EXTRACTIONS in ORTHODONTICS Jules E. Lemay III d.d.s., cert. ortho., F.R.C.D. (C) Diplomate, American Board of Orthodontics
Worsen: • Facial profile: flatter, “dished-in” look • Smile esthetics: narrower smile & arch width Space management more complex Functional problems ➡➡➡ TMD Compromises jaw growth Can create neurological and postural problems www.nextortho.com http://www.icnr.com/
NEW SCHOOL THEORY Edward H. Angle (1855-1930) No place for xtr in ortho Extractions = mutilation malpractice, “Odontocide” Creationism (Bible Theory of Creation) Assist nature in doing Creator ʼ s work • Denies influence of heredity / genetics • Proper function = key to stability • Full complement of teeth is essential • Universal expansion - bone grows around teeth 1st Ortho school (apprenticeship) - Pasadena, CA Angle Classification (1880) Edgewise appliances Founded the AAO (1990)
RATIONAL SCHOOL Calvin S. Case (early 1900 ʼ s) Etiology of maloccl.: heredity & local factors Against injudicious xtr of permanent teeth Excessive protrusion cases: Xtr indicated Expansion is possible = esthetics & stability Frequency of xtr: 3-10%
Charles H. Tweed, Jr. (1895 - 1970) N S A B Angle ʼ s student Cephalometry ➔ diagnosis Non-xtr cases = full profile & unstable Re-treated with xtr
P. R. BEGG - Australia (1898 - 1985) 1960 ʼ s Angle ʼ s student (1924) Non-Xtr Treatment = unstable Low friction, light force appliance > 50 % Xtr cases
Decision to extract teeth for orthodontics 10 Considerations Space Requirements Arch Leveling Facial Profile and Esthetics Perioral Musculature Health of the Teeth and Periodontium Arch Relationship Growth Potential Compromised / Limited treatment Patient’s Cooperation Special Conditions / Situations (Serial Extractions)
SPACE ANALYSIS AVAILABLE REQUIRED ADEQUATE DEFICIENT MONITOR ERUPTION REGAIN SPACE EXPAND / FLARE THE TEETH EXCESSIVE REMOVE TOOTH STRUCTURE: CLOSE THE SPACE - EXTRACT KEEP THE SPACE (or consolidate) - REPROXIMATION / STRIPPING
Leveling the Curve of Spee AD
Periodontium Evaluation Hard Tissue Width (alveolar bone) Thickness Health - Disease inflammation - infection parafunction occl. trauma … Sotf Tissues Width (gingiva & musosa) Thickness
COMPROMISED / LIMITED TREATMENT Chief complaint = esthetics only One arch Tx / One tooth only Don ʼ t want “perfection” $$$$ Duration of Tx Surgery refusal Refusal to wear certain appliances “You said it didn ʼ t have to be PERFECT”!
Wisdom Tooth Wisdom Orthodontic Considerations
L.A.C. ETIOLOGY - Top 9 1- Mandibular Growth 2- “Pre-existing” crowding 3- Mesial drift 4- Anterior component of occlusal forces 4- Soft tissue maturation 5- Tooth size & shape 6- Inadequate dental attrition 7- Evolution: Jaw and tooth size 8- Third Molars 9- Misc.: Mutations, Ortho relapse, etc...
3Ms vs L.A.C. : Historical perspective 3Ms Pressure = Frequent L.A.C. cause Robinson, 1859 Richardson, 1989 Cause-Effect Relationship ???
3Ms vs L.A.C. : Historical perspective Orthodontics 1930s-40s : Unefficient Mcx / limited 3Ms… help in closing extration space ??? 1971: 600 Orthos + 700 O. Surg. 65% believe Belief… Practical, easy, attractive "Timing" Logical -3Ms Eruption → L.A.C. Coincidence? MP
3Ms & L.A.C. Interproximal Contact Tightness Vert. & Ant. Contact Pressure Components Tightness L.A.C. Lower Anterior Crowding Southard 1991
Southard 1991 3Ms & L.A.C. Interproximal Contact Tightness Study; 3M xtr vs Interdental Pressure • 3M Bilaterally impacted N= 20 • 3M Unilateral Xtr • Measured Force: Interproximal contact • Pre & Post Xtr Xtr 3M Non-Xtr
3Ms & L.A.C. Southard 1992 Results / Conclusions; 3M Xtr vs Pressure • Contact Tightness… BILATERALLY! • 3Ms Xtr: little influence on contact tightness 3Ms DO NOT play a signifcant role in Lower Anterior Crowding • New Hypothesis: Patient position has an influence +++ ?
3Ms & L.A.C. Southard 1992 Study #2 : Postural Changes • 2 hrs lying down = 30% Tightness • Uprighting = Tightness • Position > 3Ms Pressure
3Ms vs Lower Ant. Crowding Removal of 8s will not prevent lower ant. crowding Studies (Roterdam - 1998) / (Kim - 2003) Non-Xtr compounds 8s impaction PMs Xtr decreases the incidence of 8s impaction May crowding cause impaction of the L8s ??? An excuse to remove the 8s… Numerous valid reasons to remove 8s 151
1979 1993 Consensus Conferences dedicated to the Management of 3 rd Molars (Orthodontic Considerations) Question: When and under what circumstances is 3Ms Xtr advised ?
Consensus on 3Ms management 1- 3Ms Xtr (asymptomatic) ✦ not justified to prevent L.A.C. FC 38 PC 26
3 rd Molar Management Consensus Conferences Some conclusions: Indications for 3 rd M removal Infections Unrestorable teeth (caries, fractures) Pathologies (cysts & tumors) Destruction of adjacent bone and teeth Orthodontics YES • Distalization NO • LAC prevention
OTHER CONSIDERATIONS Orthodontic considerations Periodontal considerations Prosthodontics: under a prosthesis Mandibular fracture prevention • Orthognathic surgery (mand. adv.) Radiotherapy
X X DC 18 DC 18 AC 17 Semi-Impacted: Options? • Expose • Upright • Extract
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