methods of gaining space in orthodontics -Extraction

Methods of gaining Space
ExtractionsExtractions
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 Increased ability to move teeth under better control: ever-Increased ability to move teeth under better control: ever-
expanding choice of extraction.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:Facial profile alteration:
 Maxi retraction of U&L anteriors: 4s (laterals)Maxi retraction of U&L anteriors: 4s (laterals)
 Lesser retraction in lower face: U4s and L5sLesser retraction in lower face: U4s and L5s
 Less overall retraction: 5s or 6s.Less overall retraction: 5s or 6s.
Deep anterior overbite:Deep anterior overbite:

CloserCloser.(.( Mechanically easier to level, as spaces areMechanically easier to level, as spaces are
closed).closed). incisors – min time and effort.incisors – min time and effort.
Open bite:Open bite:
 5 or 6 Xn. Accentuate the curve of Spee.5 or 6 Xn. Accentuate the curve of Spee.
GRABER:GRABER: RRemoval of 5s in mandibular arch preferable.emoval of 5s in mandibular arch preferable.
‘‘.’ reduces the tendency of relapse of openbite &lingually.’ reduces the tendency of relapse of openbite &lingually
inclined incisors seen occasionally with Xn of 4s.inclined incisors seen occasionally with Xn of 4s.

Extraction of Ist premolars.
ADVANTAGES :ADVANTAGES :
 Erupts before any other post teeth, after 6.Erupts before any other post teeth, after 6.
 Eruptive sequence : Xn at proper time.Eruptive sequence : Xn at proper time.
 Strategically located close to the incisors.Strategically located close to the incisors.
 Center of each half of arch .’. Ant & post crowding.Center of each half of arch .’. Ant & post crowding.
 Protraction of molars not required.Protraction of molars not required.
 4 Xn adequate anchorage for retraction of 6 teeth.4 Xn adequate anchorage for retraction of 6 teeth.
 Contact b/w canine and 2Contact b/w canine and 2ndnd
premolar satisfactory.premolar satisfactory.

1. Convex profile with
severe crowding.
2. Class II div I with deep
anterior bite.
3. Class I with severe
crowding.
4. Class I with bimaxillary
protrusion.
Indications for I st premolar extraction:

Indications for I st premolar extraction.

Extraction of 2nd
premolars:
History:
Henry(1965)
1.mild degree of crowding & excellent profile.
2.No crowding and fullness of lips.
Begg: unless carious or poorly formed.
Nance: Ist person.Mild discrepancy.
Avoids dished-in-face & less tendency for relapse.
Carey: 2.5-5mm

 DEWEL:DEWEL: Xn creates more space in borderline cases,Xn creates more space in borderline cases,
closed by reducing the anchorage value of buccal segmentsclosed by reducing the anchorage value of buccal segments
 LOGAN:LOGAN:
 U4 more esthetic than 5U4 more esthetic than 5
 Contact b/w 4 and 6 tended to stay closed.Contact b/w 4 and 6 tended to stay closed.
 Reduced possibility of buccal/lingual furrows in XnReduced possibility of buccal/lingual furrows in Xn
site ‘.’ of rapid closure.site ‘.’ of rapid closure.
 Closure of ant open bite, by reducing post verticalClosure of ant open bite, by reducing post vertical
dimension.dimension.
 De CASTRO:De CASTRO: 3 independent segments.3 independent segments.
• 5s Xed only post segment shortened.5s Xed only post segment shortened.
• 4s Xed, both segments shortened-4s Xed, both segments shortened- functionalfunctional
integrity of the dentition.integrity of the dentition.

INDICATIONS FOR 2ND
PREMOLAR EXTRACTION
1.Good profile+mild crowding
2.flat profile+moderate crowding
3.Class II div 1 on skeletal class I
+mild crowding.
4. Mild Class III inter-arch
relation+mild crowding in U arch.
5.Congenitally missing,impacted.
6. Grossly destructed/heavy restn.
7. Abnormal root morphology.
8. Open bite.

Extraction of 2nd
premolars:
ADVANTAGES:
1. Original facial contours
retained without reduction of
lip profile.

ADVANTAGES:
 U 4 more esthetic along side canine.U 4 more esthetic along side canine.
 Lesser tendency for extraction space to open in L arch.Lesser tendency for extraction space to open in L arch.
 Less possibility of buccal/lingual furrow in Xn space.Less possibility of buccal/lingual furrow in Xn space.
 Easy correction of Class II molar correction to Class IEasy correction of Class II molar correction to Class I
molar relation.molar relation.

Ist Molar Extraction:
 Avoided:Avoided:
Not provide adequate space in the ant region.Not provide adequate space in the ant region.
5 & 7 may tip in the Xn space.5 & 7 may tip in the Xn space.
Deepening of bite.Deepening of bite.
Masticatory efficiency.Masticatory efficiency.

Carious- beyond restorationCarious- beyond restoration
RCTreated, - 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&/ prominentFacial considerations: large chin buttons&/ prominent
nosenose
(4- dished-in)(4- dished-in)
((rationale: farther back less facial change)rationale: farther back less facial change)
Open bite cases.Open bite cases.
Indications:

Ist Molar Extraction:
 Not to allow U7 locked behind L7.Not to allow U7 locked behind L7.
Horizontal elastics – until danger of locking has passed.Horizontal elastics – until danger of locking has passed.
 Mesially inclined 7, lesser degree of anchor bendMesially 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-

Single arch extraction – U 6 or what to do
when non extraction treatment fails.
Raleigh Williams. AJO 1979
 Class II div 1 with perfect lower arch alignment butClass II div 1 with perfect lower arch alignment but
growth expectation inadequate.growth expectation inadequate.
 Class II div 1 active growth over. Pt non cooperative.Class II div 1 active growth over. Pt non cooperative.
 Class II div 1 with good lower arch over basal bone, withClass II div 1 with good lower arch over basal bone, with
some growth expectation.some growth expectation.
 Class II div 1 with mild open bite.Class II div 1 with mild open bite.

 Problems with Xn of 4s:Problems with Xn of 4s:
 Tipping, opening of space (5 small to fill the space)Tipping, opening of space (5 small to fill the space)
 Mesial tipping of 6, hanging palatal cuspMesial tipping of 6, hanging palatal cusp
Avoided with 6 Xn.Avoided with 6 Xn.
 Good molar relation.Good molar relation.
 U 4 occlude with L4U 4 occlude with L4
 8s erupt normally.8s erupt normally.
 Min patient cooperationMin patient cooperation
 Stable results.Stable results.
 Tuberosity not crowded.Tuberosity not crowded.
 Results similar to nonext.Results similar to nonext.
 Rx duration is reduced.Rx duration is reduced.
 Profile maintained.Profile maintained.

2nd
MOLAR EXTRACTION:
 David W.Liddle-David W.Liddle- AJO 1977AJO 1977
 Malocclusion: potential force by developing 7,8.Malocclusion: potential force by developing 7,8.
 Xn of 7s to intercept this forward force.Xn of 7s to intercept this forward force.
 4 Xn: treating the effect and not the cause.4 Xn: treating the effect and not the cause.
 10-12mm of space :satisfies arch length problem, not10-12mm of space :satisfies arch length problem, not
apparent when patient smiles.apparent when patient smiles.
 91% 7 Xn.91% 7 Xn.
 6 move distally in response to pressure.6 move distally in response to pressure.
 Over compressed CT fibers- move 3 &4 to a more normalOver compressed CT fibers- move 3 &4 to a more normal
occlusion.occlusion.

2nd
MOLAR EXTRACTION:
ADVANTAGES AND INDICATIONSADVANTAGES AND INDICATIONS
 DDisimpaction of 3isimpaction of 3rdrd
molars, faster eruptionmolars, faster eruption
 Prevention of “dished-in” at the end of facial growthPrevention of “dished-in” at the end of facial growth
 Prevention of late incisor imbricationPrevention of late incisor imbrication
 Facilitation of 1Facilitation of 1stst
molar distalizationmolar distalization
 Distal movement only as needed to correct the overjetDistal movement only as needed to correct the overjet
 Fewer “residual”spaces at the end of RxFewer “residual”spaces at the end of Rx
 Less likelihood of relapseLess likelihood of relapse
 Good functional occlusionGood functional occlusion
 Good mandibular arch formGood mandibular arch form
 Overbite reduction.Overbite reduction.

Indications:
Chipman:Chipman:
 Xn 7 - caries, ectopic, rotated.Xn 7 - caries, ectopic, rotated.
 Mild – moderate discrepancy with good profile.Mild – moderate discrepancy with good profile.
 Crowding in tuberosity area ,with a need for distalCrowding in tuberosity area ,with a need for distal
movement of 1movement of 1stst
molar.molar.
Lehman - preconditionsLehman - preconditions
 8 in favorable angulation 15-30*angle to the long axis of8 in favorable angulation 15-30*angle to the long axis of
the 1the 1stst
molar.molar.
 Normal in size/shape & root area is sufficient w.r.t 2Normal in size/shape & root area is sufficient w.r.t 2ndnd
molar.molar.
 No congenitally missing teeth.No congenitally missing teeth.

Disadvantages:
 Too much tooth substance removed in Cl I mal occlusionToo much tooth substance removed in Cl I mal occlusion
with mild crowding.with mild crowding.
 Location far from area of concern.Location far from area of concern.
 No help in correction of A-P discrepancy without patientNo help in correction of A-P discrepancy without patient
cooperation .cooperation .
 Possible impaction of 3Possible impaction of 3rdrd
molars even with 2molars even with 2ndnd
molar Xnmolar Xn
 Unacceptable positions of erupted 3Unacceptable positions of erupted 3rdrd
molars –second, latemolars –second, late
stage of fixed therapy.stage of fixed therapy.
 9-20% missing 39-20% missing 3rdrd
molars.molars.

Timing for mandibular 2nd
molar extraction:
 Kokich:Kokich:
1.1. 33rdrd
molar crowns completely formed, Xn beforemolar crowns completely formed, Xn before
roots begin to developroots begin to develop
2.2. 30*to the occlusal plane30*to the occlusal plane
3.3. 33rdrd
molars in close proximity to 2molars in close proximity to 2ndnd
molar-drift.molar-drift.
Halderson, Huggins, Lehman and Smith.Halderson, Huggins, Lehman and Smith.
Before radiographic evidence of root formnBefore radiographic evidence of root formn.(.(12-14yrs)12-14yrs)
Consensus opinion: as soon as 2Consensus opinion: as soon as 2ndnd
molar erupts.molar erupts.
angulation.angulation.

3rd
Molar Extraction:
 Xn to prevent lower anterior crowding?Xn to prevent lower anterior crowding?
 Distal movement of 6,7– impaction of 8.Distal movement of 6,7– impaction of 8.
 Xn of 8 before retracting.Xn of 8 before retracting.
Contraindications:Contraindications:
 11stst
or 2or 2ndnd
molars are extracted.molars are extracted.

Incisor Extraction:
 Mandibular incisors- therapeutic valueMandibular incisors- therapeutic value
 11stst
sign of incipient malocclusionsign of incipient malocclusion
 Difficult to treat as they relapse easily.Difficult to treat as they relapse easily.
 Not a new idea.Not a new idea.
 Jackson (1904)Jackson (1904)
 Riedel :Riedel : Xn of 2 lowerXn of 2 lower
Incisors-arch form withoutIncisors-arch form without
Expn of intercanine widthExpn of intercanine width
 Angle:Angle:
Inexcusable.disharmony b/wInexcusable.disharmony b/w
Occlusal planes, abnormal overbiteOcclusal planes, abnormal overbite

Incisor extraction:
Indications:-
 For mandibular incisors:For mandibular incisors:
 Extreme crowding / protrusion.Extreme crowding / protrusion.
 Gingival recession & loss ofGingival recession & loss of
overlying bone on labial surface.overlying bone on labial surface.
 Lateral incisors severely # inLateral incisors severely # in
young children.young children.
 Rarely-discrepancy in sizes of U &Rarely-discrepancy in sizes of U &
L incisors themselves, 1 incisorL incisors themselves, 1 incisor
can be removed.can be removed.
 Reidel- Rx time reduced.Reidel- Rx time reduced.
 min facial change.min facial change.

Incisor extraction:
Advantages:
1.1. Maintains/ reduces intercanineMaintains/ reduces intercanine
widthwidth
2.2. General arch form is maintainedGeneral arch form is maintained
– greater stability– greater stability
3.3. Retention period- lessRetention period- less
4.4. Anterior segments can beAnterior segments can be
retracted readily if need be.retracted readily if need be.
5.5. Immediate solid tooth support ofImmediate solid tooth support of
entire buccal segments.entire buccal segments.
6.6. Easy reduction of overbite-Easy reduction of overbite-
intrusion, reshapingintrusion, reshaping
7.7. Mechanotherapy is simplified.Mechanotherapy is simplified.
Space closure quick.Space closure quick.www.indiandentalacademy.com

Incisor extraction:
Disadvantages:-
 Reopening of space . Central Incisor.Reopening of space . Central Incisor.
 Danger of creating a tooth size discrepancy.Danger of creating a tooth size discrepancy.
 ReidelReidel- 2 mandi incisors Xed to maintain- 2 mandi incisors Xed to maintain
intercanine width.intercanine width.
 1 incisor Xn- deepbite- if normal tooth size1 incisor Xn- deepbite- if normal tooth size
relationship is present before Xn.relationship is present before Xn.
 Color difference of canine.Color difference of canine.

Upper Incisor Extraction:
 Rarely indicated.Rarely indicated.
 Unfavorable impaction of U incisor.Unfavorable impaction of U incisor.
 Bu/Li blocked out lateral, with good contact b/w centralBu/Li blocked out lateral, with good contact b/w central
and canine.and canine.
 Congenital missing of 1 lateral incisorCongenital missing of 1 lateral incisor
 Dilacerated tooth.Dilacerated tooth.
 Gardiner et al:Gardiner et al:
• U crowding, mesial displacement of root apicesU crowding, mesial displacement of root apices
of U3 - Xn of lateral incisor.of U3 - Xn of lateral incisor.

Summarize:
 Incisor Xn rare.Incisor Xn rare.
 Possibility must always be considered.Possibility must always be considered.
 Careful planning with diagnostic setupCareful planning with diagnostic setup

Extraction of Canines:
 Not extracted. Profile.Not extracted. Profile.
 Long path of eruption.Long path of eruption.
 Conditions where indicated:Conditions where indicated:
 Impossible to bring in alignment.Impossible to bring in alignment.
 Gross displacement Bu/LiGross displacement Bu/Li
 4 in contact with 2 & does not show palatal cusp.4 in contact with 2 & does not show palatal cusp.
Decision : position of apex.Decision : position of apex.

The Effect of Different Extraction sites upon
incisor retraction. Raliegh Williams et al AJO 1976
 Relation b/w root surface area and Xn site selection uponRelation b/w root surface area and Xn site selection upon
incisor retraction.incisor retraction.
 Efficient mechanotherapy.Efficient mechanotherapy.
 Diagnostic line.Diagnostic line.
 Larger the root surface area, greater the resistance toLarger the root surface area, greater the resistance to
movement.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

Conclusion:
 Location of the Xn site-Location of the Xn site-
• Root surface area.Root surface area.
• Predict incisor retraction.Predict incisor retraction.
 Should be considered in diagnosis, so that aShould be considered in diagnosis, so that a
desired Rx goal for the final position of incisorsdesired Rx goal for the final position of incisors
within the facial profile can be achieved.within the facial profile can be achieved.

 Orthodontic treatment may include extractions ofOrthodontic treatment may include extractions of
any tooth in the arch.any tooth in the arch.
 Based on sound diagnosis, treatment objectives.Based on sound diagnosis, treatment objectives.

methods of gaining space in orthodontics -Extraction

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