atypical extractions-oral surgery / orthodontic courses by indian dental academy

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Increased ability to move teeth under better control: ever-expanding choice of extraction.


Factors affecting choice of extraction

1. Treatment objectives

2. Type of malocclusion

3. Esthetics (large chin button, prominent nose)

4. Growth pattern.

5. Conditions of teeth.(caries, multifilled teeth, impacted, ectopic, severe rotation)

6. Health of supporting tissues.

Facial profile alteration:Maxi retraction of U&L anteriors: 4’sLesser retraction in lower face: U4’s and L5’sLess overall retraction: 5’s or 6’s.Deep anterior overbite:Closer.( Mechanically easier to level, as

spaces are closed). incisors – min time and effort.

Open bite:5 or 6 Xn. Accentuate the curve of Spee.GRABER: Removal of 5s in mandibular arch

preferable.‘.’ reduces the tendency of relapse of openbite

&lingually inclined incisors seen occasionally with Xn of 4s.www.indiandentalacademy.com

IncisorsCaninesAsymmetric premolar extractionmolars


Mandibular incisors- therapeutic importance

1st sign of incipient malocclusionDifficult to treat as they relapse easily.

Not a new idea. Jackson (1904) Riedel(1975) : Xn of lower Incisors

Angle: Inexcusable. Disharmony b/w Occlusal planes, abnormal overbite


For mandibular incisors: Extreme crowding /

protrusion. Gingival recession & loss

of overlying bone on labial surface.

Lateral incisors severely # in young children.

Discrepancy in sizes of U & L incisors themselves, 1 incisor can be removed.

Reidel- Rx time reduced. min facial change.


1. Maintains/ reduces intercanine width

2. General arch form is maintained – greater stability

3. Retention period- less4. Anterior segments can be

retracted readily, if needed.5. Immediate solid tooth support

of entire buccal segments.6. Easy reduction of overbite,

reshaping7. Mechanotherapy is simplified.

Space closure quick.


Reopening of space . Central Incisor.Danger of creating a tooth size discrepancy.1 incisor Xn- deepbite- if normal tooth size

relationship is present before Xn.Color difference of canine.


Rarely indicated. Unfavorable impaction of U incisor. Bu/Li blocked out lateral, with good contact

b/w central and canine. Congenital missing of 1 lateral incisor Dilacerated tooth. Trauma, caries & periodontal disease Gardiner et al:

U crowding, mesial displacement of root apices of U3 - Xn of lateral incisor.


Incisor Xn not often.Possibility must always be considered.Careful planning with diagnostic setup


Not extracted. Long path of eruption.

Conditions where indicated:Impossible to bring in alignment.Gross displacement Bu/Li 4 in contact with 2 & does not show palatal

cusp. Decision : position of apex.


Single premolar extraction3 premolar extraction---AJO-DO sep 2003 Class II sub division


Avoided:Not provide adequate space in the ant

region.5 & 7 may tip in the Xn space.Deepening of bite.Masticatory efficiency.


Carious- beyond restorationCarious- beyond restorationRCTreated, - than a perfectly good premolar.RCTreated, - than a perfectly good premolar.Multi filled teeth- crown.Multi filled teeth- crown.Premature Xn of 6, to preserve symmetry.Premature Xn of 6, to preserve symmetry.Facial considerations: large chin buttons&/ prominent Facial considerations: large chin buttons&/ prominent nosenose((rationale: farther back less facial change)rationale: farther back less facial change)Open bite cases.Open bite cases.

Indications:


Not to allow U7 locked behind L7. Horizontal elastics – until danger of locking

has passed.Mesially inclined 7, lesser degree of anchor

bend.


Wilkinson’s Extraction: 19428 ½ to 9 ½ yrs. Extraction of all Ist molars.

Basis:

•Additional space for eruption of 8s.

•Crowding of lower arch minimized.

•Disadvantages-

Class II div 1 with perfect lower arch alignment but growth expectation inadequate.

Class II div 1 active growth over. Pt non cooperative.

Class II div 1 with good lower arch over basal bone, with some growth expectation.

Class II div 1 with mild open bite.


Problems with Xn of 4s:Tipping, opening of space (5 small to fill

the space)Mesial tipping of 6, hanging palatal cusp

Avoided with 6 Xn.Good molar relation.U 4 occlude with L48s erupt normally.Min patient cooperationStable results.Tuberosity not crowded.Results similar to nonext.Rx duration is reduced.Profile maintained.Open bite correction


David W.Liddle- AJO 1977Malocclusion: potential force by

developing 7,8.Xn of 7s to intercept this forward force.4 Xn: treating the effect and not the cause.

10-12mm of space :satisfies arch length problem, not apparent when patient smiles.

91% 7 Xn.6 move distally in response to pressure.Over compressed CT fibers- move 3 &4 to a

more normal occlusion.


ADVANTAGES AND INDICATIONSDisimpaction of 3rd molars, faster eruptionPrevention of “dished-in” at the end of facial

growthPrevention of late incisor imbricationFacilitation of 1st molar distalization Distal movement only as needed to correct the

overjetFewer “residual”spaces at the end of RxGood functional occlusionOverbite reduction.


Chipman: Xn 7 - caries, ectopic, rotated. Mild – moderate discrepancy with good

profile. Crowding in tuberosity area ,with a need

for distal movement of 1st molar. Lehman - preconditions 8 in favorable angulation 15-30*angle to

the long axis of the 1st molar. Normal in size/shape & root area is

sufficient w.r.t 2nd molar. No congenitally missing teeth.


Too much tooth substance removed in Cl I mal occlusion with mild crowding.

Location far from area of concern.No help in correction of A-P discrepancy

without patient cooperation .Possible impaction of 3rd molars even with 2nd

molar XnUnacceptable positions of erupted 3rd molars –

second, late stage of fixed therapy.9-20% missing 3rd molars.


Kokich:1. 3rd molar crowns completely formed, Xn

before roots begin to develop2. 30*to the occlusal plane3. 3rd molars in close proximity to 2nd molar-

drift.Halderson, Huggins, Lehman and Smith.Before radiographic evidence of root formn.(12-

14yrs) Consensus opinion: as soon as 2nd molar erupts. angulation.


Xn to prevent lower anterior crowding?

Distal movement of 6,7– impaction of 8.

Pain Contraindications:1st or 2nd molars are extracted.


Relation b/w root surface area and Xn site selection upon incisor retraction.

Efficient mechanotherapy.Diagnostic line.Larger the root surface area, greater the

resistance to movement.


Non extraction 1.5mm

1st molars u&l 6.0mm

U4 and L5 8.7mm

1st premolars 9.2mm

1st premolars &1st molars 16.9mm


Location of the Xn site-Root surface area.Predict incisor retraction.

Should be considered in diagnosis, so that a desired Rx goal for the final position of incisors within the facial profile can be achieved.


Orthodontic treatment may include extractions of any tooth in the arch.

Based on sound diagnosis, treatment objectives.


“Different extractions for different malocclusions” – Sidney Brandt, Safirstein AJO 1975

Extractions in Orthodontics- Nagalakshmi & Ashima Valiathan JICD vol 37 1995

Single arch extraction- upper first molars or what to do when nonextraction treatment fails- Raleigh Williams AJO oct 1979

Second molar extractions: A review – Samir Bishara, AJO-DO 1986 may

Second molar extraction in orthodontic treatment- David W. Liddle AJO dec 1977

Third Molars: A review Samir E. Bishara AJO feb 1983


The effect of different extraction sites upon incisor retraction- Raleigh Williams & Hosila AJO 1976

Where teeth should be positioned in the face and jaws and how to get them there---Thomas Creekmore JCO sep 1997

Class II subdivision treatment success rate with symmetric and asymmetric extraction protocols- Guilherme Jansson, Dainesi, Fernando. AJO-DO sep 2003


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