Current controversies in orthodontics

CONTROVERSIES IN
ORTHODONTICS
www.indiandentalacademy.com

INTRODUCTION
Orthodontics, Dentistry’s first speciality is rich in it’s
history and also in it’s controversy. Controversies unlike
disputes never end. They cannot be settled totally by
scientific evidence substantiating any one side of the
argument.
Lysle E.Johnston – active, honest difference of opinion.

Classification
 Diagnosis
 Treatment planning
 Treatment mechanics
 Treatment modalities.
controversies
Concepts Philosophies

CONTROVERSIES IN
ORTHODONTICS
Need for orthodontic treatment
Timing of treatment
Classification of malocclusion
Functional appliances
Extraction-nonextraction controversy.
Bracket design
Orthognathic surgery
Retention and relapse.

Need for treatment
There are 2 aspects to the question of what treatment is
needed. Whether treatment is indicated at all and if so,
what treatment procedures should be used.
Psychosocial indications:
Esthetic need for orthodontic treatment: The controversy is
that whether we run the risk of denying treatment affecting
social and psychological well being or whether we over
treat our patients and force upon society standards of
appearance that are both unrealistic and unattainable.

 Studies by Dion have shown that the attractiveness of
physical appearance is an important determinant of how
much even very young children are liked by their peers.
 Physically attractive individuals are perceived as possessing
a great number of socially desirable traits such as
intelligence, friendliness, sensitivity and sincerity.
 The theoretical and empirical work on responses to facial
attractiveness leads us to at least one obvious
generalization: perceived facial attractiveness is a social
asset whereas perceived unattractiveness is a social
liability.

Functional indications:
It is obvious that severe malocclusion must affect function, at
least to the extent of making it difficult for the affected individual to
breathe, incise, chew, swallow and speak.
The reverse also is true: alterations or adaptations in function can
be etiologic factors for malocclusion, by influencing the pattern of
growth and development.
Respiration
Jaw function and TMD
The decisions about the need for treatment cannot be
made on objective assessment of functional or esthetic
impairment alone.

TIMING OF TREATMENT
Questions about the timing of orthodontic treatment relate
almost totally to the question of whether to begin
treatment for a child with obvious malocclusion early,
during the primary or mixed dentition, or whether to wait
for the adolescent growth spurt and the eruption of the
permanent teeth.
Advantages of early treatment:
Rapid change in skeletal and dental structures
because of relatively rapid growth
The need for complicated surgical and
orthodontic procedures eliminated by early
orthopedic intervention
An abnormality is prevented from occurring –
better than wait to manifest itself in it’s fullest
form

The argument..
Orthodontists prefer to wait until the permanent
teeth have erupted so a more straight forward
treatment plan can be done within a
predictable duration of time.
The question of remaining growth manifesting as
relapse does not occur.
Some malocclusions like skeletal class III due to
prognathic mandible are best treated after all
skeletal growth is complete.
Patient co operation may be the biggest
challenge in early treatment –Graber.
Patient turn out due to a long treatment duration
may not help the orthodontists cause during a
second phase of fixed appliance treatment.

Whether arch expansion procedures are more
effective if done during the mixed dentition is
debatable-no sufficient data to resolve this is
available.

CLASSIFICATION OF MALOCCLUSION
Malocclusion presents itself in numerous ways. Classification
involves the grouping together of various malocclusions into simpler
or smaller groups..
Aim.
The classification system followed today is based on Angles
classification which was perceived by him almost 100 years ago
based on his treatment philosophies, ideals and paradigms of his
time.
Many orthodontists have developed classification methods, and
among them are Kingsley, Angle, Case, Dewey, Anderson, Hellman,
Bennett, Simon, Ackerman and Proffit.

CLASSIFICATION OF MALOCCLUSION
 What we today call normal occlusion was described as early as the
eighteenth century by John Hunter.
 Carabelli, in the mid-nineteenth century, was probably the first to
describe in any systematic way abnormal relationships of the
upper and lower dental arches. The terms edge-to-edge bite and
overbite are actually derived from Carabelli's system of
classification
 Edward angle introduced a system of classifying malocclusion in
the year 1899. Edward H. Angle contributed the concept that if
the mesiobuccal cusp of the maxillary first molar rests ill the
buccal groove of the mandibular first molar, and if the rest of the
teeth in the arch are aligned, ideal occlusion will result. (this is
not the Class I as Angle actually saw it) Angle described three
basic types, what he termed malocclusion, all of which
represented deviations in an anteroposterior dimension.

 It merely described the relationship of the
teeth and did not include a diagnosis.
 It does not deal with any malocclusion in it’s
entirety. This gives rise to the issue of Analogous
and homologous malocclusions
 The Angle system does not take into account
the possibility of arch-length problems. The
reintroduction of extraction into orthodontic
therapy has made it necessary for orthodontists
to add arch-length analysis as an additional step
in classification.
 The classification does not indicate the
complexity of the problem.

 Angle described in minute detail each contacting cusp
incline, to prove his point, in ideal occlusion, every tooth
(except the lower centrals and upper third molars) should
have two antagonists.
 Angle emphasized the importance of each premolar
and canine contacting two occluding teeth.

The original classification by Angle, had Class II as a full premolar-
width distoclusion and Class III as a full premolar-width
mesioclusion. Assuming an average premolar width of 7.5 mm,
then Class I ranged from 7 mm mesioclusion to 7 mm
distoclusion, for a total range of Class I of 14 mm. This range was
far too broad, and so in 1907, Angle revised his definition, making
Class II more than half of a cusp distoclusion and Class III more
than half of a cusp mesioclusion. Angle's modification reduced the
range from 14 mm to a 7 mm range. However, 7 mm is still too
broad a range to act as a treatment goal if an orthodontist is to
treat with precision.

Canine relation classification:
Classification was based on the sagittal relation
of the maxillary canine to the mandibular
canine.
Maxillary canines are among the most stable of
dental units because they are the longest
rooted of all teeth and therefore very well
anchored to the alveolar bone. The canine is
the "keystone" tooth in the dental arch, and
like the keystone of a stone archway, it
provides a buttressing support for the incisors,
as well as the posterior teeth. Also, canines
provide a vital protective function in lateral
excursive movements.

Premolar classification:
 The premolar classification was put forth by Morton Katz as
a modification to the Angle’s classification
 premolars usually present a sharply defined cusp tip, which
is centered on the central axis of the premolar crown and
which fits precisely into the opposing embrasure. Also, the
cuspal inclines are steeper and deeper than molar cusps,
which makes a more positive fit.
 From the negative perspective, orthodontists traditionally
have not had high regard for premolars as functional dental
units and have selected premolars most often of all tooth
types for sacrifice in an extraction treatment. Also,
premolars may have anomalous tooth size or shape.

From the above discussion it is clear that the system of
classification we use today is inadequate in describing a dental
anomaly in it’s entirety, aid in treatment planning or be easy to
use. A universal classification system will be necessary which will
be accepted by all orthodontists around the world. This would help
us in standardizing malocclusion rather than disagreeing on the
very nature of problem the patient has.

Functional appliances
The use and mode of action of functional appliance is shrouded in
controversy. The reason behind this is because of the different
philosophies and basis on which each designer constructed his
appliance. There may not be a specific modus operandi behind all
functional appliances.
Quote from Brite Melson’s
The controversies herein relates to the Growth changes with functional
appliances.

 Functional appliances evolved from different concepts of
the interrelationship between the orofacial musculature ,
dentition and plasticity of growth. Each led to a working
hypothesis expressed as an appliance design.
 By 1980’s though clinical success with functional
appliances was witnessed by practitioners, questions
whether they could really stimulate mandibular growth
remained. Growth stimulation can be defined in two
ways:
 1. as the attainment of a final size larger than would
have occurred without treatment or
 2. as the occurrence of more growth during a given
period than would have been expected without
treatment.

The randomized clinical trials of the 1990’s: the
data showed that, on average, children treated
with either headgear or a functional appliance
had a small but significant improvement in their
jaw relationship, while the untreated children did
not.
 Does it really modify growth?
 Does early treatment really make any difference
in the long run, compared with treatment during
adolescence?
Advantage of early treatment: reduction in number
of patients requiring extractions or surgery.

Can mandibular growth be modified
beyond it’s true genetic potential?
 The answer seems to be elusive. As is shown by the use of the
Milwakee braces. However the Milwaukee braces phenomenon
also shows us the remarkable rebound capacity of the hard tissue
system and the dominance of inherent growth potential.
 While Angle strongly believed that the mandible could be made to
grow Case disagreed. As Case states.. “Malrelations of this
character point directly to heredity. The claim and recently
repeated inference that the mandible can be made to grow by
artificial stimuli beyond its inherent size is not in accord with any
law of organic development." Baring future chemical or genetic
manipulation, this still appears to be a valid principle, although
there are others who strongly believe otherwise.

Gianelly through various studies has shown that the mean growthGianelly through various studies has shown that the mean growth
modification of 2mm can be achieved by functional appliance treatment. Thusmodification of 2mm can be achieved by functional appliance treatment. Thus
when compared to a 6mm correction of class II relation to a class I the effectswhen compared to a 6mm correction of class II relation to a class I the effects
ofof functional appliances may not be clinically significant.functional appliances may not be clinically significant.
Harvold found significantly higher increments in mandibular lengthHarvold found significantly higher increments in mandibular length
during treatment than after treatment. But however when he compared theduring treatment than after treatment. But however when he compared the
results with untreated controls matched for age and growth status he foundresults with untreated controls matched for age and growth status he found
that thethat the changes can only be ascribed to normal age related changeschanges can only be ascribed to normal age related changes..
Studies by McNamara on the Frankl appliance and Herbst applianceStudies by McNamara on the Frankl appliance and Herbst appliance
effects on the mandible and the dentition have shown both appliances hadeffects on the mandible and the dentition have shown both appliances had
influenced the growth of the craniofacial complex in treated persons.influenced the growth of the craniofacial complex in treated persons.
Significant skeletal changes were noted in both treatment groups, with bothSignificant skeletal changes were noted in both treatment groups, with both
groupsgroups showing an increase in mandibular length and in lower facial height, asshowing an increase in mandibular length and in lower facial height, as
compared with controls.compared with controls.

McNamara and Bryan studied the Long-term
mandibular adaptations to protrusive function on 11
experimental animals.. At the end of the 14-week
experimental period, the mandibles of the treated animals
were 5 to 6 mm longer than those of the control animals.
They concluded that the results of this study do not
support the hypothesis that the mandible has a genetically
predetermined length

□ Limitations of current clinical and animal research:
□ A double blind study is not possible in testing functional appliances
and thus bias cannot be eliminated. The orthodontist is well aware of
the type of appliance he is using and probable treatment effects it can
produce.
□ Growth versus treatment changes should always be compared with
untreated controls matched for age, sex and growth status. Even
though so much criteria may be taken the experimental samples and
control samples may not be totally matched because the growth
potential of two people may not be the same unless they are
monozygotic twins. And if monozygotic twins were even used it would
be unethical to treat one sibling while leaving the other untreated.

Functional appliances and two phase
treatment
A multicenter, randomized controlled trial of 174 children to
study the dental, skeletal and psychosocial effects of Twin
Block have shown that all changes produced were purely
dentoalveolar and skeletal changes were actually so
minimal as to be considered clinically significant. However
results did show that early Twin Block use did result in an
increase in self concept and a reduction of negative social
experiences.

EXTRACTION-NONEXTRACTION
CONTROVERSY
The controversy was between the Angle’s school of thought and it’s
followers like Martin Dewey and Calvin Case.
1902 - Angle
Rousseau concepts
He believed that all humans were created to have a full complement of natural
teeth which would go hand in hand with an ideal occlusion and a harmonious
face. He idealized an occlusion thus which contained a full compliment of well
aligned teeth, which occluded along his line of occlusion.
Second: proper function of dentition would be the key to maintaining teeth in
their correct position.

It is first of all evident from the statements of Angle that his philosophic basis
was creationist dogma rather than ideals backed by strong scientific basis.
"The Extraction Debate of 1911.“
Calvin Case - "The Question of Extraction in Orthodontia," .
To substantiate the case further he presented a patient whose dental
protrusion would have worsened had a non extraction treatment had been
done. Thus emphasizing that all cases cannot be treated non extraction to
achieve a harmonious face.

Charles Tweed
Raymond Begg
With the development of the Tweed edgewise philosophy and the Begg
appliance came a period in orthodontics where premolars were
indiscriminately extracted for correction of malocclusion. This lead to
unfavorable facial appearances.
Present day status – decline in extractions?

Wick Alexander now claims only 10% of his cases are treated with extraction
and the rest being treated non extraction. Norman Cetlin treats 95% cases
with extraction and only 10% with non extraction.
The current dogma
Stability of distalised upper molars?
Expanded arches
Lower canine width cannot be increased.
Long term retention is necessary for stability.

The option to treat either extraction or non extraction should be
made objectively for each case based on strong evidence rather on some
ones opinion ‘that it woks.’

Camouflage vs Surgery
Beyond the adolescent growth spurt, even though some facial
growth continues, too little remains to correct skeletal
problems.
The possibilities for treatment are
 displacement of the teeth, to compensate for the
underlying skeletal discrepancy
 by surgical repositioning of jaws.

Characteristics of patient who would be a good
candidate for camouflage treatment are:
 Too old for successful growth modification
 Mild to moderate skeletal class II or mild skeletal
class III.
 Reasonable good alignment of teeth
 Good vertical facial proportions – neither extreme
long face nor extreme short face

Camouflage should be avoided in:
 Severe class II, moderate or severe class III, and
vertical skeletal discrepancies.
 Patients with severe crowding or protrusion of
incisors, in whom the entire extraction space will
be required to achieve proper alignment of the
incisors.
 Patients with excellent remaining growth potential
or non-growing adults with more than mild
discrepancies.

BRACKET DESIGN
Brackets are of basically two types – ribbon arch brackets and
edgewise brackets.
The ribbon arch brackets were first designed by Angle for his
Ribbon arch appliance.
The bracket was modified by inverting it by 180 degree and used
by Raymond Begg for his light arch wire appliance..

Angle- single wing bracket
Swain – twin brackets
Ivan Lee – preangulated
Jarabak – preangulated and pretorqued
Andrews – fully programmed
controversies : 0.018 slot or the 0.022 slot

BRACKET DESIGN
E.H. Angle was the first to design the Edgewise
type of bracket for his edgewise appliance.
He used the 0.022 slot for his appliance.
As the edgewise appliance originated before
the discovery of stainless steel, Angle was forced
to use gold alloy wires for making arch wires.
Gold alloy wires had a low modulus of elasticity
and therefore to increase the stiffness of the wire
in bending and torsion and to increase the
rigidity, Angle had no other choice but to
increase the dimensions of the wire and
therefore had to use the 0.022 slot.

BRACKET DESIGN
 It was Steiner who first proposed the 0.018 slot (0.018 x
0.028) and used it for the ‘Steiner’ brackets which were
single width brackets with rotation wings.
 Swain later adopted the 0.018 slot for his Siamese brackets
to improve wire characteristics due to the decreased inter
bracket span.
 With the advent of stainless steel which is 50% stiffer than
spring tempered gold it became essential to decrease
wire dimensions to reduce force levels.
 The 0.022 slot today prevails over the 0.018 slot because of
the development of newer orthodontic alloys such as TMA
and NiTi. It was the discovery of TMA with it’s stiffness
characteristics similar to gold that brought back the 0.022
slot back into the market.

BRACKET DESIGN
ADVANTAGES OF 0.018 SLOT
Decreased wire inventory
Decreased treatment time
Increased wire flexibility due to smaller
dimension of wires.
DISADVANTAGES OF 0.018 SLOT
Desired third order M/F ratios may not be
produced by newer orthodontic alloys.

BRACKET DESIGN
DISADVANTAGES OF 0.022 SLOT
Increased wire inventory
Inability to attain third order control until last
stages of treatment
Increased treatment time.
ADVANTAGES OF 0.022 SLOT
Recommended for Orthognathic cases
Can use newer orthodontic alloys with
minimum patient discomfort

BRACKET DESIGN
Are the 0.018 and 0.022 slots truly 0.018 and
0.022 …….?
 Kusy and Whitley measured 24 brackets from
eight manufacturers microscopically to
0.0001 inch .
 Three brackets were under sized whereas
the rest were oversized.
 The largest 0.018 slot measured 0.0209
whereas the largest 0.022 slot measured
0.0237.

BRACKET DESIGN
□ Are the 0.018 and 0.022 slots truly 0.018 and
0.022 …….?
Factors contributing to this variability….
Lack of verification standards
Varying manufacturer tolerances
United states versus European tooling
For example Europeans use metric tooling i.e mm,
cm , m. Their target value for machining a
bracket which would be 0.018 slot in the United
states would be 0.5mm which is actually 0.0197
inches.

BRACKET DESIGN
The 0.020 slot.
Rubin, peck and Kusy have proposed the
use of an 0.020 slot (0.5 mm)
This would reduce the burden on
inventories of users of both 0.018 and
0.022 slots and reduce manufacturer
costs.

Though both the 0.018 and 0.022 slot may still be used
based on personal preferences, a uniform slot size and tooling
units may be necessary for standardization and to know that we
really use the slot size we wanted irrespective of where the
manufacturer is based.

ORTHOGNATHIC SURGERY
 For patients whose orthodontic problems are so
severe that neither growth modification nor
camouflage offers a solution, surgical realignment
is the only possible treatment.
 It is possible to semiquantitate about the limits of
the orthodontic treatment, in the context of
producing normal occlusion

Envelop of discrepancy

The borderline patient: camouflage or surgery?
For the patient whose deformity is within the
envelop, the decision must be made in the
context of esthetic impact of the two forms of
treatment.
Acceptable results likely in
 Average or short facial pattern
 Mild anteroposterior jaw discrepancy
 Crowding <4-6mm
 Normal soft tissue features
 No transverse skeletal problems

Poor results likely
 Long vertical facial pattern
 Moderate to severe anteroposterior jaw
discrepancy
 Crowding >4-6mm
 Exaggerated features
 Transverse skeletal component of problem

RETENTION AND RELAPSE
For many years clinicians did not agree about the need for
retention. Different philosophies or schools of thought have
developed and present day concepts generally combine
several of these theories.
 The occlusion School: Kingsley stated that, “ The occlusion
of the teeth is the most potent factor in determining the
stability in a new position”. Proper occlusion is of primary
importance in retention.
 The apical Base school: It was Axel Lundstrom who
suggested that the apical base was an important factor in
maintaining correct occlusion
 The mandibular incisor school: Grieve and Tweed
suggested that the mandibular incisor must be kept upright
over the basal bone.
 The musculature school: Rogers emphasized the need for
establishing proper muscle balance for maintenance of
occlusion.

Relapse in lower anterior region: Many hypotheses have
been put forward to explain the incidence of lower incisor
crowding after treatment.
 Relationship of third molars : the mesial eruptive force
of the third molars give rise to lower anterior crowding.
This led to therapeutic extractions and removal of
impacted third molars. Ades et al compared four groups
of patients 10 years out of retention. The groups
included- third molars erupted, third molar agenesis,
third molar impaction, and third molar extraction cases.
He found no difference in the mandibular incisor
crowding, inter canine width between these groups.
 Mesial component of force and physiological mesial
migration.
 Late mandibular growth and maximum intercanine
width: continued mandibular growth even after
maturation of inter canine width can lead to incisor
crowding. A retention protocol untill completion of
skeletal growth may be necessary.www.indiandentalacademy.com

Duration of retention:
At the moment there is no agreement as
to a specific duration of retention for
patients.
There is no clinical evidence as to whether
a longer duration of retention
has better post treatment stability than
one of shorter duration.

Orthodontics may be the only specialty which has
“philosophies”. It was based on these philosophies that
most work in Orthodontics was done. However treatment
philosophies may not be enough in today's world. We need
more scientific basis to back our treatment protocols. We
need to follow ‘evidence based Orthodontics’ more than
‘opinion based orthodontics’. The only way this can be done
is to improve our clinical research.

Current controversies in orthodontics

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