Mandibular Incisor Extraction
Transcript of 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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