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

Jules E. Lemay III

d.d.s., cert. ortho., F.R.C.D. (C)

Diplomate, American Board of Orthodontics

ORTHODONTICS

in

EXTRACTIONS

 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

NEW SCHOOL THEORY

Edward H. Angle (1855-1930)

 No place for xtr in ortho  Extractions = mutilation

 Creationism (Bible Theory of Creation)  Assist nature in doing Creatorʼs work

• Denies influence of heredity / genetics
• Proper function = key to stability
• Full complement of teeth is essential
• Universal expansion - bone grows around teeth

RATIONAL SCHOOL

Calvin S. Case (early 1900ʼs)

 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%

 Angleʼs student  Cephalometry ➔ diagnosis  Non-xtr cases = full profile & unstable  Re-treated with xtr

Charles H. Tweed, Jr.

(1895 - 1970)

S N A B

1960ʼs

 Angleʼs student (1924)  Non-Xtr Treatment = unstable  Low friction, light force appliance  > 50 % Xtr cases

• P. R. BEGG - Australia

(1898 - 1985)

 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)

Decision to extract teeth for orthodontics

10 Considerations

SPACE ANALYSIS

EXCESSIVE

• CLOSE THE SPACE
• KEEP THE SPACE

(or consolidate)

DEFICIENT

• REGAIN SPACE
• EXPAND / FLARE THE TEETH
• REMOVE TOOTH STRUCTURE:
• EXTRACT
• REPROXIMATION / STRIPPING

ADEQUATE

• MONITOR ERUPTION

AVAILABLE REQUIRED

Leveling the Curve of Spee

AD

Periodontium Evaluation

Hard Tissue

(alveolar bone)

Sotf Tissues

(gingiva & musosa)

Width Thickness Width Thickness Health - Disease inflammation - infection parafunction

• ccl. trauma …

COMPROMISED / LIMITED TREATMENT

 Chief complaint = esthetics only  One arch Tx / One tooth only  Donʼt want “perfection”  $$$$  Duration of Tx  Surgery refusal  Refusal to wear certain appliances

“You said it didnʼt have to be PERFECT”!

Wisdom Tooth Wisdom Orthodontic Considerations

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 9- Misc.: Mutations, Ortho relapse, etc... L.A.C. ETIOLOGY - Top 9 8- Third Molars



3Ms Pressure = Frequent L.A.C. cause 3Ms vs L.A.C. : Historical perspective Cause-Effect Relationship ???

Robinson, 1859 Richardson, 1989

 Orthodontics 1930s-40s :

 1971: 600 Orthos + 700 O. Surg. 65% believe  Belief…

• 3Ms Eruption → L.A.C.

MP

3Ms vs L.A.C. : Historical perspective

L.A.C.

Lower Anterior Crowding

3Ms & L.A.C.

Interproximal Contact Tightness

Contact Tightness

 



Southard 1991

Pressure

• Vert. & Ant.

Components

Non-Xtr Xtr 3M

• 3M Bilaterally impacted N= 20
• 3M Unilateral Xtr
• Measured Force: Interproximal contact
• Pre & Post Xtr

Southard 1991

3Ms & L.A.C.

Interproximal Contact Tightness

3Ms DO NOT play a signifcant role in Lower Anterior Crowding

• New Hypothesis:

Patient position has an influence +++ ?

• 3Ms Xtr: little influence on contact tightness

 Results / Conclusions; 3M Xtr vs Pressure

•  Contact Tightness…

3Ms & L.A.C.

Southard 1992

BILATERALLY!

3Ms & L.A.C.

 Study #2 : Postural Changes

• 2 hrs lying down = 30% Tightness
• Uprighting = Tightness
• Position > 3Ms Pressure

Southard 1992

 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 3Ms vs Lower Ant. Crowding

151

1979 1993 Consensus Conferences dedicated to the

Management of 3rd Molars

(Orthodontic Considerations)

When and under what circumstances is 3Ms Xtr advised ?

Question:

1- 3Ms Xtr (asymptomatic)

✦ not justified to prevent L.A.C.

PC 26 FC 38

Consensus on 3Ms management

Some conclusions: Indications for 3rd M removal

 Infections  Unrestorable teeth (caries, fractures)  Pathologies (cysts & tumors)  Destruction of adjacent bone and teeth



Orthodontics

• Distalization
• LAC prevention

NO YES

3rd Molar Management Consensus Conferences

 Orthodontic considerations  Periodontal considerations  Prosthodontics: under a prosthesis  Mandibular fracture prevention

• Orthognathic surgery (mand. adv.)

 Radiotherapy

OTHER CONSIDERATIONS

DC 18

Semi-Impacted: Options?

DC 18

• Expose
• Upright
• Extract

X

X

AC 17