EXTRACTION CONTROVERSIES IN ORTHODONTICS
INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
INTRODUCTION To the common man crowding more often than spacing constitutes malocclusion. Treatment of a crowded arch requires space gaining . This has been achieved through two ways of treatment â€“ extraction or non extraction modality. Extraction to create space for accommodation of the remaining teeth of crowded dental arches was written up in the dental literature as long as 1771. It was not a new idea then and certainly is not so now. While resorting to extraction care must be exercised so that extraction is not carried beyond logical limits. There will be exceptions to the extraction approach just as it was to the non extraction concept. this seminar is a summary of the various options we have regarding extraction therapy and the controversies surrounding that. www.indiandentalacademy.com
HISTORICAL REVIEW • JOHN HUNTER – 1771 – NATURAL HISTORY OF THE TEETH. • SPOONER - 1839 • FARRAR – 1888 • PEARS – 1859 – ADVOCATED EXTRACTION IN THE DENTAL COSMOS PUBL. OF OCT. 1859 FOR SIMPLYING ORTHODONTIC PROCEDURE. • ANGLE AND EXTRACTION – PORPOSED EXTRACTION INTIALLY, LATER FOLLOWED NON EXTRACTION THERAPY. www.indiandentalacademy.com
EXTRACTION VERSUS EXPANSION DEBATE ANGLE FOLLOWED NEW SCHOOL OF THOUGHT OF NON EXTRACTION (EXPANSION). believed orthodontic forces to teeth enable bone induction. he ridiculed extraction from his seventh edition onwards. • CASE advocated extraction, was supported by DEWEY and CRYER and BEGG – ATTRITION OCCLUSION. • EXTRACTION WON OVER EXPANSION EXPANSION returned due to – 1. Bite deepening 2. Space reopening 3. Improper axial inclination, effects of extraction treatment The current trend is towards non extraction, but it has high rate of relapse root fenestration and dehiscence apical root resorption improper buccal inclination and www.indiandentalacademy.com increasing mandibular intercanine width was most unstable
DIAGNOSIS AND DECISION MAKING MODEL ANALYSIS: kesling’s diagnostic setup Carey arch perimeter Ashley howe analysis tweed merrifield analysis bolten tooth size ratio CEPH. ANALYSIS – tweed’s diagnostic triangle soft tissue profile analysis steiner’s sticks of compromise CLINICAL EXAMINATION – profile, lip competence, VTO, age and growth left. www.indiandentalacademy.com
CRITERIA FOR EXTRACTION BUCHIN states arch length discrepancy of 3 – 4mm after 8 years of age facial esthetics and sex basal bone disharmony – tweed’s triangle, ANB difference facial angle – less than 88 degrees, MP – occipit relation, amount of chin point from NB – NPog anchorage requirement pt. Co-operation www.indiandentalacademy.com
SALZMANN states labio lingual dental arch relation to facial plane size of the gonial angle axial inclination of the mandibular incisors type of crowing present direction of jaw growth basal arch length thickness and distribution of soft tissue as probable criteria for extraction
CHOICE OF TEETH TO BE EXTRACTED Choice to extract depends on direction and amount of jaw growth basal arch discrepancy facial profile position and eruption of teeth Dento alveolar proclination patients age and the state of the dentition as a whole
CHOICE OF TEETH TO BE EXTRACTED Pathological extractions I premolar II premolar II molar III molar Incisors I molars and canine Asymmetric extraction Multiple extractions www.indiandentalacademy.com
PATHOLOGICAL EXTRACTION: Initiated when the following are present, Teeth congenitally absent, Teeth carious beyond recall, Teeth missed placed or buried, Teeth malformed.
BEGGS THEORY OF ATTRITIONAL OCCLUSION: Stone age – coarse diet – mark occlusal and interproximal wear – decreased M – D width and crown height – no late incisor crowding. Modern age – soft diet – no occlusal wear – increase crowding. Begg felt that attrition has not claimed a unit of tooth material from the arch length during the patients first 20 years of life, it will be correct to obtain the same balance by eliminating the amount by extraction
I PREMOLAR EXTRACTION: Most sacrificed tooth because â€“ better anchorage balance erupts before other posterior teeth except first permanent molar. its eruption allows eruption of permanent canine (most 0ften impacted) forms center of each half of the arch
More over I premolar extraction provided about 6 -7 mm of space on each side of the arch which on most instances was sufficient enough for over jet overbite and crowding corrections. They remain the teeth of choice in max. anchorage cases where the entire space is used for anterior retraction. Maxillary first premolars extraction provides more space than second premolar extraction. AL/TZ â€“more than 5 mm AO 1992 WITZEL found that premolar extraction patients has less of a tendency to become crowded than patients treated with non extraction. RICHARD RIEDEL found that in first premolar extraction cases the intercanine width decreased post treatment and mandibular incisor irregularity increased, whether the arch was expanded or not. www.indiandentalacademy.com
EFFECTS OF PREMOLAR EXTRACTION WITZIG opposed first premolar extraction because resulted in narrow smile line upper lip appears sunken at the corner of the mouth no remedy for retruded chin in class II cases decreased vertical dimension often led to third molar impactions â€“ surgical and psychological complications.
AO 1995 BENNETT and MCLAUGHLIN opposed the allegations imposed on first premolar extraction by reviewing their drawbacks. COLLAPSE OF VERTICAL DIMENSION – no evidence to blame premolar extraction. DOUGHERTY analyzed and found a slight increase in MP angle in both extraction and non extraction case. KLAPPER found no influence of extraction or non extraction on Brachy facial or dolichofacial growth patterns. LINN compared first and second premolar extraction on vertical phase development and found no significance FLATTENING OF FACIAL PROFILE – primarily due to diagnostic errors and errors in treatment mechanics. EXCESSIVE ANTERIOR INTERFERENCES (periodontal trauma, tooth wear, root resorption, TMD) – occurred due to initial canine angulation canine retraction during L&A torque control during space closure overbite control during over jet reduction POSTERIOR CONDYLAR DISPLACEMENT www.indiandentalacademy.com
SECOND PREMOLAR EXTRACTION HENRY in 1965 gave the following criteria: a mild degree of crowding and good profile no crowding and fullness of lips second premolars extracted in group B and C anchorage cases and when the lower fives are impacted NANCE first drew attention to second premolar extraction CAREY â€“ AL/TZ discrepancy - 2.5-5mm SHOPPY observed more mesial movement of molars SCHWAB found upper and lower incisors were retracted less with respect to skeletal landmarks.
LOGAN listed other factors of significance max. I PM more esthetic than II PM contact point of mandibular first molar and first premolar stay close rapid space closure easy overbite reduction closure of anterior open bites DECASTRO â€“ felt second premolar extraction affected only the posterior segment and first premolar extraction disturbed the transitional area.
SECOND MOLAR EXTRACTION DRAWBACKS OF FIRST PREMOLAR EXTRACTION lead to THE GREAT SECOND MOLAR DEBATE. WITZIG and SPAHL cruised IPM extr. Due to reduction in vertical dimension over retraction upper incisor retroclination bite deepening anterior interferences condyle displacement and TMD www.indiandentalacademy.com
INDICATIONS SAZMANN â€“ chronological dental age be past average eruption age. - max. tuberosity underdeveloped -second molar severely caried and in buccal occlusion -max. third molar in favorable angulation, position, size and shape for eruption -attempts to bring second molar into occlusion will cause relapse.
CONTRA INDICATIONS Max. third molars too high in tuberosity poor angulation of third molars under size third molar crown or root absence of third molar tooth buds badly caried or impacted third molar
ADVANTAGES increase stability less crowding `less reopening of extraction sites less over retraction more esthetic smile more efficient deep bite reduction fewer impacted third molars shorter duration of FA prevention of dished in appearance first molar distal movement Provides around 12mm in each half of the arch â€“ needed in anterior and posterior crowding cases. www.indiandentalacademy.com
DISADVANTAGES far location of extraction site too much tooth substance removed no help in correction of A – P discrepancies without patient co – operation freq. Impacted third molars. TIMING age – 12 to 14 years third molar crown formed but root not developed third molar inclination not more than 30 degrees and close to the second molar root. www.indiandentalacademy.com
INCISOR EXTRACTION Incisor not to be extracted unless damaged beyond repair (bone loss, periodontitis, fracture, repair). MILTON FISCHER â€“ 1940 demonstrated two incisor extraction and no retention. SCHWARTZ reviewed 20 years post extraction records and found good stability. REIDEL suggested mandibular incisor extraction for better stability as intercanine width is not altered. But ANGLE ridiculed incisor extraction. REIDEL also suggested reduced treatment time. www.indiandentalacademy.com
JCO 1993 MARCH ALBERT OWEN - suggests full diagnostic set up and states patients with class I molar relationship moderate lower anterior crowding and no upper arch crowding acceptable soft tissue profile minimal to moderate over jet and overbite minimal growth potential missing or peg laterals As prerequisites for incisor extraction. DRAW BACKS: canine repositioned as incisor results in Angulation and torque problems in canine aligning excess trauma to opposed dentition color difference,gingival contour and root morphology variation canâ€™t establish ideal contact points enameloplasty required to reshape canine. www.indiandentalacademy.com
THIRD MOLAR Third molars were earlier thought to be the cause of late mandibular incisor crowding. With evolution, the human jaws are incapable of accommodating the third molars. They are extracted mainly for pathological reasons (dentigerous cyst, caries, impaction). After orthodontic treatment involving distal movement of max. arch, to facilitate retention Along with first premolar extraction in case of excessive space requirement Extr. of III molars,often presents complications-dry socket,delayed healing leading to â€œdentist fear syndromeâ€? www.indiandentalacademy.com
FIRST MOLARS Not advised generally Extracted if grossly caried, mobile, impacted or in total supra version Though larger in size provide less space for anterior retraction Increased treatment time 2/3 space used up by second molar mesialization Due to root anatomy and bone surrounding second molar mesialization results in lingual rolling Allows third molar eruption www.indiandentalacademy.com
ONE ARCH EXTRACTION JCO 1971 OCT. Criteria for one arch extraction are class I / II malocclusions overbite 3mm or less flat occlusal plane lower teeth in good alignment lower incisor 1-2mm from A-Po line Generally they are done only in the upper arch in class II malocclusion as camouflage therapy. If done in deep lower occlusal plane cases it results in lower anterior crowding and upper anterior spacing. www.indiandentalacademy.com
ANKYLOSIS JCO JUNE 1990 Ankylosis â€“ localized fusion of bone and cementum Disregarded in deciduous dentition But in permanent dentition it complicates treatment planning Intervention includes luxation corticotomy ostectomy
ASYMMETRIC EXTRACTIONS Done in patients who already have teeth extracted for other reasons -pathology (caries, fracture, periodontitis, malformation) -congenitally missing consideration is given to try to use the existing space available but in unfortunate cases we may need to further extract teeth for orthodontic reasons. Care must be taken in appliance mechanics so as not to create asymmetries which do not exist in the first place. www.indiandentalacademy.com
CANINE EXTRACTIONS Should not be done as a orthodontic therapeutic measure They play an important role in facial expression facial balance smile line landmark at which the arch turns provide cuspid rise â€“ during canine guided occlusion Extracted because of horizontal impactions, ectopic eruption and transposition.
SERIAL EXTRACTION PROCEDURES PROFFITT, AO 1990: TWEED (1966) Serial extraction results in self correction in max. and mandibular incisal segments.It allows the mandibular incisors to tip and move lingually to positions of functional balance. KIELLGREN’S serial extraction and HOTZ’S guidance of eruption – emerged in 1940. BUNON in 1743 must be credited with the original concept. Extraction is done as B-C –D –4 OR D-4. Serial extraction is a passive rather than active form of treatment complications: permanent canines erupt before I premolars erupt, enuclaeation of premolar buds leads to bone defect. Results in too premature extraction of first premolar in 1011 years old individuals www.indiandentalacademy.com
JCO1968,1971: Guidelines include: 1. Class I malocclusions 2. 3mm or less overbite/over jet 3. clear discrepancy of teeth to bone 4. Bilateral symmetry 5. Lower incisor 1 to 2 mm from A-Po line. Drawbacks: 1. Cannot avoid active appliance therapy 2. Extraction done too prematurely 3. Results in mesialwww.indiandentalacademy.com migration and deep overbite.
GUIDELINES FOR NON EXTRACTION FOGEL (1971 JCO NOV.) stresses the need for non extraction in border line cases. An excessively flattened profile continues to be more concave with increasing age due to downward and forward mandibular growth, flattening of M-P and growth increments in pogonion. Continued addition of soft tissue in the chin area contributes to an unattractive inwardly curved facial profile.
Guidelines include: 1. Class II or, occasionally, class I malocclusions. 2. 2. Broad dental arches 3. No discrepancy of teeth – to – bone in lower. 4. No discrepancy of teeth to teeth. 5. Flat lower occlusal plane or shallow curve. 6. Lower incisor within – 1to 2 mm in relation to A –Po 7. Lower teeth in good alignment 8. Lower aligned except anteriors have mild lingual inclination combined with slight irregularity.
CONTRA INDICATIONS TO EXTRACTION AL/TZ discrepancy less than 2.5mm Pleasing straight profile with prominent nose point Faces where PMD less than PMBAW Continued growth of the face leading to older appearance of face Preconceived facial pattern are not realistic and lead to dished in faces. Relapse by space re - opening due to functional forces and interdental ligaments. www.indiandentalacademy.com
CONCLUSION In a respected specialty such as orthodontics the decision to extract or not should at least be based partly on scientific outcome of treatment outcome are not purely on clinicians experience. Extraction is justified as means of relieving excessive dental crowding, in circumstances where growth cannot be expected to provide relief. Extraction of four first bicuspids will most occasions provide the space required, if not in excess. Border line cases are our greatest responsibility. If a wrong decision is made or a wrong mechanics is carried out, one really stands to do a great disservice to the patient. www.indiandentalacademy.com
Papquette et al proved that the profile becomes 2mm flatter in extraction cases. This type of information allows the clinician to make an informed decision. However, the extraction -non extraction debate continues, suggesting that more objective information is needed. It is hoped that the existence of more data will prevent the debate from hinging on the clinical experience of the most persuasive spokesperson. www.indiandentalacademy.com
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