Mandibular Incisor Extraction

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LOWER INCISOR

EXTRACTION


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Introduction

In 1757 Bourdet, a disciple of Pierre Fauchard,recommended the removal of the premolars to

relieve crowding.

Hunter (1835) extracted the first premolars to

allow incisor retrusion in cases of posteriorprotrusion.


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Schwarz (1961) reviewed 20-year postretention

records of a patient who was congenitallymissing two mandibular incisors. He was

surprised to observe good long-term stability.

As pointed out by Kokich and Shapiro (1984),

the deliberate extraction of a lower incisor incertain cases allows the orthodontist to improve

occlusion and dental aesthetics with a minimum

of orthodontic action.


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Indications

Anomalies in the number of anteriorteeth


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Ectopic eruption of incisors - The transposition

of anterior teeth, particularly of the canines, or

the severe malpositioning of a lower incisor,

indicates extraction to protect the long-termsurvival of the dentition.


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Moderate Class III malocclusions - Anterior

crossbite or an edge-to-edge relation of the

incisors with a tendency towards anterior open

bite is another indication for incisor extraction.

The occlusion improves on shortening the

length of the mandibular arch, which retrudesthe position of the lower incisors


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According to Owen, patients who aresuitable for single lower incisor extractions

usually fit the following diagnostic pattern:

Class I molar relationship,

Moderately crowded lower incisors, Mild or no crowding in the upper arch,

Acceptable softtissue profile,

Minimal to moderate overbite and overjet, No or minimal growth potential, and

Missing lateral incisors or peg shaped laterals.

JCO 1993 Mar(153 - 160): Single Lower Incisor Extractions - ALBERT H. OWEN III


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Contraindications

Deep-bite cases with horizontal growth pattern, All cases which require upper first premolar

extraction while canines are in Class I

relationship, Bimaxillary crowding cases which have no

tooth-size discrepancy in the incisor area, and

All cases having incisor discrepancy due toeither small lower incisors and/or large

maxillary incisors.


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Selection of suitable cases

Treatment strategy should begin with accuratemeasurements of required arch length and

available arch length in the entire mandibular

arch, or tooth-size-arch-length-discrepancy.

An additional consideration is the intercanine

width, and the effect of an incisor extraction onit.


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With six maxillary anterior teeth now articulatingwith five mandibular anterior teeth, the overbite

must be maintained or, if deep, reduced.

Overjet is likewise maintained or reduced to

produce centric occlusal contacts. Maxillary and

mandibular canines will finish in ideal Class Irelations.


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Boltons analysis or Neffs coeficient shouldbe considered so as to calculate the discripancy

and removal of lateral or central incisor

accordingly.

Kesslings setup of both arches is informative

and often suggests minor interproximalreduction of maxillary anteriors to allow their

retraction, alignment and maxillary to

mandibular arch coordination


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The maxillary midline will overlie the

remaining central incisor.

Absence of a mandibular dental midline will not

affect the occlusion, esthetics, periodontal

health, or stability, the principal requirements of

orthodontic therapy.

AJO-DO 1994 Feb (107 - 116): CLINICIANS' CORNER - Valinoti


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Do mandibular incisor extraction

cases exhibit less recrowding afterlong-term retention???


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Jose-antonio Canut - EJO (1996)

Alignment stability seems to be better than

that achieved in cases subjected to premolarextraction.

Riedel has suggested that incisor extractionmay give greater stability in this area in the

absence of permanent retention


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This may be due to the maintenance of teeth

nearer their original positions where muscle

pressures are less likely to introduce instability

Another possibility is the minimum stress on

adjacent anchorage during space closure,

leaving all or most of the acquired space for the

anterior correction.


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Conclusion

Four premolar extractions will continue to be the

optimum treatment for many malocclusions

having greater space requirements and the needfor improved facial esthetics. However, with

careful selection and management, there are

cases that can be successfully treated with a

mandibular incisor extraction. This approach

will be a valuable addition to our

armamentarium


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Mandibular Incisor Extraction

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