Incisor extraction /certified fixed orthodontic courses by Indian dental academy

INCISOR EXTRACTION

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INDIAN DENTAL ACADEMY
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Introduction
The debate on extraction goes a long way back into the
history of dentistry
Historically, it is well known that Dr. Angle was against
extraction.
Angle declared his non-extraction mind by the statement.
“The best balance, the best harmony, the best proportion of
the mouth in its relations to other structures require that
there shall be the full complement of teeth and that each
tooth shall be made to occupy its normal position normal
occlusion.”

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The great extraction debate of the 1920’s between
Dr. Case and Angle’s devotees were well known
and documented in orthodontic annuals.
Few dared to oppose angle and those who dared
like Dr. Case had to pay a heavy price. It was Dr.
Tweed, who publicly endorsed extraction after the
death of Dr. Angle.
In fact Dr. Tweed was so candid and generous that
he re-treated many of his cases with extraction free
of cost (during 1940’s
The introduction of light wire deferential force
technique in 1950’s by Begg-further enhanced the
acceptance of extraction as a mode of orthodontic
therapy


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The last quarter of the century saw the swing of
the pendulum more towards non-extraction.
Early treatment
Acceptance of functional therapy.
Growth modification by orthopedic methods.
RME
better anchorage control, changing esthetic for a
fuller face and profile, face-lift concepts are some
of them.
Development of three dimensionally controlled
brackets of PEA systems (Fully programmed).

Why should we extract teeth?
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Primarily for gaining space
Decrowding
Retraction
Leveling of curve of spee
Correcting the sagittal interarch discrepancy etc.
With the evolutionary trend of reduction in jaw
size, space has become scarce.


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Orthodontist is essentially a “space manager” –
creating, deploying and expanding the space in
the arch has been our primary task.
Once the non-extraction options of gaining
spaces (expansion, molar distalization,
protraction of anteriors, proximal reduction, and
derotation of posteriors) are rejected on the
merits of the case, orthodontist sets himself to
extract teeth.

Objectives
TD Foster, W.R Proffit
Extraction of teeth in orthodontic treatment
will be necessary in 2 main circumstances.
 For the relief of crowding.
 For the correction of Anterior / Posterior
dental arch relationship.


Need for extraction
Arch length – tooth material Discrepancy
 Ideally the arch length and tooth material should
be in harmony with each other. If the dentition is
too large to fit in the dental arch without
irregularity, it may be mercenary to reduce the
dentition size by the extraction of teeth.


Correction of sagittal inter arch
relationship
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Abnormal sagittal malrelationship such as class II / III
malocclusion may require extraction to achieve a normal
interarch relationship.
In a class I- it is preferable to extract in both the arches
In class II with abnormal upper proclination, normal
alignment of the lower teeth and where point A is
abnormally forward relative to the B point, it is advisable to
extract teeth only in the upper arch and to retract the
maxillary incisors and canines

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when the lower arch is crowded or molars are
not in full cusp class II molar relationship, it
might be preferable to extract in both the arches .

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Class III cases are usually treated by extracting
teeth only in the lower arch.


Different extraction
procedures:
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Balancing extraction.
Compensating extraction.
Phased extraction.
Serial extraction.
Enforced extraction
Wilkinson extraction.
Therapeutic extraction.
Atypical extraction

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Balancing extraction
This is done to maintain the symmetry and
midline of the arch

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Compensating extraction.
Removal of the equivalent tooth in the opposing
arch to maintain buccal occlusion.

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Enforced extraction
Extraction carried out by compulsion

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Wilkinson extraction
Wilkinson advocated extraction of all the four
first permanent molars between the age of 8½
and 9 years.

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Serial extraction

Orderly removal of selected deciduous teeth and
permanent teeth in a predetermined sequence


Therapeutic extractions
. The choice of teeth for-extraction depends upon.
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Arch length discrepancy
The antero-posterior positioning of teeth in
relation to the facial line
Presence of orthognathic or prognathic profile.
Age and dental development.
The degree of alvelo-dental prognathism.
Direction of jaw growth / especially lack of jaw
length.
Degree and site of crowding.

Contemporary extraction
guidelines (proffit)

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Discrepancy <4mm
extraction rarely indicated
Discrepancy 5-9 mm
Non-extraction / extraction treatment
depends on the hard tissue / soft tissue
characteristics and on how the final position of
the incisors will be controlled.
Discrepancy 10mm or more
Extraction almost always required to obtain
enough space.

Incisor extraction
Maxillary incisors
Indications
Unfavorably impacted maxillary incisors
Buccally or lingnally placed lateral incisor with
good contact between central incisor and
canines.
If a lateral incisor is crowded in linguo-version
with its apex palatally displaced and if the
canine is erupting in a forward position and
distally is inclined, lateral incisor extraction is
indicated.
Grossly carious incisor that cannot be restored.
Trauma / irreparable damage to incisors by
fracture

Mandibular incisors
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Indications
When one incisor is completely excluded from
the arch and there are satisfactory
approximate contacts between other incisors.

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Severely malpositioned incisor.

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Poor prognosis as in case of trauma, caries,

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bone loss etc


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Lower canines are severely inclined distally and
lower incisors are fanned – it is very difficult to
correct the condition by extractions further back
in the arch. The most upright incisor is selected
for extraction so that other teeth can be tipped
into correct position.
In mild class III incisor relation with an
acceptable upper arch and lower incisor
crowding, a lower incisor may be extracted to
achieve normal overjet, overbite and to relieve
crowding


contraindications
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It is often very tempting to extract a lower
incisor to relieve crowding particularly which it
is confined to the anterior segment but its
extraction should be avoided as far a possible
because it causes.
Remaining anterior teeth to imbricate
Although crowding may be relieved in the short
term forward movement of buccal teeth leaves
incisor contacts and positions less than ideal.
Deep bite.

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Lower inter canine width (ICW) decreases
resulting in a secondary reduction in the upper
inter canine width with crowding in the upper
labial segment.
Retroclination of lower incisors.
It is not possible to fit upper four incisors around
three lower incisors, either on increase in over
jet (or) upper incisor crowding have to be
accepted.

Clinical considerations
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Mandibular incisors are the objects of very
significant therapeutic value in clinical
orthodontist and their relevance as follows.
They from the first sign of an incipient
malocclusion.
They are difficult to treat as they relapse readily.
Crowding of the mandibular incisors in the most
frequent anomaly

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Wayne A. Bolton analysis (1958)
Bolton pointed out that the extraction of one
tooth or several teeth should be done according
to the ratio of tooth material between the
maxillary and mandibular arch, to get ideal
interdigitation, overjet, overbite and alignment of
teeth.


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Procedure for doing Bolton analysis

Overall ratio =

Sum of mandibular 12
x100
Sum of maxillary 12

Average = 91.3%
If overall ratio is greater than 91.3, then
mandibular tooth material is excessive.
Sum of mand =

Sum of max12 x 91.3
100


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If overall ratio is lesser than 91.3% then
maxillary material is excessive.

Sum of max =

Anterior ratio =

Sum of man12x100
91.3

Sum of man 6
x 100
Sum of max.
Average – 77.2%

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If anterior ratio is greater than 77.2% then the
mandibular anterior tooth material is excessive.

Sum of man =

6 − sum of max . 6 x 77.2
100

•If anterior ratio is less than 77.2, then maxillary
anterior tooth material is excessive.
Sum of max. =

6 − sum of man. 6
x 100
77.2


Review of literature
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As a matter of fact lower incisor extraction to
treat mandibular incisor crowding is not a new
idea.
Jackson in 1904 had illustrated a case where
one incisor had been earlier removed and he
chose to remove a second incisor because the
remaining three were crowded and the
intercanine distance was too narrow for their
alignment. Owing to the close occlusion it was
not considered practicable to increase the
distance between the canines to correct the
crowding

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Fisher: Demonstrated several cases in
1940 with a two incisor extraction plan and
no retention.
Schwarz: Reviewed 20-year post
retention records of one patient who had
congenitally missing two mandibular
incisors. He was surprised to observe
good long-term stability

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Riedel: Extreme crowding or protrusion of
incisors often accompanied by loss of gingival
line and bone overlying the labial surfaces of
incisor roots, would be good indicators for
mandibular incisor extraction.
Riedel further wrote that extraction of two
mandibular incisors may satisfy the
requirements of maintaining arch form without
expansion of inter canine width of the arch with
non-extraction or with premolar extraction
therapy, the inguinal inter canine width usually
requires to be increased in order to gain
adequate alignment and arch form.

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Salzmann, reviewing Edward H. Angle’s
philosophy of extraction in orthodontics, noted
that angle regarded the extraction of an incisor,
when the tooth was sound, to be inexcusable.
Angle warned that extracting one incisor, as
advocated by some, would lead to a less
acceptable harmony between the occlusal
planes of the remaining teeth in addition to an
abnormal incisor overbite.

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Lower incisor extraction in orthodontic
treatment
“ Vincent kokich and Peter Shapiro (angle
orthodontist 1984)”
They have presented four different cases –I their
treatment plan, which included the extraction of
one mandibular incisor and reduction of
maxillary tooth width.


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Key consideration
Tooth size analysis is an important part of the
evaluation because in some situations this may
indicate little likelihood of a successful result
with an incisor extraction as in a case of
significantly maxillary anterior excess. If the
analysis, shows lower anterior excess the incisor
extraction might have a positive effect.
Kokich and Shapiro have mentioned that the
indication are relatively low, however the
possibility of lower incisor extraction should be a
part of every orthodontist portfolio of treatment
techniques.

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Mandibular incisor extraction – post retention
evaluation of stability and relapse. Reidel R.A
1992 (AJO-DO) Little R.M
Their purpose was to access the stability of
mandibular dental alignment in patients treated.
With conventional edge-wise mechanism
following the extraction of one (or) two
mandibular incisors. The results were favorable
when compared with premolar extraction case.
Single incisor extraction
- 29%
Two-incisor extraction
- 56%
Pre molar extraction
- 70%

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When two mandibular incisors are removed, the
mandibular teeth are re-arranged so that the
mandibular canines become mandibular laterals
and if central incisors are extracted the laterals
become centrals 1st premolars assume the
place of canines.


Single lower incisor extractions
Albert owen ( JCO 1993)
 Class I molar relationship, indicating that the
final buccal interdigitation will be acceptable.
 Moderately crowded lower incisors
 Severe – premolar extractions
 Mild –without extraction
 Mild or no crowding in the upper arch
 Acceptable soft tissue profile
 Minimal to moderate overbite / overjet
 Minimal growth potential.
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Lower incisor extraction is orthodontic
treatment
Ali-Akber Babreman AJO-DO-1977.
Extraction of single mandibular incisor can be
employed as a compromise treatment of certain
malocclusions, if the end result fulfills the
requirements for healthier dentition, which is
functionally and esthetically harmonized in
relation to the surrounding structures.
Best-suited cases for this procedure are those
Crowding which have the following
specifications

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Good normal maxillary dentition
Perfect buccal interdigitation
Severe lower anterior crowding with lack of
space for almost one lower incisor.
Lower anterior arch length discrepancy is
greater than 4 to 5 mm. Anterior tooth ratio is
more than 83mm.


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Contraindications
Deep-bite case with horizontal growth pattern
Bimaxillary crowding cases, which have no tooth
size discrepancy in the incisor area.
All cases having incisor discrepancy due to
either small lower incisor / large upper incisors.
In conditions exhibiting a deep overbite pattern,
reduction of the mandibular anterior unit should
be avoided.
He concluded his study by stating that this
procedure should be considered as a last resort
measure since it involves the most important
stabilizing area of occlusion.

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Incisor extraction /certified fixed orthodontic courses by Indian dental academy

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