Lymphatic metastasis is the commonest form of cancer progression second to local spread. Blood born metastasis as well as neural spread in Oral SCC is well documented. The role of enzymes like collagenase,heparinise allows degradation of physiologic barriers facilitating the process. The presence of metastatic tumor emboli within the reticulo endothelial system is exposed to the same immune related antagonistic actions as is faced by foreign body , survival of these colony of cells would require a combination of depressed immunity with facilitation of growth factor and angiogenesis factor. The key to management of Oral SCC is prevention and early detection . Visual screening for oral cancer is the most effective diagnostic tool . Use of adjuvant diagnostic aids such as Toluidine blue , transepithelial oral cytology ( Brush Biopsy) , Tissue reflectors , HPV Screening may be useful but lack of sufficient evidence based scientific support . Treatment of oral Cancer : Clinically identifiable disease can be effectively biopsied . transoral Incisional biopsy of obvious oral lesions would confirm the disease . Further evaluation with the use of imaging modalities will help in staging the disease (TNM Classification staging) .Refer Table 1 Joint Oncological clinics helps in planning the treatment and assisting the patient with the course of treatment. Joint meetings would require primarily the following specialists such as head and neck specialists; a Consultant Surgeon, a Consultant in Oncology and Palliative Care Consultant. Treatment for the oral SCC would require surgical resection with or without radiotherapy and chemotherapy. The use of immunotherapy , gene therapy and anti angiogenesis therapy although show promise are very much in its infancy.
Head & Neck SCC being a loco regional disease primarily , Surgery followed by radiotherapy holds great promise both in disease control and quality of life.Surgical ablation would mean excision of the primary tumor with a wide margin and addressing the metastatic neck. Inclusion of the clinically and radiographically negative neck in a neck dissection varies from centre to centre and is site specific . This is reffered to as staging neck dissection or prophylactic neck dissection . The Nodes in the neck are grouped into V levels and total removal of level I level V along with the Internal Jugular vein, Spinal accessory Nerve and the sternocleidomastoid muscle is referred to as Radical neck dissection (RND). Preservation of one or more of the functionally important structures such as spinal accessory nerve, Internal Jugular Vein and sternocleidomastoid muscle while dissecting the rest of the lymph nodes is Modified RND Selective Neck Dissection is excision of one or more group of lymph nodes that drain the primary site directly or indirectly. Reconstruction in oral cancer surgery is of paramount importance due to its impact on aesthesis and function . Restoration of form and function and total rehabilitation of the patient may require counselling and vocational therapy. Principles of reconstruction involves replacement of ablation tissue with identical tissue from the patient's own body. Local ,Regional or Microvascular flaps help in obtaining tissue match and texture. The survival of the transplanted tissue depends on its vascularity . Use of microvascular free tissue transfer permits ideal reconstructive choices. The radial forearm free flap for soft tissue reconstruction and fibula for bony replacement seems to be work horse of modern day reconstructive surgery. Radiotherapy - The use of ionizing radiation dates back to the end of the nineteenth century following discovery of radium by Marie and Pierre Curie. The principle involved destruction of rapidly dividing cells including malignant cells with radiation. Post surgical Radiotherapy is far more effective than presurgical radiation in eliminating microscopic disease not removed with surgery. Radiation acts by ionizing the cellular water molecule into active free radicals which in turn affects the DNA of cancer cells. The optimum time to irradiate is 6-8 weeks post surgery during the intermediate healing phase. Vol-1 issue-3 May-2013
A total of 6000- 7500 cGy in fractional dozes is given to the target area which irradiates the primary site and the susceptible neck.The normal side effects of radiation incude Radiation mucositis, Xerostomia, Taste impairment and Osteoradionecrosis.Side effects of the Radiotherapy can be minimized by employing adequate dental care, administration of agents that protects salivary tissue during radiation , prevention of secondary infection .
Advances in radiation technology includes 1.Super voltage irradiation Linear accelerator that spare superficial structure while targeting deeper tissue. 2.Brachytherapy Implanted radiation sources in the form of seeds or needles allow constant radiotherapy with higher tissue death. 3.Neutron beam irradiation damages tissue more directly and are effective on hypoic tumors. 4.Hyperfractionated therapy is doubling the radiation doze by twice a day treatment. 5.Use of radiosensitizer and oxygen enhancement therapy makes the target cells more susceptible to radiation . The role of Chemotherapy in Oral SCC was much debated in the past .The main reason being it was considered a loco regional disease effectively managed with surgery with or without radiotherapy. This however gave way to combination of Chemo radiation as an effective technique in Organ preservation especially with larynx and Oropharynx. The rationale was founded upon high response rates in patients with Head and Neck SCC to a variety of agents including Methotrexate, Vinblastine, 5-Flurouracil, Cisplatin, Carboplatin and the taxoids either in combination or alone. These response rates were found to be 50% in previously untreated patients .
The targeting and transport of genetic material does appear to be the biggest obstacle. Use of technology such as nanotherapy is in experimental stages. The suppression of TGF ,Angiogenic factors are other alternates to prevent cancer progression. A better understanding of molecular biology and the ambitious human genome project does allow advances in the research and development of targeted therapy Even with advances in surgical techniques ,and other forms of therapies cure may be impossible and life can be maintained with the aim of pain control, and preservation of dignity. Selective use of surgery to reduce tumour bulk to reduce pain and preserve function. Palliative radiotherapy ,nutritional support with gastrostomy feeding tubes, Pain control with morphine or other narcotic analgesics, Home healthcare facility during terminal stages allow death with dignity to such patients. Table: 1
TNM Staging of oral cavity squamous cell carcinoma Primary tumour staging (T)
Tx - tumour cannot be assessed T0 - no evidence of primary tumour Tis - carcinoma in situ T1 - tumour 2 cm or less in greatest dimension T2 - tumour greater than 2 cm and less than 4 cm in greatest dimension T3 - tumour greater than 4 cm in greatest dimension T4 - tumour invades adjacent structures (mandible, maxilla, skin, extrinsic muscles of the tongue) Nodal status (N) Nx - nodes cannot be assessed N0 - no regional nodal metastases
Nodal staging is the same for SCCs of the oral cavity,
Neo-adjuvant or induction chemotherapy schedules also help in downstaging the disease prior to definitive local therapy. The simultaneous use of combination of Chemotherapy with radiotherapy is reverred to as adjuvant or combined therapy and was found as effective without surgery and used for laryngeal SCC. Adjunctive therapies such as gene therapy involves trancfer of genetic materials into cancer cells with selective destruction of malignant cells while sparing normal cells thus overcomung the defeciencies of CT and RT.
N1 - single ipsilateral node, = 3cm N2
oropharynx, hypopharynx and larynx.
N2a - single ipsilateral node, 3-6 cm N2b - multiple ipsilateral nodes, < 6 cm N2cbilateral nodal metastases OR contralateral nodal metastases < 6 cm N3 : any nodal metastasis > 6 cm Metastases (M) M0 - no metastases M1 - distant metastases present
Vol-1 issue-3 May-2013
Dr. J. Pratheep, Dr. S. Subramonian, 3 Dr. V. Vasanthakumar 2
1)& 2) Reader, Rajas Dental College, Kavalkinaru 3) Reader, CKS Teja Dental College, Tirupathi
Abstract Reconstruction for oral cancer and severe trauma defect plays an important role considering the form and function. Selecting a flap to reconstruct the defect depends on the size and position of the defect. Considering the donor site morbidity, time and expense, regional pedicled flaps dominates free flap. Some of the regional pedicled flaps are pectoralis major myocutaneous flap, temporalis flap, trapezius flap, buccal fat pad flap and sternocleidomastoid flap (SCM). We present the technical details of harvesting a SCM in the reconstruction of mandibular defect.
Key words Reconstruction,Myocutaneous Flap, Mandibular Defect, Sternocleidomastoid.
Defect in the oral cavity can be reconstructed using a flap with skin and the muscle to reconstruct defects in the oral cavity. SCM fits the criteria and permits one-stage reconstruction at the time of the primary resection and eliminates the need for skin grafts to the donor sites1. Partial epithelial loss of the skin paddle occurs in some cases and surviving dermis became 2 resurfaced with epithelium .Raising a SCM flap based on the perforating vessels of the superior thyroid vascular pedicle increases the arc of rotation and applications for the flap improved3. Facial paralysis repair by the pedicled SCM muscle restores both static and dynamic symmetry of nose and mouth with improvement in facial expression. The upper third of the SCM muscle was constantly supplied by branches of the occipital artery. The middle third of the SCM muscle received its blood supply from a branch of the superior thyroid artery (right SCM/left SCM: 53%/53%), the external carotid artery (27%/20%), or branches of both (20%/27%). The lower third of the muscle was supplied by a branch arising from the suprascapular artery (73%/73%), the transverse cervical artery (7%/13%), the thyrocervical trunk (13%/13%), or the superficial cervical artery (7%/0%). The neoprene-latex injected into the subclavian artery reached the four lower levels in all SCMs (the middle third of the SCM). In 13% of the SCMs, this injection also reached level II (the upper third of the SCM). With a double injection (inferior and middle pedicles), levels I and II were reached in 5 100% of the cases . Vol-1 issue-3 May-2013
Advantages6: 1.Contour the soft tissue defect 2.Re animate facial paralysis 3.Transposed with or without segment of the clavicle and/or sternum as a composite pedicle flap for reconstruction of the mandible 4.Reconstruct floor of mouth 5.To protect the carotid artery
Pre-operative intra oral
6.It may assist in shoulder elevation following poliomyelitis when transposed to the acromial process of the clavicle. Disadvantages7: 1.Upper SCM composite muscle flap is poorly viable 2.Blood supply to the skin paddle based over the lower third of the muscle is similarly unreliable 3.Upper and lower ends of the muscle are areas of oncological significance 4.Inclusion of clavicle for mandibular reconstruction is usually no longer required as superior flaps are available Diagramatic view
Technique: Neck incisions can be modified according to the requirement of the surgeon considering access, nodal clearance, previous incisions, site of the tumor, pre or post op radiotherapy and the reconstruction plan. Here we have used the Schobinger incision with the vertical limb ending over the paddle of skin and the muscle. The skin is prepared and the incision marked and made. Considering the clearance of the disease and reconstruction, the skin flap was raised in a standardized fashion. Skin incision made with no. 15 blade followed by cautery and dissect below the sub-platysmal plane. Posterior neck was dissected with utmost care as the damage of the SCM muscle occurs and we may miss the plane and end up in severe bleeding. Proper retraction in upward direction helps the operator to enter the sub-platysmal plane and identify the SCM muscle. Marginal mandibular nerve was sacrificed. External jugular vein and anterior jugular veins were tied as we isolate the SCM muscle.
Segmental mandibulectomy done and level I to IV was cleared. The defect was evaluated and thereconstruction flap was selected. Vol-1 issue-3 June-2013
The sternocleidomastoid (SCM) muscle has 3 pedicles. The superior pedicle is a branch given off in about 70% of cases by the occipital artery, the middle is formed by a branch of the superior thyroid artery, and the inferior pedicle arises from the suprascapular or the transverse cervical artery8. Further minor arterial branches enter in between. The shoulder was extended with sand bag. The margins and the skin paddle of the muscle drawn with a marker. The muscle was harvested from the lower sternal origin and clavicular origin with skin paddle. The operator should have a proper vision of the flap's borders. Slowly elevate the muscle with utmost care as the pedicles should not be traumatized. Once the flap was harvested the length of the flap was evaluated and then suturing was done without any tension. Reconstruction plate can be used to gain the contour of the mandible. The SCM flap can be placed enclosing the reconstruction plate and sutured with the adjacent muscles and the skin paddle can be sutured with the mucosal tissues.
Conclusion: SCM flap is a simple and effective flap for the reconstruction of the oral defect which avoids or helps in addressing many problems that happens with other regional myocutaneous flaps. It can alsobe used for primary reconstruction sparing the free flaps for secondary reconstruction if needed after clearance of recurrence. References:
1.Ariyan S. “The sternocleidomastoid myocutaneous flap”. Laryngoscope. Apr;90(4):676-9, 1980 2.Ariyan S. “ One stage reconstruction for defects of the mouth using a sternomastoidmyocutaneous flap”. PlastReconstr Surg. May;63(5): 618-25, 1979 3.Avery CM. “The sternocleidomastoid perforator flap”. Br J Oral Maxillofac Surg. Oct;49(7):573-5, 2011 4.Yang C, Cui L. “Transposition of pedicled sternocleidomastoid muscle for repair of facial paralysis in late stage”. ZhongguoXiu Fu Chong Jain WaiKeZaZhi. Jan;16(1): 48-50,2002 5.Leclere FM, Vacher C, Benchaa T. “Blood supply to the human sternocleidomastoid muscle and its clinical implications for mandible reconstruction”. Laryngoscope. Nov; 122(11):2402-6, 2012 6.Conley J, Gullane PJ. “The sternocleidomastoid muscle flap”. Head Neck Surg. Mar-Apr; 2(4): 308-11,1980 7.Stell and Marran's head and neck surgery 4th ed;2000 8.Marx RE, McDonald DK. “The sternocleidomastoid muscle as a muscular or myocutaneous flap for oral and facial reconstruction”. J Oral Maxillofac Surg. Mar;43(3):155-62, 1985
Post operative -frontal
Post operative -lateral Vol-1 issue-3 May-2013
Dr.Aravind Krishnan, Dr.Sreelal T, Dr.Anuroopa.A
Partial edentulism is one of the most relevant oral
(1)Post Graduate, (2) Professor and HOD, (3) Reader
conditions noticed in dental practice .A complete
Department Of Prosthodontics, SMIDS, Kulasekharam
functional and esthetic rehabilitation of their patients is of prime concern for the success of the general practice. But in certain conditions where the regular treatment modalities has to be changed or modified in order to enhance the quality of treatment, a flexible denture is an alternative treatment option. Flexible dentures are Nylon based thermoplastic material which are Flexible in nature. In 1940's , Arpad and Tibor Nagy's research lead
to the introduction of a newer thermoplastic,Valplast
Management of situations like unilateral or bilateral undercuts conventionally includes alteration of the denture prosthesis bearing area, adaptation of the denture base, careful planning of the path of insertion and the use of resilient lining material But in certain conditions where the regular treatment modalities has to be changed or modified in order to enhance the quality of treatment, a flexible denture is an alternative treatment option. The Article reviews about the various Flexible denture materials, advantages, disadvantages, indications, contra indications and various commercially available flexible denture products
material.Valplast (Valplast Int. Corp. - USA) and Flexiplast (Bredent - Germany) were first introduced to dentistry in the 1950s,which were similar grades of Polyamides (nylon plastics).Rapid Injection Systems (currently known as The Flexite Company - USA), originated in 1962, introduced the first Flexite thermoplastic which was a flouropolymer (a Teflon-type of plastic).Acetal was first proposed as an unbreakable thermoplastic resin removable partial denture material in 1971.DENTSPLY introduced the Success FRS, “flexible resin system” which utilizes a flexible tissue colored
thermoplastic resin for flexible partial dentures. Cosmetic
Thermoplastic, Nylon, Flexible, Proflex
Dental Materials introduced “Aesthetic Perfection T” which is a new line of thermoplastic Acetal, Acrylic, and Polycarbonate materials that can be used in most thermoplastic procedure.
Vol-1 issue-3 May-2013
Indications of Flexible denture includes challenging cases
They are very strong, resistant to wear and fracture, and is
like Unilateral or bilateral undercuts, pediatric patients and
quite flexible. Thermoplastic acetal is considered as an
cleft palates .It is an ideal replacement for acrylic when
ideal material for pre-formed clasps in partial dentures,
patients are allergic to denture acrylics and in patient with a
unilateral partial dentures, cast partial denture
history of repeated partial denture frame breakage. It is an
frameworks, provisional bridges, occlusal splints, and
easy and affordable alternative to implants or fixed partial
implant abutments. Acetal resins resist occlusal wear and
dentures and also for tooth or tissue-coloured clasps in high
are well suited for maintaining vertical dimension during
esthetic areas. Additional applications comprises
provisional restorative therapy. It does not have the natural
cosmetic gum veneers,bruxism appliances, implant
translucency and vitality of thermoplastic acrylic or
retained over-dentures , full dentures for patients with
polycarbonate, hence used as short-term temporary
protuberant bony structures or large undercuts, unilateral
space maintainers ,temporary prostheses (short and long-
Thermoplastic Polycarbonate is a polymer chain
term), obturators and speech therapy appliances,
of bisphenol-A carbonate. Compared to Acetal they are
orthodontic devices, occlusal splints and sleep apnea
very strong, resistant to fracture but flexible during
appliances, anatomical bite restorer
(used during full
occlusal force, hence consequently will not maintain the
mouth rehabilitations),sleep apnea appliances. Flexible
vertical dimension .They are ideally suited for provisional
partials for people with special needs are athletes, police
crowns and bridges and not suitable for partial denture
and firefighters, military personnel, prisoners and prison
framework. One of the major advantages is that it exhibits
officers, any person who might be exposed to physical
excellent esthetic properties.
harm or injury.
Thermal polymerized PMMA is yet another
Although flexible dentures are treatment choice
material which is easy to adjust, handle and polish,
for various clinical scenarios ,it is contraindicated in
relineable and repairable at the chair-side, available in
following situations such as deep overbites (4mm or more)
both tooth and gingival colors, translucency and vitality,
where anterior teeth can be dislodged in excursive
providing excellent esthetics. But it demonstrates high
dentition with minimal undercuts for
porosity, high water absorption, volumetric changes and
retention, situations where there is less than 4 mm of inter-
residual monomer .They have got a poor impact
occlusal space in the posterior area, bilateral free-end distal
resistance, with an adequate tensile and flexural strength
extensions with knife edge ridges or lingual tori in the
for a variety of applications. .Flexite M.P, a thermoplastic
mandible and bilateral free-end distal extension on maxilla
acrylic, is a special blend of polymers with the highest
with extremely atrophied alveolar ridges.
impact rating of acrylic.It has a surface hardness of 55-65,
There are various types of flexible denture base
making it popular for bruxism appliances as well as
materials available; they are thermoplastic Acetal,
dentures.Thermo plastic Nylon is a resin derived from
Thermoplastic polycarbonate, thermoplastic Acrylic and
diamine and is a dibasic acid monomers with high physical
strength, heat resistance and chemical resistance.It is
Thermoplastic Acetal is available in basically
easily modified to increase stiffness and wear
two forms; homo polymer and co polymer .Acetal as a
resistance.They have excellent balance of strength,
homo-polymer has got good short term mechanical
ductility and heat resistance which is hence the best
properties, where as co-polymer has better long-term
candidate for metal replacement applications.
Vol-1 issue-3 May-2013
They have got inherent flexibility and hence used primarily
Valplast dentures are to be soaked
in water for 10-15
for flexible tissue born partial dentures. They does not have
minutes a day, or overnight at least three times a week.
enough strength to use for occlusal rest seats, and won't
Loose particles can be removed with the use of a sonic
maintain vertical dimension when used in direct occlusal
denture cleaner, or by placing the appliance under running
water. Brushing a Valplast appliance is not recommended
Thermoplastic nylon is injected at temperatures from
as this may remove the polish and roughen the surface over
274 to 293 degrees Celsius and has a specific gravity of
time. Sunflex are strong and biocompatibe They are
1.14. Mold shrinkage amounts to 0.014 in/in. The tensile
unbreakable, light weight .Tissue coloured clasps are the
strength is 11000 psi and the flexural strength is 16000 psi.
major advantages of this type of partial dentures. Sun Flex
Nylon is a little more difficult to adjust and polish, but the
are more stain resistant and has got a Perfect degree of
resin can be semi translucent and provides excellent
flexibility. Another advantage of this is that Dentures will
esthetics for flexible tissue born partial dentures.
not warp or become brittle and Aesthetically superior
Advantages of thermoplastic materials include
Functional Benefits of the Flexible Material
predictable long-term performance, stable and resist
1. Flexibility of the material is an important benefit and it
thermal polymer unzipping, high creep resistance ,high
helps to shift the burden of force control from design
fatigue endurance ,excellent wear characteristics ,solvent
features of the appliances to the properties of base material
resistance, very little or no free monomer, no porosity,
2. Leverage is a critical component of RPD. Flexible denture
exhibit higher dimension and color stability, more flexible
reduces leverage effects of its extensions and hence good
and stronger than their traditional counterparts.
support and retention is achieved
Elastomeric resins are added to the resin polymer formulas to create greater flexibility which in turn reduces
3. Occlusal rests and guide planes need not be prepared in abutment teeth.
fracturing. The materials are reinforced with glass filler or
4. Stress distribution of Flexible denture is important and is
fibers to enhance their physical properties and they can
accomplished by flexibility of major connector and acts as
produce single cast or pressed restorations that are strong,
a stress breaker.
lightweight, flexible appliances in tissue or tooth color
Advantages include more
matched materials that never need adjusting.
acceptable esthetics, has good flexibility like titanium,ease
Commercially available products are Valplast ,Duraflex
of insertion in the mouth with alveolar undercuts or even if
,Flexite,Proflex,Lucitone ,Impak ,in which Valplast and
there is slight shifting of the remaining teeth over time, the
Lucitone are Monomer free.
flexibility of the denture material, allows the use of
Pro-flex were introduced by Pickett
prosthesis with little adjustment.There is no need of
dental Lab in 1998 and is indicated in anatomical
modification of the remaining teeth and hence can be used
considerations like bilateral undercuts. It is Hypoallergenic
for patients with tilted teeth. It is heated up in hot water for
and is aesthetic, tough, durable and dense. Valplast are used
about a minute and can easily be adjusted and inserted in
as Partial dentures and unilateral restorations They are
the undercut area and rebasing is possible.
highly biocompatible nylon thermoplastic with unlimited
But the dis advantages are that being a plastic
design versatility. Valplast are virtually invisible but is
material,it cannot be made into thin sections like metal ,and
expensive and non invasive. Special instructions for
it takes longer time for patient to get used to a flexible
valplast flexible denture wearer include -Clean Valplast
partial denture.It does not conduct heat and cold like
flexible dentures regularly.
metal.The remaining teeth have to be in fairly good periodontal health. Vol-1 issue-3 May-2013
Flexing causing unfavorable forces that in turn result in bone loss.It is highly expensive.It requires more chair-side time for adjustment and need special instruments (knives and polishing kit). It is hard to repair if fractured ,hence only rebasing is possible Conclusion: Dentistry is been updated ,researched and perfected in order to provide the patient with efficient and quality treatment and modify their life style.Use of Flexible denture has been advocated by many prosthodontists because of its advantages and the general characteristic features .Flexible denture can be considered as an effective alternative in various partial edentulous conditions that require tedious surgical skills and time consuming procedures. References: 1. â€œFlexible denturesâ€? an alternate for rigid dentures? Volume 1 Issue 1 Journal of Dental Sciences and Research ,Dr. Sunitha N Shamnur, Dr. Jagadeesh KN,Dr. Kalavathi SD, Dr. Kashinath KR 2. Flexible denture base material: A viable alternative to conventional acrylic denture base material Contemp Clin Dent. 2011 Oct-Dec; 2(4): 313317. J. P. Singh, R. K. Dhiman, R. P. S. Bedi, and S. H. Girish 3. Flexible Denture for Partially Edentulous Arches - A Case Report Journalofdentofacialsciences Vol. 1 Issue 2 Laxman Singh Kaira, H R Dayakara, Richa Singh 4. Flexible removable partial denture for a patient with systemic sclerosis and microstomia General Dentistry November /December 2007 Nachum Samet .Schmel Tau ,Michael Findler ,Srinivas.M,Mordechi Findler 5. Flexible Partial Dentures - A hope for the Challenged Mouth People's Journal of Scientific Research
Vol. 5(2), July 2012 G.K. Thakral,
Himanshu Aeran, Bhupinder Yadav, Rashmi Thakral 6. An evaluation of the hardness of flexible Denture Base Resins Health Sciences 2012 Dr.Sheeba Gladstone,Dr.Sudeep.S,Dr.Arun Kumar
Vol-1 issue-3 May-2013
Dr.Ruby Mathew, Dr.RamachandraPrabhakar, 3 4 Dr.M.K.Karthikeyan, Dr.SaravananR., 5 6 Dr.RajvikramN., Dr.C.Vishnu Chandran 2
(1) 3rd year postgraduate,( 2) Professor and HOD,(3& 4) Professor, (5) Reader,( 6)Senior lecture, Department of orthodontics, Thai Moogambigai Dental College.
Abstract The aim of this study was to assess the efficiency of early and late class 2 division-1 treatment in the mixed and permanent dentition by systematically reviewing the literature.Literature search was performed randomly over the period 1995 to 2012.The criteria includes randomized clinical trials of early versus late class - II treatment, statistically significant differences were observed between the treatment and observation groups.The search strategy resulted in 17 articles 2phase treatment started before adolescence in the early permanent dentition.Early treatment also appears to be less efficient,in that it produced no reduction in the average time a child is in fixed appliance during second stage of treatment and did not decrease the proportion of complex treatment involving extractions or orthopedic surgery.
Key words Early vs. late treatment, class II division I,systematic review.
One rationale for early treatment is that correction of the visible aspects of malocclusion at an early stage in a child's maturation will prevent the development of poor selfconcept.16self-concept defines an individual's organization of self-attitudes,including perceptions and beliefs with respect to body structure and appearance,referred to as body image.16
Materials and Methods: To identify all the studies that examined the relationship between early vs. late orthodontic treatment for class - II division 1 malocclusion. The survey covered the period from 1995 to 2012 with the interest in the particular heading outcomes of early vs. late treatment for class - II division 1 malocclusion. Self-concept measures using PiersHarris scale were included in the trials. An 80 item forced choice self report designed to quantitatively assess how children feel about themselves. Inconsistencenies and response biases were assessed using the Piers-Harris methods. The following characteristics were used for the study: Preoperative and postoperative dental cast, photographs and lateral cephalometric radiographs and plaster models are taken. Treatment duration and patient compliance were evaluated.
Introduction: There is lack of consensus regarding the degree of success of different treatment modalities applied during the early to late mixed dentition stages.6,12The concept of early treatment is controversial.Some define it as removable or fixed appliance intervention in the primary ,early mixed (permanent first molars and incisors present),or midmixed (inter-transitional period,before the emergence of first 6,12 premolars and permanent mandibular canines). Early treatment modalities of class II division I malocclusion involves headgear,functional appliance such as 3 bionator,herbst appliance. Primary goals of early treatment is to restrain and control excessive vertical maxillary growth especially in the posterior region,preventing downward and backward rotation of the mandible and possibly even producing forward rotation of 11 the mandible with continued growth.
The Piers-Harris Children's Self-Concept Scale NO. OF ITEMS
EXPLANATION OF MEASURE
The extent to which a child admits or denies problematic behavior
2. Intellectual school status
Self-assessment of abilities with respect to intellectual and academic task, including general satisfaction with school and future expectations.
3.Physical appearance attributes
Attitudes concerning physical characteristics as well as attributes such as leadership and the ability to express ideas
General emotional disturbance and dysphoric mood and ability to make friends.
Evaluation of popularity with classmates,being chosen for games,
A general feeling of being a happy person and easy to get along with, and feeling generally satisfied with life.
Vol-1 issue-3 May-2013
Discussion: J.F.CAMILLA TULLOCH, CEIB PHILLIPS AND WILLIAM 3 R. PROFFIT evaluates the influences on the outcomes of early treatment for class - II malocclusion.In the first phase of a randomized clinical trial of early versus late classII treatment,the change in jaw relationship,reduction in ANB angle was favorable in 76%of the headgear,83% of the functional appliance and 31%of control(observation only)groups.75%of children undergoing early treatment with either headgear or a modified bionator,experience a favorable or highly favorable reduction in sketetal discrepancy.Cooperation, measured as the number of hours of reported wear,or the clinical assessment of compliance,explained little of the variation in treatment response. J.F.CAMILLA TULLOCH,CEIB PHILLIPS AND WILLIAM R. PROFFIT1 evaluates the treatment objectives of preadolescent children with overjet greater than 7mm were randomly assigned to observation only,headgear (combination),or functional appliance(modified bionator) and were monitored for 15 months.It concludes that children with moderate to severe class II malocclusion,early treatment followed by later comprehensive treatment on average does not produce major differences in jaw relationship or dental occlusion,compared with later on stage treatment. 4 JULIA VON BREMEN AND HANS PANCHERZ assesses the efficiency of early and late class II division I treatment in the mixed and permanent dentition.This articles examined 204 patients with class II division I malocclusion treated in the early mixed dentition (n=54), late mixed dentition (n=104) and permanent dentition (n=46).Patient treated exclusively with fixed appliances had a shorter treatment duration (19 months)for herbst and 24 months for multibracket than did patients treated with functional appliances or a combination of appliances (38 months for functional appliances and 49 months for a combination).It concludes that for both duration and outcomes, class II division I malocclusion treatment was more efficient in the permanent dentition than it was in the early or late mixed dentition.Furthermore treatment with fixed appliances was more efficient than treatment with removable appliances. LORNE D. KOROLUK,CAMILLA TULLOCH AND CEIB 5 PHILLIPS investigate incisor trauma in children with overjets greater than or equal to 7mm who were enrolled in a clinical trial of II phase early orthodontic treatment for class II malocclusion.In phase 1,children were randomly assigned to treatment in the mixed dentition with either modified bionator or combination headgear or a group in which treatment was delayed until the permanent dentition.Early growth modification treatment might have some effect on the incidence of trauma,but to be effective it might have to be initiated soon after the eruption of the maxillary incisors.
J.F.CAMILLA TULLOCH, WILLIAM R.PROFFIT AND CEIB PHILLIPS11talks about a 2 phased,parallel,randomized trial of early (preadolescent) vs. later (adolescent)treatment for children with severe overjet 7mm class - II malocclusion.Favorable growth changes were observed in about 75% of those receiving early treatment with either a headgear or a functional appliance.After a second phase of fixed appliance treatment for both the previously treated children and the untreated controls,however early treatment had little effect on the subsequent treatment outcomes measured as skeletal change,alignment and occlusion of the teeth,or length and complexity of treatment.The differences created between the treated children and untreated control group by phase 1treatment before adolescence disappeared when both groups received comprehensive fixed appliance treatment during adolescence.This suggests that 2 phase treatment started before adolescence in the mixed dentition might beno more clinically effective than 1-phasetreatment started during adolescence in the early permanent dentition.Early treatment also appears to be less efficient,in that it produced no reduction in the average time a child is in fixed appliances during a second stage of treatment, and it did not decrease the proportion of complex treatments involving extractions or orthognatic surgery. TSUNG-JU HSIEH, YULIYA PINSKAYA AND EUGENE 6 ROBERTS compares the treatment outcomes of early treatment (mixed dentition)with that of late treatment (early permanent dentition)using objective evaluation criteria.Pretreatment and post-treatment records of all patients completed from 1998 to 2000 in the graduate orthodontics clinic at the Indiana university school of dentistry were evaluated by the American board of orthodontics objective grading system and comprehensive clinical assessment.Two definitions of early treatment were used in this study 1. All patients started in the mixed dentition with early treatment objectives and 2. Female individualswere more than 10 yrs and male individuals were more than 10.5yrs of age when treatment began.Comparison of the final results between early vs. late treatment groups showed that the early treatment group had significantly longer treatment time and worse comprehensive clinical assessment scores than the late treatment. ADEBIMPE O.IBITAYO,VALMY PANGRAZIOKULBERSH,JEFF BERGER AND BURCU 10 BAYIRI compares treatment outcomes of growing and nongrowing class - II patients characterized by mandibular retrusion and increased vertical dimension.Seventeen patients of 9yrs were treated with a bionator fabricated with posterior bite blockand high pull headgear,while 15 patients of 23yrs received Lefort 1 osteotomy for maxillary impaction and mandibular advancement.In the functional appliance group,the mandible showed a more favorable growth direction and rotation. Vol-1 issue-3 May-2013
Both the functional appliances and orthognatic surgery resulted in similar dentoskeletal treatment changes.Both groups had stable results over time and finished treatment with similar cephalometric measurements. JAMESR.WORTHAM,CALOGERO DOLCE,SUSAN P.MCGORRAY,HUONG LE, GREGORY J.KING AND 14 TIMOTHY T.WHEELER compares the arch dimension changes in phase 1 and phase 2 treatment of class - II malocclusion.This was prospective randomized clinical trial conducted in the department of orthodontics at the university of florida between 1990 to 2003.During the first phase 86 patients were treated with the bionator,93 were treated with headgear/biteplane and 81 served as the observation group.For phase 2 all subjects were then treated with full orthodontic appliances.Arch dimension were taken at the baseline,at the end of early treatment,beginning of orthodontic appliance and at the end of orthodontic treatment.There were no differences after phase1 or phase 2 treatment of class - II malocclusion. TIZIANOBACCETTI,LORENZOFRANCHI,VERONIC A GIUNTINI,CATERINA MASUCCI,ANDREA VANGELISTI AND EFISIO DEFRAIA15compare the outcomes of prepubertalvs pubertal treatment of deepbite patients with a protocol includingbiteplane and fixed appliances.A total of 34 patients received treatment with removable biteplane appliances in the mixed dentition at a prepubertal stage in the mixed dentition(early treatment group),24 patients were treated at a pubertal stage in the permanent dentition( late treatment group).All subjects of both groups were reevaluated after an average period of 15 months after the completion of fixed appliance therapy.Treatment of deepbite at the puberty in the permanent dentition leads to significantly more favorable outcomes than treatment before pubertyin the mixed dentition. Conclusion: In this study it concludes that,long treatment time,related to continuous phase1 to phase2 treatment was associated with poor compliance during the later stages of phase2 6 treatment. Mcnamara et al demonstrated an age dependent mandibular growth response with the use of the functional regulator2 appliance when they recorded more mandibular growth noted in younger patients.He concludes that mandibular response favoured later intervention that is observed 4.0 mm/year in older patient,while 3.2mm/year in younger patients.2 Wieslander also attempted to achieve the “best of orthopedic worlds”by intensive phase1 treatment of young patients,the protrusions were reduced rapidly,and the profiles straightened in phase1.
However,the pause between phase1 and phase2 became a problem since overjet reappeared in a number of patients.This leads to a prolonged retention phase that extended beyond 3 2 years in some instances. David Chin concludes that early growth modification might have some effect on the incidence of trauma with the expected cost of trauma per child to be less for those who had 2 phase orthodontic treatment.17 Early treatment for class - II malocclusion has shown that favorable growth responses,although quite possible and even likely,are not always achieved.7 but early treatment intervention improves Dentofacial attractiveness may well improve a child's social interactions.16Phase 1 therapy does not gives any significant impact on the vertical dimension of the posterior dentoalveolar sectors of the dental arches.9Early orthodontic treatment produced more stable long term orthodontic results and yield improved mandibular incisor 8 stability. To initiate “growth modifications”procedures before the late mixed dentition ,functional appliance do work,their use represents a practice management decision,not 12 a biological treatment imperative. Recent findings questioning the efficiency of early treatment have forced orthodontists to ask themselves whether their decision to “start now”is being influenced too heavily by practice 13 management considerations.
References: 1.J.F.CAMILLA TULLOCH, CEIB PHILLIPS AND WILLIAM R.PROFFIT:Benefit of early class2 treatment :progress report of a two phase randomized clinical trial.AJODO 1998;113:62-72. 2.ANTHONY A. GIANELLY:One-phase versus two-phase treatment.AJODO 1995;108:556-9. 3.J.F.CAMILLA TULLOCH,WILLIAM R.PROFFIT AND CEIB PHILLIPS: Influences on the outcome of early treatment for class2 malocclusion.AJODO 1997;111:533-42. 4.JULIA VON BREMEN AND HANS PANCHERZ:Efficiency of early and late class2 division 1 treatment.AJODO 2002;121:31-7. 5.LORNE D. KOROLUK,J.F.CAMILLA TULLOCH AND CEIB PHILLIPS:Incisor trauma and early treatment for class2 division 1malocclusion.AJODO 2003;123:117-26. 6.TSUNG-JU HSIEH,YULIYA PINSKAYA AND EUGENE ROBERTS:Assessment of orthodontic treatment outcomes:early treatment versus late treatment.AO 2005:75;162-170. 7.Z.MIRZEN ARAT AND MELIHA RUBENDUZ:Changes in dentoalveolar and facial heights during early and late growth periods:a longitudinal study.AO 2004;75:69-74.
Vol-1 issue-3 May-2013
8.TAKANOBU HARUKI AND ROBERT M. LITTLE: Early versus late treatment of crowded first premolar extraction cases:postretention evaluation of stability and relapse.AO 1998;68(1)61-68. 9.LORENZO FRANCHI,TIZIANO BACCETTI,VERONICA GIUNTINI,CATERINA MASUCCI, ANDREA VANGELISTI AND EFISIO DEFRAIA:Outcomes of two phase orthodontic treatment of deepbite malocclusions.AO 2011;81:945-952. 10.ADEBIMPE O.IBITAYO,VALMY PANGRAZIOKULBERSH,JEFF BERGER AND BURCU BAYIRLI:Dentoskeletal effects of functional appliances vs.bimaxillary surgery in hyperdivergent class2 patients.AO 2011;81:304-311. 11.J.F. CAMILLA TULLOCH,WILLIAM R. PROFFIT AND CEIB PHILLIPS:Outcomes in a 2-phase randomized clinical trial of early class2 treatment.AJODO 2004;125:65767. 12.S.JAY BOWMAN:One stages versus two stage treatment:are two really necessary?AJODO 1998 VOL.113 NO.1. 13.NORMAN WAHL:Orthodontics in 3 millennia.chapter12:Two controversies:Early treatment and occlusion.AJODO 2006;130:799-804. 14.JAMES R. WORTHAM,CALOGERO DOLCE,SUSAN P. MCGORRAY,HUONG LE,GREGORY J.KING AND TIMOTHY T. WHEELER:Comparsion of arch dimension changes in 1phase vs 2phase treatment of class II malocclusion.AJODO 2009;136;65-74. 15.TIZIANO BACCETTI,LORENZO FRANCHI,VERONICA GIUNTINI,CATERINA MASUCCI,ANDREA VANGELISTI AND EFISIO DEFRAIA:Early versus late orthodontic treatment of deepbite:a prospective clinical trial in growing patients.AJODO 2012;142:75-82. 16.CARL DANN,CEIB PHILLIPS,HILIARY L.BRODER AND CAMILLA TULLOCH:self-concept,class2 malocclusion and early treatment.AO 1995;65(6):411-416. 17.DAVID R.CHEN,SUSAN P.MCGORRAY,CALOGERO DOLCE AND TIMOTHY T.WHEELER:effect of early class2 treatment on the incidence of incisor trauma.AJODO 2011;140:E155-E160.
Vol-1 issue-3 May-2013
Abstract Minimally invasive dentistry is an advance in 1
science which is concerned with the ultra conservative
Dr.Anjana.S, 2Dr. Sreelal.T, 3Dr. Shibu.A,
treatment of the infected and affected oral tissues.
Dr Anuroopa.A, 5Dr Aparna Mohan
Through an increasing range of relevant clinical
(1)Post Graduate (2) Professor and HOD (3&4) Reader (5) Senior lecturer
approaches , minimally invasive treatment preserves a
Sree Mookambika Institute of Dental Sciences
maximum amount of oral tissue and provides least invasive intervention often regarded by patients as painless and atraumatic Technological advances this field makes minimally invasiveprosthodontics appropriate solution for more and more cases.
Key words Minimallyinvasive prosthodontics, Lumineers, laser, flexible denture, naso alveolar moulding, shortened dental arch
It deals with the ultra-conservative treatment of 3
infected and affected oral tissue. It bridges the traditional gap between prevention and surgical procedures. It can be accomplished by using technology such as air abrasion,
lasers, DIAGNOdent, caries indicator dye,
Minimum (or minimal) intervention dentistry can
transillumination, magnification, digital x-rays, implants,
be defined as a philosophy of professional care concerned
Invisalign, apex locators, rotary endodontic instruments and
with the earliest detection and best possible cure of diseases
endoscopy as well as materials such as glass ionomer, bone
on micro molecular levels followed by minimally invasive
graft materials, bonding restoratives that make restorations
and patient friendly treatment to repair irreversible damage
cause by such diseases.1 MID is a concept that embraces all
The three main components of minimally
aspects of dentistry which aids in tissue preservation by
invasive dentistry are(1) Dietary prevention , (2)Dental
preventing disease from occurring and intercepting its
prophylaxis and(3)Minimally invasive restorationswhich
progress by removing and replacing it with as little tissue
has made enormous advancementsin adhesive and implant
loss as possible. Minimally invasive dentistry or
dentistry. These changes have altered diagnosis, treatment
microdentistry forms a part of Minimum Intervention
plan, and treatment options in clinical dentistry by forcing
Dentistry(MI)were the treatment procedure are minimally
clinicians to think in terms of conserving tooth structure,
invasive by nature.
vital tissues, and aesthetics.
Vol-1 issue-3 May-2013
Application Of Minimally Invasive Procedure In Prosthodontics
These dentures havegreater flexibility, can be relined and when repaired does not warp. Theyare
Minimally invasive dentistry has a wide spread
aesthetically superior as well as comfortable for the patient.
applications in all branches of prosthodontics especially in
fixed and removable prosthodontics. In fixed prosthodontics it
Preservation of Tooth Structure-The principles of crown
is widely used in the preparation of laminate veneers, partial
preparation described by Shillingburg determine the shape
veneer crowns, inlay retained bridges, resin bonded bridges,
and form of tooth preparations, which involves the concept
ovate pontic, cantilever bridge, cordless retraction technique
of minimally invasive procedure. Ideally a supra gingival
and laser tooth preparation technique. Use of high torque hand
finish line should be given in posterior teeth and a sub
pieces also enables us to provide a minimally invasive
gingival finish line in anterior teeth which extend by 0.51
treatment procedure. In removable prosthodontics, flexible
mm, not more than half the depth of the gingival sulcus to
denture, telescopic prosthesis and over denture follow the
ensure an intact
principle of minimally invasive dentistry. Minimally invasive
retraction cord in the gingival sulcus prior to preparing the
procedure in implant prosthodontics is achieved through
finish line will allow displacement of the gingival margin
Interactive CBCT, Flapless implant surgery; CAD CAM
for access and help minimize gingival trauma during
guided surgery and Single stage implant. Resin infiltration
technique and laser technology has molded dentistry in to a
Exposure of a greater height of clinical crown
superspecialty which made the treatment procedures less
may involve either gingivectomy
cumbersome and more comfortable for the patient. Splints,
osseous recontouring. It is a means of enhancing retention,
palatal lift prosthesis and auxiliary prosthesis aids in less
by increasing the clinical crown length of the tooth 10. Laser
invasive treatment procedure. Naso-alveolar molding and short
will be the ideal treatment modality as it is minimally
dental arch concept also is a part of minimally invasive
invasive in nature.
procedure in dentistry.
or flap surgery with
With the advent of newer technology minimally
invasive procedures can be performed using hi- torque hand
Telescopic-anchored prostheses are functionally
pieces whichoffers the better torque and at lesser noise
comparable with conventional fixed partial dentures, and are
level. Angular Hand piece designed for working on last
considered to be a most effective replacement for lost teeth and
molar 450 head angle for better accessibility favors to do a
are well tolerated psychologically. Telescopic crowns have
conventional tooth preparation. Super torque cartridges
been used mainly in RPDs to connect dentures to the remaining
have an added advantage with better durability, reliability,
dentition and as retainers in abutment- bone detachable
excellent performance and corrosion resistance
prostheses. Accordingly, detachable prostheses are usually
Laminate veneers are a thin layer of ceramic bounded to the facial surface of minimally prepared tooth. They are indicated for stained tooth that cannot be bleached, to treat a traumatizedteeth and fractured or worn out dentition .It can also be used for functional corrections such as to correct canine guidance,diastema or malformed teeth.Lumineers are contact lens type of veneer without removal of tooth structure. The teeth are moderately etched to prepare for placement of veneers that makes it conservative in nature.
indicated only for patients with multiple abutments distributed bilaterally in strategic positions along the dental arch. It is used successfully in RPD as well as FPD supported endosseous implants in combination with natural teeth, 17, 18
and also to splint periodontally compromised
dentition. Flexible denture is also a minimally invasive prosthesis that fulfills patient's needs because of its versatile advantages which includes replacement of metal clasps with colored clasps that blends with natural teeth and are more stainresistant than conventional acrylic prosthesis.
Vol-1 issue-3 May-2013
Cantilever fixed partial dentures are FPDs with
Clinical Applications of Lasers in
only one side of the pontic is attached to the retainer.They
FPDs includes LASER curettage in gingival sulcus prior
provide minimum tooth reduction as they use only one side
to tooth preparation to achieve good periodontal health and
of the pontic as abutment.
thus esthetics. Low level laser therapy has a wide range of
Inlay retained bridges are indicated when teeth
application in prosthodontics which includes LILT (low
with restorations are used as abutment in case of replacing
intensity laser treatment) tooth conditioning after tooth
teeth in the premolar,molar region.They are less destructive
preparation in vitalized teeth, HILT tooth decontamination/
to toothstructure and the marginal finishing line easy to
preparation prior to definitive cementation of the porcelain
clean.It is contra indicated when pontic span too large,in
crowns , HILT laser curettage in the gingival sulcus every 3
patients with excessive para-functional habits, clinical
to 6 months after final cementation of porcelain crowns and
crown too short,weakend periodontium,occlusal
laminate veneers and LILT gingival conditioning at follow
disturbances, in abutment teeth with tilting and in poor oral
hygiene. Resin bonded fixed partial denture is a conventional restoration which is indicated in the replacement of teeth in the mandibular anterior region .Little tooth structure has to be removed for this technique and most of the preparation is made on enamel making it a minimally invasive procedure. Resin cements are used in luting resin bonded bridges. It provides a relatively simple option to overcome the low tensile strength and poor adhesion quality ofconventional cement. They have much higher tensile strength and when used in combination with dentine bonding agentsare less sensitive to repetitive dislodging forces. Laser is an apt tool to execute minimally invasive procedure as it produces less vibrations with minimum audible drills, less micro-fractures, reduced discomfort to patients and minimum need for local anesthetic. Laser cavities facilitate good adaptation of composite to enamel and dentin because of increase in the surface roughness and openings of dentinal tubules. Gingival 13
Retraction using Lasers is less aggressive to the periodontal tissues compared to the conventional ones. Lasers may be used to perform pre-prosthetic surgeries like hard and soft tissue tuberosity reduction ,torus removal ,treatment of unsuitable residual ridges including undercut and irregularly resorbed ridges ,treatment of unsupported soft tissues ,hyper plastic tissue, nicotinic stomatitis under the palate of a full or partial denture, epuli, denture stomatitis, and other problems associated with long-term wear of ill-fitting dentures.
Implant Prosthodontics: Minimally invasive procedures in implantology is accomplished with the aid of lasers for prosthetic hard and soft tissue surgery, uncovering implants, correcting soft tissue, treating periimplantitis and disinfecting implants. Single-stage implant19 placement surgery is considered as a minimally invasive procedure as it is aless time consuming technique with a greater comfort, function and convenience. It offers a gain in comfort for the patient by less traumatic technique and diminished treatment period by avoiding the second stage surgery. 20 Flapless implant surgery uses a tissue punch technique which makes the surgical field bloodless and also reduces further bone loss. With the aid of computed tomography (CT) a 3-dimensional (3-D) computer model was fabricated followed by a Surgical Guide using a stereolithographic technique. Other minimally invasive procedures in Prosthodontics include presurgicalnaso-alveolar molding, shorten dental arch and resin infiltration technique. Presurgicalnasoalveolar molding is a minimally invasive procedure done to correctcleft lip, alveolus and palate. It provides a foundation for a less invasive surgical repair to restore the normal anatomy in unilateral or bilateral cleft lip palate patients. This approach allows for the controlled, predicted repositioning of the alveolar segments without the need for lip adhesion surgery
Shortened dental arch,(Fig-1) a current treatment concept is a recent minimally invasive dental procedure tailored to satisfy individual need and adaptive capability of the patient. In this concept the patient is restored with minimum number of teeth in the posterior region which would provide better comfort oral hygiene and reduced treatment cost. Vol-1 issue-3 May-2013
Resin infiltration technique is the application of resins on interproximal caries lesions has lead to the development of new materials, which infiltrate and seal the carious lesion, improving the inhibition of caries progression. It is atreatment options for interproximal 14 caries by delaying the time point. Conclusion: Minimally invasive dentistry is a concept that bridges the traditional gap between prevention and surgical procedures. It is based ona large body of scientific knowledgewhich promises further evolution toward a more primary preventive approach, facilitated by emerging technologies for diagnosis, prevention and treatment.
10)Smith D G. Toothwear: Crown lengthening procedures. In: Barnes I E, Walls A W G, editors. Gerodontol pp.109-117. Oxford: Wright, 1994 11) Maiorana C. Lasers in the treatment of soft tissue lesions. J Oral Laser Applications 2OO3; 3:7-14 12) Eduardo CP, The state of the Art of lasers in esthetic and Prosthodontics. J Oral Laser Applications 2OO5; 5:135-143. 13)Gherlone EF et al. The use of 98O nm Diode and 1O64 nm Nd:YAG lasers for gingival retraction in fixed prosthesis J Oral Laser Applications 2OO4;4:183-19O. 14) Ho Phark, DDS; Sillas Duarte Jr, DDS, MS, PhD; Hendrik MeyerLueckel, DDS, PhD,MPH; SebastianCaries Infiltration With Resins: A Novel Treatment Option for Interproximal Caries DMG October 2009, Volume 30, Issue 3 15) Langer A. Telescope retainers for removable partial dentures. J Prosthet Dent 1981;45:37-43. 16) Langer A. Telescope retainers and their clinical application. J
Prosthet Dent 1980;44:516
1) Yamaguchi K. 路 Miyazaki M. 路 Takamizawa T. 路 Inage H. 路 Kurokawa
17)Besimo C, Graber G. A new concept of overdentures with telescope
H. Ultrasonic, Determination of the Effect of Casein Phosphopeptide-
crowns onosseointegrated implants. Int J Periodontics Restorative Dent
Amorphous Calcium PhosphatePaste on the Demineralization of Bovine
DentinCaries Res 2007;41:204207 2) Joseph A. Whitehouse; Welcome to the world of Minimally invasive dentistry .J MinimInterv Dent 2009; 2 (2) 3)Murdoch C A , Mc Lean M E Minimally invasive dentistry JADA, Vol 134, January 2003 4) Ericson What is minimally invasive dentistry?Oral Health Prev Dent. 2004;2Suppl 1:287 5)Ardu S. Minimally invasive dentistry: A treatment philosophy. PractProcedAesthet Dent 2008;20(7):426-427. 6)Novy BB, Fuller CE. The material science of minimally invasive
18) Besimo C, Graber G, Schaffner T. Hybrid prosthetic implant supported suprastructuresin edentulous mandible. Conus crowns and shell-pinsystems on HA-Ti-Implants: part 2.Prosthetic construction principles.ZWR 1991;100:7019)Esposito M, Grusovin MG, Chew YS, Coulthard P, Worthington HV. . One-stage versus
two-stage implant placement. A Cochrane
systematic review of randomized controlled clinical trials Eur J Oral Implantol. 2009 Summer;2(2):91-9 20)Kusek ER. Use of the YSGG laser in dental implant surgery: scientific rationale and case reports. Dent Today.2006; 25:98-103
esthetic restorations.CompendContinEducDent 2008;29(6):338-347 7) F. M. BlairR. W. Wassell and J. G. Steele Crowns and other extracoronal restorations:Preparations for full veneer crowns British Dental Journal Vol 192 No. 10 May 25 2002 8) Silness J. Periodontal conditions in patients treated withdental bridges. II. The influence of full and partial crowns onplaque accumulation, development of gingivitis and pocket formation. J Perio Res 1970; 5: 219-224. 9). Silness J. Periodontal conditions in patients treated with dental bridges. III. The relationship between the location of the crown margin and the periodontal condition.. J Perio Res1970; 5: 225-229.
Vol-1 issue-3 May-2013
3D Dimension diagnostic aid CBCT in orthodontics
Dr. Sathya Chandran, Dr.Ramachandra Prabakar, 3 Dr.Saravanan, 4 Dr.Karthikeyan, 5 Dr.Raj Vikram, 6 Dr. Eshwara prasath 2
(1&6) 2nd year postgraduate, (2)Dean and HOD, (3& 4) Professor, (5) Reader, Department of orthodontics, Thai Moogambigai Dental College.
Abstract Cone Beam Computed Tomography (CBCT) is a revolutionary diagnostic aid in orthodontics used at present. Aim of this paper is to emphasize the process and the significance of CBCT in orthodontics in various treatment modalities which overcomes the 2 dimensional conventional method of radiography used to 3 dimensional imaging.
Key words Cone beam computed tomography, tmj disorder, orthodontic implants, impacted teeth.
Introduction: The advancement in technology and innovations of imaging systems for orthodontic practice require a continuous update of their applications and assessments of their strength and weakness, as well as guidelines for utilization. Orthodontists are challenged by the increasing number and complexity of these systems and softwares. Accurate diagnostic imaging is an essential requirement for the optimal diagnosis and treatment 1 planning of orthodontic patients . In addition, it is a critical tool that allows the clinician to monitor and document the treatment progress and outcome. The purpose of this article is to update orthodontists about the current options and applications of the latest imaging techniques in orthodontic practice and to review the existing software advances5. Materials & Methods: The authors reviewed the limitations of 2 dimensional imaging over the 3 dimensional computed tomography 9 which is cone beamed . The Cone Beam Computed Tomography (CBCT) has contributed in diagnosis and profound understanding of diagnosis to development of more efficient biomechanical treatment approaches and biological considerations.
The cone-beam computed tomography (CBCT) scanners were introduced in the late 1990s. Shortly after, the US Food and Drug Administration (FDA) approved the first CBCT unit in 20015. Since then, there has been an enormous interest in this new technology for its clinical and research applications. The CBCT is an imaging acquisition technique that utilizes a volumetric scanning machine. This technology uses a cone-shaped X-ray beam directed towards a flat two-dimensional (2D) detector. When both rotate around the patient's head, a series of 2D images are generated. The software then reconstructs the images into three-dimensional (3D) data set using a specialized 5, 10, 4. algorithm . Currently, there are more than 4 CBCT systems from 20 different companies available commercially. The commonly used CBCT imaging acquisition systems are the 3D Accuitomo (J. Morita, Kyoto, Japan), CB MercuRay (Hitachi Medical Corporation, Osaka, Japan), iCAT (Imaging Sciences International, Hatfield, PA), Galileos (Sirona Dental Systems LLC, Charlotte, NC), New-Tom 3G (QR srl, Verona, Italy), Scanora 3D (SOREDEX, Milwaukee, WI), and Kodak 9500 (Kodak Dental Systems, 5, 10 Rochester, NY) . There are large variations in the quality and characteristics of the images or the reconstructed volumes and the radiation doses between most of these CBCT systems. Machines with reduced radiation doses and less powerful tubes are often associated with poor image quality, low contrast resolution and increased noise. The exposure parameters, the source-detector distance, the field of view (FOV), the data reconstruction algorithm, and the software used are among the major factors responsible for those variations5. The currently available CBCT units utilize radiation doses ranging from 87 to 206 ĂŹSv for a full craniofacial scan11. These radiation doses are slightly higher than the conventional radiographic techniques such as the lateral cephalograms or the panoramic radiographs and markedly lower than that of multi-slice CT. The scan time varies between 10 to 75 seconds, depending on the FOV and 13 the CBCT unit used . Vol-1 issue-3 May-2013
The 3D CBCT data can greatly expand the orthodontist's diagnostic capabilities. It offers a comprehensive evaluation of the dentition and is very useful for identifying abnormalities such as missing teeth, supernumerary teeth, eruption disturbances, teeth malpositions, and/or root irregularities that could delay or prevent tooth movement4, 6, 7. CBCT can be considered the technique of choice for examining and pin-pointing the impacted teeth8. The exact position of impacted tooth and its relations to the adjacent roots or important anatomical structures such as the maxillary sinus or the mandibular canal when planning surgical exposure and subsequently orthodontic management can be precisely assessed by 8,7,2 3D CBCT .
Fig 1: the picture shows all 360 slices at a single shot ,
Discussion: Craniofacial imaging is a crucial content of an orthodontic patient's record. The gold standard for orthodontic patient's records is the efficiency to achieve an accurate replication of the real 10 anatomical structures or the â€œanatomic truthâ€? . Although at present the use of the traditional imaging in orthodontics has been adequate, the achievement of the ideal imaging goal of replicating the anatomic truth has been limited by the traditional technology such as the 2D frontal and lateral cephalograms, panoramic radiographs, and intraoral/extraoral photographs9. Recently, higher emphasis has been placed on the CBCT technology, the 3D images, and virtual models. The main advantage for the use of CBCT is that the clinician can get more accurate data from single scan than from the many 2D radiographs 9 traditionally used, with less radiation exposure .
Fig 2 :A shows the pre object apparatus of x-ray source path of rotation and object, 2B shows the image area detector with x-ray beams in shape of cone4.
Using CBCT scans, alveolar bone can be accessed from all aspects not only on the mesial and distal surfaces of the tooth. This allows for the assessment of the width of available bone for buccolingual movement of teeth during orthodontic management especially in cases requiring arch expansion or labial movement of 6 incisors . Fenestrations, dehiscence, and/or external apical root 7 resorption can be precisely visualized on the 3D images . Evaluation of alveolar bone volume, which is especially important in periodontally compromised adult orthodontic patients, is one of the beneficial uses of CBCT in orthodontics. The width of alveolar ridges for placement of implants is another variable that can be investigated using CBCT6,2. Temporomandibular joint (TMJ) disorders with Orthodontic patients are common 11 . During period of development, the disorders may alter the facial growth pattern and may also affect the growth of the ipsilateral part of the mandible with compromisation in the maxilla, tooth position, occlusion, and cranial base. CBCT allows the orthodontists to assess and quantify these changes associated with TMJ disorders more accurately than the 2D images as these changes occur in the vertical, horizontal, 11, 12 and transverse directions . Vol-1 issue-3 May-2013
CBCT is especially indicated when more information about the morphology and internal structure of the bony components of the TMJ is in need. Studies have shown that CBCT images provide higher reliability and accuracy than CT and panoramic radiographs in the detection of condylar cortical erosion11, 12, 13. CBCT images also allow for the visualization of the TMJs from different views and efficient evaluation of its relationship to the dentition and Occlusion. Preoperative implant site assessment is probably one of the most useful applications of CBCT in orthodontics. In the orthodontic field, osseointegrated implants are either used for anchorage or as a prosthetic replacement of missing teeth. The accurate determination of root angulations and the available space are essential for successful placement of the implant6, 4. CBCT can be used to accurately assess the space availability and root angulations as well as the 3D quantification of the alveolar bone at the implant site.
Fig 2: shows the malposition of a 13 yr old patient due to odontoma in relation to 11 causing impaction of permanent teeth diagnosed by 3D CBCT.
Conclusion: In orthodontics, the application of CBCT technique has made a remarkable breakthrough in diagnosis and the treatment plan by giving the orthodontists inspiration to do better of what they do the best. However the hunt for further advanced diagnostic aids is evidenced in recent years like of how 2D imaging is replaced by 3D imaging due to the advantages and disadvantages in detecting the exact location of supernumerary and impacted teeth and in appropriate treatment 12, 13 planning . Likewise, advantages and disadvantages of CBCT must be considered together, and only when more information is in need, the use of this technique is suggested. Its unnecessary prescription should otherwise be avoided.
Fig 3: 3D CBCT volume allows for better visualization and provides more details about the morphology and position of the TMJ and the condyles from different views. In addition, the TMJ cross-section view permits complete and thorough examination of the joint through a group of cross section slices.
Vol-1 issue-3 May-2013
Fig 4:Axial and sagittal sections showing the buccal and lingual bone thickness, as well asthe relationship between the implant and the inferior alveolar nerve (labeled in red color).The 3D view is important in the evaluation of space availability.
Adams, G., Gansky, S., Miller, A., Harell, W. & Hatcher D.
1.Dan Grauera; Lucia S.H. Cevidanes; Martin A.Styner ; Inam
(2004). Comparison between traditional 2-dimensional
Heulfed;Eric T.Harmon ; Hongtu Zhuf; William R.Proffit :Accuracy and
cephalometry and a 3-dimensional approach on human dry skull. Am J Orthod Dentofac Orthop 126:397-409.
Landmark Error Calculation Using Cone-Beam Computed To m o g r a p h y G e n e r a t e d C e p h a l o g r a m s , ( A n g l e O r t h o d .
Cevidanes, L., Oliveira, A., Grauer, D., Styner, M. & Proffit,
W. (2011). Clinical application of 3D imaging for assessment
2.Snehlata Oberoi, DDS, MDS, Associate Professor of Clinical Orofacial
of treatment outcomes. Semin Orthod 17:72-80.
Sciences, Center for Craniofacial Anomalies, Department of Orofacial
Hilgers, M., Scarfe, S. & Scheetz, J. (2005). Accuracy of
Sciences, School of Dentistry, University of California at San Francisco,
linear temporomandibular joint measurements with cone
San Francisco, California: CBCT Evaluation of Impacted Canines and
beam computed tomography and digital cephalometric
Root Resorption, P C S O B u l l e t i n november 2 0 1 1
radiography. Am J Orthod Dentofacial Orthop 128:803-811.
3.Patil NA,Gadda R, Salvi R, Cone beam Computed Tomography A
12. Kumar, V., Ludlow, J., Cevidanes, L. & Mol, A. (2008). In vivo comparison of conventional and cone beam CT
Third Dimension, J Contemp Dent 2012; 2(3): 84-88.
synthesized cephalograms. Angle Orthodontist 78: 873879
4.Xubair,Graber,Vanarsdall,Vig;Orthodontics - Current Principles and Techniques - Graber 5th edition 2011
Swennen, G. & Schutyser, F. (2006). Three-dimensional
5.Ahmed Ghoneima1,2, Eman Allam1, Katherine Kula1 and L. Jack
cephalometry: spiral multi-slice vs cone-beam computed
Windsor1: Chap 8-Three-Dimensional Imaging and Software Advances
tomography. Am J Orthod Dentofac Orthop 130: 410416
in Orthodontics , Orthodontics - Basic Aspects and Clinical Considerations March, 2012 6.Kee-Joon Lee, Euk Joo, Kee-Deog Kim, Jong-Suk Lee, Young-Chel Park, and Hyung-Seog Yuf, : Computed tomographic analysis of toothbearing alveolar bone for orthodontic miniscrew placement, (Am J Orthod Dentofacial Orthop 2009;135:486-94) 7.Hongyu Ren; Jun Chen; Feng Deng; Leilei Zheng; Xiong Liu; Yanling Dong:Comparison of cone-beam computed tomography and periapical radiography for detecting simulated apical root resorption, ( A n g l e Orthod. 2013;83:189195. 8.Hossein Nematolahi,Hamed Abadi,Zahra Mohammadzade,Mostafa Soofiani Ghadim: The Use of Cone Beam Computed Tomography (CBCT) to Determine Supernumerary and Impacted Teeth Position in Pediatric Patients: A Case Report ,J Dent Res Dent Clin Dent Prospect 2013;7(1):47-50 | doi: 10.5681/joddd.2013.008
Vol-1 issue-3 May-2013
Porcelain Laminates a problem based treatment approach
A. Leoney P. S.Manoharan
Reader,2Professor, Department of Prosthodontics, Rajah Muthiah Dental College,Chidambaram
Porcelain laminates have been used for over the past
History and examination: A 19 year old female,
25 years, with many of its own limitations and
reported to the dental office, requiring correction of
drawbacks. Evidence based dentistry has narrowed
discolored maxillary and mandibular teeth. History
down the key to success for such a restoration to
and examination revealed discolored direct
“selection of the case”. With the advancement of
composite restorations in relation to the upper
laboratory support and simplification of techniques
anteriors, which was done elsewhere, more than a
and material use, porcelain laminates have found its
year back (Fig.1a and 1b).
place in general practice. This paper is a case report, which outlines the treatment approach with porcelain laminates, with special emphasis on
Further intra-oral examination revealed improper contacts and contours of composite restorations from maxillary second premolar to premolar, with crazing and significant surface and marginal discoloration.
problem areas. It also provides simple tips and
The remaining teeth were also discolored possibly
solutions to the readers to avoid or overcome
due to fluorosis which was suggestive through her
biological, mechanical or esthetic predicaments
associated with such restorations.
Diagnostic work up: When one is considering a cosmetic treatment option such as veneers, it is
especially important to follow this logical sequence of events.
Porcelain laminates, Diagnostic wax up, Smile design, etc.
Introduction Porcelain laminates have been used over the past 25 years with many of its own limitations and drawbacks. Failure due to de-bonding has been found as one of the prime drawbacks. Occlusion, preparation design, choice of bonding agents has been listed as other co-variables1,2. Recently, evidence based dentistry has narrowed down the major cause of such failures to be “selection of the case”. Other reasons for failure can be discoloration, which may be due to poor color stability of the resin used for cementation. With advancements of laboratory technology and simplification of technique and material use, porcelain laminates have found its place in general practice. Thus, it becomes mandatory for the restoring dentist to anticipate various predicaments during the treatment phase. Presented below, is a case report of an esthetic rehabilitation with smile design of a patient, with special thrust on the problem areas and possible suggestions and tips to avoid them
Fig.1-b Vol-1 issue-3 May-2013
Diagnostic casts (Fig.2) were made and evaluated on a semi-adjustable articulator [Artex Kirback] (Fig.3) with face-bow transfer. Duplicate casts were made so that a diagnostic wax-up (Fig.4) can be created. The maxillary and mandibular teeth had Class II div 1 malocclusion, with labial positioning of both maxillary canines with moderate rotation on the right side. Arch tooth size and available space was measured as it would help us to plan the diagnostic wax up and further treatment. Various treatment options were suggested to the patient, viz., crowns, laminates and indirect composites. Porcelain laminates [IPS emax Press] was opted by the patient after evaluating the advantages, disadvantages of each treatment and associated treatment charges.
Tooth preparation was carried out in a single sitting for all the maxillary anterior teeth including the first premolars on Fig.2
both sides following local anesthetic infiltration. Basic tooth preparation principles were carried out with subgingival margins and palatal overlap of 2mm from the incisal edge. Labial/incisal clearance was checked with the indices which were fabricated from the diagnostic wax up, the use of which was very crucial when the preparation of the rotated and malposed canines were carried out. The margins were placed away from the centric contact and free of protrusive interferences. Contact points are relieved by proximal strips indicated by (Fig.6) and final finishing is
Clinical procedure: Systematic step by step management
done with smooth diamond points. Care is taken to limit the preparation to only the enamel so that the luting agent used,
work up was planned. As the young lady had a history of
can bond better with enamel and retention is superior than
rheumatic heart disease, she was referred to a physician to
when placed in dentin.  The rotated canine posed little
obtain opinion regarding the use of antibiotic prophylaxis
difficulty in limiting the preparation to enamel. So,
and local anesthetic during the procedure.
additional dentin was removed with the consent of the patient, so that adequate clearance can be obtained for
Diagnostic wax up was carried out with green inlay wax and the esthetic outcome was explained to the patient. The anticipated smile line was scribed on the lower anterior teeth for reference later. Two Putty indices were made which included full arch index as well as an horizontally cut
esthetic restoration (Fig.6). Depth orientation burs were used and principles of tooth preparation were faithfully followed4,5,6. Isolation is crucial for margin capture during impression making. Poly-vinyl-siloxane was used with
index (Fig.5) were fabricated to guide the incisal and labial
putty-wash reline technique in a stock tray after performing
clearance during tooth preparation.
gingival displacement with retraction cords. Vol-1 issue-3 May-2013
Laboratory procedure: Casts were poured with type IV dental stone and removable dies were prepared. Individual wax patterns for the respective laminates were fabricated in the lab using pressable ceramic [IPS e max press] and staining was carried out according to the selected shade. Smile design is an often discussed topic in anterior esthetic rehabilitation. Though the literature gives us a plethora of dimensions in smile designing4,8, the practical application is incorporating them systematically. A simple smile design chart(Table .1) as mentioned above would help the operator
Provisional were fabricated with acrylic resin using the putty indices as guide for contours and were temporarily cemented. The provisional restorations were adjusted, so that a rough appraisal of treatment outcome can beperceived both by the patient and the dentist. While selecting the shade a lighter shade was selected for the patient taking into all the standard parameters into consideration viz., skin color, sclera color and patient
to carry out a comprehensive esthetic work up for anterior restorations. Smile re-designing or re-establishing the original smile is purely based on the patients' decision after explaining the anatomic and functional limitations. These limitations like tooth structure available, exposure of gums, space available, inclination/ rotation of natural teeth, overjet/over-bite and forces exerted on the restoration can restrain the patients' option on retaining the original smile.
Table no. 1: SMILE DESIGN WORK SHEET Smile parameter Assessment
Suggestions for work up
2mm of visibility of Smile curve transferred to the cast on the lower anterior teeth all anterior teeth
Lighter than the proposed shade
Reproduce the lost Modifications if any should be done with maintenance of contours embrasure and self-cleansing surfaces
Width of teeth
Golden proportion, Space analysis Tooth size, arch length discrepancy alignment
Face Form / profile/ symmetry
Compare with color Should complement the selected shade of skin and sclera
Form a convex smile Curve
Staining can be done after try-in
Esthetic build up [Dentist- technician communication]
Follow the lower lip countour ( diagnostic casts &Provisionals), incisal embrasures created with balance of negative space and sex of the patient Vol-1 issue-3 May-2013
Optical illusion is a physical property of light reflection and perception, which can be exploited in designing the contours of the restoration. The labio-proximal line angle can be brought closer to the midline of the tooth or away near the proximal surfaces (Fig.8) depending on whether to narrow or broaden the appearance of the restoration, though the space available is a fixed determinant. Longitudinal or horizontal grooves can be created to give narrow or a broad dimension to the tooth.
Stains near the proximal surfaces also give an illusion of narrow teeth. Incisal embrasures(Fig.8)augments the esthetics. Try-in and delivery of Laminates: During try-in composite resin was used to hold the laminates in place and adjustments were carried out which included contacts, labial/palatal/ proximal contours, margins. Shade modification and characterization if any, were noted and then communicated to the laboratory for further refinement and final glazing. The laminates were cemented after the application of primer (Monobond S,
Fig 8: Schematic illustration of factors affecting the restoration
ivoclar vivadent, Liechtenstein), bonding agent and dualcured composite luting resin cement (N variolink ivoclar vivadent, Liechtenstein ). Isolation was carried out in perfection during the entire procedure so that it would eliminate any contamination which would affect bonding9. Postoperative photographs (frontal, lateral and occlusal photographs) were taken and compared with preoperative photographs and discussed the positives of the treatment procedure. Patient's perception and feedback of the laminate treatment was found to very
satisfactory (Fig 9).Patient was instructed to cleanse inter-dental areas and avoid excessive consumption of staining beverages or carbonated drinks to prolong the durability of the restoration. Periodic recall would enable the patient to be seen by the treatment provider and documentation of follow up of restorations.
Fig. 10 Vol-1 issue-3 May-2013
Tooth reduction is restricted to enamel and 0.7 to DISCUSSION: Anterior esthetic rehabilitation has always been a challenge for the restoring dentist as these restorations are
0.8mm of labial reduction was achieved in this case by the special three wheel diamond. Preparations extending
subjected to the critical review of the observers starting from
to dentin can reduce the bond strength between the resin
the layman to the fellow dentist. More than the visual appeal
and the laminate. According to a study by Piemjai M and
which these restorations can contribute, they also should be
Arksornukit M bonding techniques and curing systems
biologically compatible, functionally harmonious and last
of resin cements influenced the fracture resistance of
for a considerable period of time without any mechanical failure. These are basic objectives that should be achieved for any restoration and replacement. As discussed above, 'selection of the case' is crucial, while rehabilitating with
porcelain laminates. Dry bonding with autopolymerization resin provided the highest fracture resistance of porcelain. Porcelain bonded to enamel with
restorations suchas porcelain laminates. Some common
this resin had much higher fracture strength than when
diagnostic key factors which would affect the prognosis and
bonded to dentin. Incisal reduction of 1.2mm was carried
acceptance of treatment are listed.An individual with a
out with palatal extension of 1.5mm. This was decided in
traumatic bite/para-functional habits may not be able to
the wax-up stage based on centric contacts and incisal
sustain such restorations. In the same way, a consumer of acidic beverages may increase the risk of failure due to erosion of enamel and subsequent failure of bonding by the resin. A steep incisal guidance which needs rehabilitation can also suggest a limitation for such restorations.
guidance. Though supra-gingival margins would suffice for such esthetic porcelain laminates, a sub-gingival margin with radial shoulder, was provided in this case as the tooth was discolored (Fig 10).
Once the case is selected, the treatment plan should be outlined based on the above mentioned diagnostic criteria. Diagnostic casts with face-bow transfer will provide the dentist information regarding the esthetic plane, alignment, occlusion and space availability vs. space needed. It also can be used to do a mock preparation and perform an esthetic wax build-up [ivory wax is preferred though blue inlay wax is used in this case]. This diagnostic wax-up can be used to fabricate putty indices as shown in the figure for clearance assessment during tooth reductionand also to provide an idea of treatment outcome to both the patient and the restoring 10,11
. In this case this step has played a major role, as it
simplified the difficulties that could arise in the tooth preparation because of alignment problems such as rotations and labial placement of canines.The mal-aligned canines
were given an esthetic facelift (Fig.9).Location of margins of the preparations, centric/proximal contacts and incisal guidance is also visualized in this procedure.
Vol-1 issue-3 May-2013
Patients and dentists may have conflicting
The consistency of the luting agent, pressure
opinions regarding the definition of an esthetically
exerted during cementation and the film thickness of the
pleasing smile. Everydentist is likely to encounter
luting agent may affect the luting composite thicknessUse of
malcontent patients who may have difficulty
desensitizing agents to alleviate the postoperative sensitivity
communicating their esthetic desires for smiles
have been advised by some authors when dentin is exposed
andmay even refuse to pay for successful treatment
or near exposure after tooth preparation16,17,18. However, it
outcomes that they misperceive as failures. Learning
was found that retention of crowns and laminates have been
how to work with suchpatients is essential. Part of
considerably reduced by their application
achieving patient satisfaction is encouraging their
preparations, the clinician is advised to limit the preparation
participation in designing their smile. With the useof
only to enamel, use adequate water coolant during
such a restoration an exacting acrylic/wax smile
preparation to reduce the postoperative sensitivity. In the
would be required for the patient to anticipate the
case discussed above, except the canine, other preparations
were well within the enamel. Mild postoperative discomfort
. In veneer
Shade selection is carried out with standard
in the form of sensitivity was reported by the patient for two
shade guide taking into consideration the general color
days following luting the restoration, which subsided
of the skin and sclera. In such cases where the entire
without any intervention.
anterior segment is to be restored, the clinical
During the fabrication of laminates a carefully devised
judgment of the dentist would determine the esthetic
dentist-technician communication chart would reduce the
outcome. Discussion with the patient and the patient's relatives about the shade preference will help the dentist in the decision making. Documentation of pretreatment and post treatment photographs taken with standard lighting and distance with the patients lips at rest and during active smile would help the patient to compare appreciate the treatment outcome.
repetitions of laboratory work after try-in procedure. This should include the specifications required by the dentist based on the treatment planning in smile design. Regardless of the color, shape or attention to detail, there must be sufficient time to adequately finish all restorations. Both esthetics and function can best be satisfied when the
Ideally, a porcelain veneer can mask completely the
restoration acquires its maximal finish as seen in (Fig.9,11
underlying discolored tooth substance with minimal
and 12). In the final analysis, the restoration will look better
reduction of sound tooth substance (0.30.7 mm for the
for a longer period of time. Life expectancy of the restoration
labial surface and 0.51.0 mm for the incisal edge). The
may, in fact, be directly dependent on just how well this task
veneer's color, however, can be affected by the
is accomplished . It has been said that treatment is never
underlying discoloration. However, severe
successful unless the patient is satisfied in terms of comfort,
discolorations can be masked by high density alumina
esthetics and functions like chewing. Problems may arise
core veneers .
from patients who hold what most people consider
Ceramic to luting agent thickness ratio can contribute to mechanical failure. A sufficient and even thickness of ceramic combined with a minimal thickness of luting composite will provide the 15
restoration a thickness ratio above 3 .
unrealistic expectations, most commonly with respect to the .
esthetic outcome This can be avoided by a systematic work up, which includes the history, realizing patient's demands and expectations, thorough dentist- patient communication along with diagnostic wax ups and temporaries. Vol-1 issue-3 May-2013
Piemjai M, Arksornnukit M. Compressive fracture resistance
of porcelain laminates bonded to enamel or dentin with four adhesive systems: J Prosthodont. 2007 Nov-Dec;16(6):457-64. 8.
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enamel: Dent clin north AM, 1983: 27: 6671-84. 9.
Quinn F Mcconnell RJ, Birne D. Porcelain laminates: A
review: Br. Dent. J, 1986; 161: 61-65. 10. Robbins JW, Colour chracterisation of porcelain veneers: Quintessence int, 1991; 22: 853-56. 11. Christensen GJ.. Resin cements and postoperative sensitivity: J Am Dent Assoc. 2000 Aug;131(8):1197-9. 12. Cherukara GP, Davis GR, Seymour KG, Zou L, Samarawickrama DY. Dentin exposure in tooth preparations for
CONCLUSION: A case of anterior esthetic rehabilitation with porcelain laminates was discussed, taking into consideration the biological, mechanical, esthetic
porcelain veneers: a pilot study:
J Prosthet Dent. 2005
Nov;94(5):414-20. 13. Matsumura H, Aida Y, Ishikawa Y, Tanoue N.Porcelain. Laminate veneer restorations bonded with a three-liquidsilane bonding agent and a dual-activated luting composite: J Oral Sci. 2006 Dec;48(4):261-6. 14. Reshad M, Cascione D, Magne P. Diagnostic mock-ups as an objective tool for predictable outcomes with porcelain laminate
and functional demands. A sound knowledge of the
veneers in esthetically demanding patients: a clinical report.
basics with the skill of the dental technician would
Reshad M, Cascione D, Magne P. J Prosthet Dent. 2008
pave way for the path of success in any restoration.
When it comes to esthetics, an extra mile has to be
15. Chu FC. Clinical considerations in managing severe tooth discoloration with porcelain veneers: J Am Dent Assoc. 2009
tread by the dentist to imbibe the dimensions of
beauty and harmony and apply them to the
16. Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed
restorations in his practice.
Prosthodontics. Elsevier publication, 4th edition. 17. Shillingburg HT, Sumiya Hobo, Lowell D. Whitsett, Richard Jacobi, Susan E. Brackett. Fundamentals of Fixed
Peumans M, De Munck J, Fieuws S, Lambrechts P,
Vanherle G, Van Meerbeek B. A prospective ten-year clinical trial of porcelain veneer: J Adhes Dent. 2004 Spring;6 (1):6576. 2.
Heather J. Conrad, Wook-Jin Seong, Igor J. Pesun :Current
ceramic Materials and systems with clinical recommendations: A systematic review: J Prosthet Dent 2007;98:389-404. 3.
Exner HV. . Predictability of color matching and the
possibilities for enhancement of ceramic laminate veneers: J
Prosthodontics. Quintessence books, 3rd edition. 18. Ronald E. Goldstein. Change your smile. 3rd edition Quintessence books. 19. Magne P, Kwon KR, Belser UC, Hodges JS, Douglas WH. Crack propensity of porcelain laminate veneers: A simulated operatory evaluation: J Prosthet Dent. 1999 Mar;81(3):327-34. 20. Weinberg LA. N Y State Dent J. Tooth preparation for porcelain laminates: Dent Clin North Am. 1989 Apr;33(2):30518, 210-9. 21. Quinn F, McConnell RJ, Byrne D. Porcelain laminates: A review. Br Dent J. 1986 Jul 19;161(2):61-5.
Prosthet Dent. 1991 May;65(5):619-22. 4.
Magne P, Belser UC.Novel porcelain laminate preparation
approach driven by a diagnostic mock-up: J Esthet Restor Dent. 2004;16(1):7-16 5.
Goldstein RE. Finishing of composites and laminates:
Dent Clin North Am. 1989 Apr;33(2):305-18, 210-9. 6.
Lu bocovich. Smile designing for the malcontent patient:
Compend Contin Educ Dent. 2010 Jul-Aug;31(6):412-6.
Vol-1 issue-3 May-2013
Dr.Gajendra.V,2Dr.Hema.G,3 Dr.Kathiga Kannan, Reader,3 Professor & Head,Departmentt of Oral Medicine & Radiology, SMIDS,Kulashekaram, TamilNadu. 1&2
in oral diseases An over view GENE THERAPY IN OROMUCOSAL LESIONS: Gene therapy is considered to be one of the most exciting areas of medicine for the future. It aims to correct the underlying genetic defects in human disease rather 1 than just focusing on symptoms . Gene therapy is the introduction and expression of recombinant genes in somatic cells for the purpose of 2 treating disease .Initially, gene therapy was associated with either the correction of inherited genetic disorders or treatment of life threatening conditions3. Currently, gene therapy protocols has been approved in humans for experimental studies with severe combined immunodeficiency (SCID), cystic fibrosis, AIDS, malignant melanoma, various carcinomas, hypercholesterolemia and brain tumors.4 In gene therapy, the new genetic information uses the host cells machinery to express its encoded gene product. In this sense, DNA is being used like any 2 pharmacological agents to induce therapeutic effects . In DNA therapy drug delivery is simplified; we need only one delivery system capable of inserting new DNA. In addition, this form of therapy offers a new approach for disease therapeutics by providing a potentially permanent treatment by targeting delivery of genes into the genome of stem cells. In this way, the transgene will be inherited by stem cell progeny, and therapy will be sustained after administration of a single gene dose. Finally it may be possible to localize expression of a therapeutic gene by delivering genes to particular cells or by using tissue or cell specific promoters to limit expression to cells of interest2. Epidermal and oral keratinocytes are potential vehicles for gene therapy. Several featuresof these tissues can be utilized to achieve delivery of therapeutic gene products for local or systemic delivery. These qualities include 1) presence of stem cells 2) the cell,strata and site specfic regulation of keratinocyte gene expression 3) tissue accessibility 4)secretory capacity 5) tissue culture models simulate invivo epithelium 6) 2 grafting techniques available 7) inherent safety features. In addition oral diseases are difficult to treat with conventional, topical drug application, since saliva tends to dilute topical agent. Direct delivery of genes into the surface epithelium would circumvent such difficulties in 2 drug delivery .Gene therapy, thus holds a bigger promise for disease therapeutics in the near future.
Gene Transfer: Clinical use of gene transfer can be accomplished in either of two ways. Completely invivo, when the foreign gene is administered to the patient's by viral or physical methods. Exvivo, when the foreign gene is applied to certain of the patient's cell that are temporarily maintained outside of the body in a sterile environment and after a suitable 1 period, returned to host . Gene transfer can be used clinically for two purposes ; Gene therapy, it can be defined as the gene transfer for the purpose of the treating human disease, this includes the transfer a new genetic material as well as the manipulation of existing genetic material. This holds true especially for cancer cells, where dominantly activated oncogenes are targeted. Gene therapeutics the use of gene transfer to produce biomolecules with pharmacological functions. Gene therapeutics could be employed for either treatment or 1 prophylactic purposes . Genetic material can be transferred via a vector, vector is defined as the vehicle that is used to deliver the gene of interest. Ideal features of vector include it should target specific tissues or organs, necessity to maintain prolonged expression of transgene, the possibility of engineering cells invitro and then re-implanting them, potential side effects on the host such as toxicity and immunization must be prevented1. Vectors can be viral on non viral. viruses are the closest delivery vehicle to this ideal vector. By removing the virulent genes from a virus and substituting the therapeutic gene, we can create a tamed virus that can be used as a safe delivery vehicle. Therefore altered viruses have become the most commonly used gene therapy vectors in clinical trials. Commonly used virus vectors are retrovirus, adenovirus, 2 adeno-associated virus . Nonviral methods include physical methods such as electroporation, microinjection, gene gun and chemical methods include cations and polycations, lipid vectors, cationic lipid vectors. Advantages of these nonviral vectors are it has no replication risk, transfect both dividing and nondividing cells, less immunogenecity.Disadvantage in 2 limited transfection . Vol-1 issue-3 May-2013
GENE THERAPY IN OROMUCOSAL LESIONS: Three groups in oral diseases that are actively using this science, all for quite different purposes with different approaches these include 1)Gene transfer to salivary glands 2)Gene transfer to oromucosal keratinocytes 3)Gene therapy to oral cancer Gene transfer to salivary glands: Salivary glands present an inviting target for invivo gene transfer because of other anatomic location and ease of access. Studies were aimed at repair of salivary glands whose acinar cells have been irreversibly damaged. The two common situations that result in acinar cell damage, and thus inability of glands to secrete fluid, are therapeutic radiation (for head and neck tumors with salivary glands in radiation field) and Sjogren's syndrome. The aim of the study was to convert surviving ductal cells into acinar like cells that secrete salt and fluid. This is an example of what is termed organ engineering, changing the basic function of a cell type and efforts was also directed at creating a recombinant adenovirus that contains a water channel gene. Gene therapeutics: The approach here is to use normally functioning salivary glands to deliver in their secretions, biopharmaceuticals encoded by transferred foreign gene. Researchers hypothesized that over expression of naturally occurring salivary anticandidal peptide (histatin) has the possibility of treating, or even preventing the severe mucosal (oral-pharyngeal-oesophageal) candidiasis that accompanies immunosuppression due to infection (as in AIDS) or to therapeutic treatment (for ex, as a result of transplants). Another example, investigators have isolated gene for fimbrillin, a surface protein of the important periodontopathic bacterium porphyromonas gingivalis. Their aim is to construct a recombinant adenovirus containing this gene and transfer it to salivary glands. They anticipated that the soluble protein product of this gene will be secreted locally around the gland as well as in saliva. They expected that locally secreted fimbrillin to elicit an immune response leading to production of secretory IgA. This secretory IgA would be secreted in saliva and neutralize p. gingivalis inhibiting its ability to participate in plaque formation. Similarly, secreted fimbrillin in saliva could bind to pellicle components, blocking the attachment of p. Gingivalis. This strategy, or a similar one, although in its infancy, could prove to be a very useful new tool against periodontal diseases, 1 especially in populations at high risk .
Gene transfer to oromucosal keratinocytes Epidermal keratinocytes are grown in cultures to generate organotypic mucosal equivalents with morphological features of the invivo tissue. By this, it has been used in treatment of burn therapy and for treatment of nonhealing epidermal ulcers. There are reports that cultured oral keratinocytes have been grafted to oral surgical defects. Which persisted at 2 these sites and exhibited normal epithelial morphology . POTENTIAL CLINICAL APPLICATIONS OF KERATINOCYTE GENE THERAPY A) Genetic Diseases Recessive monogenetic diseases: Recessive disorders may be treated by introduction of a normal gene into keratinocytes so that its expression would compensate for the lack of expression of the defective, mutated gene. An example for the treatment of a recessive disorder in keratinocytes is gene therapy for xeroderma pigmentosum. This condition is caused by an inherited defect in a DNA repair enzyme and results in an increased risk of epidermal cancer. The goal of gene therapy would be to transfer and express a normal copy of the repair enzyme to cause the disease phenotype to revert5. Dominant monogenetic diseases: The gene addition approach used to treat recessive disorders would not be of value in the treatment of dominant, monogenic disorders since disease cells continue to express a 2 defective gene product . In this case, successful gene therapy would first require disruption of abnormal gene expression before transferring and expressing a normal gene. Example for a keratinocyte-specific autosomal dominant disorder to which gene therapy is applied is â€œEpidermolysis bullosa simplex (EBS)6. While EBS does not lead to serious manifestations in oral cavity, this therapeutic approach may be of value in learning how to treat an oral disease caused by dominant-acting mutation2. b) TREATMENT OF ACQUIRED DISEASES: Treatment of infectious diseases In oral cavity HPV and HSV infection are among the most common viral induced lesions. HPV has been associated with the development of squamous cell carcinoma and benign proliferative conditions while HSV is thought to cause primary and recurrent oral 2 ulcers . Vol-1 issue-3 May-2013
The goal of gene therapy would be either to protect the cells from infection or to limit the infectious process of previously infected cells. For ex oral cancer cells that Harbor HPV may have their malignant phenotype altered by use of antisense molecules7 and ribosomes8 directed to the HPV transforming genes. Transfer of genetically altered HSV sequences has provided a strategy through which HSV pathogenecity can be modified. C)RE-EPITHELIALIZATION AND WOUND HEALING: Expression of gene products which stimulate wound healing may be useful to accelerate reestablishment of oral and epidermal integrity after injury. Genetically modified keratinocytes transplanted to wounds may act as biological dressing by expressing into the wound a therapeutic protein which would favour wound healing9. Alternatively, a therapeutic gene could be applied directly to the healing cells. When gene for human epidermal growth factor was transferred to wound, the growth factor was secreted 10 by cells in wound and healing was accelerated . Such applications are examples of a gene therapy approach where only transient expression of therapeutic gene is required. This therapeutic approach may prove 2 particularly in treatment of chronic oral ulcers .
APPLYING GENE THERAPY TO ORAL CANCER: Potential uses of gene therapy in oral cancer include treatment of recurrent disease and adjuvant treatment-for example, at surgically resected margins. Localized distant metastatic disease is another potential target of gene therapy in patients with oral cancer. Due to the requirement for direct injection, oral cancer is a particular appropriate target, since most primary and recurrent lesions are accessible to injection11. There are several general strategies utilized in a gene therapy approach to cancer including 1) Addition of tumor suppressor gene (gene addition therapy) Cancer cells generally demonstrate impaired cell cycle progression largely due to mutations and over expression of cell cycle regulators several genetic alterations have been described in oral cancer, including mutations of P53, the retinoblastoma gene (RB1), P16 & P2112.
The most extensively studied mutations in oral cancer are those of P53. Since the protein P53 plays a role in cell-cycle was initially tested in squamous cell carcinoma pts by injecting the primary or regional tumor with an adenoviral vector expressing wild type P53. Adenoviral P53 (AdP53) was demonstrated to be safe and well tolerated, however it has limited tumor response11. 2) Deletion of a defective tumor gene(gene excision therapy) 3) Down regulation of the expression of genes that stimulate tumor growth (Antisense RNA). Gene expression can usually be inhibited by RNA that is complementary to the strand of DNA expressing the gene. This “antisense” RNA can prevent the activity of several known oncogenes including myc, fos and ras and can inhibit viruses such as HSV-1, HPV and HTLV-1 such therapy can theoretically be directed toward carcinoma cells whose malignant phenotype is dependent upon the expression of particular oncogenes. Inhibition of expression of these oncogees may alter phenotype thus aborting tumor growth. 4) Enhancement of immune surveillance (Immunotherapy) The immunologic gene therapy approach to oral cancer involves increasing the immunogenic potential of tumor cells or augmenting the patient's immune response to a tumor. 5) Activation of prodrugs that have a chemotherapeutic effect (“suicide gene therapy) “Suicide gene therapy for cancer inserts a gene into the tumor that encodes for a protein that will convert a nontoxic prodrug into toxic substance. The most extensively studied approach utilizes herpes simplex virus Thymidine kinase (HSV-TK). This gene encodes a viral enzyme that phosporylates ganciclovir into monophosphate form, which is then further phosphorylated by intracellular enzymes into an active triphosphate compound 13 that terminates DNA synthesis . Other strategies include introduction of viruses that destroy tumor cells as part of the replication cycle, delivery of drug resistance genes to normal tissue for protection from chemotherapy and introduction of genes to inhibit tumor angiogenesis. Limitations in cancer gene therapy: Tumor may have lost surface receptor for the vectors, due to mutations tumor cell cycle may be too deranged to progress to apoptosis, many cancers may not be curable by a single modality therapy. Future directions of cancer gene therapy are, aimed at proper delivery system; selective and specific cancer targeting, metastatic tumor targeting may require systemic 11 tumor specific targeting which needs different approaches .
Vol-1 issue-3 May-2013
Future perspectives: Modification of bacteria to control the pathogenecity of dental infections agents. A major challenge in dentistry is the fabrication of biomaterials for replacement or augmentation therapy related to enamel, dentin, cementum, PDL, bone, cartilage and oral mucosa. For example during endodontic therapy, dentists will be able to seed genetically developed pulpal tissue into the canal to grow and fill the chamber. Recombinant vaccines designed to reduce dental caries and periodontal diseases. Promising research is in progress related to development of vaccines against H. simplex, human papilloma virus, human immunodeficiency virus with significant oral complications. Production of oral mucosal lubricants for xerostomia, building disease resistant dental structures, delivery of gene therapeutics for oral fungal infections and genetically based therapeutics (eg. Endorphins, neutrotrophins) for neurological disorder eg: Trigeminal Neuralgia Production of systemic gene products from oral tissues, gene therapy mouth washes to oral cancer. Limitations of gene therapy include short lived nature of gene therapy, immune response, problems with viral vectors, multigene disorders, cost effective, awareness of 2 patient, it requires special knowledge and skill .
References 1)Bruce J Baum, Brian C O' Connell: The impact of gene therapy on dentistry. JADA,Vol 126, Feb 1995,179-189. 2)Garlick J.A, Fenjves E.S:Keratinocyte gene transfer and genetherapy. Crit Rev Oral Biol Med.7(3):1996:204-221. 3)Roemer K, Friedmann T. Concepts and strategies for human gene therapy.Eur J Biochem 1992:208:211-225. 4)Currently approved human gene transfer studies. Hum Gene Ther 1994:5:1067-74 5)Weatherall DJ:Scope and limitations of gene therapy. Br Med Bull:1995:51:1-11. 6)Coulombe PA,Hutton ME, Vassar R, Fuch SE. A function of keratins and a common thread among dfferent types of epidermolysis bullosa Simplex diseases. J Cell Biol 1991:115:1661-1674 7)Steele C, Cowsert, Shillitoe EJ: Effects of human papillomavirus type 18 specific antisense oligonucleotides on the transformed phenotype of human carcinoma cell lines. Cancer Res 1993:53:2330-2336. 8)Chen Z, Kamath P, Zhang S, Weil MM, Shillitoe EJ. Effectiveness of three ribozymes for cleavage of an RNA transcript from human papilloma virus type 18. Cancer Gene therapy 2:263-271. 9)Vogt PM,Thompson S, Andree C, Liu P, Breuing K, Hatzis D etal. Genetcally modified keatinocytes transplanted to wounds reconstitute the epidermis. Proc Natl Acad Sci USA 1994:91:9307-9311. 10)Andree c, Swain WF, Page CP, Macklin MD, Slama J, Hatzis D, et al. In vivo transfer and expression of a human epidermal growth factor gene accelerates wound repair. Proc Natl Acad Sci USA 91: 12188-12192. 11)Gleich LL. Gene theraphy for head and neck cancer. Laryngoscope 110;2000:708-726.
12)Xi S, Grandis. JR. Gene therapy for the treatment of oral
The early efforts show that treatment of oral diseases will be broadly affected by impact of molecular biology. While there is little evidence to date of the efficacy of gene therapy in clinical trails, the potential for gene therapy is still great, is that it may provide a new way of looking at disease therapeutics. Gene therapy is in an early stage yet holds great promise for its ultimate clinical application. Dentistry will be affected profoundly by gene based science, or current materials and methods are abandoned in favour of emerging bioengineered technologies for disease prevention, tissue repair and disease resistance. â€œThe best way to predict the future is to invent itâ€?.
Matthews T, Boehme R. Antiviral activity and mechanism of
squamous cell carcinoma. J
Dent Res 82(1):2003,11-16.
Action of Ganciclovir. Rev Infect Dis(3):1988;490-494.
Vol-1 issue-3 May-2013
Keratocystic Odontogenic Tumor Of the mandible A case report
Dr Thomas Varghese, DrKarthigaKannan, 3 4 Dr Jassim K A, Dr Merin George, (1&4)PG student,(2) Professor - Department of Oral Medicine & Radiology (3)PG student - Department of Oral Pathology , Mar Baselios Dental College, Kothamangalam, Ernakulam (Dist).Kerala
Abstract Jaw cysts are very common due to the presence of odontogenic epithelial remnants. The odontogenickeratocyst (OKC) is an epithelial developmental cyst of the jaws. This lesion is commonly found in the mandible, and can become quite large due to its rapid growth and its extension into the adjacent structures. In 2005 the WHO working group considered odontogenickeratocyst (OKC) to be tumor and recommended the term Keratocysticodontogenic tumor (KCOT), separating lesion from the ortho keratinizing variant. Clinically the parakeratinizing lesions are characterized by aggressive growth and tendency to recur after surgical treatment. We present the case of a 22 year old female with KCOT in relation to right posterior mandibular region. The clinical, radiological, and histopathological features of this tumour and its surgical management are discussed.
Case Report: A 22 year old female patient reported to the Department of Oral medicine and radiology of Mar Baselios Dental College ,Kothamangalam,Ernakulam with a chief complaint of pus discharge from the right lower back tooth region for the past 6 months [figure 1].she noticed a displacement of teeth in the same region for the past one month [figure 2]..Rest of the dental and medical history was unremarkable.
Key words Odontogenickeratocyst (OKC); Keratocysticodontogenic tumor (KCOT); Nevoid basal cell carcinoma syndrome.
Introduction: Odontogenickeratocysts (OKCs) are developmental odontogenic cysts of epithelial origin, first identified and described in 1876 and further characterized by Phillipsen in 1956.1 This lesion was recently renamed as keratocysticodontogenictumour (KCOT) and reclassified as an odontogenic neoplasm in the World Health Organization's 2005 edition of its histological classification of odontogenictumours. According to this edition the KCOT has been defined as ''A benign uni- or multicysticintraosseoustumour of odontogenic origin, with a characteristic lining of parakeratinized stratified squamous epithelium and potentially aggressive, infiltrative behaviour. It may be solitary or multiple. The latter is usually one of the part of inherited naevoid basal 2 cell carcinoma syndrome .
Fig. 1: Facial profile view of the patient demonstrating no visible swelling On extra oral clinical examination there was no gross facial asymmetry noticed on the face. On intra oral examination a solitary diffuse swelling of size 2x2 cm seen in relation to the lingual aspect of 44,45,46 region.colour of the swelling is pale pink ,surface is smooth , shiny and displacement of 44,45 is noticed. On palpation the swelling is bony hard in consistency ,borders are not clearly defined ,it is not a compressible or reducible swelling with the slight expansion of lingual cortical plate [figure 3].
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Intra oral Periapical radiograph, occlusal Lateral occlusal radiograph shows a radiolucency radiograph and Orthopantomographs were performed. IOPA of size 3x1 cm seen which extends from the cervical area of of 44,45,46 region shows a radiolucent area of size 3x3 cm 48 to distal aspect of 44 with lingual cortical plate which extends from the distal aspect of 44 to the distal aspest expansion[figure 5] of 46 ,superior inferiorly from the alveolar crest and it extends downwards. [figure 4]
Fig. 2: Intraoral shows displacement of teeth. Fig. 6 : OPG shows well defined radiolucency with sclerotic outline and scalloped border.
OPG shows a well-defined radiolucency with sclerotic outline and scalloped borders of size 3x3 cm in relation to the 44,45,46 region. [Figure 6]
Fig. 3 :. Intraoral shows swelling on the lingual aspect
Fig. 4: IOPAR shows radiolucency with scalloped outline
Fig. 5 Lateral occlusal view shows lingual cortical plate expansion.
Aspiration gives blood tinged creamy fluid. Based on the history,clinical and radiographic features a provisional diagnosis of odontogenickeratocystwas made. Surgical enucliationdone under general anaesthesia and chemical cauterization with Carnoy?s solution was done. Biopsy report shows cystic lining, surrounded by moderately dense connective tissue. The parakeratinised corrugated epithelium is almost 6-8 layers thick. The retiridegs are absent and sloughing of the epithelium from the connective tissue is also noted. The basal cells are columnar with polarized nuclei;cystic lumen shows fibrillareosinophilicmaterial suggestive of keratin. Based on histopathology we finally diagnosed as Keratocysticodontogenic tumor [figure 7].No recurrence has been determined after 9 months of post operative follow up [figure 8].
Fig. 7 Histopathology 10x zoom Vol-1 issue-3 May-2013
Fig. 8: post operative OPG after9 months. Discussion: KCOT is a benign uni or multicystic, intraosseoustumour of odontogenic origin, Keratocysticodontogenic tumors (KCOT) occur from the first to the ninth decades with a peak in the second and third decades. Males are more commonly affected than females. The mandible is involved more frequently than the maxilla, the percentage of KCOTs occurring in the mandible ranges from 65- 83% of cases.With roughly onehalf originating at the angle of the mandible2. While the KCOT is generally regarded as anintraosseous lesion, rare peripheral cases have beenreported. The majority of cases involve the gingival oralveolar mucosa in the canine3 premolar region . Most keratocysticodontogenic tumors are discoveredincidentally during review of routine dental radiographs. Occasionally, pain, swelling, and drainage will herald asecondary infection of the cyst. Imaging studies generallyshow unilocularradiolucencies with well-demarcatedsclerotic margins. Larger lesions may become multi-loculated with scalloped borders. The cyst is often associated with an impacted tooth, and mimic radiologically like dentigerous cyst. Adjacent teeth may be displaced, but root resorption rarely occurs. CT scans and contrast-enhancedMRI may be useful in assessment of [1, 2,,3 ]. cortical perforationand soft tissue involvement Histologically OKCs have been classified into three categories: parakeratinised, Orthokeratinised, or a combination of the two types. Mostly (86.2%) were parakeratinised, 12.2% were orthokeratinised, and 1.6% had features of both orthokeratin and parakeratn. Orthokeratinised OKCs have a substantially lower recurrence rate than parakeratinised. This case is a parakeratinisedvarity. Multiple OKCs are found in some patients. Gorlin and Goltz established the association of multiple basal cell epitheliomas, jaw cysts and bifid ribs, a combination that is referred as the â€œGorlin -Goltz Syndromeâ€?, or the nevoid basal cell carcinoma syndrome 4 (NBCCS) .
Multiple treatments for the Keratocysticodontogenictumor have been proposed and debated. The challenge lies in minimizing both the risk of recurrence and morbidity of an extensive resection. Numerous modalities ranging from decompression alone, to simple enucleation with or without curettage, to resection have been employed in the management of KCOT.  Simpleenucleation has a recurrence rate of 17% to 56%.
Conclusion: KCOT patients are mostly asymptomatic. Most Keratocysticodontogenic tumors are discovered incidentally during review of routine dental radiographs. It is more aggressive and recurrent one. In any case clinical and radiographic follow-up is mandatory for years after surgery, because recurrence of this lesion may occur even years later. References: 1.Shear M (1992). Odontogenickeratocyst In: Cysts of the Oral Regions, 3rd ed. 2.Keratocysticodontogenic tumor a case report and review of literature Asokan et al:Int J Dent Case Reports 2012; 2(1): 87-91. 3.Pindborg JJ and Hansen J: ActaPatholMicrobiolScand Studies on odontogenic cyst epitheliu m 1963;58:283- 294 4.Thompson L, Goldblum J, editors. Head and neck pathology; avolume in the series foundations in diagnostic pathology. Phila-delphia: Elsevier; 2006. 5.KeratocysticOdontogenicTumor,Elizabeth A et al. Head and Neck Pathol (2010) 4:9496..
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Minimal Invasive Dentistry A new perspective Abstract The current treatment philosophy is to prevent and detect diseases at the earliest stage in order to avoid invasive treatment. With the current understanding of the nature of dental diseases and its process, the treatment philosophy is now changing to a more conservative approach and the concept of minimal intervention is gaining popularity in modern dentistry throughout the world. The aim of this review article is to give dental professionals an overview of the concepts of MID and recent innovations in the treatmentof dental caries.
Key words Minimal Invasive Dentistry, Dentin caries, Caries Excavation
Introduction Current knowledge regarding caries disease has substantially evolved within the last decade. Understanding of its dynamic lead to a risk factor approach which left the treatment of cavities a minor role to play in the whole planning. Using this background, Minimally Invasive Dentistry (also minimum intervention dentistry - MID) builds its framework.The “minimally invasive” approach totreating dental caries incorporates the dental science of detecting, diagnosing,intercepting and treating dental caries on the microscopic level. This approach to treating dental caries includes many non- surgical modalities, as well as the key concept that dental caries should be treated as an infectious disease and includes the following concepts: Early caries diagnosis. The classification of caries depth and progressionusing radiographs. The assessment of individual caries risk (high, moderate, low).
Dr Santhini G Nair,2Dr S Rajesh
1.Senior lecturer, Department Of Conservative Dentistry &Endodontics.NIMS. 2.Prof.,& HOD. -SMIDS,Kulasekharam
The reduction of cariogenic bacteria, to decrease the risk of further demineralization and cavitation. The arresting of active lesions. The remineralization and monitoring of noncavitated arrested lesions. The placement of restorations in teeth with cavitatedlesions, using minimal cavity designs. The repair rather than the replacement of defective restorations. Assessing disease management outcomes atpreestablished intervals.
MINIMAL CAVITY DESIGNS Preservation of natural tooth structure should be the guiding factor for the smallest, as well as the largest, cavity. Cavity preparation design and restorative material selection depend on occlusal load and wear factors. The tunnel preparation is performed byaccessing the carious dentin from the occlusalsurface, while preserving the marginal ridge. Tunnel preparations are technicallydifficult to do because of access and visibility and the small amount of tooth structure removed. Internal preparations preserve the marginal ridge and the proximal surface enamel. Minibox or slot preparations involve theremoval of the marginal ridge, but do not includethe occlusal pits and fissures if caries removal inthese areas is not necessary. These cavities mayhave either a box or a saucer shape and may berestored with resin-based composite oramalgam. M I N I M A L I N VA S I V E P R E P A R A T I O N TECHNIQUES(Noack et al. (2004) 1.Excavation techniques: i)Manual rotary. ii)Sono abrasion. iii)Air abrasion. iv)Chemo-mechanical excavation. v)Enzymatic digestion. vi)Photobalation. 2. Disinfection techniques: a)Ozone treatment b)Photodynamic therapy c)Antibacterial therapy 3. Sealing techniques a)Fluoride releasing materials b)Dentin adhesives C)Antibacterial resin materials Vol-1 issue-3 May-2013
ATRAUMATIC RESTORATIVE TECHNIQUE: This technique was developed in Tanzania in mid 1980s and introduced into clinical setting in 1990s. It mainly evolved in response to the unavailability of restorative care in population groups with limited resources. It involves the removal of only soft, demineralized tooth tissue with hand instruments followed by filling the cleaned cavity with adhesive Technique: Isolate tooth with cotton rolls Clean tooth surface with wet cotton pellet Widen lesion entrance with Hatchet Caries removal with Excavator Pulpal protection Ca(OH)2 paste Cavity conditioning and rinsing Condense with press finger technique Check the bite and remove excess material ART uses the beneficial property of GIC such as: Fluoride release. Inhibition of secondary caries. Ability to remineralziation. Conventional Excavation with Burs Carbon-steel or tungsten-carbide burs Tungsten-carbide burs replaced carbon-steel burs once the process of hardening steel with tungsten carbide was introduced to the dental bur industry. Microscopic tungsten-carbide particles are held together in a matrix ofcobalt or nickel at the head (working end) of the bur. The head has typical spiral like cutting edges with or without additional cross cuts to improve cutting efficiency. Carbon steel burs possess the same cariesremoving propertiesas tungsten-carbide burs and are less expensive, but they are much more prone to corrosion and dulling. For caries removal, a round bur is recommended with diameters corresponding to the size of the carious lesion.Water irrigation is optional because generally low-speed (700 to 800 rpm) counter-angle hand-pieces are employed. It is generally advised to start carious dentin excavation from the periphery towards the centre of the lesion in order to minimize the risk of infection in case of accidental pulp exposure. Larger burs are recommended for this reason as well. Tungstencarbide or carbon-steel burs in low-speed counter-angle hand-pieces are the most efficient method to excavate carious lesions in terms of time and are therefore still the most widely used caries-excavation method. Polymeric burs In an attempt to develop a selective caries-removal rotating instrument, a “plastic” bur was made of a polyamide/ imide (PAI) polymer, possessing slightly lower mechanical properties than sound dentin. However, soon it became clear that if the bur touches sound or caries-affected dentin, it quickly becomes dull and produces undesirable vibration, making further cutting impossible.
The blade design was developed to remove dentin by locally depressing the carious tissue and pushing it forward along the surface until it ruptures and is carried out of the cavity. The commercial version of these burs (SmartPrep, SSWhite Burs; Lakewood, NJ, USA) consisted of a polymer(PEKK polyether-ketone-ketone) with a particular hardnessof 50 KHN, which was higher than the hardness attributed to carious dentin (0 to 30 KHN), but lower than that of sound dentin (70 to 90 KHN). As opposed to conventional carbide burs, their cutting edges were not spiralled but straight. One disadvantage was that by keeping to the recommendation to excavate caries from the centre to the periphery in order to avoid contact with sound tooth tissue, the bur would be prematurely and irreversibly damaged. Ceramic burs A new line of slow-speed rotary cutting instruments made of ceramic materials is now commercially available for removal of carious dentin. The CeraBurs (Komet-Brasseler; Lemgo, Germany) are all-ceramic round burs made of alumina-yttria stabilized zirconia and are available in different diameter sizes The manufacturer claims that besides its high cutting efficiency in infected, soft dentin, the use of this instrument for caries removal replaces both the explorer and the excavation spoon (commonly needed to evaluate the degree of decay removal) by simultaneously providing tactile sensation, self-evidently reducing preparation. AIR ABRASION Air abrasion is an old technology that is finding a new place in modern science based dentistry.The concept of air abrasion was originally given by Dr. R.B. Black, way back in 1943, in the era of 'extension for prevention', operative dentistry. The 1st commercial air abrasion equipment was AIR DENT by SS White Company. Air abrasive technology uses a high speed stream of purified alumina particles traveling in high velocity stream of air to remove the tooth structure. Hence this technique has recently termed by Kelvin as Kinetic cavity preparation Modern version of AirDENT (1992) Abrasive The abrasive used is purified aluminium oxide particles or alpha-alumina i.e. a non-toxic substance often in medicine, food. The particle size is about 27.5µ .Currently 2X alumina particle sizes are available with 3 pressure choices. Science and anatomy It removes only the decayed tooth structure leaving the healthy tooth structure intact, hence the pain and discomfort associated with the traditional use of the needle and drill is avoided and no impingement on vital tissues. Air abrasive tools, techniques and procedures A setting of 60 psi with 27µ particle size and 0.014 inch tip is comfortable and adequate for starting most procedures. a) Clean the surface of the tooth, place caries detector die. b) Place the nozzle at right angle 45° and no more than 1mm to the surface of the tooth to be treated. c) Start with 3 second burst at 80 psi to trace out the grooves, pits and fissures of the occlusal surface of the molar. Vol-1 issue-3 May-2013
the burst should be interrupted over areas of sound enamel such as isthmus separating the mesial and distal pits of mandibular molars and oblique ridge of maxillary molars. d) Observe and diagnosis for residual decay which if present should be removed (at once setting 60 psi) in a similar manner and use short controlled bursts. e) One aspect of micro-dentistry is the amount of powder that ends up in the mouth.High speed suction is always used. Also a 2 x 2 inch wet gauge may be placed in the mouth.
EXCAVATION BY SONO-ABRASION
Main indication: Class I, III and V carious lesions: Class I: Excellent when tooth does not show radiographic evidence of significant caries and teeth may have potentially fissured occlusal grooves. Class III: Small Class III most common and important indications. Non carious tooth must be protected with rubber dam, 0.002 inch (50µm) thick matrix band. Margin repair composite laminate. Pediatric patients. Health compromise in which LA cannot be given. Apprehensive patients. Less common:Class II, IV difficult and unpredictable needs to be mastered.
OLength ways halved torpedo (9.5mm long, 1.3mm wide). oSmall hemisphere (1.5mm diameter). oLarge hemisphere (12.2mm).
Contraindications: Severe dust allergy. Asthma Chronic pulmonary disease. Recent extraction. Recent periodontal surgery or PDL disease. Subgingival preparation. Wound / lacerations in mouth e.g. after recent orthodontic appliances. Advantages: Patient acceptance: lack of vibration, decreased heat, decreased pressure and pain produced during cavity preparation. Unique ability to produce extremely conservative preparations. Smell of carious material is eliminated. Disadvantages: Technique not familiar, so dentists require a learning period to occlusion themselves limited visibility. Tactile perception minimal. Only small cavity preparations can be accomplished. Al2O3 gets accumulated. Excellent suction required. High cost. Walls rounded and uneven. Difficult to remove existing restoration. Soft caries absorbs alters the particles.
Caries excavation by “sono-abrasion” is based on the use of cutting tips coupled to high-frequency, sonic, air-scaler hand-pieces under water cooling. Oscillate in the sonic region <0.5KHz. Tips describe on elliptical motion with a transverse distance between 0.08-0.015mm and longitudinal movement 0.055-0.135mm. Diamond coated on one side with 40µm grit diamond. Air cooled with H2O with flow rate, 2030mL/min.Operational air pressure is 3.5bars. Have 3 three different instrument tips
Torque applied should be 2N.This technique was unilaterally developed using different shaped tips to help prepare predetermined cavity outlines. CHEMO MECHANICAL CARIES REMOVAL Non-invasive alternative for the removal of carious dentine. It mainly involves the chemical softening of carious dentin followed by its removal of gentle excavation. A CMCR reagent is based on this principal causing further degradation of the partially degraded collagen, by cleavage of the polypeptide chains in the triple helix and / or hydrolyzing the cross linkages. MOA of chemo-mechanical caries: Dentine consists of mineral (70%), water 10%) and an organic matrix (20%) , of this organic matrix, 18% is collagen .Collagen is an unusual protein which contains large amount of proline and 1/3rd of amino acid content is glycine.The polypeptide chains are coiled into triple helices which are known as tropocollagen units. These tropocollagen units then orientate side by side to form a fibreil bonds between the polypeptide chain and between the tropocollagen units form cross-links and give the collagen units stability. In dentin the fibres are in the form of a dense meshwork which gets mineralized.When caries occur, acids produced by plaque bacteria by anaerobic fermentation of carbohydrate initially cause solubilisation of the mineral in enamel. As the process progresses, dentinal tubules provide access for penetrating acids and subsequent invasion by bacteria which results in a decrease in pH and cause further acid attack and demineralization. When the organic matrix has been demineralized, the collagen and other matrix component are susceptible to attack and forming the zones of caries.In this, out of the 2 zones of carious dentine, theCMCR reagent causes the further degradation of partially degraded collagen in the outer layer by cleavage of polypeptide chains in the triple helix and / or hydrolyzing the cross linkages.
Vol-1 issue-3 May-2013
Development of chemo-mechanical agents The principal of CMCR is based on arising from studies by Goldman and Kronman working in New Jersey US in the 1970's. They stated with studying the effect of NaOCl, which is a non-specific proteolytic agent, on the removal of carious material from dentine. It alone, however was too erosive. Hence, they incorporated it into Sorensen's buffer (which contains glycerine, sodium chloride, sodium hydroxide) a reaction occurred which resulted in a product effective in removal of glycine to form N-monochloroglycine and the reagent subsequently became known as GK-1019. In subsequent studies they found that the system was more effective if glycine was replaced by amino butyric acid, the product then being N-monochloroaminobutyric acid (NMAB) also designated GK-101E.The mechanism of action of NMG and NMAB on collagen is still unclear and knowledge of the chemistry of chlorination of amino acids and their effects is still very limited. Originally it was thought that the procedure involved chlorination of the partially degraded collagen in the carious lesion and the conversion of hydroxyproline to pyrrole-2carboxylic acid.11 More recent work suggests that cleavage by oxidation of glycine residues could also be involved.This causes disruption of the collagen fibrils which become more friable and can then be removed. The NMAB system was patented in the US in 1975 and a further patent taken out by the National Patent Dental Corporation, New York in 1987. It received FDA approval for use in the USA in 1984 and was marketed in the 1980's as Caridex. It consisted of two solutions, Solution I containing sodium hypochlorite and Solution II containing glycine, aminobutyric acid, sodium chloride and sodium hydroxide. The two solutions were mixed immediately before use (pH approx.11) which was stable for one hour.A delivery system was also available whichconsisted of a reservoir for the solution, a heater and a pump which passed the liquid warmed to body temperature through a tube to a hand piece and an applicator tip which came in various shapes and sizes. The solution was applied to the carious lesion by means of this applicator which was used to loosen the carious dentine by a gentle scraping Application was continued until the dentineremaining was deemed sound by normal clinical tactile criteria. With suitable accessible soft lesions, after 510 minutes treatment only clinically sound dentine remained. CARISOLV Because of the time required for CMCR treatment and large volumes of solution needed and the fact that the delivery system was no longer commercially available, use of CMCR, despite its potential, became minimal.
During this time however, Medi team in Sweden continued to work on the system and the latest CMCR reagent known as Carisolv hit the headlines in January 1998. Although it is similar to the caridex and NMAB systems, it is in the form of a pink gel which can be applied to the carious lesions with specially designed hand instruments. It is marketed in 2 syringes, to be mixed prior to application. Syringe 1: 0.5% NaOCl. Syringe 2: 3 amino acids: glutamic acid, leucine lysine. NaCl. Erythosine (to make it readily visible). Carboxymethyl cellulose (for viscosity). H2O. NaOH pH 11. Mode of action Carisolv is alkaline in nature with a pH of around 11.Upon mixing, the positively and negatively charged groups of amino acids become chlorinated due to presence of NaOCl and NaOCl constituents. This leads to interaction with dentin which involves proteolytic degradation of collagen rather than demineralization of collagen, softening and removal of the carious altered dentin and preserving the sound dentin. The gel consistency allows the active molecules access to the dentin for a longer period than the equivalent irrigating solution in Caridex system. This gel also helps by lubricating the hand instrument specifically designed for Carisolv. PEPSIN-BASED CARIES EXCAVATION A new experimental gel consisting of pepsin in a phosphoric acid/sodium biphosphate buffer is being considered as an alternative chemo-mechanical caries excavation agent (SFC-VIII, 3M ESPE;Seefeld, Germany). The main advantage of this new enzyme-based solution is that it can be more specific by digesting only denatured collagen(after the triple-helix integrity is lost) than the sodium hypochlorite-based agents. According to the manufacturer, the phosphoric acid dissolves the inorganic component of carious dentin, while it at the same time gives pepsin access to the organic part of the carious biomassto selectively dissolve the denatured collagen. To avoid overexcavation, the SFCVIII gel should be used in combination with a prototype plastic instrument having hardness between that of sound and infected dentin OZONE THERAPY FOR CARIES EXCAVATION Ozone therapy is based on the promise that the primary carious lesion when exposed to ozone becomes sterile and remineralizes after some time. Principle Ozone therapy is based on the concept of complete elimination of a acidophilic bacteria, fungi and viruses and thus creating a sterile environment of remineralization to take place. It has been proven that 10 seconds of application of ozone gas at a concentration of 2200ppm could eliminate 99% of the carious micro-flora. Effect of Ozone: (On caries, plaque, saliva an dental alloys) o Ozone quickly dissipates in water and kills the microorganisms via a mechanism involving the rupture of their membrane in such lesions. Vol-1 issue-3 May-2013
oStrong oxidizer for cell walls and cytoplasmic membrane of bacteria. oLeads to oxidative decarboxylation of plaque pyruvate generating acetate and CO2 as by product. oIt oxides volatite sulphur. FLUORESCENCE-AIDED CARIES EXCAVATION (“FACE”) This technique was developed as a direct method to clinically differentiate between infected and affected carious dentin. Based on the fact that several oral microorganisms produce orange-red fluorophores as by-products of theirmetabolism (porphyrins), infected carious tissue will fluoresceespecially in the red fraction of the visible spectrumdue to the presence of proto- and meso-porphyrins. Inthis way, continuous visual detection of orange-red fluorescenceduring caries excavation was thought to be convenientfor clinicians.By feeding a slow-speed hand-piece with a fiber-optic violetlight source (370 to 420 nm) and allowing the operatorto use a 530-nm yellow glass filter, areas exhibiting orangeredfluorescence can be selectively identified and removedwith the bur.
LASER EXCAVATION The word “laser” is an acronym for “Light Amplification by Stimulated Emission of Radiation” The indications for the use of lasers in dentistryare nowadays broad, varying from caries diagnosis, disinfection of periodontal pockets or root canals, photodynamic therapy of oral tumours, soft-tissue surgery, caries removal, and cavity preparation. Especially in the field of operative dentistry, erbium lasers have been pointed out as most promising due to their specificity in ablating enamel and dentin without side effects to the pulp and surrounding tissues when the approprate parameters are employed. The erbium-loaded yttrium-aluminum-garnet (Er:YAG) and the erbium,chromium: yttrium-scandiumgallium-garnet(Er,Cr:YSGG) lasers are the two types of erbium-based devices currently available on the market.The mechanism by which enamel and dentin are removed during Er:YAG irradiation consists of explosive subsurface expansion of water interstitially trapped in the dental hard tissues. During irradiation, the water molecules absorb the incident radiation, causing sudden heating and water evaporation. As a result, a high-stream pressure is formed, inducing a violent, yet controlled expansion and ejection of dental hard tissue components.50 In contrast, the Er,Cr:YSGG laser system, usually known as a “laser powered hydrokinetic system”, delivers photons straight into an air-water spray directed to the target tissue. This phenomenon induces microexplosive forces into water droplets, which is said to contribute significantly to the mechanism ofhard-tissue removal.
It can be undertaken with a range of visible red and near infra red laser systems using low power (100mw) visible red semiconductor diode lasers and tolonium chloride and (toluidine blue) dye are now available.PAD technique has been shown to be effective for killing bacteria in complete biofilms, such as sub-gingival plaques, which are typically resistant to the action of antimicrobial agents.It can be used effectively in carious lesions, since visible red light transmits well access dentine, and can be made species specific by tagging the dye with monoclonal antibodies. Major clinical applications: Disinfection of root canals. Periodontal pockets. Deep carious lesions. Sites of peri-implantitis. Advantages: Does not give rise to deleterious thermal effects. Does not cause sensitization and killing of adjacent human cells fibroblasts, keratinocytes. Residual reactive O2 species produced by E are removed by enzyme covalance naturally present in tissue and lactoperoxidase and normal component of saliva.
CONCLUSION With the development of new dental restorativematerials and advances in adhesive dentistry, abetter understanding of the caries process and thetooth's potential for remineralization and changesin caries prevalence and progression, the management of dental caries has evolved from G.V. Black's“extension for prevention” to “minimally invasive.” Minimally invasive dentistry is based on alarge body of scientific evidence that has beensummarized and discussed. The future promisesfurther evolution toward a more primary preventive approach, facilitated by emerging technologies for diagnosis, prevention and treatment.Altogether, irrespective of the caries excavation methodchosen, it remains clinically recommended to finish the cavity margins in clean/sound tooth tissue in order to achieve the best performance of adhesives, while being at the sametime least invasive with regard to caries excavation and most conservative with regard to sound-tissue preservation.
PHOTO-ACTIVATED DISINFECTION ( PAD) Low power laser energy in itself is not particularly lethal to bacteria but is useful for a photochemical activation of oxygen releasing dyes. Singlet oxygen released from the dies causes membrane and DNA damage to microorganisms. Vol-1 issue-3 May-2013
REFERENCES 1.Ahmed AA, Garcia-Godoy F, Kunzelmann KH. Self-limiting caries therapy with proteolytic agents. Am J Dent 2008;21:303-312. 2.Alfano RR, Yao SS. Human teeth with and without dental caries studied by visible luminescent spectroscopy. J Dent Res 1981;60:120-122 3.Allen KL, Salgado TL, Janal MN, Thompson V. Removing carious dentinusing a polymer instrument without anesthesia versus a carbide bur withanesthesia. J Am Dent Assoc 2005;136:643-651. 4.Aoki A, Ishikawa I, Yamada T, Otsuki M, Watanabe H, Tagami J, Ando Y, Ya-mamoto H. Comparison between Er:YAG laser and conventional techniquefor root caries treatment in vitro. J Dent Res 1998;77:1404-1414. 5.Armengol V, Jean A, Rohanizadeh R, Hamel H. Scanning electron microscopic analysis of diseased and healthy dental hard tissues after Er:YAGlaser irradiation: In vitro study. J Endod 1999;25:543546. 6.Arnold WH, Konopka S, Gaengler P. Qualitative and quantitative assessment of intratubular dentin formation in human natural carious lesions.CalcifTissInt 2001;69:268-273. 7.Bachmann L, Diebolder R, Hibst R, Zezell DM. Changes in chemical composition and collagen structure of dentine tissue after erbium laser irradiation. SpectrochimActa A 2005;61:2634-2639. 8. Banerjee A, Kidd EA, Watson TF. In vitro evaluation of five alternativemethods of carious dentine excavation. Caries Res 2000;34:144-150. 9. Banerjee A, Kidd EA, Watson TF. Scanning electron microscopic observations of human dentine after mechanical caries excavation. J Dent2000;28:179-186. 10.Banerjee A, Watson TF, Kidd EA. Dentine caries excavation: A review ofcurrent clinical techniques. Br Dent J 2000;188:476-482. 11.Barwart O, Moschen I, Graber A, Pfaller K. Invitro study to compare the efficacy of N-monochloro-D, L-2-aminobutyrate (NMAB, GK-101E) and waterin caries removal. J Oral Rehab 1991;18:523-529. 12.Bayne SC, Thompson JY, Studervant CM, Taylor DF. Instruments andequipment for tooth preparation. In: Roberson TM, Heymann HO, Swift-JrEJ (eds). Studervant's Art & Science of Operative Dentistry. St. Louis:Mosby, 2002:307-344. 13.Beeley JA, Yip HK, Stevenson AG. Chemo-mechanical caries removal: A review of the techniques and latest developments. Br Dent J2000;188:427-430. 14.Bjorndal L, Thylstrup A. A structural analysis of approximal enamel carieslesions and subjacent dentin reactions. Eur J Oral Sci 1995;103:25-31. 15.Black GV. Cavity preparation. In: Black GV (ed). A work on operative dentistry. Chicago: Medico-Dental Publishing Company, 1908:105-116. 16. Black RE. Technique for non-mechanical preparation of cavities and prophylaxis. J Am Dent Assoc 1945;32:955-965.
Vol-1 issue-3 May-2013
Prosthodontic considerations in periodontally compromised dentition
DrAparna Mohan1, DrAnuroopa A.2, Dr James Rex3 1
Senior Lecturer,2& 3Reader, Department of Prosthodontics, SMIDS,
A systematic approach
Rehabilitation of periodontally compromised dentition requires a multidisciplinary approach where in a periodontist,an endodontist and a maxillofacial prosthodontist goes hand in hand for a successful treatment.
Prosthetic rehabilitation of periodontally compromised
The goal of every dentist is to restore the carious or missing dentition with fixed partial denture which is biologically acceptable to the gingival tissues.The dental surgeon will always face difficultieswhile managing a periodontally compromised dentition due to its weak nature and complexity.In this article we discuss the various treatmentmodalities for a periodontallycompromised dentition and the modification needed to be done while treating a weak abutment teeth.
dentition facilitates improvement in esthetics as well as function while splinting of these teeth also enhances the support through
distribution of masticatory forces. The
various treatment procedures done for a periodontally compromised dentition can be dealt under two headings, (A) the pre-prosthodonticperiodontalprocedures which includes periodontal procedures done prior to definitive prosthodontic
prosthodonticmodifications done while restoringa periodontally compromised dentition.
A) ROLE OF PERIODONTAL PROCEDURES IN PROSTHODONTICS
Interdisciplinary approach, Perio-prostho relationship,Knife edge finish line.
Mucogingival Surgery Muco-gingival surgery is one of the most common surgical procedure done for the coverage of denuded roots, to increase attached gingival and to create adequate vestibular depth. The various techniques to increase attached gingivaare the free gingival autografts and apical displacement flap surgeries which not only
improves the esthetics but also the function of the abutment
Dentistry has moved into a new era in which it can no
teeth (Figure-1 and 2).
longer be practiced as a secluded specialty. In order to satisfy the needs of the patients a team approach is preferred where in multiple specialties
pool in over an
individualapproach. Likewise, thevarious periodontal aspects to be considered in designing a prosthesis is dealt as â€œPeriodontal Restorative Inter-relationshipâ€?.
Root Coverage Surgery As the name implies, this technique isrecommended for the coverageof root of the abutment teeth. There are mainly two techniques for this and they are Langer's technique,wherein a connective tissue graft is used under a partial thickness flap and Tarnow technique which utilizes a semi-lunar coronally displaced flap. Vol-1 issue-3 May-2013
A ) P R O S T H O D O N T I C M O D I F I C AT I O N O F T H E RESTORATION IN PERIODONTALLY COMPROMISED DENTITION
A periodontally compromised dentition should be restored with extreme care and precision. In such cases a metal margin finishing is preferredover ceramic or acrylic veneering as the polished surface of the metal reduces theaccumulation of plaque and pathogenic micro-organism.It is indicatedin cases with severe cervical erosion, in extensive restorations or caries extending beyond gingival crest, in short clinical crowns andin persistent root sensitivity. In such cases a subgingival margin should be prepared with extreme care. When the intracrevicular margins are adjacent to thin gingiva on the root, special care should be given so that the sulcular contours of the artificial crown should be flat, mimicking the shape of the root. The gingiva adjacent to a flat root surface develops a thick free gingival margin when the underlying bone is thick. In these situations it may be advisable to create a thicker intra-crevicular crown contour similar to that of a natural crown
Crown Contour - In an abutment teeth with
involvement and Grade I or early Grade II mobility a full coverage restoration is indicated. Theprinciples of tooth preparation are same as that for a normal tooth except that the preparation has to be fluted or barreled into anatomic 1
Crown Lengthening Procedures Intooth witha short
depressions following the exact contour of the root. On the
clinical crown, it is necessary to increase the size of the
crown, the plaque retention is on the buccal and lingual surfaces
clinical crownto enhance the retention of a cast
occuring primarily at the infra-bulge area of the tooth. Hence
restoration. This is done with an apically displaced
reduction or elimination of infra-bulge is indicated to reduce
flap and ostectomy.
plaque retention.There are various theories of crown contour 2
Ridge Augmentation Procedures - Ridge
put forward to discus this aspect and they areThe Gingival
augmentation procedures are done to correct excessive
Protection Theory, The Gingival stimulation theory, The
loss of alveolar bone that most commonly occurs in the
Muscle action theory andThe Theory of access for oral hygiene.
anterior region as a consequence of advanced
Embrasure - Another most commonclinical scenarioin
periodontal disease.This is managed either by the
periodontally compromised teeth is an open embrasure which
placement of a thick mucosal autograft obtained from
results in horizontal food impact leading to halitosis.It also acts
palate or tuberosity or by placement of non-porous
as anidus for growth of microorganism.In such cases the teeth
dense hydroxyl-apatite under a split thickness flap or a
may be reshaped with a restorations or crown to relocate
pouch created under a full thickness flap and/or a
gingival embrasures close to the new level. The proximal
double flap technique used in conjunction with
surfaces are recontoured and broadened so that the contact areas
are apically repositioned. Vol-1 issue-3 May-2013
But if the proximal contact area is excessively broad andmade
It is contraindicated in patients with gingivitis and early
bulky in restoration,it will result incrowding out the gingival
or moderate periodontitis and Lindhe's situation III.
papillae in the cervical region. This can make oral hygiene
Splints are broadly classified in to temporary or
difficult resulting in gingival inflammation and attachment
reversible splints or provisional and permanent splints.
Reversible splints includethe ligature wire splint,
Contact Area-Contact area of the teeth also changes in patients
circumferential wiring splint, bonded splints and
with periodontally compromised dentition.Itshould be directed
removable appliances splint. Removable appliance
incisal or occlusal and buccal in relation to the central fossa,
splints are the Hawley's Retainer, a continuous clasp
except in connector between maxillary first and second molars
RPD and swing-lock RPD.Permanent splints fabricated
Pontic Design - Like a crown contour,pontics not only follows
after completion of the periodontal therapy can be a
all design principle but also some additional points associated
telescopic prosthesis , fixed partial denture with non
with the contour of the tissue facing surfaces. In the mandibular
rigid connector, fixed partial denture with rigid
posterior region where esthetics is not a major consideration, a
connectors, Maryland splints and long span fixed partial
spheroidalpontic is the design of choice.. A spheroidalpontic
denture with cross arch stabilization .(figure-3)
contacts the ridge without pressure the tip of the ridge or the buccal surface. In the maxillary posterior area, the modified ridge lap satisfies both esthetics and hygiene. Mandibular anterior area also requires a ridge lap design. When there is excessive bone loss and a rigid connector in a non-esthetic posterior region, the pontic is not required to touch the ridge. There should be at least 3mm of space so that the patient can maintain hygiene. In non esthetic posterior areas, when there is excessive bone loss, pontic is not required to touch the ridge. Occlusion7 -A freedom in centric occlusion with even contact in anterior as well as posterior region with anterior guided occlusion is the preferred occlusion in a periodontally compromised dentition. The occlusal forces should be guided in axial direction and the steepness of the cuspal inclines should be reduced with minimum over jet and overbite in the anterior teeth. During lateral excursion there should not be any contacts in cantilevers. 8
Provisional Restoration - The interim restoration should behave a fit, polish and contour as for the final restoration. Long term temporary restoration if indicated should be definitely fabricated in heat cure acrylic material. SplitningAs Part Of Periodontal Therapy9-Splinting refers to joining together of two or more teeth for stabilization. It is done to protect teeth with mobility, to distribute occlusal forces of teeth weakened by loss of periodontal support and to prevent natural tooth from migration.Splinting is indicated in Lindhe's class IV and V.
MANAGEMENT OF HEMISECTIONED TOOTH12 Hemisection is defined as a surgical separation of a multi-rooted tooth through the furcation area in such a way that a root or roots may be surgically removed along with the associated portion of the crown. In mandibular molars, there are three option and they are as follows : (1)Mesial root with crown removed while retaining the distal root and crown,(2) mesial root with crown retained wherein distal root and crown is removed and (3) both crown and root are separated but retained. Vol-1 issue-3 May-2013
In a hemi-sectioned mandibular tooth an intra-
Major connectors in a cast partial denture should not
crevicular margin should be given to cover portions of the root
impinge the free gingival margins. It shouldbe placed
resected. The margin should be apical to pulp chamber floor
6mm away from the gingival margin. When periodontally
andnot closer that 3mm without interfering the biologic
compromised mandibular anterior teeth require
width. A knife edge finish line or chamfer is the finish line of
stabilization, a special design of major connector can be
choice. If hemisection is done to molar and both the sections
used for splinting teeth together where a lingual plate
are retained, then individual crown with both units soldered
should extend to the middle third of the surface of the
together is the ideal treatment option. If only one root is
mandibular anterior teeth or a double lingual bar is
retained after hemisection, then it can be restored with a single
preferred treatment of choice.
crown or can be also be used as an abutment for short span
three or four unit FPD. If hemisection is done in maxillary
Teeth preserved by periodontal therapy should be
molar,then it is called skyfurcation. There are three from of
restored with cast restoration for its normal function.
hemi-section in maxillary first molar and they are as follows-
Success of a periodontally weakened teeth lies on
Distobuccalhemisection, mesiobuccalhemisection and
rehabilitating it with an occlusal scheme which improves
palatal hemisection. Mesiobuccal root is most commonly
its stability and designing a prosthesis which favors the
removed while the palatal root is retained. If the palatal
esthetics and function. Hence an interdisciplinary
section is retained and FPD used as abutment, then the
approach is essential in treating a periodontally
emergence profile should be made flat with slight lingual flare
compromised dentition wherein a periodontist saves the
teeth and a prosthodontist restores its function. REFERENCES
PERIODONTAL PROCEDURES IN REMOVABLE PROSTHESIS
In patients with partially edentulous situation with periodontally compromised dentition, the various treatment options are the periodontal prosthesis, swing lock cast partial denture and the conventional cast partial denture. The components of the partial denture should be placed without affecting the periodontal health of the abutment teeth. damaged endodontically treated teeth- a clinical report.LecistaRomana De Stomatologievol VI 2010, 156159.Among direct retainers, anI-bar type of clasp has little or no detrimental effect of periodontal health. This design utilizes a gingivally approach clasp, mesially positioned occlusal rest and a proximal plate. Any direct retainer should be passive and exert no force on teeth when the partial denture is at rest. An occlusal rest should be designed so that the occlusal forces are directed along the vertical axis of the tooth. The angle formed by the occlusal rest and the vertical minor connector should be less than 90째. By doing this, the occlusal
1.Newman, Takei, Klokkevold, Carranza. Carranza's clinical periodontology. Tenth edition. Reed Elsevier India private limited, Noida. 2.Rosensteil 3.W. F. P. Malone, D.L.Koth. Tylman's theory and practice of fixed prosthodontics. Eighth edition.Ishiyaku Euro America, Inc. Publishers. Tokyo. St. Louis. 4.Herbert. T.Shillingburg. Fundamentals of fixed prosthodontics, Third edition. Quintessence publishing, IL. 5.Behrand D, Cerammometal restoration with supra-gingival margins. JPD; 1982:47, 625 6.Becker M.C. et al, Current theories of crown contours margin placement and pontic design. JProsthetDent;1981: 45: 268-271. 7.Dawson. 8.Yuodelis, R A. Faucher R; Provisional restorations; an integrated approach to periodontics and restorative dentistry, Dent Clin North Am.1980: 24(2) 285-303. 9.Kegel W, SelipskyH and Phillips C . The effect of splinting on tooth mobility during initial therapy, J of clinical Periodontal.1979: 6;45-58. 10.Gordon T telescope reconstruction;An approach to oral rehabilitation. J A D A 1966, 72,97-105. 11.Kourkouta. S,Hemmings. K.W, Laurd .L, restoration of periodontallly compromised dentition using cross arch bridges. Principles of perio-prosthetic patient management. BDJ 2007.4. 189-195 12.Appleton IE ; Restoration of root resected teeth. J Prosthet dent 1980; 44; 150-153. 13.Periodontal consideration in removable treatment , a review of literature. Haralambor Petridis, Timothy J Hempton, Int J Prosthodont 2001; 14:164- 172. 14.UmutCakan, BulemYuzugullu.prosthodontic and periodontal reconstruction .
forces are directed along the long axis of the abutment teeth. Vol-1 issue-3 May-2013
of Our Speciality A STUDY
Dr Ramandeep Singh Bhullar, 3 DrS.Ram Kumar, Dr Nanda Kumar, 4 Prof C Ravindarn
1)Reader, Department of Oral and Maxillofacial surgery, Sri Guru Ram Das Institute of Dental sciences and Research, Sri Amritsar. 2) & 3)Professor, 4) Professor and Head Department of Oral and Maxillofacial surgery, Sri Ramachandra Dental College,Chennai- 600116
Abstract Although there is no supporting evidence there is a perception that public is unfamiliar with what an oral and maxillofacial surgery is and what an oral and maxillofacial surgeon does? The purpose of this study was to evaluate through a survey the level of awareness among general public and health care professionals of the proper providers of treatment for the maxillofacial region and their level of knowledge of the specialty of oral and maxillofacial surgery The results showed that little above 70%of medicos and almost all of the dentists were aware of the specialty, but the response from public was only 52%. The name of the speciality was well understood by the health care professionals but not by 48% of the general public .The study showed that one half of the public is still unaware with what an oral and maxillofacial surgery is and what an oral and maxillofacial surgeon does.
Key words Oral&Maxillofacial surgery ,Public awareness,Survey
Materials and Methods:
Despite all the progress that has occurred in the speciality of oral and maxillofacial surgery majority of the population is still unaware of the speciality and what its practitioners do. This was supported by studies in British literature in 1996 and 19942,3. The survey showed that medical and dental practitioners have heard of the speciality but they were not fully aware of what was the scope of oral and maxillofacial surgeon. More than half of the general public was not aware of the speciality named oral and maxillofacial surgery.Ever since the change in the name of the specialityfrom “oral surgery” to “oral and maxillofacial surgery” in 1977, there has been concern whether public understands the meaning of the name Although it accurately describes the anatomic region and scope of treatment provided by its practitioners, the term maxillofacial not only is difficult to pronounce but it may not be the one with which they are not familiar. According to a survey published in 2002, speciality designation identification rate for OMFS was 77% in Virginia Common Wealth University Richmond1. Therefore this study was designed to provide an answer to question regarding recognition and scope of oral and maxillofacial surgery among Indian population
A questionnaire was designed for the purpose of this study. Questionnaire was divided into two parts, part 1had three questions asking the opinion of the responder a) whether they have heard the name of this speciality, b) they understand the name and c) the basic qualification of oral and maxillofacial surgeon, Part 2 had 15 specific condition in which responders were asked to choose whether maxillofacial surgeon has role in treatment of these conditions or not .the study included five different groups general public, medical practitioners, medical students, dental practitioners and dental students. Total of 600 survey sheets were sent and maximum of 100 responses per group were considered. Vol-1 issue-3 May-2013
Whether OMFS has role intreatment of these conditions? General Medical Medical Dental Public Students Practitoners Students Oral cancer 42 73 68 83 Dental problems 34 79 79 92 Cuts on face 25 49 66 59 Neck surgery 17 00 26 90 Orbital injuries 17 19 33 Cleft lip and palate 37 30 63 71 Brain injuries 00 00 07 00 Wisdom teeth removal 59 54 75 81 Sports injuries 37 75 84 85 Sinusitis 09 00 10 21 Acne, moles and warts 09 19 10 Malpositioned jaws 50 52 72 81 Cosmetic surgery 25 52 70 85 Dental implants 42 52 72 85
Dental Practitoners 92 98 76 64 23 56 72 00 100 74 42 23 10 64 48 82
Table I: values show percentage and responders opinion whether maxillofacial surgeon has a role in treatment of these specific conditions, the values shows the positive response which indicates that maxillofacial surgeon has a role in treatment of these conditions
Discussion: This survey demonstrated that almost all of dental practitioners, majority of medical practitioners and half of public were aware of speciality named oral and maxillofacial surgery. Medical professionals were not aware of the wide scope of oral and maxillofacial surgeon. Public has little knowledge about scope of oral and maxillofacial surgery. This might be attributed to long and complicated name of speciality. There is a tremendous overlap between the speciality of ENT, plastic surgery and OMFS, with no definitive procedure to each speciality. Each surgeon is credentialed for a surgical procedure on his or her level of training and expertise in general the survey demonstrated that public does not recognize the role of maxillofacial surgeon in cosmetic surgery, cleft lip and palate surgery and neck surgeries. General public would prefer the services of maxillofacial surgeon in treating the fracture of jaws, removal of wisdom tooth
However it appears that greater progress must be made in education of medical students and more importantly general public, if the speciality of oral and maxillofacial surgery is to be practiced in its full scope. Conclusion: Despite all the progress that has occurred still a large portion of our population is still unaware of the speciality. If the patients are to receive the best treatment available it is essential to educate health care consumers and providers about the different specialities available and their role within health profession. References: 1.Daniel M Laskin, John A Ellis, Al M Best; Public recognotin of speciality designations. Of oral MaxillofacSurg 60:1182-1185, 2002. 2.Hunter J M, Rubiaz T, Rose L; Recognition of the scope of oral and maxillofacial surgery by the public and health professionals. J Oral maxillofacSurg 54: 1227, 1996. 3.Ameerally P, Fordyce AM, Marin IC; So you think they know what we do, The public and professional perception of oral and Maxillofacial Surgery. Br J Oral Maxillofacial Surg 32: 142,1994.
This survey was conducted in the department of oral and maxillofacial surgery Ramachandra medical college and research institute Chennai. Therefore the results may not be applicable in other parts of the country. Vol-1 issue-3 May-2013
Antioxidants and it’s role in Oral Cancer A review 1. A. Sri Kennath J Arul (MDS., MBA.,) Professor (Oral and Maxillofacial Pathology), Best Dental Science College, Madurai, Tamil Nadu, India 2. A. Sri Sennath J Arul (MBBS., MD.,) Medical Practitioner, Tamilnadu, India.
3. Sonika Verma (MDS) Senior Lecturer, Oral Pathologist, India.
4. Rashmika Verma, (BDS) Dental Surgeon, Rotorua, New Zealand
Abstract Reactive oxygen species have emerged as the major final common pathway of tissue injury and that failure to counter their deleterious effects increases the likelihood of developing degenerative diseases. It is clear that cells require an effective defense against such oxidative stress and an important line of defense is provided by antioxidants. Further, the role of oxidative damage in carcinogenesis is increasingly being speculated. Cancer causation is linked experimentally and clinically to cellular and DNA damage by oxidants, and therefore antioxidants may properly be viewed as potentially reducing the risk of cancer. With the aforementioned in mind, the aim here is to briefly discuss antioxidants, with emphasis on its role in oral cancer.
Key words Reactive oxygen species, antioxidants, oxidative stress, oral cancer
Introduction A paradox in metabolism is that while the vast majority of complex life requires oxygen for its existence, oxygen is a highly reactive molecule that damages living organisms by producing reactive oxygen species. Reactive oxygen species (ROS) is a collective term used by biologists to include not only the oxygen centered radicals (nascent oxygen, superoxide and hydroxyl) but also some nonradical derivatives of oxygen such as hydrogen peroxide, hypochlorus acid and ozone. The cells of the body are constantly exposed to endogenous as well as exogenous oxidants. The exposure to oxidants is by patho-physiological conditions like inflammation, ischemia or reperfusion injuries and external factors like tobacco, radiation or alcohol etc.
This increases the intracellular level of ROS or oxidative stress; that can produce major interrelated derangements of cell metabolism, including DNA strand breakage (often an early event), raises intercellular calcium, damages membrane ion transporters and/or other specific proteins, and cause peroxidation of lipids. Indeed in most human diseases, oxidative stress is a secondary phenomenon, a 1 consequence of the disease activity. This oxidative damage/stress, associated with ROS is believed to be involved not only in the toxicity of xenobiotics but also play patho-physiological role in ageing of skin and several diseases like atherosclerosis, cataract, cognitive dysfunction, cancer (neoplastic diseases), diabetic retinopathy, critical illness such as sepsis and acute respiratory distress syndrome, shock, chronic inflammatory diseases of the gastrointestinal tract, organ dysfunction, disseminated intra-vascular coagulation, deep injuries, respiratory burst inactivation of the phagocytic cells of immune system, production of nitric oxide by the vascular endothelium, ischemia/reperfusion injury and release of iron 2 and copper ions from metalloproteins. To protect the cells and organ systems of the body against ROS, a highly sophisticated and complex antioxidant protection system has been evolved that includes a variety of components both endogenous and exogenous in origin; that function interactively and synergistically to neutralize free radicals. These include: nutrient-derived antioxidants, antioxidant enzymes and metal binding proteins. The various defenses are complementary to one another because they act on different oxidants or in different 3 cellular compartments. The aim of the present article is to briefly discuss antioxidants, with emphasis on role of antioxidants in oral cancer. Antioxidants are the substances or agents that scavenge reactive oxygen metabolites, block their generation or enhance endogenous antioxidant capabilities. They are named so because of their ability to combat oxidation.4 According to the mode of action, antioxidants can be 4,5 grouped into: a)Scavenging antioxidants: They prevent oxidative stress by literally scavenging radicals as they form. Vitamins like C, E, carotenoids and curcumin are scavenger molecules. b)Preventive antioxidants: They function largely by sequestering transition metal ions and preventing Fenton reactions, they are therefore largely proteins by nature e.g: transferrin, lactoferrin, ceruloplasmin, and desferrioxamine. c)Enzyme antioxidants: They function by catalyzing the oxidation of other molecules e.g. superoxide dismutase, glutathione peroxidase and catalase. According to the type, antioxidants can be grouped into:3,6 a)Enzymatic: Superoxide dismutase (SOD), Catalase, Glutathione peroxidases, Glutathione transferase and Peroxidase. b)Non-Enzymatic: Nutrient (-Tocopherol, -Carotene, Ascorbate, Glutathione, Selenium)Non-nutrient (Ceruloplasmin, Transferrin, Uric acid, Peptides) Vol-1 issue-3 May-2013
Role of Antioxidants in Oral Cancer: Oral cancer is one of the 10 most frequent cancers worldwide, with about three quarters of all cancers occurring in th developing countries. It represents the 5 most common cancer in the world. There is a striking difference in the incidence and the mortality rates across the world, with highest rates generally registered in a few developing countries including India, Pakistan and Bangladesh, where this is the most common form of cancer. On the basis of cancer registry data, it is estimated that annually about 1,20,000 new oral cancer cases develop in India. The role of oxidative damage in carcinogenesis is increasingly being speculated. Cancer causation is linked experimentally and clinically to cellular and DNA damage by oxidants, and therefore antioxidants may properly be viewed as potentially reducing the risk of cancer.7 Ames suggested that antioxidants are capable of producing cancer regression, inhibition of metastasis and 8 9 prevention of carcinogenesis. According to Shklar, antioxidants have the ability to destroy cancer cells through three major mechanisms. a) Immuno-enhancement: In normal human beings, the development of cancer cells stimulates a potent immune response that locates the cancer cells and destroys them. Signals produced by the developing cancer cells are interpreted by the host's immune system. The immune cells are capable of elaborating cytotoxic chemicals that can infiltrate and destroy the cancer cells. The cytotoxic chemicals include: tumor necrosis factor- (TNF-), carried by macrophages and mast cells; tumor necrosis factor- (TNF-) carried by lymphocytes. b) Molecular Genetic pathway: Antioxidant nutrients can: a) Enhance the expression of wild type p53, which is a wellknown cancer suppression gene product b) Diminish the expression of mutant p53, which is the oncogene expressed in a large number of malignant tumors. c) Angiogenesis inhibition: Proliferating cancer cells produce cytokines or chemical mediators and stimulate the proliferation of endothelial cells to form an extensive vascular supply to nourish the developing tumor. If the blood supply to the tumor does not develop, the tumor growth would be sufficiently inhibited. Antioxidants stimulate cellular differentiation and prevent development of such blood supply. Role of carotenoids: Carotenoids are a family of antioxidant phytonutrients including alpha carotene, beta carotene, lutein and lycopene. The antioxidant actions of carotenoids are based on their singlet oxygen quenching properties and their ability to trap peroxyl radicals, scavenge free radicals and protect the cell membrane lipids from the harmful effects of oxidative degradation. The quenching involves a physical reaction in which the energy of the excited oxygen is transferred to the carotenoid, forming an excited state molecule.
The ability of â-carotene and other carotenoids to quench excited oxygen, however, is limited, because the carotenoid itself can be oxidized during the process. This is known as auto-oxidation. This is dose-dependent and dependent upon oxygen concentrations. At higher concentrations, it may function as a pro-oxidant and can activate proteases. â-Carotene is also scavenger of peroxyl radicals, especially at low oxygen tension. Carotenoids act as antioxidants by reacting more rapidly 10 with peroxyl radicals than do unsaturedacyl chains. Vitamin A: The role of vitamin A in epithelial differentiation was first demonstrated in 1925 when squamous metaplasia was reported in vitamin A deficient rats. The first study that associated vitamin A deficiency with cancer appeared in 1941.11,12 In laboratory studies, the carotenoids have been shown to have anti-mutagenic activity in bacterial systems. In many cell culture systems, carotenoids prevent transformation induced by chemicals and radiation.The mechanism involved in cancer inhibition by these agents has not yet been determined; but they produce effects on cell differentiation; immunologic function; interaction of cells with growth factors, such as epidermal growth factor; and changes in gene expression. Such mechanism may be important in their anticarcinogenic 13 activity. Suda et al showed that the topical administration of â-carotenoids reduced the number and size of carcinomas in hamsters that had been exposed to topical 14 7,12-dimethylbenz (a) anthracene (DMBA). Others also have shown a decreased incidence and severity of DMBA-induced tumors with the use of beta carotenoid supplements.15 Lycopene: Lycopene is a carotenoid without provitaminA activity and one of the most potent antioxidants and has been suggested to prevent carcinogenesis by protecting critical biomolecules including lipids, low-density lipoproteins (LDL), proteins and DNA. Lycopene, because of its high number of conjugated double bonds, exhibits higher singlet oxygen quenching ability 16 compared to â-carotene or á-tocopherol. Lycopene is highly lipophilic and is most commonly located within cell membranes. It is therefore expected that in the lipophilic environment, lycopene will have 17 maximum ROS scavenging effects. Lycopene was shown to be the most effective antioxidant in protecting the 2,29-azobis 2,4-dimethylvaleronitrile (AMVN)induced lipid peroxidation of the liposomal membrane. It was also found to protect lymphocytes against NO2induced membrane damage and cell death twice as efficiently as â-carotene.18 Levy et al showed that lycopene inhibited the growth of human endometrial, mammary and lung cancer cells grown in cultures and was more effective than âcarotene.19
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LaVecchia C, suggested that the Mediterranean diet, which is rich in fruits and vegetables, including tomatoes, could be responsible for the lower cancer incidences in that region.20 Dorgan JF et al,in a recent case-control study from the Breast Cancer Serum Bank in Columbia, Missouri, concluded that only serum lycopene and none of the other antioxidants showed a significant inverse relationship with breast cancer risk.21 Agarwal S and Rao AV, in their studies involving healthy human subjects in their laboratory indicated that lycopene from traditional tomato products was absorbed readily, increased serum levels and lowered oxidative damage to lipids, lipoproteins, proteins and 16 DNA. Kucuk O et al, suggested that tomato extract supplementation in the form of capsules lowered the PSA 22 levels in prostate cancer patients. Role of Vitamin C: Vitamin C, a potent, water-soluble antioxidant, has been known as an essential micronutrient since the late 1700s, when the British Navy supplemented the diet of their sailors with citrus fruits to prevent 23 scurvy. As an antioxidant, it scavenges free radicals and reactive oxygen molecules, which are produced during metabolic pathways of detoxification.24 Vitamin C's antioxidant mechanisms help to prevent cancer in several ways. It combats peroxidation of lipids that are linked with ageing process and degeneration. In elderly people, it was found that administration of 400 mg of vitamin C/day for a period of one year was associated with reduced serum lipid peroxide levels. Vitamin C can work to protect DNA from damage caused by free radicals. It arrests harmful effects by stimulating detoxifying enzymes in the liver. It blocks the formation of fatal antigens, decreasing the risk of cancers of oral cavity, larynx, esophagus, lung, pancreas, stomach, colon and rectum, breast, ovary, endometrium and prostrate. It has been shown that a low intake of L-Ascorbic Acid (L-AA) is associated with an increased risk of cancers of the stomach, esophagus, oral cavity, larynx, and cervix. The association between L-AA and oral carcinoma is based solely on dietary assessments that have concluded that an increased risk was present when fruit and vegetable intake was low.25 Role of Vitamin E (รก-Tocopherol): Vitamin E occurs in nature in eight different forms, which differ greatly in their degree of biological activity and is the major lipid soluble antioxidant found in cells. Vitamin E is more appropriately described as an antioxidant than a vitamin. This is because, unlike most vitamins, it does not act as a co-factor for enzymatic reactions. It is a chain breaking antioxidant i.e. it is able to repair oxidising radicals directly, preventing the 26,27 chain propagation step during lipid peroxidation.
References: 1.Young IS and Woodside JV. Antioxidants in health and disease. J Clin Pathol 2001; 54:176- 86. 2.Halliwell B, Gutteridge JMC. In: Free radicals in Biology and Medicine. 2nd ed.1989: p89-98. 3.Langseth L. Oxidants, antioxidants, and disease prevention. ILSI Europe concise monograph series 1995:4. 4.Rangan U, Bulkley GB. Prospects for treatment of free radical-mediated tissue injury. Br. Med. Bulletin 1993;49:700-18. 5.Ames BN, Shigenaga MK, Hagen TM. Oxidants, antioxidants, and the degenerative diseases of aging. Proceedings of the National Academy of Sciences 1993;90:7915-22. 6.Agarwal S, Sohal RS. Relationship between aging and susceptibility to protein oxidative damage. Bioche Biophys Res Commun 1993;194:1203-6. 7.Percival M. Antioxidants. Clinical nutrition insights. NUT031 1/96 Rev. 10/98.p 1-4. 8.Ames BN. Dietary carcinogens and anticarcinogens. Oxygen radicals and degenerative diseases. Science 1983;221:1256-64. 9.Shklar G, Schwartz J. Tumor Necrosis factor in experimental cancer regression with alphatocopherol, beta-carotene, canthaxanthin and algae extract. Eur J Cancer Clin Oncol 1998;24:839-50. 10.Miller NJ, Sampson J, Candeias LP, Bramley PM, Rice-Evans CA. Antioxidant activities of carotenes and xanthophylls. FEBS Lett. 1996;384:240-2. 11.Lippman SM, Kessler JF, Meyskens FL Jr. Retinoids as preventive and therapeutic anticancer agents (Part I). Cancer Treat Rep 1987;71(4):391405. 12.Halter SA. Vitamin A: Its role in the chemoprevention and chemotherapy of cancer. Hum Pathol 1989;20:205-9. 13.Bertram JS, Peng A, Rundhaug JE. Carotenoids have intrinsic cancer preventive action. FASEB J 1988;2:1413A 14.Suda D, Schwartz J, Shklar G. Inhibition of experimental oral carcinogenesis by topical beta-carotene. Carcinogenesis 1986;7:711-5. 15.Das U. A radical approach to cancer. Medical Science Monitor 2002;8(4): RA 79-92. 16.Agarwal S, Rao AV. Tomato lycopene and low density lipoprotein oxidation: a human dietary intervention study. Lipids 1998;33:981-4. 17.Rao AV. Bioavailability and in-vivo antioxidant properties of lycopene from tomato products and their possible role in the prevention of cancer. Nutr Cancer 1998;31:199-203. 18.Agarwal S, Rao AV. Tomato lycopene and its role in human health and chronic diseases. CMAJ 2000;163(6):739-44. 19.Levy J, Bosin E, Feldmen B, Giat Y, Miinster A, Danilenko M et al. Lycopene is a more potent inhibitor of human cancer cell proliferation than either รก-carotene or ร-carotene. Nutr Cancer 1995;24: 257-66. 20.LaVecchia C. Mediterranean epidemiological evidence on tomatoes and the prevention of digestive tract cancers. Proc Soc Exp Biol Med 1997;218:125-8. 21.Dorgan JF, Sowell A, Swanson CA, Potischman N, Miller R, Schussler N et al. Relationship of serum carotenoids, retinol, รกtocopherol, and selenium with breast cancer risk: results from a prospective study in Columbia, Missouri (United States). Cancer Causes Control 1998;9:89-97. 22.Kucuk O, Sakr FH, Djuric Z, Li YW, Velazquez F, Banerjee M, et al. Lycopene supplementation in men with prostate cancer (PCa) reduces grade and of preneoplasia (PIN) and tumor, decreases serum prostate specific antigen and modulates biomarkers of growth and differentiation [abstract P1.13]. International Conference on Diet and Prevention of Cancer; 1999 May 28-June 2; Tampere, Finland. 23.Friedrich W. Vitamins. New York. Walter de Gruyter Publishing 1988; 3rd Ed. 992 - 1012. 24.Carr AC, Frei B. Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans. Am J Clin Nut 1999;69:1086-107. 25.Ames BN, Shigenaga MK, Hagen TM. Oxidants, antioxidants, and the degenerative diseases of aging. Proceedings of the National Academy of Sciences 1993;90:7915-22. 26. Brigelius-Flohe R, Traber MG. Vitamin E: Function and Metabolism. FASEB J 1999:13:1145-55. 27.Brigelis-Flohe R, Kelly F, Salonen J, Neuzil J, Zingg J, Azzi A. The European Perspective On Vitamin E : Current Knowledge And Future Research. Am J Clin Nut. 2002;76:703-16. 28.Shklar G, Schwartz J, Grau D, Trickler DP, Reid S. Prevention of experimental cancer and immunostimulation by vitamin E(immunosurveillence). J Oral Pathol Med 1990;19:60-4. 29.Gridley G, McLaughlin JK, Block G, Blot WJ, Gluch M, Fraumeni JF Jr. Vitamin supplement use and reduced risk of oral and pharyngeal cancer. Am J Epidemiol 1992; 135:1083-92.
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