EXTRACTIONS in ORTHODONTICS Jules E. Lemay III d.d.s., cert. - PowerPoint PPT Presentation

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