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1. SECOND MOLAR DEBATE
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2. Introduction
Decrowding of arches - concept
bicuspid -sacrificial extraction
problems with bicuspid extraction
• dishing of the facial profiles
• relapse of treated occlusions
• TMJ disorders
• an alternative extraction-second molar
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3. HISTORICAL PERSPECTIVE
1.angle non extraction approach-1907
2.calvin case -expansion of arches
3.charles tweed and Dr.Raymond begg
bicuspid extraction establishiment-1940
4 1960-arguments for and against extraction
treament
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4. DEBATE-bicuspids versus second
molars
1.orthopedic considerations
• a. Face
-excessive space as a result of 4 bicuspid
extraction requiring excessive tooth
movement for space closure resulting in
shrinkage of arch length
narrower smile line of teeth
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5. • As the teeth are over retracted into
extraction sites ,premaxilla is brought in
too far diminishing the support for upper
lip, lending an aged and sunkenin
appearance to the individual.
• Over retraction of the upper anteriors does
nothing to correct the retruded chin often
associated with skeletal class-ii cases.
• Loss in vertical height compounds the
problem of insufficient lower facial height
• in cases treated with bicuspid extraction
wherein thereis mandibular insufficiency-
results in a longer and pointed nose.www.indiandentalacademy.com

6. • Bicuspid extraction shrinks the radius of
the dental arch.
2 Effect of second molar extraction on face-
• smile displayed is broad and full.
• Premaxillary support for the upper lip
prevents lengthening of nose and dishedin
appearance of face.
• But no published research demnstrating
facial profile flattening.
• Staggers-AJO;1998 CONCLUDED 2 groups
had fewer differences and facial profile
flattening occurs due to-www.indiandentalacademy.com

7. • Errors in management of treatment
mechanics.
• Skeletal factors.
2.TEMPEROMANDIBULAR JOINT-
• Effect of bicuspid extraction
:DR.H.E.WILSON OF ENGLAND observed
,many patients who had 4 bicuspid
extractions type of orthodontics
exhibited tmj malarthrosis.
• Tmj problems can be intracapsular or
extracapsular.www.indiandentalacademy.com

8. • Intracapsular problems are due to riding of the
disc by the condyle during various movements of
the jaw
• Extracapsular problems are duw to muscles
which have to overwork or work in a way they are
not designed due to which pain and fatigue result
in tmj.
Common causes of intracapsular and extracapsular
problems are severe loss of vertical dimension
andseverly retruded mandibles due to
excessively retracted premaxilla.
• Second molar consideratios of tmj
• as the buccal segments are distalised into the
extraction spaces they open the bite.www.indiandentalacademy.com

9. •Thus it increases the vertical height often compromised
in class-2 patients.This aids orofacial musculature in attaining
physiologically acceptable muscle-length to work ratio and
prevents their overconstriction and imbalance.
•BY increasing vertical dimension condyles are brought
downwards and forwards which prevents their posterior and
superior displacement in the glenoid fossa;a condition often
associated with class-2 deepbite cases and severly retruded
.mandibles.
•When the upper anteriors are in deep bite in a overly retract
situation their inclined lingual surfaces interfere with orthope
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10. Balanced closure of the mandible resulting in a neuro
muscular reflexive feedback mechanism that guides
the mandible in a more posterior direction causing
it to impinge on the sensitive bilaminar zone which
inturn results tmj malarthrosis.
Witzig and Spahl recommended removal of second
molars when extractions are required to
1.to support vertical dimension
2.for healthy tmj.
3.for a pleasingfull face.
But studies by larrson and Ronnermann[1981;EJO]
CONCLUDED NO RISK OF DEVELOPING tmj disorders
when undergoing orthodontic treatment
withbicuspid extractions.www.indiandentalacademy.com

11. • Alanen and kirveskari advocated
thatpremature contacts with 4 bicuspid
extraction would predispose the patient to
tmj disorders rather than orthodontic
treatment
• Gianelly[1991;AJO] IN HIS STUDY OBSERVED
THAT condyles were in a similar position in
4bicuspid extraction cases when
compared to untreated control samples.
2.ORTHODONTIC CONSIDERATIONS
a.3.molars-extraction of bicuspids in severe
crowding cases does not aid in the relief of
crowding in the posterior segment andwww.indiandentalacademy.com

12. • 3-molars are predesined to get impacted.
In case of crowding which is not severe
bicuspid extraction fails torelieve
posterior crowding due to following
reasons=
• the reduced amount of space after anterior
alignment is insufficient for completely
impacted 3-molars.
• 2.age at which bicuspids are extracted is a
factor that does not lend to the relief of
posterior crowding.
Hence in addition to the 4 bicuspid extractionwww.indiandentalacademy.com

13. Extraction of 4 third molars by surgical
method is a necessity.
SECOND-MOLAR orthodontic considerations
regarding -3’molars=
• the space gained by extraction of2-molars
is enough for alignment of anterior teeth as
well as for the 3-molars as they move
forwards to close contact with first molar.
Vertical dimension
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