Extraction controversies in orthodontics /certified fixed orthodontic courses by Indian dental academy

EXTRACTION
CONTROVERSIES IN
ORTHODONTICS

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INDIAN DENTAL ACADEMY
Leader in continuing dental education


INTRODUCTION
To the common man crowding more often than spacing constitutes
malocclusion. Treatment of a crowded arch requires space gaining .
This has been achieved through two ways of treatment – extraction or
non extraction modality.
Extraction to create space for accommodation of the remaining teeth of
crowded dental arches was written up in the dental literature as long as
1771. It was not a new idea then and certainly is not so now. While
resorting to extraction care must be exercised so that extraction is not
carried beyond logical limits. There will be exceptions to the
extraction approach just as it was to the non extraction concept.
this seminar is a summary of the various options we have regarding
extraction therapy and the controversies surrounding that.

HISTORICAL REVIEW
• JOHN HUNTER – 1771 – NATURAL HISTORY OF
THE TEETH.
• SPOONER - 1839
• FARRAR – 1888
• PEARS – 1859 – ADVOCATED EXTRACTION IN THE
DENTAL COSMOS PUBL. OF OCT. 1859 FOR
SIMPLYING ORTHODONTIC PROCEDURE.
• ANGLE AND EXTRACTION – PORPOSED
EXTRACTION INTIALLY, LATER FOLLOWED NON
EXTRACTION THERAPY.

•
•

EXTRACTION VERSUS EXPANSION DEBATE
ANGLE FOLLOWED NEW SCHOOL OF THOUGHT OF NON
EXTRACTION (EXPANSION).
believed orthodontic forces to teeth enable bone induction.
he ridiculed extraction from his seventh edition onwards.
• CASE advocated extraction, was supported by DEWEY and CRYER
and BEGG – ATTRITION OCCLUSION.
• EXTRACTION WON OVER EXPANSION
EXPANSION returned due to –
1. Bite deepening
2. Space reopening
3. Improper axial inclination, effects of extraction treatment
The current trend is towards non extraction, but it has
high rate of relapse
root fenestration and dehiscence
apical root resorption
improper buccal inclination and
increasing mandibular intercanine width was most unstable

DIAGNOSIS AND DECISION MAKING
MODEL ANALYSIS:
kesling’s diagnostic setup
Carey arch perimeter
Ashley howe analysis
tweed merrifield analysis
bolten tooth size ratio
CEPH. ANALYSIS – tweed’s diagnostic triangle
soft tissue profile analysis
steiner’s sticks of compromise
CLINICAL EXAMINATION – profile, lip competence,
VTO, age and growth left.

CRITERIA FOR EXTRACTION
BUCHIN states
arch length discrepancy of 3 – 4mm after 8 years of
age
facial esthetics and sex
basal bone disharmony – tweed’s triangle, ANB
difference facial angle – less than 88 degrees, MP –
occipit relation, amount of chin point from NB – NPog
anchorage requirement
pt. Co-operation

SALZMANN states
labio lingual dental arch relation to facial plane
size of the gonial angle
axial inclination of the mandibular incisors
type of crowing present
direction of jaw growth
basal arch length
thickness and distribution of soft tissue
as probable criteria for extraction


CHOICE OF TEETH TO BE EXTRACTED
Choice to extract depends on
direction and amount of jaw growth
basal arch discrepancy
facial profile
position and eruption of teeth
Dento alveolar proclination
patients age
and the state of the dentition as a whole


CHOICE OF TEETH TO BE EXTRACTED
Pathological extractions
I premolar
II premolar
II molar
III molar
Incisors
I molars and canine
Asymmetric extraction
Multiple extractions

PATHOLOGICAL EXTRACTION:
Initiated when the following are present,
Teeth congenitally absent,
Teeth carious beyond recall,
Teeth missed placed or buried,
Teeth malformed.


BEGGS THEORY OF ATTRITIONAL OCCLUSION:
Stone age – coarse diet – mark occlusal and interproximal
wear – decreased M – D width and crown height – no late
incisor crowding.
Modern age – soft diet – no occlusal wear – increase
crowding.
Begg felt that attrition has not claimed a unit of tooth
material from the arch length during the patients first 20
years of life, it will be correct to obtain the same balance
by eliminating the amount by extraction


I PREMOLAR EXTRACTION:
Most sacrificed tooth because –
better anchorage balance
erupts before other posterior teeth except first
permanent molar.
its eruption allows eruption of permanent canine
(most 0ften impacted)
forms center of each half of the arch


More over I premolar extraction provided about 6 -7 mm of
space on each side of the arch which on most instances
was sufficient enough for over jet overbite and crowding
corrections.
They remain the teeth of choice in max. anchorage cases
where the entire space is used for anterior retraction.
Maxillary first premolars extraction provides more space than
second premolar extraction.
AL/TZ –more than 5 mm
AO 1992 WITZEL found that premolar extraction patients has
less of a tendency to become crowded than patients treated
with non extraction.
RICHARD RIEDEL found that in first premolar extraction
cases the intercanine width decreased post treatment and
mandibular incisor irregularity increased, whether the arch
was expanded or not.

EFFECTS OF PREMOLAR EXTRACTION
WITZIG opposed first premolar extraction because
resulted in narrow smile line
upper lip appears sunken at the corner of the mouth
no remedy for retruded chin in class II cases
decreased vertical dimension
often led to third molar impactions – surgical and
psychological complications.


AO 1995 BENNETT and MCLAUGHLIN opposed the allegations
imposed on first premolar extraction by reviewing their drawbacks.
COLLAPSE OF VERTICAL DIMENSION – no evidence to blame
premolar extraction.
DOUGHERTY analyzed and found a slight increase in MP angle
in both extraction and non extraction case.
KLAPPER found no influence of extraction or non extraction on
Brachy facial or dolichofacial growth patterns.
LINN compared first and second premolar extraction on vertical
phase development and found no significance
FLATTENING OF FACIAL PROFILE – primarily due to diagnostic
errors and errors in treatment mechanics.
EXCESSIVE ANTERIOR INTERFERENCES (periodontal trauma,
tooth wear, root resorption, TMD) – occurred due to
initial canine angulation
canine retraction during L&A
torque control during space closure
overbite control during over jet reduction
POSTERIOR CONDYLAR DISPLACEMENT

SECOND PREMOLAR EXTRACTION
HENRY in 1965 gave the following criteria:
a mild degree of crowding and good profile
no crowding and fullness of lips
second premolars extracted in group B and C anchorage cases
and when the lower fives are impacted
NANCE first drew attention to second premolar extraction
CAREY – AL/TZ discrepancy - 2.5-5mm
SHOPPY observed more mesial movement of molars
SCHWAB found upper and lower incisors were retracted less with
respect to skeletal landmarks.


LOGAN listed other factors of significance
max. I PM more esthetic than II PM
contact point of mandibular first molar and first premolar
stay close
rapid space closure
easy overbite reduction
closure of anterior open bites
DECASTRO – felt second premolar extraction affected only
the posterior segment and first premolar extraction
disturbed the transitional area.


SECOND MOLAR EXTRACTION
DRAWBACKS OF FIRST PREMOLAR EXTRACTION
lead to THE GREAT SECOND MOLAR DEBATE.
WITZIG and SPAHL cruised IPM extr. Due to
reduction in vertical dimension
over retraction
upper incisor retroclination
bite deepening
anterior interferences
condyle displacement and TMD

INDICATIONS
SAZMANN
– chronological dental age be past average eruption age.
- max. tuberosity underdeveloped
-second molar severely caried and in buccal occlusion
-max. third molar in favorable angulation, position, size
and shape for eruption
-attempts to bring second molar into occlusion will cause
relapse.


CONTRA INDICATIONS
Max. third molars too high in tuberosity
poor angulation of third molars
under size third molar crown or root
absence of third molar tooth buds
badly caried or impacted third molar


ADVANTAGES
increase stability
less crowding
`less reopening of extraction sites
less over retraction
more esthetic smile
more efficient deep bite reduction
fewer impacted third molars
shorter duration of FA
prevention of dished in appearance
first molar distal movement
Provides around 12mm in each half of the arch – needed in anterior and
posterior crowding cases.

DISADVANTAGES
far location of extraction site
too much tooth substance removed
no help in correction of A – P discrepancies without
patient co – operation
freq. Impacted third molars.
TIMING
age – 12 to 14 years
third molar crown formed but root not developed
third molar inclination not more than 30 degrees and close
to the second molar root.

INCISOR EXTRACTION
Incisor not to be extracted unless damaged beyond repair
(bone loss, periodontitis, fracture, repair).
MILTON FISCHER – 1940 demonstrated two incisor
extraction and no retention.
SCHWARTZ reviewed 20 years post extraction records and
found good stability.
REIDEL suggested mandibular incisor extraction for better
stability as intercanine width is not altered.
But ANGLE ridiculed incisor extraction.
REIDEL also suggested reduced treatment time.

JCO 1993 MARCH ALBERT OWEN - suggests full diagnostic set up and
states
patients with class I molar relationship
moderate lower anterior crowding and no upper arch crowding
acceptable soft tissue profile
minimal to moderate over jet and overbite
minimal growth potential
missing or peg laterals
As prerequisites for incisor extraction.
DRAW BACKS:
canine repositioned as incisor results in
Angulation and torque problems in canine aligning
excess trauma to opposed dentition
color difference,gingival contour and root morphology variation
can’t establish ideal contact points
enameloplasty required to reshape canine.

THIRD MOLAR
Third molars were earlier thought to be the cause of late
mandibular incisor crowding.
With evolution, the human jaws are incapable of
accommodating the third molars. They are extracted
mainly for pathological reasons (dentigerous cyst, caries,
impaction).
After orthodontic treatment involving distal movement of
max. arch, to facilitate retention
Along with first premolar extraction in case of excessive
space requirement
Extr. of III molars,often presents complications-dry
socket,delayed healing leading to “dentist fear syndrome”

FIRST MOLARS
Not advised generally
Extracted if grossly caried, mobile, impacted or in total supra
version
Though larger in size provide less space for anterior
retraction
Increased treatment time
2/3 space used up by second molar mesialization
Due to root anatomy and bone surrounding second molar
mesialization results in lingual rolling
Allows third molar eruption

ONE ARCH EXTRACTION
JCO 1971 OCT.
Criteria for one arch extraction are
class I / II malocclusions
overbite 3mm or less
flat occlusal plane
lower teeth in good alignment
lower incisor 1-2mm from A-Po line
Generally they are done only in the upper arch in class II
malocclusion as camouflage therapy.
If done in deep lower occlusal plane cases it results in lower
anterior crowding and upper anterior spacing.

ANKYLOSIS
JCO JUNE 1990
Ankylosis – localized fusion of bone and cementum
Disregarded in deciduous dentition
But in permanent dentition it complicates treatment planning
Intervention includes
luxation
corticotomy
ostectomy


ASYMMETRIC EXTRACTIONS
Done in patients who already have teeth extracted for other
reasons
-pathology (caries, fracture, periodontitis,
malformation)
-congenitally missing
consideration is given to try to use the existing space
available but in unfortunate cases we may need to further
extract teeth for orthodontic reasons.
Care must be taken in appliance mechanics so as not to create
asymmetries which do not exist in the first place.

CANINE EXTRACTIONS
Should not be done as a orthodontic therapeutic measure
They play an important role in
facial expression
facial balance
smile line
landmark at which the arch turns
provide cuspid rise – during canine guided occlusion
Extracted because of horizontal impactions, ectopic eruption
and transposition.


SERIAL EXTRACTION PROCEDURES
PROFFITT, AO 1990:
TWEED (1966) Serial extraction results in self correction in max. and
mandibular incisal segments.It allows the mandibular incisors to tip
and move lingually to positions of functional balance.
KIELLGREN’S serial extraction and HOTZ’S guidance of eruption –
emerged in 1940.
BUNON in 1743 must be credited with the original concept.
Extraction is done as B-C –D –4 OR D-4.
Serial extraction is a passive rather than active form of treatment
complications: permanent canines erupt before I premolars erupt,
enuclaeation of premolar buds leads to bone defect.
Results in too premature extraction of first premolar in 1011 years old individuals

JCO1968,1971:
Guidelines include:
1. Class I malocclusions
2. 3mm or less overbite/over jet
3.
clear discrepancy of teeth to bone
4. Bilateral symmetry
5. Lower incisor 1 to 2 mm from A-Po line.
Drawbacks:
1. Cannot avoid active appliance therapy
2. Extraction done too prematurely
3. Results in mesialwww.indiandentalacademy.com overbite.
migration and deep

GUIDELINES FOR NON EXTRACTION
FOGEL (1971 JCO NOV.) stresses the need for non
extraction in border line cases.
An excessively flattened profile continues to be more
concave with increasing age due to downward and forward
mandibular growth, flattening of M-P and growth
increments in pogonion. Continued addition of soft tissue
in the chin area contributes to an unattractive inwardly
curved facial profile.


Guidelines include:
1. Class II or, occasionally, class I malocclusions.
2. 2. Broad dental arches
3. No discrepancy of teeth – to – bone in lower.
4. No discrepancy of teeth to teeth.
5. Flat lower occlusal plane or shallow curve.
6. Lower incisor within – 1to 2 mm in relation to A –Po
7. Lower teeth in good alignment
8. Lower aligned except anteriors have mild lingual
inclination combined with slight irregularity.


CONTRA INDICATIONS TO
EXTRACTION
AL/TZ discrepancy less than 2.5mm
Pleasing straight profile with prominent nose point
Faces where PMD less than PMBAW
Continued growth of the face leading to older appearance of
face
Preconceived facial pattern are not realistic and lead to dished
in faces.
Relapse by space re - opening due to functional forces and
interdental ligaments.

CONCLUSION
In a respected specialty such as orthodontics the
decision to extract or not should at least be based
partly on scientific outcome of treatment outcome
are not purely on clinicians experience. Extraction
is justified as means of relieving excessive dental
crowding, in circumstances where growth cannot
be expected to provide relief. Extraction of four
first bicuspids will most occasions provide the
space required, if not in excess.
Border line cases are our greatest
responsibility. If a wrong decision is made or a
wrong mechanics is carried out, one really stands
to do a great disservice to the patient.

Papquette et al proved that the profile becomes
2mm flatter in extraction cases. This type of
information allows the clinician to make an
informed decision.
However, the extraction -non extraction
debate continues, suggesting that more
objective information is needed. It is hoped that
the existence of more data will prevent the
debate from hinging on the clinical experience
of the most persuasive spokesperson.

Extraction controversies in orthodontics /certified fixed orthodontic courses by Indian dental academy

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