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ď‚— 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. www.indiandentalacademy.com
Facial profile alteration: Maxi retraction of U&L anteriors: 4’s Lesser retraction in lower face: U4’s and L5’s Less 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
Incisors Canines Asymmetric premolar extraction molars
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Mandibular incisors- therapeutic importance 1st sign of incipient malocclusion Difficult 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
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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. www.indiandentalacademy.com
1. 2. 3. 4. 5. 6. 7.
Maintains/ reduces intercanine width General arch form is maintained – greater stability Retention period- less Anterior segments can be retracted readily, if needed. Immediate solid tooth support of entire buccal segments. Easy reduction of overbite, reshaping Mechanotherapy is simplified. Space closure quick. www.indiandentalacademy.com
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.
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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. www.indiandentalacademy.com
Incisor Xn not often. Possibility must always be considered. Careful planning with diagnostic setup
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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.
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Single premolar extraction 3 premolar extraction---AJO-DO sep 2003
Class II sub division
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Avoided: Not provide adequate space in the ant region. 5 & 7 may tip in the Xn space. Deepening of bite. Masticatory efficiency.
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Indications: Carious- beyond restoration RCTreated, - than a perfectly good premolar. Multi filled teeth- crown. Premature Xn of 6, to preserve symmetry. Facial considerations: large chin buttons&/ prominent
nose
(rationale: farther back less facial change) Open bite cases.
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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: 1942
8 ½ to 9 ½ yrs. Extraction of all Ist molars. Basis: •Additional space for eruption of 8s. •Crowding of lower arch minimized. •Disadvantages-www.indiandentalacademy.com
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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.
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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 L4 8s erupt normally. Min patient cooperation Stable results. Tuberosity not crowded. Results similar to nonext. Rx duration is reduced. Profile maintained. Open bite correction www.indiandentalacademy.com
David W.Liddle- AJO 1977 Malocclusion: 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. www.indiandentalacademy.com
ADVANTAGES AND INDICATIONS Disimpaction of 3rd molars, faster eruption Prevention of “dished-in” at the end of facial growth Prevention of late incisor imbrication Facilitation of 1st molar distalization Distal movement only as needed to correct the overjet Fewer “residual”spaces at the end of Rx Good functional occlusion Overbite reduction.
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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. www.indiandentalacademy.com
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 Xn Unacceptable positions of erupted 3rd molars –second, late stage of fixed therapy. 9-20% missing 3rd molars.
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Kokich: 1. 3rd molar crowns completely formed, Xn before roots begin to develop 2. 30*to the occlusal plane 3. 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. www.indiandentalacademy.com
Xn to prevent lower anterior crowding? Distal movement of 6,7– impaction of 8. Pain Contraindications: 1st or 2nd molars are extracted.
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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.
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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
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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.
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ď ś Orthodontic treatment may include extractions of
any tooth in the arch. ď ś Based on sound diagnosis, treatment objectives.
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“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, AJODO 1986 may Second molar extraction in orthodontic treatment- David W. Liddle AJO dec 1977 Third Molars: A review Samir E. Bishara AJO feb 1983 www.indiandentalacademy.com
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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