International Dentistry Australasian Edition - Vol. 13, No. 2 - 2018

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VOL. 1 3 NO. 2 IN THIS ISSUE

Akila S. Vithanage, Roy George, Laurence J Walsh Misadventure and accidents in endodontics: An Australian perspective Sanzio Marques Restoration of occlusal cavities in the posterior dentition with Admira Fusion Peter Raftery Clinical opinion - modern dental anaesthesia Tif Qureshi A quick, durable smile makeover Cornelis H Pameijer and Osvaldo Zmener Adhesive dentistry meets restorative dentistry and endodontics – part one Julia BuĚˆhler Step by step from VITA ENAMIC blank to inlay Carsten Fischer Press for success using an extraordinary combination of strength and aesthetics

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Contents Volume 13 No. 2

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Clinical Misadventure and accidents in endodontics: An Australian perspective Akila S. Vithanage, Roy George, Laurence J Walsh

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Case Report Restoration of occlusal cavities in the posterior dentition with Admira Fusion Sanzio Marques

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Clinical Clinical opinion - modern dental anaesthesia Peter Raftery

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Clinical A quick, durable smile makeover Tif Qureshi

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Clinical Adhesive dentistry meets restorative dentistry and endodontics – part one Cornelis H Pameijer and Osvaldo Zmener

Interview Step by step from VITA ENAMIC blank to inlay Julia Bühler

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Case Report Press for success using an extraordinary combination of strength and aesthetics Carsten Fischer

58 Products

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Henry Schein Halas wins 2018 Australian Dental Industry Award The winners of the 2018 Australian Dental Industry Awards were announced on 24th March 2018 at a gala dinner held in conjunction with ADX18 in Sydney. Henry Schein Halas was awarded the ADIA Dental Industry Partnership Award, which recognises the corporate success in building cooperative partnerships with dentists and allied oral healthcare professionals that reflect the truly symbiotic relationship that exists between dental industry and dental professionals.

Henry Schein Halas was recognised for its ongoing support of Youth With a Mission (YWAM) Medical Ship which works in rural areas of Papua New Guinea (PNG). Henry Schein Halas has been supporting YWAM Medical Ships’ work in PNG since 2010. Their support has included the annual provision of dental consumables and equipment for their dentistry programs, including four brand-new dental chairs for the MV YWAM PNG’s on-board clinic. This fit-out project was completed with the support of Planmeca.

Mike Covey, Managing Director of Henry Schein Halas, said “One of our values as a company is to expand access to care for at-risk and underserved populations through the support of not-for-profit organisations. We’ve found YWAM to be an excellent partner in helping to achieve this. Their medical ship is able to access extremely remote areas in PNG with dental care – a nation that only has 1 dentist for every 100,000 people.” He went on to say “We are grateful to receive this award and we hope this it provides an opportunity to shine a light on the wonderful work YWAM is doing in PNG.” Over the last eight years, YWAM Medical Ships with the support of Henry Schein Halas, has provided more than 29,600 dental procedures to over 16,700 individuals in rural and remote communities in PNG. YWAM Medical Ships Managing Director, Mr Ken Mulligan said “There are many stories of lives that have been touched through our partnership with Henry Schein Halas. We’ve seen patients come to our dental clinic who have knocked out their own teeth because of the pain. To be able to provide dental care with state of the art equipment and supplies right in remote villages has been incredible”. He continued, “ Many local dentists and dental workers have also been able to receive training and experience in our clinic, which has helped improve patient care in their own communities. We are very thankful for Henry Schein Halas’ consistent and strong support that has helped so many – I am pleased their support has been recognised through this award. We look forward to achieving much more together.”

Henry Schein Halas, through the Henry Schein Cares Foundation, is grateful for the support from supply partners Planmeca, GC, Hu-Friedy, 3M and Kavo Kerr whose contribution allows them to provide YWAM with their wish list of supplies for each outreach.

Dentists, dental assistants, dental therapists and dental hygienists are invited to volunteer about the MV YWAM PNG for a two-week outreach in PNG. For more information or to apply visit www.ywamships.org.

Vol. 13 No. 2 ISSN 2071-7962 PUBLISHING EDITOR Ursula Jenkins

EDITOR-IN-CHIEF Prof Dr Marco Ferrari

ASSOCIATE EDITORS Prof Cecilia Goracci Prof Simone Grandini Prof Andre van Zyl

EDITORIAL REVIEW BOARD Prof Paul V Abbott Prof Antonio Apicella Prof Piero Balleri Dr Marius Bredell Prof Kurt-W Bütow Prof Ji-hua Chen Prof Ricardo Marins de Carvalho Prof Carel L Davidson Prof Massimo De Sanctis Dr Carlo Ercoli Prof Livio Gallottini Prof Roberto Giorgetti Dr Patrick J Henry Prof Dr Reinhard Hickel Dr Sascha A Jovanovic Prof Ivo Krejci Dr Gerard Kugel Prof Edward Lynch Prof Ian Meyers Prof Maria Fidela de Lima Navarro Prof Hien Ngo Prof Antonella Polimeni Prof Eric Reynolds Prof Jean-Francois Roulet Prof N Dorin Ruse Prof Andre P Saadoun Prof Errol Stein Prof Lawrence Stephen Prof Zrinka Tarle Prof Franklin R Tay Prof Manuel Toledano Dr Bernard Touati Prof Laurence Walsh Prof Fernando Zarone Dr Daniel Ziskind PRINTED BY KHL PRINTING, Singapore International Dentistry - Australasian Edition is published by Modern Dentistry Media CC, PO BOX 76021 WENDYWOOD 2144 SOUTH AFRICA Tel: +27 11 702-3195 Fax: +27 (0)86-568-1116 E-mail: dentsa@iafrica.com www.moderndentistrymedia.com

© COPYRIGHT All rights reserved.

No editorial matter published in International Dentistry Australasian Edition may be reproduced in any form or language without the written permission of the publishers. While every effort is made to ensure accurate reproduction, the authors, publishers and their employees or agents shall not be held responsible or in any way liable for errors, omissions or inaccuracies in the publication whether arising from negligence or otherwise or for any consequence arising therefrom.

The Henry Schein Halas team receiving their award: From left-right: Mike Covey, (Managing Director), Calum Coogan, Anisa Zackria, Anita Birkin, Jessica Chasen, Russell Christian and Mark Thorn 4 INTERNATIONAL DENTISTRY – AUSTRALASIAN EDITION VOL. 13, NO. 2

Published in association with

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CLINICAL

Misadventure and accidents in endodontics: An Australian perspective Akila S. Vithanage,1 Roy George,1 Laurence J Walsh2

Abstract Objectives: To provide an overview of the recent history of complaints and litigation relating to endodontics in Australia.

Methods and Materials: Data on complaints was extracted from annual reports of the national regulator (the Australian Health Practitioner Regulation Agency, AHPRA). For co-regulated Australian jurisdictions, data on complaints were derived from the annual reports of the Office of the Health Ombudsman (Qld) and the NSW Dental Council. The major patterns were compared to trends in the international literature. Results: Instrument separation, perforations, and extrusion of irrigation fluid may occur during endodontic treatment, as well as other triggers for adverse outcomes.

Clinical significance: Assessment of the difficulty of the case prior to commencing endodontic treatment is essential, as is thorough planning of the treatment which follows successful obturation of the treated tooth. Using a proforma to assess case difficulty is recommended.

Key words: Endodontics, negligence, complaints, malpractice Short title: Accidents in endodontics

Introduction

Akila S. Vithanage BOralH(DentSci), GradDip(Dent) Roy George MDS, PhD Laurence J Walsh PhD DDSc 1

Griffith University School of Dentistry and Oral Health, Southport, Australia 2 The University of Queensland, Brisbane, Australia Corresponding author: Professor Laurence J. Walsh The University of Queensland School of Dentistry UQ Oral Health Centre, 288 Herston Road, Herston QLD 4006 Australia E: l.walsh@uq.edu.au T: + 61-7-33658160 F: + 61-7- 33658199

Medical negligence is a significant concern for health professionals across the globe, with a trend of rising incidence of complaints to regulators. In the Australian state of Queensland, where there are currently 3,456 dentists (including 321 specialists), during the 12 months to July 2017, there were 374 complaints lodged with the Office of the Health Ombudsman regarding Queensland dentists, of which 238 (64%) were based on concerns regarding professional (technical) performance.1 Over the same period, a total of 179 cases were sent to the national registration body (The Australian Health Practitioner Regulation Agency, AHPRA) for further action by the Office of the Health Ombudsman. In New South Wales, where there are some 5,402 dentists (including 483 specialists), during the 12 months to July 2017, there were 403 complaints lodged to the NSW Dental Council, of which 308 (76%) related to professional performance.2

Complaints and their triggers Complaints regarding endodontic treatment occur across all jurisdictions in Australia, and a summary of these is shown in Table 1. Typical triggers for complaints are shown in Table 2, and examples of accidents, malpractice and negligence in Table 3.

Negligence is a mistake, while malpractice is a wilful breach of duty of care. One must remember that the number of complaints reported recorded by regulators such as AHPRA (or recorded in the literature) does not capture the volume of incidents that are resolved within the practice environment, where the patient does not go on to lodge a formal complaint.

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Table 1. An overview of 69 complaints relating to endodontics based on reports from the Australian Health Practitioner Regulation Agency from 2011-2015.

Complication

Cases

Treatment Planning

18

Informed Consent

10

Infection Control

3

Record Keeping & Professionalism

28

Maintaining Current Standards of Care

15

Anaesthesia

3

Radiology

2

Pharmacology

2

Endodontic Specific Procedures

6

Post-Operative Failure

2

Litigation for endodontic adverse outcomes In addition to complaints made to regulators, aggrieved patients may also pursue legal action for damages. Triggers for litigation may be malpractice, negligence or accidents.

A range of events during endodontic treatment could be possible triggers for a complaint (Table 1). Litigation involves compiling the details of the complaint and its impact on the patient, drawing on the clinical notes, reports from relevant expert peers (general dentists or specialists) to assess whether the treatment offered was appropriate, reasonable and necessary. The litigation process also involves determining the extent of loss or damage suffered as a result of the treatment. While most jurisdictions in Australia cap the amounts awarded for damages (e.g. under the Civil Liability Act 2002 (NSW)), such limits may be overlooked when there is evidence of “an intentional act that is done by the person with attempt to cause injury” (Section 3B Civil Liability Act). For example, in a 2012 dental negligence case in NSW involving restorative dentistry, an extraordinary judgment was made of over AUD $330,000 plus costs.3 According to the American Academy of Endodontists, in the United States more than 15 million root canal treatments are performed every year (i.e. more than 41,000 per day), with specialist endodontists performing on average 25 root canal treatments each week, as opposed to general dentists

who average fewer than 2 per week. The reported satisfaction rate with specialist endodontic treatment is 89%, meaning that 11% had borderline or negative experiences.4

Events that may lead to complaints From an analysis of 1271 endodontic malpractice claims in Finland, the most common events arising from endodontic treatments undertaken in general practice were broken instruments (24% of submitted claims), followed by perforations (22%) and reactions to irrigant solutions or medicaments (5%).5,6 Negative known impacts of failed or incomplete endodontic treatment can also include serious infections, leading to systemic complications including life-threatening infections (brain abscesses, and osteomyelitis), irreversible brain damage and death. Four fatalities from endodontic procedures undertaken in the US have been described.7 Other events that have been reported in the global literature on endodontic treatment include poor record keeping and case documentation, lack of informed consent, incorrect diagnosis and treatment planning, and the use of outdated techniques and materials.

Prevention of adverse events Thorough treatment planning, proper processes for gaining

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Table 2. Endodontic events that may trigger a complaint

Failure to recognise a canal (e.g. MB2 in upper first molars) Perforations Separation of instruments Ledges or transportation of canals Not adequately treating cases with complex anatomy (e.g. dens invaginatus, or teeth eith unusual root canal morphology) Not taking sufficient radiographs to properly diagnose and treat the case, or taking excessive radiographs due to poor alignment or other radiographic errors Extrusion of irrigation solutions Extrusion of root filling materials or sealers from the confines of the root canal system Air embolism from the use of compressed air in the root canal space Sinus perforations Nerve damage Infection requiring hospitalization

informed consent, stringent infection control, and correct record keeping and professional behaviour apply to all areas of clinical practice. In 2012, the NSW Court of Appeal (case 223) prosecuted a dentist for endodontic treatment of a patient without appropriate documentation of consent.

Seeking additional opinions on a case becomes important when there is a clinically complex situation such as true endoperio lesion that requires carefully planned multidisciplinary treatment. The American Association of Endodontics classification of difficulty of cases provides a widely used method for assessing the difficulty of endodontic cases prior to commencing treatment.8 Teeth where endodontic treatment is planned need to be evaluated for issues including canal curvature and patency, and the presence of calcified canals on the pre-operative radiograph. When an instrument separation occurs and the instrument cannot be retrieved immediately, the patient should be advised of the event, and referred to an endodontist for management. It is essential that the treatment notes made at the time document the situation and the advice given.

To reduce the likelihood of perforations and file separations, employ a radiographic tube-shift technique to reveal accessory and additional canals or canal bifurcations. A common triad of errors involves failure to diagnose, failure to treat and failure to refer. For example, if the dentist does not identify problems with root canal patency, then the situation of a file binding and separating may occur. Not disclosing this to the patient or arranging for the broken file to be retrieved may then constitutes deception and a failure to refer.

References 1. http://www.oho.qld.gov.au/about-us/ our-performance/annual-reports/ 2. https://www.hpca.nsw.gov.au/sites/default/files/ dental_council_annual_report_2016-17.pdf 3. https://www.gerardmaloufpartners.com.au/ Publication-1386-Successful--24330-2c000-MedicalNegligence-claim-against-regional-Dentist.aspx 4. https://www.aae.org/specialty/about-aae/newsroom/endodontic-facts/

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Table 3: Examples of malpractice, negligence and accidents in endodontics Malpractice Not using dental dam

Negligence

Accidents

Fracture of tooth due to improper selection of clamp.

Failure to ensure leak proof dental dam

Fracture of a clamp Tear in rubber dam due to the dam being weakened by chemical solvents or sharp instruments

Using blunt, rusty or corroded files.

Improper use of rotary files (e.g. unwrapping files that have bound onto the root canal walls)

Extrusion of droplets of fluid into the periapical tissues when using normal irrigation methods

Failure to inform the patient of possible complications or consequences of treatment.

Failure to recognise and manage perforations

Late discovery of vertical/horizontal root fractures midway through treatment that renders the tooth un-restorable.

Failure to check/or adjust occlusion of temporary or final restorations of the access form

Rubber dam clamp being dislodged by tongue movement.

Performing root treatment of a tooth with a hopeless periodontal prognosis of that is not restorable Cementing a crown or post-core after root canal therapy with grossly deficient margins.

5. Vehkalahti MM, Swanljung O. Trends in Endodontic Malpractice Claims and their Indemnity in Finland in the 2000s.

J Dent Oral Hlth 2017;4:1-7. www.jscholaronline.org/articles/JDOH/Trends-inEndodontic-Malpractice.pdf 6. Vehkalahti MM, Swanljung O. Operator-related aspects in endodontic malpractice claims in Finland. Acta

Odontol Scand. 2017;75(3):155-160.

7. http://www.dentistryiq.com/articles/wdj/print/ volume-2/issue-8/you-and-your-practice/a-review-of-dentalnegligence.html 8.https://www.aae.org/specialty/wp-content/ uploads/sites/2/2017/06/2006casedifficultyassessmentf ormb_edited2010.pdf

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CASE REPORT

Restoration of occlusal cavities in the posterior dentition with Admira Fusion Sanzio Marques1

Introduction Tooth-coloured restorations with composites in the posterior region have now become a standard feature of modern dentistry, as more and more patients express a desire for a restoration which blends in with their natural dentition. Due to the high occlusal loads exerted on the posterior teeth, the selection of strong materials is imperative. For this reason, the composition of composites has evolved significantly and positively in recent years, to the benefit of their physical properties above all.

Adhesive techniques offer additional advantages, with the preservation of the remaining dental hard tissue deserving particular mention. Cavity preparations are no longer restricted solely to geometric models focusing on biomechanical principles. Direct restorations with composites are bonded to the tooth substance, and therefore the aim is only to remove caries and existing restorations selectively and to smooth the borders of the cavity. This means that the teeth are not only weakened less, but are actually strengthened by the fabrication of the adhesive fillings.

Placement of adhesive fillings is technique-sensitive. It is important to ensure compliance with the rules of these techniques so as to avoid microleakage and hypersensitivities in particular. If these requirements are satisfied, composite fillings are considerably superior to amalgam fillings, for example, due to their high quality and good aesthetics.

A material launched on the market in recent years with the indication for restorations in the posterior region is the OrmocerÂŽ (organically modified ceramic). It consists of organic/inorganic hybrid polymers, and its properties include very low shrinkage, excellent biocompatibility and outstanding aesthetics.

Description of clinical case A patient presented at our dental practice with the desire to have the amalgam fillings in teeth 46 and 47 (lower right first and second molars) replaced for aesthetic reasons (Fig. 1). Aesthetic restorations with the nanohybrid OrmocerÂŽ restorative material Admira Fusion (VOCO) were indicated.

1

Dr Sanzio Marques, Brazil

Contact: www.sorrisobelo.com.br

Figure 1: Teeth 46 and 47 with amalgam fillings to be replaced for aesthetic reasons

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Figure 2: Isolation with rubber dam.

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CASE REPORT

Figure 3: Prepared class I cavities.

Figure 4: Application of Futurabond DC (VOCO) adhesive system.

After isolation with a rubber dam (Fig. 2), the amalgam fillings were removed and the cavity preparation performed (Fig. 3).

The Futurabond DC (VOCO) adhesive system was massaged in for around 20 seconds (Fig. 4) and the solvent then removed with a stream of air. The adhesive was lightcured for 10 seconds (Fig. 5).

As the cavities were small and shallow and Admira Fusion has a low degree of polymerization shrinkage, the cavities were each restored with a single increment (Fig. 6).

A spatula was used to remove the excess material and

Figure 5: Light -curing of adhesive layer for 10 seconds

6

7

8

9

Figure 6, 7, 8 and 9: Cavities were each restored with a single increment. The occlusal surfaces were sculpted with fine spatulas and probes, without intermediate curing of these increments. The restorations were then cured for 20 seconds each.

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MARQUES

Figure 10: A fine probe was used to sculpt occlusal fissures.

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Figure 11: Characterisation of the fissures was performed with a brown composite shade to create accents and the impression of depth.

13

Figure 12 & 13: Restorations before finishing and polishing.

14

15

17

16

18

Figure 14, 15, 16, 17 & 18: Finishing and polishing of the restoration with successive use of diamond-coated rubber polishers, goat’s hair brushes with diamond compound, silicon carbide brushes and felt polishers.

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perform initial sculpting of the anatomical shape of the tooth (Fig. 7 and 8). The top layer was smoothed with a brush to facilitate the finishing and polishing.

A fine probe was used to shape the occlusal fissures prior to curing the Ormocer® restorative material (Fig. 9 and Fig. 10). The restoration was light-cured for 20 seconds. The fissures were then characterised with a composite shade (FinalTouch from VOCO) (Fig. 11) and cured for 20 seconds before a final layer of composite was applied. The restoration was then cured for a further 20 seconds.

Even before the rubber dam was removed, the satisfactory morphological characteristics of the restorations were already clearly visible (Fig. 12 and 13).

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The finishing and polishing were performed with abrasive, diamond-coated rubber polishers, brushes and felt polishers (Fig. 14, 15, 16, 17 and 18).

The patient was extremely pleased with the finished results, which can be seen in Fig. 19, 20 and 21.

Conclusion The nanohybrid Ormocer® restorative material Admira Fusion proved an excellent choice. It is easy to use and can be sculpted and polished optimally. The described technique was relatively simple and even the use of just one shade of material proved sufficient to satisfy the aesthetic requirements when placing a restoration in the posterior region.

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Figure 19 & 20: Finished restorations with harmony between aesthetics and function.

Figure 21: Once finished, the fillings displayed homogeneous occlusal contacts.

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CLINICAL

Clinical opinion - modern dental anaesthesia Peter Raftery1

Working full-time in clinical endodontics I would estimate that approximately 9 out of 10 cases I treat are non-vital teeth, the remainder being the dreaded so-called ‘hot pulps’ of irreversible pulpitis. The differences between these two types of case in terms of the requisite local anaesthesia (LA) for access cavity preparation could not be more different. In fact the owners of the necrotic pulps often ask me what “that machine” (the Electronic Apex Locator) beeping in the background does, implying that their dentist skip LA injections for root-treatments; an “ouch” from the patient in response to a file tip boring into the alveolus seemingly indicates canal patency and working length! I don’t follow this practice and advocate effective pre-operative local anaesthesia for all endodontic procedures to minimise post-operative pain long after the pharmacologic effect of the drug has worn off.1 As for the hot pulps - I am normally asked to manage these because of the “ouch” persisting despite concerted attempts at LA; the dreaded missed inferior alveolar dental nerve (IADN) block.

Failing to achieve sufficiently profound local anaesthesia can be dispiriting, but is not particularly rare. In 1984 Kaufman et al2 reported over a 5-day period that 13% of general dental practitioners experienced a failure of local anaesthesia meaning that 10% of treatments had to be abandoned. The most commonly reported ‘miss’ being the failed IADN blocks. Failed IADN (lidocaine) blocks in patients with irreversible pulpitis were even more common (32%) as reported in a more recent UK study.3 When considering local anaesthesia, like all clinicians, I will select an anaesthetic agent and injection technique.

Anaesthetic agent

1 Peter Raftery, Specialist Endodontist The Wessex Dental Specialist Centre, Fareham

My own preferred agent is an articaine 4% preparation with adrenaline 1:100,000, having recently left behind my previous standard: lidocaine 2% preparation with adrenaline 1:80,000. I say “preferred” because whilst I do not cancel patients if we have run out, I will always reach for the gold ampoules given the choice. This preference is based on a mixture of my past experiences and the available evidence.

Whilst it would be difficult to effectively share my past clinical experiences in any meaningful way here, I shall try to distil some of the recently published evidence.

When confronted with any new evidence from the dental literature it is necessary to consider its provenance. The methodology of any study can influence its quality and so it is worth bearing in mind the likely strength of the evidence4, for example results from a well-designed Randomised Controlled Trial (RCT) can be a more robust method for determining true effect than authors’ opinions following case-reports. Where possible it is appropriate to base clinical decision making on the highest quality evidence possible but without blindly overemphasising methodology to the exclusion of all evidence not derived from RCTs.5 This is a concept that will be revisited to help inform the argument on the safety of articaine use in dentistry.

Articaine preparations for dental use were first introduced in Germany in 1976, the United Kingdom in 1998 and the United States in 2003. An excellent detailed review on articaine was published in the BDJ in 2011 by Yapp6 which concluded articaine to be “a safe and effective local anaesthetic drug to use in all aspects of clinical dentistry for patients of all ages, with properties comparable to other common local

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anaesthetic agents.”

A 2010 systematic review7 on the efficacy and safety of articaine in dental use yielded a meta-analysis - a powerful statistical tool for distilling evidence - and the pooled data from nine separate clinical trials concluded that articaine was superior to lignocaine in anaesthetic efficacy in the first molar region and just as safe a drug. Dr John Meechan, the UK Chairman of the Dental Directorate Drug and Therapeutics committee, commented on this analysis urging caution that the lack of a universally accepted outcome measure adopted among these nine studies to indicate ‘successful local anaesthesia’ will have affected the robustness of the findings on the efficacy (but not safety) of articaine.8 A quick Pub Med search of the literature shows that the purported safety issue regarding dental use of articaine, in which articaine has been suggested to be neurotoxic, has been raised in some occasional dental case reports authored or co-authored by Haas.9-14 Yet in the fields of ophthalmological surgery and surgery of the hand and foot, where articaine use is widespread and long-standing, there is not a single reported case of paraesthesia. The sporadic dental publications suggest an increased risk of paraesthesia of the lingual nerve following articaine use for IDN blocks but do not explain why - if the drug were neurotoxic - does it not affect all nerves equally? It seems that the lingual nerve, structurally similar to other peripheral nerves throughout the body, is most often affected by articaine and only during the IANB approach. It is difficult to accept that articaine per se is harmful when there is a worldwide scarcity of reports linking paraesthesia with articaine use in Gow-Gates mandibular nerve block, incisive/mental nerve block, or maxillary injections, be they infiltration or nerve blocks.15 The retrospective studies suggesting an increased risk of neurotoxicity with articaine are biased from a patient recruitment perspective terms and not the high levels of evidence preferred when making definitive clinical recommendations. Mere correlation doesn’t prove effect and whilst Yapp6 called for further RCTs on articaines to determine whether any increase in paraesthesia is attributable to articaine, Haas11 concedes that “it would take an unrealistically large trial or cohort to detect statistically significant differences for an event as rare as nonsurgical paraesthesia”.

Since it is unlikely that any strong evidence will be forthcoming soon, or ever, linking articaine use in dentistry with any negative effects, I expect that articaine 4% will continue to be chosen and used without any side effects

over and above those realistically expected from use of any alternative local anaesthetic agent or preparation to great effect by many clinicians.

Leaving safety aside and considering instead the publications on the efficacy of articaine injection techniques, there is a weight of evidence from well-designed studies demonstrating articaine’s benefits - particularly in instances when a lidocaine IADN block has failed.

Injection technique The common local infiltration and regional block injections, familiar to all Dentists, work in the majority of instances but, as mentioned earlier, the IADN can fail to anesthetise clinically normal pulps and this rate of failure is around 8 times higher with inflamed pulps16. Detailed explanations as to why inflamed pulps are more resistant to local anaesthetic are beyond the scope of this article but in brief • Once deposited, the LA drug in solution establishes equilibrium between positively charged (dissociated) ionic form and uncharged molecular form. Inflammation reduces tissue pH, maintaining a greater proportion of LA in the dissociated form, unable to cross the lipid nerve membrane to exert its effect in the way the molecular form can.

• The increased blood flow through inflamed tissues clear the deposited drug from point of need more quickly.

• LA binds to sodium channels on pain nerve (nociceptors) membranes; inactivating them. These ‘paralysed’ nerves cannot initiate or propagate nerve firing = anaesthesia.

When tissues are inflamed, nociceptor membranes preferentially express slightly different sodium channels that require more lidocaine to be rendered inactive.

• Some of the chemicals released in inflamed tissues cause a reduction in the threshold necessary for nociceptor firing meaning more nerves in a greater area require blocking.

Once a block has failed one has the choice to abandon treatment (as per Kaufman, 1984 2) or to make further attempts at achieving LA. This can be another attempt at the (missed) IADN block or by one of the supplementary routes to local anaesthesia described by Meechan17. The most prevalent of these being an intra-osseous injection or intraligamentary injection. A recent study has looked at the efficacy of these choices, as well as a buccal infiltration of articaine, in just this situation3. Clinicians familiar with Albert Einstein’s definition of insanity (“Insanity: doing the same thing over and over again and expecting different results.”) won’t be surprised to hear that the most effective LA strategy following a missed lidocaine IADN block is not another attempt at a lidocaine IADN block. This option performed

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poorest rendering only 32% of symptomatic pulps numb. The best option was the buccal infiltration of articaine which rescued the situation in 82% of cases, outperforming intraosseous (68%) and intra-ligamentary (48%) approaches. This ability of articaine, infiltrated buccal to an irreversibly pulpitic tooth, in allowing continuation of endodontic access cavity preparation in most cases where a lidocaine IADN block has failed was also shown by Matthews.18 I am not aware that this practice (of infiltrating articaine buccal to mandibular teeth) is widespread but its performance in recent well-designed studies seems set to change that. A buccal infiltration of articaine alone performed as well as IADN blocks with lidocaine19 and IADN blocks with articaine20 in achieving pulpal anesthesia in healthy volunteers. Separate studies, also in healthy volunteers, demonstrated that lidocaine IANB injections supplemented with buccal infiltrations of articaine were significantly more successful than the IANB alone21 or when supplemented instead with buccal lidocaine for pulpal anaesthesia in mandibular teeth.22 When all else has failed, another supplementary route to local anaesthesia that I find useful is the intra-pulpal injection. In the absence of profound anaesthesia, if the patient is able to tolerate access cavity preparation until such a time as a small hole into the pulp chamber can be made - pressurised deposition of local anaesthetic into the pulp chamber brings about almost instantaneous anaesthesia. It is interesting to note that this effect seems to be more mechanical than pharmacological since saline performed equally as well as lidocaine.23

Conclusion Simply loading a 4% articaine cartridge into a syringe does not guarantee profound anaesthesia but it is a genuinely different agent to other amide LA (lignocaine, prilocaine). I use it routinely but find it invaluable in certain clinical situations such as ‘hot pulps’ where a greater lipid solubility means more of the administered dose can enter neurons24 by virtue of its molecular structure and a lower systemic toxicity of the drug allows articaine use in concentrations higher than other amide LAs.25

References 1. Gordon SM, Dionne RA, Brahim J, Jabir F, Dubner R 1997.

Blockade of peripheral neuronal barrage reduces postoperative pain.

Pain, V70:209-1S. 2. Kaufman E, Weinstein P, Milgrom P 1984. Difficulties in achieving local anesthesia. Journal of the American Dental Association, V108:20S-8.

3. Kanaa M, Whitworth J, Meechan J 2012. A prospective randomized trial of different supplementary local anesthetic techniques after failure of inferior alveolar nerve block in patients with irreversible

pulpitis in mandibular teeth. Journal of Endodontics, V38; 421-S. 4. Yusof Z, Han L-J, Poon P, Ramli A 2008. Evidence-Based Practice Among a Group of Malaysian Dental Practitioners. Journal of Dental Education, V 72; 1333-42. See Figure 2 - free access via Google Scholar.

5. Smith & Pell 2003. Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials. British Medical Journal, V327;1459-61.

6. Yapp K, Hopcraft M, Parashos P 2011. Articaine: a review of the literature. British Dental Journal, V210: p323-9.

7. Katyal V 2010. The efficacy and safety of articaine versus lgi nocaine in dental treatments: a meta-analysis. Journal of Dentistry, V38 p 307-17.

8. Meechan J 2011. Articaine and lignocaine. Evidence-Based Dentistry, V 12; 21-2.

9. Haas D & Lennon D 1995. A 21 year retrospective study of reports of paresthesia following local anesthetic administration. Journal of the Canadian Dental Association, V61: 319-30.

10. Haas D, Harper D, Saso M, Young E 1990. Comparison of articaine and prilocaine anesthesia by infiltration in maxillary and mandibular arches. Anesthesia Progress, V37; 230-7.

11. Gaffen A & Haas D 2009. Retrospective review of voluntary reports of nonsurgical paresthesia in dentistry. Journal of the Canadian Dental Association, V75; 579.)

12. Garisto G, Gaffen A, Lawrence H, Tenenbaum H, Haas D 2010. Occurrence of paresthesia after dental local anesthetic administration in the United States. Journal of the American Dental Assoc ration, V141; 836-44.

13. Haas D &, Lennon D 1996. A review of local anesthetic induced paresthesia in Ontario in 1994 (abstract 1834). Journal of Dental Research V 75; P 247.

14. Miller P & Haas D 2000. Incidence of local anaesthetic induced neuropathies in Ontario from 1994-1998 (abstract 3869). Journal of Dental Research, V79 (Spec Iss): 627.

15. Malamed S 2006. Nerve injury caused by mandibular block analgesia. International Journal of Oral and Maxillofacial Surgery 2006; 35: 876-877) 16. Hargreaves K & Keiser K 2002. Local anesthetic failure in endodontics: Mechanisms and Management. Endodontic Topics, V 1, p26-39.

17. Meechan J 2002. Supplementary routes to local anaesthesia.

International Endodontic Journal, V35; p 885-96.

18. Matthews R, Drum M, Reader A, Nusstein J, Beck M 2009.

Articaine for supplemental buccal mandibular infiltration anesthesia in patients with irreversible pulpitis when the inferior alveolar nerve block fails. Journal of Endodontics, V35; 343-6.

19. Corbett I, Kanaa M, Whitworth J, Meechan J 2008. Articaine infiltration for anesthesia of mandibular first molars. Journal of Endodontics, V 34; 514-8.

20. Jung I, Kim J, Kim E, Lee C, Lee 5 2008. An evaluation of buccal infiltrations and inferior alveolar nerve blocks in pulpal anesthesia for mandibular first molars.Journal of Endodontics, V34; pl1-3.

21. Kanaa M, Whitworth J, Corbett I, Meechan J 2009. Articaine buccal infiltration enhances the effectiveness of lidocaine inferior alveolar nerve block. International Endodontic Journal, V42:238-46.

22. Haase A, Reader A, Nusstein J, Beck M, Drum M 2008.

Comparing anesthetic efficacy of articaine versus lidocaine as a supplemental buccal infiltration of the mandibular first molar after an inferior alveolar nerve block. Journal of the American Dental Association V139 :1228-35.

23. Van Gheluwe & Walton 1997. Intrapulpal injection: Factors related to effectiveness. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, V83; 38-40.

24. Becker & Reed 2006. Essentials of local anesthetic pharmacology. Anesthesia Progress, V53: 98-109.

25. Oertel R, Rahn R, Kirch W 1997. Clinical pharmacokinetics of articaine. Clinical Pharmacokinetics, V33: 417-425.

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A quick, durable smile makeover

Tif Qureshi1

A 27-year-old female patient presented at the practice as she was unhappy with her crooked front teeth (Figure 1). She was interested in porcelain veneers to align them.

She was not overly concerned about the colour of her teeth, but wished to have them whitened a little during the treatment process.

Initial assessment

1

Dr Tif Qureshi Partner at Dental Elegance, Sidcup, UK Director of the IAS Academy.

For more information: Dr Tif Qureshi, email: tif@iasortho.com www.iasortho.com

It was explained to the patient that there were alternatives to porcelain veneers available to her, including traditional comprehensive orthodontic treatment or a range of techniques for anterior alignment only.

A full orthodontic and functional assessment diagnosis was undertaken (Figures 2-5).

The patient had a skeletal classification of II with a decreased Frankfort mandibular plane angle.

Other orthodontic findings were a class II, division II, incisor relationship and molar class I relationship on the right and class II on the left. The canines were class I on the right and half class II on the left.

The patient had an increased overbite of 40% and an overjet of 3mm. Her upper lateral incisors were crowded and mild crowding was also evident in the lower arch. The centre line was coincident. No abnormalities were detected with the soft tissues, and her lips were symmetrical and competent. Lower face height was slightly reduced.

A crossbite affected her UL6 and LL6. There was no canine guidance and posterior interference on the anterior slide. The patient did not have any temporomandibular joint Figure 1: The patient was unhappy with her crooked front teeth disorder complaints or symptoms.

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2

3

4

5

Figures 2-5: Some views from the full orthodontic and functional assessment diagnosis that was undertaken.

Treatment options After consultation and presentation of the findings, all orthodontic options were discussed.

The patient declined the comprehensive route because she had undergone orthodontic treatment in the past, which had relapsed, and she wanted quicker results. She was interested in just having anterior orthodontic alignment, as this approach required a shorter treatment time, and she was not concerned about her back teeth.

A digital 3D image of her outcome was created. The patient opted for anterior alignment orthodontics with the Inman Aligner and edge bonding with composite. The image helped the patient to visualise the result and how it could

Figure 6: An impression was taken using a putty and wash two-stage technique.

dramatically improve her appearance. This choice of treatment meant that she would not have to undergo tooth preparation in order to have veneers.

The patient understood that the Inman Aligner could only treat the anterior region. She was also made aware of the need for permanent retention and the potential for relapse if this was not maintained.

Treatment planning An occlusal photograph was taken at the chairside and uploaded into the dental diagnostic crowding calculator, Spacewize, and the calibration tooth details entered. An ideal curve was then digitally plotted. The space calculation

Figure 7: Minimal interproximal reduction and predictive proximal reduction of 2.4mm was carried out over seven contacts.

Figure 8: After about 10 weeks, the patient’s anterior teeth had aligned.

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9

Figure 9: Old composite was lightly removed from the incisal edges.

10

11

Figures 10 and 11: Each tooth was restored using Heraeus Kulzer Venus Diamond in layers of the Opaque Light and B1 shades, with a hint of Bleach Light.

Orthodontics

Figure 12: The composite was light-cured through Deox gel.

confirmed that this case was treatable with an Inman Aligner.

The difference between available space and required space was 2.8mm, which could be created with interproximal reduction (IPR) incrementally as the treatment progressed.

An impression was taken using a putty and wash two-stage technique (Figure 6). The putty was hand mixed and the basic impression was taken with a cling film wafer using Kulzer impression materials. The cling film was removed and a flowable silicone material was injected into the tray and around the teeth. The impression was then inserted back into the mouth to produce a very high definition result.

The final impression was sent to the UK-certified Inman Aligner laboratory with the Spacewize trace (Noar et al, 2015) to produce an Archwize digital set-up. A 3D-printed model was returned and shown to the patient for her consent.

The printed model helps significantly with the consent process.

The advantage of a 3D print over a 3D image is that a patient can hold the models and really appreciate the potential outcome with a clearer idea of scale, position and shape. A model helps to improve patient understanding of treatment goals and results in improved consent. If they are not satisfied, they can decline treatment before it begins.

In this case, the patient was happy to proceed and an Inman Aligner based on the 3D print was built and then fitted.

Minimal IPR (El-Mangoury et al, 1991; Radlanski, 1991) and predictive proximal reduction (PPR) of 2.4mm was carried out over seven contacts in a progressive and measured manner (Figure 7). After about 10 weeks, the patient’s anterior teeth had aligned (Figure 8) and simultaneous bleaching was carried out.

Super-sealed home trays were used with Philips Zoom Daywhite. This whitening system contains 6% hydrogen peroxide and the patient bleaches for only 35 minutes a day.

An impression was taken for the wire retainer using Heraeus Kulzer Xantasil. It is a single-mix, medium body alternative to alginate and produces impressions with excellent detail, which set within 90 seconds.

An indirect stainless steel wire was then made by the laboratory for improved accuracy and a passive fit (Becker and Goultschin, 1984).

Composite restoration and finishing The patient returned for edge bonding of the front six teeth. Old composite was lightly removed from the incisal edges (Figure 9).

Each tooth was restored using Kulzer Venus Diamond in layers of the Opaque Light and B1 shades, with a hint of Bleach Light (Figures 10 and 11).

The composite is laid freehand in a reverse triangle technique, which blocks out the light transmission on the join, so no preparation is needed.

Opaque Light dentine was placed first on the palatal up to the incisal edge, then B1 enamel and a little Bleach Light over the facial surface, extending about 2mm beyond the margin.

The composite was light-cured through Deox gel in accordance with the manufacturer’s instructions (Figure 12).

Venus Diamond is the perfect material to use for edge bonding because of its high strength in thin sections. It also has a terrific colour match, is simple to layer and has great polishing qualities (Figures 13-15).

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15

Figures 13-15: Venus Diamond is the perfect material to use for edge bonding because of its high strength in thin sections.

14

During the same appointment, a fixed stainless steel wire retainer was bonded to the lingual surfaces using Kulzer Venus Diamond Flow, to prevent tooth relapse (Figure 16).

Venus Flow has been used in many cases to bond retainers because of its high strength and predictability. An impression was also taken using Xantasil to create a clear Essix retainer for the patient to wear at night.

The patient’s teeth were given a light polish immediately after the edge bonding restoration. She returned two weeks later to have her teeth polished with the Kulzer Venus Supra high gloss polisher.

Venus Supra was selected as it does not cut or damage the composite. It is also simple to use and the rubberised

Figure 16: A fixed stainless steel wire retainer was bonded to the lingual surfaces using Kulzer Venus Diamond Flow, to prevent tooth relapse.

Figure 17: The red disc was used for basic polishing and to create and enhance the tooth contour.

Figure 18: The grey disc produced a high gloss finish.

Figure 19: A flexible felt and mylar disc with polishing paste was used for the final shine

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Figure 20: The patient was thrilled with her teeth.

polishers are the correct shapes to achieve a high lustre.

In this case, the red disc was used for basic polishing and to create and enhance the tooth contour (Figure 17), then the grey disc produced a high gloss finish (Figure 18). A flexible felt and mylar disc with polishing paste was used for the final shine (Figure 19).

Long-lasting, aesthetic result A successful result was achieved using a non-invasive, progressive approach. This outcome is only possible if alignment and whitening techniques are carried out before any tooth preparation is even considered. Patients’ own perceptions of what they think suits them can change, if they are allowed to see their teeth transform gradually.

Edge bonding means that preparation to the teeth is

21

avoided and the restorations are very simple to repair and replace if required. With nanohybrid composite materials like Venus Diamond, edge bonding has become simpler and more predictable to place for a natural aesthetic result.

The patient was thrilled with her teeth (Figure 20). The result was just how she imagined veneers could look.

Instead of complex ceramic treatment, alignment, bleaching and bonding involved no invasive tooth surface preparation, the treatment cost a quarter of the price of veneers and presented no biological risk.

At the 12- and 18-month reviews (Figures 21 and 22), the patient was still happy with her new smile and no adjustments were needed.

Reprinted with permission by Aesthetic Dentistry Today April 2017

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Figures 21 and 22: At the 12- and 18-month reviews, the patient was still happy with her new smile and no adjustments were needed.

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Adhesive dentistry meets restorative dentistry and endodontics – part one Cornelis H Pameijer1 and Osvaldo Zmener 2 Abstract Although adhesion to enamel has been a successful clinical procedure with good long-term results since the 1960s, the durability of the resin/dentine bond has been raised as an issue of concern during the past two decades. There are contradictory findings between experimental ex vivo and in vivo tests with the use of adhesive materials. Furthermore, the possible toxic effects of leached components from resin/based materials to the pulp, with in addition bacterial leakage and degradation of the interface adhesive resin/dentine are factors that greatly affect the long-term service of a restoration/endodontic treatment. Endodontics is not exempt from these factors and while the treatment is totally different, many adverse conditions can compromise the outcome of a root canal treated tooth. A thorough understanding of the physiopathology of the pulp/dentine complex and the physical properties and biocompatibility of the materials that are being used for treatment improves treatment outcomes and can result in long-term success. In that respect successful endodontic treatment is closely intertwined with adhesive restorative dentistry.

Key words: Dentine, dentine bonding, endodontics, hybrid layer, resin/dentine interface

1

Cornelis H Pameijer DMD, MScD, DSc, PhD, Professor Emeritus, University of Connecticut School of Dental Medicine, USA.

2

Osvaldo Zmener DDS, Dr Odont, is Head Professor, Postgraduate Program for Specialized Endodontics, School of Dentistry, University of El Salvador/AOA, Buenos Aires, Argentina.

Private Practice limited to endodontics, Buenos Aires, Argentina.

Introduction The restoration of vital teeth affected by caries involves the complete removal of the infected tissues, protection of the pulp with an appropriate material and replacement of the lost hard structures with a material that meets biocompatibility standards and can restore function and aesthetics. Dental amalgam, cements and liners have been used in the past with great success, however, direct adhesive restorations are now the preferred treatment of choice. The continued improvement of operative techniques and materials is in part driven by patients’ demands for better aesthetics. The use of enamel adhesives started in the 1950s (Buonocore, 1955; Buonocore et al, 1966), however, the majority of the early materials revealed a poor clinical performance (Kramer and McLean, 1952). From the 1990s, a new generation of more reliable materials and techniques were introduced to the dental profession. These materials required as a first step dentine preparation with an acid gel, achieving demineralisation of the intertubular and peritubular dentine. Dentine is composed of a high percentage of water and organic material such as type I collagen together with noncollagenous proteins, proteoglycans, phosphoproteins and glycoproteins intertwined by a tubular network (Tjäderhane et al, 2012). Most of these dentinal tubules contain a cytoplasm extension of the odontoblasts. The odontoblastic processes establish a direct pathway of communication between a prepared cavity surface and pulp tissues. The odontoblastic processes are normally accompanied by the extension of pulp nerves (Figure 1) and the internal space of the tubules is filled with fluids. Consequently, the procedures for caries removal and cavity preparation as well as the direct application of restorative materials are always performed on vital pulp/dentine substrates. Therefore, clinicians should be aware of the various factors that regulate the response of the vital pulp and dentine structures to restorative materials. The biological evaluation of dental materials tested, according to the guidelines of the ANSI/ADA Spec # 41 (2015) [ISO 7405:2008 (E)], indicate that most of the contemporary adhesive materials and techniques are safe to the pulp/dentine complex.

In spite of this, there were many clinical reports of postoperative sensitivity and/or pulpal inflammation beneath dental restorations when tooth coloured resin-based materials were used (Council on Dental Materials, Instruments and Equipment, 1988;

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Figure 1: A: SEM micrograph showing longitudinally fractured dentinal tubules (white arrows) and intertubular dentine (ID).

(Original magnification x3000). B: SEM micrograph showing an odontoblast like-cell (OD) and the odontoblast process (arrow). (Original magnification x10.000). C: SEM micrograph of a longitudinally fractured dentine tubule showing the presence of an odontoblast process (white arrow) accompanied by a nerve fibre (black arrow) and a lateral branch (interrupted arrow). D: Dentine (Original magnification x5000). D: SEM micrograph of two dentinal tubules (DT) showing odontoblast process (white arrows) and two interconnected branches (black arrows). ID: Intertubular dentine. DN: Dentine. (Original magnification x5000)

Costa et al, 2017). As a result of the sometimes contradictory findings between experimental ex vivo and in vivo tests and the clinical use of adhesive materials in humans (Wataha, 2012), the dental practitioner cannot be offered a guarantee concerning the lack of toxic effects and deleterious consequences of currently used materials and their reaction to the pulp. Bacterial microleakage as well as the stability of the bond at the interface is still a major concern. This text will discuss the biological relationship between contemporary adhesive materials and the pulp/dentine complex. Furthermore, factors influencing the long-term durability of adhesive restorations will be addressed for restorative dentistry and endodontics.

Biocompatibility tests of restorative materials: are they reliable?

After caries removal, the preparation of a cavity suitable for restoration involves enamel and dentine and on occasion part of the root cementum. Reaction of the pulp to operative procedures has been historically reported by Langeland (1959, 1961) in early subhuman primate studies. Copious water-cooling during high-speed cavity preparation appeared to be a crucial factor to cause the least amount of insult to the pulp. More recently MjĂśr (2001a) reported

similar findings. Considering the fact that caries lesions, promotes the development of pulpal alterations (Langeland, 1987; Heyeraas et al, 2001), the clinician has to realise that the pulp will suffer subsequent additional injury from cavity preparation and placement of the final restoration.

Thus, the pulp has to cope with a multifactorial attack. The impact of each individual factor on the long-term results of a dental restoration is difficult to predict.

Recommended pre-marketing tests start with the primary in vitro cytotoxicity tests using cell and tissue cultures [Dobie et al, 2002; Al-Sabek et al, 2005; Sun et al, 2016; ANSI/ADA Specification #41 (2015) (ISO-7405:2008 E)].

Many laboratory experiments use healthy dentine samples while clinicians usually deal with caries affected dentine.

Although in vivo tests are more reliable procedures for evaluation of material biocompatibility, most manufacturers and researchers still rely on in vitro tests to assess the clinical performance of restorative materials (Wataha, 2012). The primary in vitro tests must be followed by secondary in vivo biocompatibility tests in connective and bone tissues of mammalian small laboratory animals. The secondary tests constitute an important safety pre-marketing evaluation of newly developed materials. They can show whether the components of, for instance, resin-based materials can elicit damage to the surrounding tissues when implanted in connective tissue or bone in small animals such as rats, rabbits or guinea pigs. Most materials generate mild to moderate inflammatory reactions of the surrounding tissues when evaluated over short-term periods of 10 and 30 days.

But after 90 to 120 days they usually show acceptable biological responses. Nevertheless, there are reports of postoperative sensitivity ranging from minor to severe pain after caries excavation and restoration with adhesive resinbased materials (Council of Dental Materials, Instruments and Equipment 1988; Costa et al, 2017). More reliable pulp reactions can be obtained from tests in large mammalian animals, the tertiary tests; also called usage tests (Wataha, 2012). Ideally, subsequent well-controlled double-blind clinical trials in human subjects (gold standard) are recommended before marketing a new material (Van Dijken, 2004; Andersson-Wenckert et al, 2004; Accorinte et al, 2005; Nowicka et al, 2013; Koubi et al, 2013; Van Dijken et al, 2015). The usage tests mimic the in vivo clinical treatment in human teeth and can be done in rats (Higashi et al, 2000; Mori et al, 2014; Dammaschke et al, 2010), guinea pigs (Shayegan et al, 2012), cats (Olgart et al, 1974), dogs (Faraco and Holland, 2001), swine (Koliniotou-Koumpia et al, 2014) monkeys (MjĂśr and Tronstad, 1974; Akimoto et al, 1998; Pameijer and Stanley,

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3a

3b

Figure 2: Microphotograph of a histology section from a subhuman primate tooth showing a 70-day pulp reaction to an indirect restoration with a test material. A considerable amount of tertiary (reparative) dentine (TD) that constricts part of the root canal space can be seen. D: Dentine; P: Pulp (H & E stain; Original magnification x100) Figure 3: A: Beneath a deep caries lesion bacteria have invaded the dentinal tubules while the acidic environment has destroyed the surrounding mineralized tissue (square area). (H & E stain; Original magnification x100). B: Higher magnification of the square area in A showing numerous bacteria in the dentinal tubules. Arrows indicate destroyed dentine (H & E stain; Original magnification x1000)

1998, Cannon et al, 2014) and the teeth of goats (Zhang et al, 2008). These teeth must be free of caries and have healthy pulps. When human teeth are used, they should be from young patients, for instance premolars scheduled for extraction for orthodontic reasons. The recommended Class V cavity preparations should have as much as possible standardised depths and extend as much as possible to the mesial and distal proximal surfaces and placed on enamel and into dentine. However, there are some limitations pertinent to a reliable interpretation of the results as well with respect to the clinical significance. For instance we know that when practicing routine restorative dentistry there are a number of clinical variables that deviate from the ideal conditions of teeth employed in usage tests (Mjör, 2001b).

Histological data from an experiment in subhuman primates using healthy teeth can generate information concerning the biocompatibility and reactivity of a test material. In the example of Figure 2 in a postoperative period of 70 days a considerable amount of reparative dentine was observed, which over time could have constricted the root canal space entirely. There is a fine line between a material that stimulates reparative dentine just so much to protect the pulp and a material that elutes components that continue to stimulate the odontoblasts to produce reparative dentine that is excessive and therefore counterproductive. Teeth that require adhesive restorations usually have decay that differs in depths and size, or have recurrent decay in failed restorations. As a result, the clinical and histological reactions of the pulp/dentine complex to operative procedures and restorative materials is quite different from what takes place in unaffected teeth. In teeth affected by caries bacteria have advanced through the dentinal tubules towards the pulp while the acidic environment caused by their by-products,

together with collagenolytic enzymes activated by the low pH, have destroyed the surrounding mineralised tissues (Figure 3). Under these conditions, the pulp showed different degrees of degenerative or inflammatory changes (Langeland, 1959; Langeland 1961; Mjör, 2001a), while the dentine frequently revealed sclerotic alterations and/or dystrophic calcifications within the pulp tissues, including the apposition of tertiary dentine on the pulp chamber walls. The tertiary dentine can also be localised in the area of the pulp horns. Bacteria that invades tertiary dentine can cause slight to severe pulpal reactions (Warfvinge, 1986). On occasion the calcification of tertiary dentine can be so extensive that the pulp chamber is completely filled (Langeland, 1987), while the root canals are narrowed by mineralised tissue (Appleton and Williams, 1973; Vasiliadis et al, 1983a; Vasiliadis et al, 1983b; Björndal and Mjör, 2001).

Therefore, in daily practice reactions of a compromised pulp will be very different from the reaction of healthy pulps used in experimental usage tests. Thus, the direct correlation of experimental results to the actual clinical outcome should be made with great caution.

Pulp reactions to a material may depend not only on the toxicity of material components but also on the remaining dentine thickness (RDT), the distance between restorative material and the pulp (Langeland, 1967; Qvist and Stoltze, 1982; Murray et al, 2000). It is generally accepted that a RDT of 2 mm or more is safe to avoid possible harmful effects of a restorative material to the pulp. However, in order to obtain accurate data of the biological properties of an experimental material, the ANSI/ADA Spec, #41 [ISO 7405-2008 (E) standards] recommends that the RDT must be approximately 1 mm or less. In adult teeth physiological aging causes dentine tubule occlusion, resulting in a

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Figure 4: A 15-day postoperative microphotograph of an exposed vital rat pulp treated with 37% phosphoric acid for 15 seconds followed by rinsing with sterile twice-distilled water. Note the presence of a thin fibrous capsule at the exposed pulp surface and some dilated blood vessels (arrows). D: Dentine; P: Pulp (H & E stain; original magnification x100). B: Higher magnification from the square area in A. Note the presence of the fibrous capsule (arrow) and dilated vessels in the adjacent areas (H & E stain; original magnification x450).

reduction of dentine permeability (Pashley, 1985; Pashley, 1996) thus lessening the potential toxic action of materials.

Note that the scenario for pulp capping is quite different.

RDT is irrelevant since the test material is in direct contact with the exposed pulp. In a clinical situation pulp reactions depend on several factors, i.e. toxicity of the capping material, location of the exposure, dimension of the exposure, presence of infected or affected dentine, and maturation of the tooth. Under these conditions the ability of the pulp to react to different injuries is significantly compromised, especially when a pulp exposure was caused by a caries lesion. Understandably pulp reactions are very different from the usage tests conditions, in which healthy pulps are exposed and essentially only the toxicity of the capping materials is tested.

Another difference between the experimental usage tests and the actual clinical situation is the location of the preparation. According to the ANSI/ADA Spec. #41(ISO 7405 Standards) placement of the cavity has to be in dentine. In clinical practice however, caries lesions are frequently occurring in root cementum, especially in the older population. Consequently, there are two factors to consider.

First, after removal of caries the RDT is usually small.

However, dystrophic calcification is a mitigating factor reducing the reaction of the pulp (Amir et al, 2001).

Secondly, root cementum is very thin and easily destroyed during cavity preparation resulting in postoperative immediate or late dentine sensitivity (Murray et al, 2000; Murray et al, 2001).

Realising the differences between the results of the usage tests and the actual clinical situation, some researchers have induced inflammatory pulp reactions prior to pulp exposures and placement of the capping material (Mjör and Tronstad, 1972; Mjör and Tronstad, 1974; Lervik and Mjör, 1977).

Most of these experiments revealed that under these conditions the reparative ability of the pulp was similar in all samples depending on the type of material tested. From a clinical point of view the experiments performed in humans revealed that it is not possible to analyse the pulpal cellular changes that take place based on signs, symptoms and vitality tests. This has lead to the conclusion that pulpal responses to a restorative material or operative technique are best analysed by histopathological and histomorphometric methods (Browne et al, 1980; Warfvinge, 1987; Pameijer, 1992; Accorinte et al, 2005; Nowicka et al, 2013).

Unfortunately, the cellular events are not easily standardised and measured, especially when teeth of young individuals are used. A greater capacity to respond to different type of insults has been observed (Björndal et al, 1998).

In summary, results of experiments on healthy teeth with intact pulps in animals or humans are mostly reliable but should nevertheless be interpreted with caution as these conditions may be more favorable than the actual clinical situation. To date, there are no standardised studies on the healing of pulps in teeth with inflamed pulps when adhesive restorative techniques are used. In teeth showing some degree of pulpal inflammation beneath a deep caries lesion, the adaptation and penetration of resin-based materials after acid etching may be prevented by the early mineralisation of peritubular dentine and precipitation of dissolved mineral salts within the lumen of dentinal tubules. In addition, the augmented pressure exerted by fluids in the dentinal tubules of an inflamed pulp may also prevent the penetration of resins. Vasoconstrictors in anaesthetic solutions may decrease the internal pressure of an inflamed pulp (Ciucchi et al, 1995) causing another variable. What should be emphasised is that defence against pulpal inflammation is not unlike what occurs in other connective tissues in the body (Holland et al, 2001; De Rossi et al, 2014). With one

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Figure 5: A: SEM microphotograph of a dentine surface treated with 37% phosphoric acid for 20 seconds followed by 5.25% EDTA solution and finally rinsed with sterile twice-distilled water. Note the empty dentinal tubules and the microporosity of the intertubular dentine (arrows), which was caused by the acid (original magnification x4000). B: SEM microphotograph showing the unprotected dentine collagen fibers (arrows) after acid-etch treatment (Original magnification x5000). (Courtesy of Dr Jorge Olmos)

exception, the dental pulp is confined within hard tissues causing a very different reaction resulting in pain. The many studies on the pulp/dentine reaction to adhesive dental materials are unfortunately characterised by important differences in the tests methods. In our opinion, it is necessary to use one single and universally accepted standardised method to allow comparison of the results between different researchers. The ANSI/ADA Spec. #41 or ISO 7405 (the guidelines have most recently been synchronised) offer this possibility but the guidelines are more often not followed carefully, misinterpreted or ignored. Heyeraas et al (2001) have suggested that the use of new experimental technologies in conjunction with the present knowledge of morphogenetic factors and tissue engineering will allow researchers to find improved experimental methods in order to get a more reliable evaluation of the pulp/dentine complex to resin-based restorative materials and techniques.

Concluding remarks The use of intact teeth in animals or humans to determine pulpal responses to different operative techniques and/or materials does not accurately mimic the typical clinical situation since healthy teeth without caries or inflamed pulps are used for testing of experimental materials. However, the biocompatibility of these materials and the degree of pulp reaction it produces provide good evidence as to the suitability for commercial use. The ultimate test, however, is the performance in humans.

Pulp/dentine complex reaction to resin-based materials The advent of bonding in restorative dentistry by means of the acid etch technique was introduced in the mid 1950s

by Buonocore (1955) and based on resin technology developed by Hagger (1951). Early strong resistance slowly gave way to general acceptance and bonding materials and techniques completely changed the way dentistry is being practiced today. Initially only hydrophobic resins were available. However, over time these were supplanted by hydrophilic resins and about 30 years of research resulted in a change from using 85% phosphoric acid liquid for 60s to etch only enamel to 35-37% phosphoric acid gels for 15s–20s to etch both dentine and enamel. The biologic and clinical effects of the early restorative materials were dramatic for dentine and pulp tissues. Most of the treated teeth reacted with severe pulpal inflammation and pulp necrosis (Langeland, 1966; Heyeraas et al, 2001). Consequently, the majority of these teeth required endodontic therapy or were extracted by emergency dental services. More recently, restorative materials and techniques have improved by gaining knowledge of enamel and dentine bonding procedures. Currently tooth-colored resins are the material of choice by most clinicians. These improved resins are based on dimethacrylate monomers comprising a matrix of resins and inorganic fillers. The total-etch technique using phosphoric to etch enamel and dentine as part of adhesive restorative treatment has been an issue of concern. However, a study by Lee et al as early as 1973 demonstrated that phosphoric acid gels at a concentration of 35%-37% for 15s–20s did not notably increase the permeability of dentine. When higher concentrations (50%-72% for five minutes) were used the acid only penetrated a few micrometers into dentine and did not reach the pulp chamber. The same was observed in deep cavities (Lee at al, 1973). Aida et al (1980) used different concentrations

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of phosphoric acid (10%, 30%, 50% and 70%) to investigate clinically and histopathologically the effect of the total etch technique. Pulp reactions were studied in 120 class I cavities of vital human permanent teeth in patients ranging from 10 to 42 years in age. None of the phosphoric acid concentrations elicited pulpal inflammation. Similar results were obtained by Retief et al (1974). Why this does not happen is a legitimate question to ask. Perdigão and Lopes (1999) offered two explanations. Because of the high concentration of the phosphoric acid, crystals of calcium phosphate are formed, which block the deeper penetration of the acid. Secondly, the interaction of the acid with dentine is limited by the buffering action of the hydroxyapatite and protein contents of dentine. These observations suggest that the limited penetration of phosphoric acid into dentine and the subsequent removal by vigorous rinsing do not have a deleterious effect on the pulp. Furthermore, Zmener and Kokubu (2003; unpublished data) observed that 35% or 37% phosphoric acid for 15 seconds in direct contact with vital rat pulps, followed by vigorous rinsing with sterile twicedistilled water, did not have a harmful effect. In this experiment the pulps were protected with a silicone film followed by a glass ionomer cement. After 15 days, histological analysis of the pulps showed a thin fibrous layer with normal pulp tissue (Figure 4). The main difference of opinion among researchers revolves around the question as to whether the total etch technique caused pulpal inflammation or does it make the dentinal tubules more permeable to the toxic components of resin-based materials.

Yet, many practitioners still prefer to use cement bases or liners for pulp protection, in spite of scientific data that has demonstrated that treatment of dentine by acid etching constitutes a biologically acceptable procedure (Tay et al, 1997; Perdigão and Lopes, 1999; Armstrong et al, 2003; Toledano et al, 2007). From a clinical point of view the preventive use of bases or liners to protect the pulp cannot be criticised, however, it can significantly reduce the dentine surface available for bonding.

Acidic agents Phosphoric acid as well as other acidic agents on dentine surfaces will remove the smear layer caused by cavity preparation, demineralise the dentine and widen the dentinal tubules. This has been conclusively demonstrated by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), which showed resin tags penetrating the dentinal tubules (Perdigão and Lopes, 1999; Breschi et al, 2008; Tjäderhane et al, 2013) giving the restorative material “micromechanical retention” which is frequently erroneously interpreted as an “adhesive mechanism”. The acidic agents also increase the

microporosity of the intertubular dentine leaving the collagen fibres unprotected (Figure 5). In a study using transmission electron microscopy (TEM), Tay et al (1997) demonstrated that acid treatment of dentine in deep cavities does not cause harmful effects on the pulp. Their data has been confirmed

by Ferracane and Condon (1990) who showed that the actual cause of pulp damage comes from leaching of residual unreacted monomers and the elution of other leachable components from the resins. The toxic effects produced on cell cultures and connective tissues, which were in direct contact with adhesive resins were largely investigated by several authors (Hanks et al, 1991; Rathbun et al, 1991; Costa et al, 2000). The unreacted monomers persist in polymerised resins and undergo a rapid elution from the bulk of the material. Costa et al (2000) demonstrated that the leaching of unbound molecules along with other components from resin-based materials caused severe inflammatory reactions on the subcutaneous connective tissues of the rat. On many occasions the severity of the inflammation persisted during long-term periods. These findings agreed with those of Rathbun et al (1991) who observed loss of components from BIS-GMA dental composites in organic water-based mediums.

Most of the present adhesive systems are composed of light polymerisable hydrophilic monomers which micromechanically attach to the collagen fibres that are exposed after acid-etching of dentine. This structure is composed of a mixture of residual hydroxyapatite crystals and resin impregnated collagen fibers, commonly referred to as the hybrid layer (Erickson, 1992). The remaining hydroxyapatite crystals tend to stabilise the collagen and prevent its denaturation and collapse (Perdigão and Lopes, 1999). Clinical steps to avoid collagen collapse after etching involve lightly drying the dentine with filtered compressed air leaving the surface slightly moist. Too much drying will result in desiccation of dentine causing collapse of the collagen which will prevent the penetration of the adhesive resin (Gwinnett, 1992).

The final step of the restorative treatment is to placement of a tooth-colored resin composite to restore form, function and aesthetics. According to Van Meerbeck et al (1994) the hybridisation of collagen is a very important step. The authors reported that of a total of 1,117 class V cavity preparations in 346 patients evaluated after six months and three years, the group in which the smear layer was removed and hybridised behaved clinically better compared to the group without that treatment. However, many studies demonstrated that the hybridised areas are subjected to further degradation processes which in turn significantly reduced the long-term durability of the restorations. Over time the mineralised

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dentine matrix may be destroyed by the acidic environment produced by the microbial products and the activation of endogenous matrix metalloproteinases (MMPs) and cysteine cathepsins, a group of fossilised mammalian collagenolytic enzymes expressed by odontoblasts that are present in the dentine matrix and capable of degrading extracellular matrix components (van Strip et al, 2003; Sorza et al, 2004; Carrilho et al, 2007; Sulkala et al, 2007; Tersariol et al, 2010; Liu et al, 2011). These events occur because after acid etching adhesive monomers are unable to fully cover the exposed collagen fibrils, which remain vulnerable to the time-dependent MMPs and cysteine cathepsins attack. Based on the knowledge of the role of these enzymes in the hybrid layer degradation process researchers have proposed different strategies to prevent the collagenolytic degradation of the resin/dentine interface. Among these strategies the MMPs and cysteine cathepsins inhibition by specific agents such as galardin (Breschi et al, 2010), or non-specific ones such as chlorhexidine digluconate (CHX) (Gendron et al, 1999; Hebling et al, 2005; Bracket et al, 2007;

Tjäderhane et al, 2013) and ethylene diaminetetracetic acid (EDTA) (Osorio et al, 2005; Thompson et al, 2012) have been reported to be effective to protect the resin/dentine interface. CHX appears to be the most accepted method as in addition it has disinfection properties.

The hydrolytic degradation of the resin/dentine bond is another issue of concern that clinicians should be aware of.

Water sorption of the resin/dentine interface is considered responsible for adhesion degradation (Feitosa et al, 2012).

In an ex vivo experiment Van Landuyt et al (2010) reported considerable degradation of the resin/dentine interface after a relatively short six months storage in water. In a clinical situation, however, the resin/dentine interface is usually protected by the surface resin/enamel bond (Torkabadi et al, 2009; Reis et al, 2008). Howver, hydrolytic degradation of the resin/dentine bond is of concern. A vital pulp has a permanent hydrostatic water pressure provided by blood and lymphatic circulation (Heyeraas, 1989). Therefore, under in vivo conditions, the main source of water uptake by the resin/dentine interface is through the dentinal tubules due to

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pulpal pressure. (Feitosa et al, 2012). This pressure together with MMPs and cysteine cathepsins allow for degradation of the hybrid layer, which negatively affects the long-term durability of the restoration. A worse scenario caused by enzymatic and hydrolytic degradation is the subsequent bacterial penetration into the dentinal tubules and diffusion of their endotoxins often resulting in pulpal inflammation and eventual periapical pathosis (Tay et al, 1994; Bergenholtz, 2000; Mjör and Ferrari, 2002; Zmener, 2014). Beneath resin restorations or in carious affected teeth with permeable dentine, bacteria can reach the pulp chamber causing irreversible inflammation. When dentine is highly calcified, however, bacteria appear to be less dangerous (Björndal and Mjör, 2001). Clinicians must be aware that in deep caries lesions, the leathery dentine is invaded by bacteria.

Below it, bacteria and their toxic by-products have advanced towards the pulp or have reached the pulp tissues already.

In a histological study in human patients between 1990 and 2000 at the endodontic department of a private clinic (Zmener and Domingues; unpublished data), 852 teeth presenting with asymptomatic deep carious lesions without pulp exposures endodontic treatment was indicated. After the pulps were extirpated they were fixed in 10% buffered formalin and prepared for histological evaluation.

Microscopic findings of Hematoxylin and Eosin (H&E) stained sections revealed that 13.14% presented with acute inflammation, 76.76% were chronically inflamed, while 10.09% were necrotic. In both acute and chronically inflamed pulps the pathology was mainly observed in the coronal pulp. Other common histopathological findings in the chronically inflamed pulps were the presence of a great number of lymphocytes, macrophages and multinucleated giant cells. It has been long recognised that macrophages and lymphocytes are specific target cells in recognising antigenic products (Jontell et al, 1998). Macrophages are essential cells to phagocyte foreign particles, dead cells (mainly polymorphonuclear and red cells) or foreign bodies (Metzger, 2000) to be further processed by lymphocytes. As is the case in other inflamed tissues of the body, this mechanism is produced in the pulp via intercellular connections. These intercellular connections are not detectable in stained paraffin sections, but easily observed with the SEM (Zmener and Pameijer, 2012).

Recovery of the pulp is the ultimate goal after caries removal and cavity restoration with adhesive resin-based materials. Even in the presence of a mild or moderate inflammatory reaction the pulp can heal, providing atraumatic clinical procedures are practiced for cavity preparation and restoration. Tertiary dentine (reparative dentine) has been deposited on the pulp chamber walls,

especially under caries affected areas. Tertiary dentine is formed by surviving odontoblasts or by newly developed odontoblast-like cells and is an indication of pulp healing.

However, in teeth with deep caries lesions that have affected the pulps there is almost no chance for healing. A case in point is an early assay by Mjör and Tronstad (1974), who induced severe pulp pathologies in healthy monkey teeth by filling deep cavities with soft caries dentine. After different time periods the cavities were excavated and restored.

Eighty two and 90 days postoperatively, the teeth were extracted and prepared for histological evaluation. The results showed that the pulps had healed by apposition of tertiary dentine. It should be emphasised, however, that essential differences exist between the results from the above described simulated caries attacks in teeth with healthy pulps and progressive caries affected teeth in a clinical situation with subsequent restorative treatment.

Summary and concluding remarks In cases of deep caries lesions endodontic treatment is not necessarily always indicated. With proper restorative materials and techniques the pulp, even when inflamed, has the capacity to heal, thus maintaining the vitality of the tooth.

Adhesive dentistry involving acid-etch-techniques and resinbased materials can be used successfully as long as practitioners have an understanding of the biocompatibility and physical properties of the materials they use.

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step self-etching dental adhesives on human periodontal ligament fibroblasts in vitro.

J Adhes Dent 18: 99 – 109 Tay FR, Gwinnett AJ, Pang AM, Wei SHY (1994) Structural evidence of sealed tissue interface with a total-etch wet-bonding technique in vivo. J Dent Res 73: 629 – 636 Tay FR, Gwinnett AJ, Wei SH (1997) Ultrastructure of the resin-dentine interface following reversible and irreversible rewetting. Am J Dent 10: 77 – 82 Tersariol IL, Geraldeli S, Minciotti CL, Nascimento FD, PääKkönen V, Martins MT, Carrilho MR, Pashley DH, Tay FR, Salo T Tjäderhane L (2010) Cysteine Cathepsins in human dentine – pulp complex. J Endod 36: 475 – 481 Thompson JM, Agee K, Sidow SJ, McNally K, Lindsey K, Borke J (2012) Inhibition of endogenous dentine matrix metalloproteinases by ethylene diaminetetraacetic acid. J Endod 38: 62 – 65 Tjäderhane L, Carrillo MR, Breschi L, Tay FR, Pashley DH (2012) Dentine basic structure and composition – an overview. Endod Topics 20: 3 – 29 Tjäderhane L, Nascimento FD, Breschi L, Mazzoni A, Tersariol ILS, Geraldeli S, Tezvergik – Mutulay A, Carrilho MR, Carvalho RM, Tay FR, Pashley DH (2013a) Optimizing dentine bond durability: control of collagen degradation by matrix metalloproteinases and cysteine cathepsins. Dent Mat 29: 116 – 135 Tjäderhane L, Nascimento FD, Breschi L, Mazzoni A, Tersariol ILS, Geraldeli S, Tezvergil-Mutulay A, Carrilho M, Carvalho RM, Tay FR, Toledano M, Osorio R, Osorio E, Aguilera FS, Yamauti M, Pashley DH, Tay F (2007) Durability of resindentine bonds: effects of direct/indirect exposure and storage media. Dent Mat 23: 885 – 892 Torkabadi S, Nakajima M, Ikeda M, Foxton RM, Tagami J (2009) Influence of bonded enamel margins on dentine bonding stability of one-step self-etching adhesives. J Adhes Dent 11: 347 – 353 Van Dijken JWV (2004) Durability of three simplified adhesive systems in class V non-carious cervical dentine lesions. Am J Dent 17: 27 – 32 Van Dijken JWV, Pallersen U (2015) Randomized 3 – year clinical evaluation of class I and II posterior resin restorations placed with a bulk-fill resin composite and a one-step self-etching adhesive. J Adhes Dent 17: 81 – 88 Van Landuyt KL, De Munck J, Mine A, Cardoso MV, Peumans M, Van Meerbeck

B (2010) Filler debonding & subhydric-layer failures in self-etch adhesives. J Dent Res 89: 1045 – 1050 Van Meerbeck B, Peuman M, Verschueren M, Gladys S, Braem M, Lambrechts P, Vanherle G (1994) Clinical status of ten dentine adhesive systems. J Dent Res 73: 1690 – 1694 Van Strip AJ, Jansen DC, DeGroot J, ten Cate JM, Everts V (2003) Host-derived proteinases and degradation of dentine collagen in situ. Caries Res 37: 58 – 65 Vasiliadis L, Darling AI, Levers BGH (1983a) The amount and distribution of sclerotic human root dentine. Arch Oral Biol 28: 645 – 649 Vasiliadis L, Darling AI, Levers BGH (1983b) The histology of sclerotic human root dentine. Arch Oral Biol 28: 693 – 700 Warfvinge J (1986) Dental pulp inflammation; experimental studies in human and monkey teeth. Swed Dent J. Suppl. 39: 1 – 36 Warfvinge J (1987) Morphometric analysis of teeth with inflamed pulp. J Dent Res 66: 78–83 Wataha JC (2012) Predicting clinical biological responses to dental materials.

Dent Mat 28: 23 – 40 Wenckert – Andersson IE, Van Dijken JWV, Kieri C (2004) Durability of extensive class II open – sandwich restorations with a resin – modified glass ionomer cement after 6 years. Am J Dent 17: 43 – 50 Zhang W, Walboowers F, Jansen JA (2008) The formation of tertiary dentine after pulp capping with calcium phosphate cement loaded with PLGA microparticles containing TGF- 1. J Biomed Mat Res 85A: 439 – 444 Zmener O, Pameijer CH (2012) Scanning electron microscopy of periapical granulomas of endodontic origin. Rev Asoc Odontol Argent 100: 77 – 83 Zmener O (2014) Operative Dentistry and Endodontics. 1. The degraded resin-dentine interface allows for bacterial penetration: An open route to the dental pulp. Rev Asoc Odontol Argent 102: 145 – 149

Reprinted with permission by Endodontic Practice February 2018

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INTERVIEW

Step by step from VITA ENAMIC blank to inlay Julia Bühler1

VITA ENAMIC has been used clinically for more than five years. The spectrum of possible applications ranges from inlays to veneers to crowns. In the following interview, Senior Physician Dr. Julia Bühler (University Center for Dental Medicine, Basel, Switzerland) uses a case study to report on her experiences and describes key clinical success factors.

How do you evaluate the clinical use of VITA ENAMIC and what do you think are the advantages, as compared to traditional ceramics?

Thanks to the material properties, there is more freedom in the preparation, e.g., when space is limited. And processing is easy: Milling and polishing can be carried out much faster.

What are the key clinical success factors for using hybrid ceramics for single tooth restorations?

The more flexible preparation is less invasive. The material is more forgiving than traditional ceramics in less favorable conditions, such as with thin edges. Its easy workability is also an advantage in everyday clinical practice: Intraoral corrections/repairs can be carried out simply and safely (in this case, conditioning with aluminum oxide instead of hydrofluoric acid).

What should dentists focus on and what are the critical process steps?

Complying with preparation guidelines remains essential for achieving a good, longlasting restoration. Despite the polymer content, VITA ENAMIC is ultimately a ceramic: It is important to observe minimum layer thicknesses. During the insertion process, it is important to keep the area completely dry, and the workpiece and the tooth must be pretreated very carefully. Maintaining the right conditioning times is also essential for longterm success.

For the manual finishing of VITA ENAMIC, a special polishing set is recommended by the manufacturer – what experience have you had with this?

1

Dr. Julia Bühler, Senior Physician, Basel, Switzerland

®

VITA and other VITA products mentioned are registered trademarks of VITA Zahnfabrik H. Rauter GmbH & Co. KG, Bad Säckingen, Germany.

The set works perfectly. By using different abrasive polishers for the pre-polish and highgloss polish, restorations can be polished to a high gloss in a matter of seconds. The wear of the polishing instruments was significantly reduced with the latest generation.

How durable do the restorations appear to be in the follow-up appointments, for example regarding surface quality?

I've been regularly working with VITA ENAMIC for about four years now and so far – from a subjective standpoint – I have no complaints. The surface durability seems to be comparable to more traditional ceramics. However, we will have to wait for long-term studies to be conducted.

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Figure 1: Initial situation: Tooth 26 has been restored with an insufficient amount of amalgam.

Figure 2: Preparation: Even when VITA ENAMIC is used, the minimum layer thicknesses of the material must be adhered to.

Figure 3: Preparation: If dentine support is insufficient, it is recommended to reduce the cusps.

Figure 4: Production result: Hybrid ceramics can be milled very quickly.

Figure 5: Post-processing: The VITA ENAMIC Stains Kit is recommended for shade characterization.

Figure 6: Situation under the rubber d dam: Fine adjustments and final polishing are made easy with the polishing set.

Figure 7: Final result immediately after the removal of the rubber dam: The hybrid ceramic has already adapted perfectly to the natural tooth substance.

In the present case, you have characterized the inlay with VITA ENAMIC shades. How can you achieve good intraoral color durability?

longer the polymerization. The recommended minimum times from the manufacturer may be doubled.

It is important to have sufficient light curing. As a general rule of thumb, the darker and more opaque the shades, the

Source: swiss dental community, 6/2017, teamwork media GmbH, Germany

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CASE REPORT

Press for success using an extraordinary combination of strength and aesthetics Carsten Fischer1

Introduction The aim of an all-ceramic rehabilitation is to achieve a functional, aesthetically pleasing, long-lasting restoration. There are many criteria which determine the route chosen (patient-specific parameters, preparation, material, fixture, etc.), but these should not affect the defined objective. It is therefore essential that technicians respond flexibly to situations and select the “perfect” material and the optimal manufacturing process on an individual basis. For us, the option to work in the digital workflow is a strong argument for a material.

Many materials and different production technologies exist for manufacturing allceramic restorations, which all have their benefits and must be selected by the technician on a case-by-case basis.

1. A “keyboard” of pressable ceramics Which ceramic is best suited to which indication? At this point, it’s worth taking a look at the wider ceramics family. A statement by the DGZMK (The German Society of Oral and Maxillofacial Surgery) divides pressable ceramics into: 1. Material composition: oxide ceramics, silicate ceramics 2. Manufacturing process: integral shape, casting, hot pressing, copy grinding, CAD/CAM 3. Clinical application: conventional cementation, fixed using adhesive

1.1 Differentiation by material composition

1

Carsten Fischer, MDT Sirius Ceramics, Frankfurt am Main, Germany

Silicate ceramics (e.g. feldspar and glass ceramics) are ideal for restorations on individual teeth (veneers, inlays, onlays) because they behave similarly to enamel. With values of between 50 to 200 MPa, it has low bending strength. In the jaw area, which is under a lot of functional strain, or in multi-faceted restorations, oxide ceramics are preferable (e.g. zirconium oxide). They have a low proportion of glass, resulting in high resistance (bending strength of conventional zirconium oxide of 1000 to 1200 MPa). The limited light-optical properties are balanced out to some degree using a veneer or translucent zirconium oxide (3rd generation). (“Cave: There is a correlation between translucency and strength. The higher the translucency of zirconium oxide, the lower its bending strength). Lithium disilicate has also been established as an equivalent.

The strong glass ceramic has a high crystalline proportion of lithium disilicate and lithium orthophosphate. Thanks to improved light-optical properties, the material is also wellsuited to, and safe for, monolithic treatments. Conventional lithium disilicate (IPS e.max) has an average final strength of around 360 MPa. We are now hearing discussions that this is just the “lower” measured bending strength and that the actual value is higher.

However, in this area we practicians are initially guided by the comprehensive studies from the past few years, in which the researchers always assumed 360 MPa.

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Figure 1: Overview of the four different translucency levels of GC Initial LiSi Press with fluorescing properties

Figure 2: LiSi Press after pressing: the non-existent or very thin reaction layer simplifies removal from the mould and blasting.

1.2 Differentiation by manufacturing process

• Lithium disilicate (e.g. IPS e.max, GC Initial LiSi Press): pressing, grinding (e.max) • Oxide ceramic (e.g. Zirlux zirconium oxide): milling • Veneering ceramic (e.g. GC Initial): manually “ The press technology is highly relevant when manufacturing pressable ceramic restorations and is an essential component of day-to-day life in our laboratory.

CAD/CAM (grinding, milling) and pressing should be mentioned as manufacturing technologies for pressable ceramic restorations. The choice of manufacturing method generally depends on the material. For example, oxide ceramics are now used using CAD/CAM technology. Press technology (lost wax technique) is a popular process for glass ceramics and lithium disilicate. A hybrid technology is also often used, in which wax objects are milled by machine and then pressed in the classic fashion.

We prefer this method in our day-to-day work when lithium disilicate is used. With the hybrid technology, we can make maximum use of the benefits of the digital workflow and minimise faulty steps in the manual technology.

Examples from everyday use in the laboratory - material and manufacturing technology • Hybrid ceramic (e.g. Cerasmart): grinding

The decision on the type of clinical fixture for a pressable ceramic restoration is based on the material’s bending strength. Ceramics with a bending strength of under 350 MPa are fixed using adhesive. For ceramics with a bending strength of more than 350 MPa, there is a choice between conventional, self-adhesive or adhesive fixture.

The criteria mentioned demonstrate the wealth of ceramic materials that a dental laboratory has to work with. To be able to cover everything, it is hardly enough to have only

Figure 3: With around 450 MPa, this provides a high degree of safety for monolithic restorations in the posterior region.

Figure 4: Higher resistance also provides a safe basis for a partially reduced veneer (Initial LiSi).

1.3 Differentiation by clinical application

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Figure 5: Optimal interface to GC Initial LiSi. This veneering ceramic has been manufactured exclusively for lithium disilicate structures.

Figure 6: The initial situation poses Figure 7: Insufficient restorations in the a major challenge for us as the upper posterior region and tooth team responsible for treatment. structure damage in the front tooth area.

one pressable ceramic system. This is why a carefully thought-through ‘keyboard’ of pressable ceramics is used in our laboratory. The transitions are often fluid and sometimes “blurry”, but we need different pressable ceramic materials nonetheless. With a graded range, we make individual aesthetically pleasing and clinically long-lasting restorations for each patient, without losing sight of the need for efficiency in everyday life in the laboratory.

2. Press technology as a building block for success One “key” on our pressable ceramic keyboard is press technology and we gratefully profit from its advantages.

These include the 1:1 transposition of wax modelling into ceramic, the efficient process, the high quality of the material and the good aesthetic results. Because there is often no need for conventional stratification, this reduces the amount of work required, the sources of errors and the factors which can affect the material’s structure. For us, the indication “monolithic” is a decisive argument for a material. In our laboratory, monolithic restoration in the posterior region has been established as a firm standard. An overview of the benefits of press technology: • Loss-free transfer of wax modelling to ceramic, • Aesthetic benefits, • Precise moulding of edge regions, • Microscopically exact ceramic layers, • No sinter shrinkage.

The success of press technology can be traced back to the innovative material lithium disilicate - high-strength glass ceramic.

When deciding on a new lithium disilicate, we set the bar high and take our lead from the classic IPS e.max Ivoclar Vivadent (Schaan, Liechtenstein). The newcomer GC Initial LiSi Press is generating a beneficial impetus for this standard.

IPS e.max Press set a bar that is still viewed as the standard across the board today. This relates to both the

aesthetic qualities and the physical properties. We have also come to recognise the benefits of lithium disilicate and won’t accept limitations in a new product where it is concerned.

We’ve been spoilt by the good light-optical properties, the wide range of colours and translucency, and the high strength for a glass ceramic. Today, we are no longer able to do without these features. Based on the existing standards, there has been an impressive process of development over the past few years in which other manufacturers were also involved, e.g. GC (GC Europe, Leuven). Now, with GC Initial LiSi Press, there is another lithium disilicate available for pressing which combines the aforementioned advantages and develops them further.

3. GC Initial LiSi Press GC LiSi Press has succeeded in optimising the physical properties and material qualities. Furthermore, the colour saturation has been amended. On the one hand, the fluorescent effect is well-balanced and natural. On the other, the levels of value and chroma are ideal and this can be seen in the higher colour density. The opportunities that GC Lustre Pastes and GC Initial LiSi veneering ceramic offer are also impressive. We can work within a rounded product portfolio which opens up excellent opportunities.

• Optimised material qualities, • Improved light-optical properties (colour density), • Simplified manufacturing process, • Ideal equivalent: LiSi veneering ceramic, Lustre Pastes.

3.1 Optimised material qualities Essentially, the physical properties of a ceramic are influenced by the composition of the raw materials and the added materials, as well as the manufacturing process.

Among other things, the grain size determines the quality of the material. GC Initial LiSi Press has a refined grain. The

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Figure 8 and 9: The prepared posterior teeth prior to impression.

Figure 10: The situation was cleanly moulded using polyether impression-making material.

High Density Micronization (HDM) technology was developed specially for the manufacture of this lithium disilicate. This results in evenly dispersed lithium disilicate microcrystals which fill the entire glass matrix. (“Cave: if the crystals are larger, the matrix structure cannot be fully exploited.) The small grains are the basis for LiSi Press’s good material properties. From our perspective as practicians, it makes complete sense to continue developing the basic substance. The smaller the grain, the less the glass matrix is open to attack, through etching, for example, and the greater the apparent resistance to ageing. For single tooth crowns on implants, for example, this increases our confidence in the long-term stability. The individual small grain also helps to ensure effective polishing. The residual roughness is considerably reduced. The surfaces are extremely smooth and homogeneous. It should also be noted that the refined grains also ensure lower abrasion values and greater ageresistance.

3.2 Improved light-optical properties HDM technology also seems to have a positive impact on the aesthetic qualities. LiSi Press is divided into four levels of translucency, the nomenclature of which takes its lead from IPS e.max. As technicians, therefore, we don’t have to learn any new terminology but can work with the different translucency levels as usual: HT (= highly translucent, high translucency), MT (= medium translucent, medium translucency), LT (= low translucent, low translucency), MO (= medium opaque, barely translucent) (Fig. 1).

The colour density is adapted to the natural tooth substance. The fluorescing qualities and the optimised value guarantee aesthetically pleasing results, with barely any difference from the natural tooth. It is even possible to

Figure 11: The wax models sprued on the ring base with the front tooth crowns as an example.

perform monolithic restorations in the posterior region without noticeable aesthetic issues. With monolithic application, we have previously been able to achieve impressively natural-looking results.

3.3 Simplified manufacturing process We distinguish between the pressing of manually modelled objects and the pressing of milled wax structures. The actual pressing process is similar to the usual process in essence.

What makes LiSi Press’s manufacturing process unique is the thin reaction layer (Fig. 2). There is no need for “etching” acidification in hydrofluoric acid after removal from the mould. This is another convincing argument for the new pressable ceramic. We would ideally like to remove an application as sensitive and critical as acidification from our laboratory. This makes the procedure and the working processes within the laboratory considerably safer. The extremely thin reaction layer after pressing is based on the investment LiSi Press Vest, a new development from GC. The manufacturer is highly skilled in the area of investment materials and in this case, they concentrated on the timeconsuming reaction layer after pressing. The problem was solved with a special formula. There is barely any reaction layer present, making the process of removal from the mould considerably simpler. The pressed object is just blasted with glass beads. After this, the technician focuses directly on refining the restoration. In our experience, 15 to 20 minutes can be saved for each unit.

3.4 Veneering technology GC Initial Lustre Pastes NF are used to refine monolithic restorations (Fig. 3). The three-dimensional ceramic stains encourage high colour depth and ensure vibrant

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translucency. Where aesthetics are concerned, we like to work partially monolithically and veneer the visible portions with GC Initial LiSi (Fig. 4). This veneering ceramic includes a colour and layer system (Fig. 5) which distinguishes itself through an agreed heat extension coefficient, a low firing temperature and high stability. It is not complicated to use and can be used in both individual layering, which many technicians like, and in the cutback technique. We prefer partial monolithic veneering and have had very good and stable results with it for many years now. We always design critical areas (palatal, occlusal) fully anatomically. This means that aesthetic aspects and safety are perfectly combined.

GC Initial LiSi Press combines strength and aesthetic aspects. The material can be used for many indications and its shape and colour remain wholly stable, even after multiple firings.

Strength: • 450 MPa Indications: • Tabletops/partial crowns • Veneers, inlays • Crowns in the front and posterior region • Implant crowns Aesthetics: • Perfect fluorescence and opalescence Process: • Classic press technology (LiSi Press Vent) but with extremely thin reaction layer • Veneering technology: GC Initial Lustre Pastes NF, GC Initial LiSi veneering ceramic

tooth area, partially anatomically reduced crown frameworks were to be produced and veneered.

4. Case report

Symbiosis: Classic tool and digital workflow

The patient consulted the practice with a challenging situation in her upper jaw (Fig. 6 and 7). She had insufficient metal ceramic restorations in the posterior region. The front tooth area had a marked lack of hard tooth tissue. After an initial diagnosis and consultation, pressable ceramic rehabilitation was chosen. For us, portrait photography is an important component of diagnosis, as it can be used to collect important information for planning the therapy. In this case, it was important to consider the origins of the tooth damage, which could be traced back to defective functions, to provide a restoration based on gnathological criteria. Because it can be worked perfectly in the posterior area using manual modelling, we opted for press technology. The eight individual crowns were to be constructed first in the CAD software, then milled in wax, finely reworked manually (edge regions, occlusion) and then pressed in ceramic. In the front

CAD/CAM manufacture of wax crowns was followed by manual adaptation. Essentially, fine modelling requires our gnathological knowledge and manual skills. We use these tried-and-tested dental tools every day, despite CAD/CAM and digital aids. The art lies in being able to interpret and implement the connections between form and function. With a probe and modelling wax, we developed a morphology which follows the biomechanical criteria. All functional surfaces were cleanly modelled, both dynamically and statically. We carefully created cusps, fine bulges, delicate fissures, strips and all the other functional elements inside a tooth in wax. The individual crowns were fixed to the ring base of the muffle using wax wire and a sprue. To guarantee a smooth flow of viscose ceramic during the pressing process, the sprue should be fixed in the direction of flow of the ceramic and at the thickest part of the wax object (Fig. 11).

4.1 Caring for the posterior teeth Preparation of the posterior teeth followed a functional pretreatment (Fig. 8 and 9). The preparation design was based on the known parameters for pressable ceramic restorations. The situation was cleanly moulded using polyether (Fig. 10) and the master model was manufactured in the laboratory.

As the material of choice, we viewed GC Initial LiSi Press as ideally suited. On the one hand, the dentist responsible for treatment is very familiar with the adhesive technology for implantation, which is a decision criterion for pressable ceramic. Functional criteria also played a significant role in the choice of material. Traditional pressable ceramic would be too soft for the relatively high strain of the chewing function. On the other hand, a conventional zirconium oxide would be too hard and, due to its light-optical properties as a monolithic structure, is not well-suited. It is also impossible to manufacture using press technology. This is why translucent zirconium oxide - lower bending strength - was also ruled out. We felt that press technology was the only suitable manufacturing process. It offers the major advantage that anything that we model in wax can be transferred to ceramic 1:1. The CAD/CAM wax crowns can be adapted precisely to the occlusal particularities using the articulator. It was in precisely this situation that taking into account the gnathological situation was a success for determining parameters.

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Figure 12: Spraying the wax surfaces with the SR liquid to refine the surfaces using the example of the front tooth crowns.

Figure 13: Thorough dispersal of the liquid with pressurised air using the example of the posterior tooth crowns.

Figure 13a-13b: The milling of wax in the CAD / CAM workflow is for us essential (hybrid technology)

Place in mould, press, remove from mould Investment is carried out using the phosphate-bonded investment GC LiSi PressVest. The wax surfaces are sprayed with the SR liquid in advance and any surplus is thoroughly dispersed (Fig. 12 and 13). SR liquid contains a high concentration of a surface-refining solution. This ensures that the reaction layer, which is minimal in any case, is easy to remove. The muffle could now be filled with the investment material, mixed according to the manufacturer’s instructions.

GC LiSi Press Vest has excellent flow capabilities (Fig. 14) but precise investment is essential for loss-free transfer of the modelling. In line with the instructions, the muffles were preheated (850 °C) and the pressing process was started once the pellet (Fig. 15) had been selected. (“Cave: We recommend the single-use pressing stamp. Quick cooling

after the pressing process should be avoided.)

After it had cooled, the muffle was cut into segments with a cutting disc. When doing so, one must ensure that it has cooled sufficiently. Next, the minimal reaction layer on the pressed objects was blasted with glass beads (pressure: 4 bars and then 2 bars).

“Cave: Aluminium oxide must not be used for removal from the mould. Hydrofluoric acid is not required.

Finishing The objects were finished with small ceramically-bound stones anddiamonds (Fig. 16 and 17). The rotating tools should be used at low rotational speeds, for cooling and with low pressure. One should avoid overheating the ceramic. After a pre-polish with rubber polishers (Fig. 18),

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Figure 14: The investment material GC LiSi Press Vest is characterised by particularly good flow capability.

Figure 16: Finishing the surfaces with small ceramically-bound stones.

Figure 15: The different colours and translucencies of the lithium disilicate GC Initial LiSi Press.

Figure 17: Finishing with diamantes. It should be ensured that it has cooled sufficiently.

Lustre Pastes and glazing were used for colouring.

Next, the monolithic restorations were checked on the model (Fig. 19 and 20) and cemented in the mouth in the practice using adhesive (G-CEM LinkForce, GC) (Fig. 21).

4.2 Caring for the front teeth Rehabilitation in the front tooth area had a high degree of difficulty (Fig. 22). The first requirement for a smooth redwhite procedure was a surgical crown extension. The dentist used a deep-drawing template of the set-up as orientation for the aesthetic sequence of the crown edges (Fig. 23 to 27). During the healing phase, CAD CAMmanufactured long-lasting temporary solutions helped to shape the ginigiva (Fig. 28).

Eight months later, an impression was taken of the situation (Fig. 29).

Figure 18: Pre-polish with coordinated special rubber polishers.

Producing the crown structures The master model was digitalised and the STL data were imported into the construction software (3Shape). The set-up (Fig. 30) could be milled in wax in accordance with the planning documents (Fig. 31) and could then be transferred into GC Initial LiSi Press. After the quick process of removal from the mould, the LiSi Press crowns fitted very well on the master model (Fig. 32).

Veneering To refine the front tooth crowns, the proportion of enamel was carefully reduced (cutback) (Fig. 33). To achieve good colour depth and vibrant translucency, we first applied GC Lustre Pastes (ceramic stains).

As a next step, the crowns were completed with incisal and effect materials (GC Initial LiSi) and fired (Fig. 35 and 36). (“Cave: The LiSi restorations should not be heated or

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Figures 19 and 20: Checking the monolithic posterior crowns on the model.

Figure 21: The situation post-adhesive cementation of pressable ceramic monolithic posterior tooth crowns.

Figure 22: Challenge: rehabilitation in the upper front tooth area.

Figures 24 and 25: Surgical crown extension and pre-preparation of the teeth for fitting of the long-lasting temporary solution.

Figures 24 and 25: Surgical crown extension and pre-preparation of the teeth for fitting of the long-lasting temporary solution.

Figure 23: A rail template visualised the ideal crown sequence in the cervical area.

Figures 26 and 27: Immediately after the surgical crown extension (left) and the situation after a few weeks (right).

cooled too quickly. Quick temperature changes can cause the material to tear. During firing, a suitable firing tray - e.g. a honeycomb tray - as well as retaining bolts and fluid firing pads should be used.)

Finishing

Figure 28: Post-operative situation with long-lasting temporary solution after eight weeks.

Even after just a few steps, the aesthetic restoration was almost finished (Fig. 37 and 38). The incisal edges were prepared and the surface texture created with purposemade special rubber polishers (Fig. 39 and 40). The polishing was designed simply (Reminder: small grain size)

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Figure 29: Eight months later: Preparation for impressionmaking.

Figure 30: Crowns constructed in the software for milling the wax caps.

Figure 31: The milled wax caps were....

Figure 32: ...transferred into LiSi Press using press technology..

Figure 33: Cutback in the enamel area as preparation for thin film veneering.

GC Lustre Pastes are then applied.

Figure 35: Finishing of the crowns with incisal and effect materials (GC Initial LiSi).

Figure 36: Firing on suitable honeycomb firing trays, matching retaining bolts and fluid firing pads.

Figures 37- 40 The structures, refined with thin-layer veneering, are finished in shape and morphology after firing (above) using specially designed rubber polishers.

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Figure 41: Situation immediately after adhesive cementation of the crowns.

Figure 42: Harmonious view of the lips. Shape and colour adapt extremely well.

Figures 43 and 44 Before/after juxtaposition. The patient was treated with individual pressable ceramic crowns in the upper front tooth and posterior region, after a functional pre-treatment and a surgical crown extension.

so as to achieve a smooth, homogeneous surface quickly.

After the restorations were checked on the model and in the mouth, the crowns were finally cemented (G-CEM LinkForce, GC) (Fig. 41 to 44). The light-optical properties of the front tooth crowns were impressive. A touch of veneering ceramic enabled us to achieve a vibrant internal play of colours.

5. Conclusion To be able to cover all indications for pressable ceramic restorations, we require different groups of materials (oxide ceramics, hybrid ceramics and lithium disilicate) depending on the indication. The manufacturing technique varies accordingly (cf. point 1.2). As a hybrid process, press technology has been a regular feature of everyday work in our laboratory for several years. Now that we have achieved excellent results with lithium disilicate for a long

time, we see in GC Initial LiSi Press a logical development and aesthetic improvements. The four benefits that are important to us are increased bending flexibility (450 MPa), increased light-optical properties (colour density), the simplified manufacturing process (minimal reaction layer) and the ideal counterpart to GC Initial veneering system (GC Initial LiSi), as well as the excellent Lustre Pastes stains.

Working within a system offers us a high degree of certainty that we will find the right material for the indication in question.

Acknowledgements The patient case study was created in collaboration with Dr Rafaela Jenatschke, Frankfurt. We would like to thank her and her team for their excellent collaboration, for the trust shown and for the teamwork which is essential for creating aesthetically pleasing and functional restorations.

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PRODUCTS

DENTAL PRO

GC

INTERDENTAL BRUSHES

G-AENIAL UNIVERSAL INJECTABLE

Quality Made in Japan with stainless alloy brush stem, more durable and longer lasting

G-aenial Universal Injectable is a beautiful, high strength universal composite, applied with irresistible convenience of direct injection delivery. GC’s ingenious composite technology heralds a new era in composite placement

Control Ergonomically designed, ridged octagonal handle for superior control, comfort and ultimately a better clean Comfort Unique two-stage bristle system, ultrasoft, slim bristles at the tip to allow for comfortable insertion with more rigid bristles are further down the brush stem for thorough plaque removal Resealable Packaging Convenient resealable package for safe hygienic storage Value Very competitively priced given the high quality materials used during the manufacturing process Available sizes - 0, 1, 2, 3, 4, 5

Universally Superior Technology G-aenial Universal Injectable features 150nm glass fillers densely packed and individually bound within a hydrophobic resin in an injectable consistency. The heightened structural density of G-aenial Universal Injectable is the foundation for its universally superior physical properties Universally Satisfying G-aenial Universal Injectable, features a wide shade selection with exceptional tooth-matching aesthetics and beautiful polish. Along with benchmark physical properties and strong radiopacity (252%AI).

Available in shades: BW, A1, A2, A3, A3.5, A4, B1, B2, CV, CVD, AO1, AO2, AO3, JE & AE 1.7g Syringe (1.0ml), 5 each of Dispensing Tip Needle & Dispensing Tip Long Needle & 1 Light protective Cap.

VOCO

KURARAY NORITAKE

MERON PLUS QM

CERABIEN™ZR FC PASTE STAIN

Resin-reinforced glass ionomer luting cement in QuickMix syringe In Meron Plus QM, VOCO offers a resin-reinforced glass ionomer luting cement in a paste-paste version in the practical QuickMix syringe, with all the advantages of the tried-and-tested Meron Plus products – from self-adhesion to the thin film thickness right up to the continuous fluoride release. High adhesion values above those of a conventional glass ionomer luting cement ensure secure and reliable hold even in unfavourable conditions such as those encountered with short cores. Meron Plus QM is self-curing or can also be individually controlled when removing the excess.

Kuraray Noritake introduces a new paste-type surface stain.

CERABIEN™ ZR FC Paste Stain enables the easy characterization of full zirconia restorations and is available in 27 shades. The extensive shade range assists with the reproduction of a wide variety of shades.

CERABIEN™ ZR FC Paste Stain has a full complement of blue and grey shades (Light Gray, Dark Gray, Grayish Blue and Blue) making the reproduction of blue-grayish transparency effects for incisal areas possible. With two types of glaze (Glaze and Clear Glaze), controlling the appearance of transparency across the entire crown is made simpler. CERABIEN™ ZR FC Paste Stain can be baked at 750°C during the fabrication of full zirconia restorations.

All products available from: HENRY SCHEIN HALAS • Tel: 1300 65 88 22 • www.henryschein.com.au

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PRODUCTS

ORAVANCE

B&L

CORTICO-CANCELLOUS BONE GRANULES

BETA MINI

Now available in pure cancellous or pure cortical bone granules. With an optimal ratio of 50% cortical and 50% cancellous bone, Oravance granules are the natural allograft choice in bone void filling.

Granule Size: 500μm–1000μm.

Ratio: 50% Cancellous & 50% Cortical Preservation Method: Freeze-dried Storage: Room temperature

Introducing the new Beta mini cordless Obturation Device for Optimal Backfill • Unique design and engineering – incorporates 360 degree Swivel Needles, as well as cordless and ergonomic features, to maximize user convenience.

• Balance – Great weight distribution for ease of use.

• Secondary safety feature – thermal protector cap prevents accidental burns from a hot needle or gutta purcha.

• Available in 3 colours – Black, White and New Pink.

GC

BIOHORIZONS

RUSCELLO FLOSS

MEM-LOK COLLAGEN MEMBRANE

The world’s first “Microfiber” Floss • Super fine fiber • Superior cleaning efficacy • Highly hydrophilic fiber • Best tool for medicament delivery • exceptionally soft texture • Great mint flavour

Easy handling, long lasting Mem-Lok is a Type I Collagen resorbable barrier membrane of bovine origin. The macromolecular pore size allows vital nutrient transfer while the cell occlusive membrane prevents soft tissue ingrowth, MemLok has a predictable resorption time of 26 - 28 weeks.

Mint Unwaxed* (White), Mint Waxed (Pink, Purple, Green, Yellow) 30m *Unwaxed Ruscello floss is indicated for use in dental practice

Applications include: Extraction sockets Sinus Augmentation – sinus window Ridge preservation Bone augmentation around implants Bony defects Peri-implant bone defect around implants

DIRECTA

NU SMILE

®

HYGOVAC BIO New, sustainable and shorter aspirator tubes manufactured from renewable resources

NEO MTA DENTAL CEMENT

Taking the necessary steps towards a more sustainable future it is important that future plastic materials are made from renewable raw materials as well as resource efficient, recyclable and safe from both a health and environmental aspect. Hygovac Bio is now available in two new sizes, providing an opportunity to broaden the application of use.

Finally, the MTA dentists have been waiting for - Affordable MTA specifically optimized for pediatric dentistry - the lowest cost per dose of any MTA on the market - Ideal treatment for pulpotomies, direct and indirect pulp capping, and apexification - It is quickly wash-out resistant, non-staining, radiopaque formulation is quickly washout resistant and has excellent handling properties - BioActive and non-toxic, causes precipitation of calcium phosphate, promoting dentinal bridging - Excellent Handling - Mixes to a putty-like consistency, easy to apply

Find more information on Orsing Website: www.orsing.se/products/aspirator-tubes-and-accessories/hygovac-bio

Pure MTA containing no resin, unlike hybrid MTA/resin blends: 1g Powder 4.0cc Gel, 2.5g Powder 4.0cc Gel, 7g Powder 10.0cc Gel

Hygovac Bio is a range of aspirator tubes made of renewable resources, developed to save and reduce the use of fossil resources and the level of greenhouse gas emissions.

All products available from: HENRY SCHEIN HALAS • Tel: 1300 65 88 22 • www.henryschein.com.au

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