Controversies in orthodontics /certified fixed orthodontic courses by Indian dental academy

CONTROVERSIES IN ORTHODONTICS

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

Contents
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Introduction
Origin of controversies
Etiology Of Malocclusion
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a] Genetic V/s environmental factors.
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b] Role of nasal obstruction and tongue thrust
Extraction vs Non Extraction
One phase vs. two phase
Third molars a dilemma! Or is it?
Orthopedics in orthodontics : fiction or reality
Occlusion, orthodontic treatment and TMD

Introduction

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Controversy – a prolonged argument/ dispute
especially when conducted publicly.
Orthodontics – the art of straightening teeth
The science performed in ortho
Without a clear formulation of the hypothesis to be
tested
Without any evaluation of the validity and
reproducibility of the variables chosen for study


Introduction

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Dev. is based on clinical experience and induction based
on single cases.
Field of ortho is broad


The background, nature, and origins of orthodontic
controversies
Orthodontics

traditionally has been a speciality in
which opinions of leaders were important
Angle
Begg
Tweed

“Disagreements are then a risk rather than exception”


So where does the problem arise?


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Variety of opinion – “Good Orthodontics”
No consensus exist today, and some opinions are even
mutually exclusive.

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0ne phase vs. two phase treat.

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The techniques are based upon subjective assessment of
quality rather than any scientific validation
“opinion – based” / “evidence based”
Such science can neither validate the superiority of a
technique nor help to make rational choices among
alternatives

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Bimax case – begg tech/ SWA

Orthodontic research
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Number of observed general rules, and
causal relationships
Repeated observation confirmed
explanation of a general set of rules

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E.g. Angle’s Class II elastic force

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Deductive research
“A hypothesis based upon present
experience is formulated and an
experiment is carried out to test this
generally”
Karl Popper in 1968

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Patient’s assumptions concerning the
ability of health professionals:
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Distinguish b/w normal & abnormal

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Accurately characterize abnormalities by a process of
differential diagnosis

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Assess the severity of the condition and judge the
consequences of intervention vs. non intervention


Patient’s assumptions concerning the
ability of health professionals:

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Identify alternative clinical procedures and know the relative
odds in favor of desired outcome for each option

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Evaluate the relative cost/ risk/ benefit ratios of each
alternative

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Make a decision that is comprehensible to the patient & best
meets the patient’s need


Controversies of growth prediction



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Why would an orthodontist place importance on being
able to predict?

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Can orthodontist predict craniofacial development at
therapeutically useful levels of accuracy and precision?



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Why would an orthodontist place importance on being
able to predict?
To understand and modify the general process of
development
To control our patients response to therapeutic
inclination
E.g. Max. intrusion splint – restrict max. growth


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Can orthodontist predict craniofacial development
at therapeutically useful levels of accuracy and
precision?
Different craniofacial phenomenon are predictable
with different levels of precision.
Orthodontist should examine their degree of
success for each parameters.
restrict max. growth – Class II
restrict mand. growth – Class III


Orthodontists can predict…………….
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The head and face of pre- adolescent and adolescent children
will continue to change in shape and size until the age of 20
yrs.

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The growth of jaws and face from mixed dentition period to
maturity will be greater in inferior direction than in anterior.

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Class II malocclusion identified after eruption of molars to
occlusal contact will rarely, if ever resolve spontaneously.


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Antr. crowding & rotations visible after the permanent
incisors have completely erupted will only rarely resolve
spontaneously.

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In absence of adjacent tooth, permanent teeth would tend to
migrate mesially.

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Unopposed teeth would tend to supraerupt.

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The prominence of dentition within the face will decrease
during maturation.


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Therapeutic intervention that alter occlusal intercuspation will
tend to open Mb plane angle.

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Mb incisors that have been displaced or proclined antrly
during treat. will tend to relapse in the post retention period.

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Arches in which buccal segments have been expanded will
tend to relapse to their pre treat. widths. Esp Mb arches. (Mx
arches corrected before fusion of midpalatal suture can be
excepted from this rule)

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Intercanine width that has been increased returns to their pre
treat. widths.

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Attempts to retract canine by anchoring them posterior teeth
tend to result in advancement of posterior teeth esp. in Mx
arches.

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Angle of Mb would tend to be close with respect to cranium
spontaneously from mixed dentition period to maturity in the
absence of treat.

Orthodontists cannot predict…………….
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The magnitude and timing of spontaneous growth
remodelling at specific sites in head, face and jaws. (e.g. Mb
Growth)

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The impact of specific therapeutic intervention upon the
expression of each individual inherent growth potential. (e.g.
functional therapy)

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Amount of correction that can be achieved at a specific
anatomic loci.

Orthodontists cannot predict…………….

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The amount of post therapeutic accommodation/ relapse that
can occur. (e.g. orthagnathic surgeries)

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Completeness of particular patients: co-operation with the
therapeutic process.


Etiology of malocclusion
Genetic vs. environmental
Role of nasal obstruction & tongue thrust
1.

2.


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Hapsburg jaw – Prognathic jaw
Inherited two possible ways:
Inherited disproportion between the size of teeth and that of the jawsproducing crowding/spacing.
Inherited disproportion between size/shape of upper and lower jaws –
producing improper occlusal relations.

anthropological evidence - population groups that are
genetically homogenous
Melanesians of Philippine islands



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mobilization of population  increase in malocclusion in
modern man.
Edward Angle and his contemporaries - improper function of
jaws
earlier part of the 20th century - Mendelian genetics
Prof. Stockhard (1930)
Increase in malocclusion accompanying urbanization is the
result of increased out-breeding



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Hypothesis was cast in doubt since
Dogs – carry gene of achondroplasia
Chung et al- on Polynesian population of Hawaii
Migration inter-racial breeding malocclusion
There was no evidence of dramatic facial deformities as
observed in Stockhard’s experiments.



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Familial and Twin studies - Lundstrom (1984), Corrucini
(1980), Potter (1986), Bolton and Brush, Harris and Johnson
(1991)

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No single explanation for malocclusion.

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Result of a complex interplay of function, heredity or
environment.



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Hereditary abnormalities in relation to malocclusion can be
classified as:
A) Dental characteristics
B) Dental malocclusions
C) Skeletal malocclusions
D) Malformation syndromes



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A) Dental characteristics

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Tooth size- Osborne et al (1958) - twin studies  tooth
crown dimensions are strongly determined by heredity.

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Supernumerary teeth- Brook (1984) and Rule (1995) 
supernumerary teeth follow a familial trait,
but they do not follow a simple Mendelian pattern.
Jasmine’s (1993) work on twins also supports this.

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Shape – Alversalo and Portin (1969)
missing and malformed lateral incisors  common gene
effect.
Their association with familial trends, other dental
anomalies like missing teeth, ectopic canines, etc. suggests a
polygenic etiology.
Significant genetic components :
Etiology of submerged primary molars (Kurol-1981)
Ectopic maxillary canines (Zilberman-1990) and (Peck1994).


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Tooth morphogenesis –
Amelogenesis imperfecta
Dentinogenesis imperfecta
Hypodontia
Ectodermal dysplasia


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B) Dental malocclusion

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Harris and Smith (1982)
crowding, rotations and occlusal relations are entirely nongenetic in nature.
If seen in Siblings - intra familial environment
bone based direction and proportions - moderately strong
genetic corelation.
variables of tooth positions are environmentally induced.

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Lundstrom, Chung:
on sibling pairs showed that the genetic component
over jet > overbite > molar relationship
C) Skeletal malocclusions
1] Sagittal
a) Class.11 Div1: Twin studies indicate the presence of high familial
correlation, showing polygenic inheritance.

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b) Class.11 Div 2: syndrome than a malocclusion. Studies by
Markovich, Kloeppel, Korkhous, and Peck et al - genetics plays a vital
role in its etiology.



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c) Class.III:
most heavily influenced malocclusion by genetics.
Suzuki (1961) - 1362 class-III individuals
Results - increased incidence in members of the same family.
2] Vertical
Anterior open bite - Blacks
Deep bite - Whites
“All these indicate a genetic difference in the inherent facial
morphology.”


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D) Malformation syndromes

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1] Mandibular Deficiency
a) Robin Complex: Etiology-Heterogeneous.
b) Treacher Collins Syndrome: Autosomal dominant
c) Stickler Syndrome: Autosomal dominant

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2] Mandibular Prognathism
a) Macrocephaly: Autosomal dominant.
b) Klinefelter’s Syndrome: xxy- Karyotype.
c) Marfan’s Syndrome: Autosomal dominant
3] Facial Asymmetries
a) Hemifacial-Microsomia: Sporadic, with autosomal
dominant or récessive nature.



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Proffit

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“The pertinent question for the etiologic process of
malocclusions not whether there are inherited
influences on the jaws and teeth, because obviously
there are, but whether malocclusion is often caused
by inherited characteristics”


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Respiratory pattern as an etiologic factor for malocclusions:
 Respiration - Primary determinant of jaw and tongue
posture.
 Altered respiratory pattern  change posture of head,
jaw, and tongue  alters equilibrium  jaw growth
and tooth position affected.

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Effects - Increased face height, supra-erupted posteriors, open
bite, mandible rotates downward and backward & a narrow
maxillary arch.

Harvold, Tomer and Vargevik (81):
Total nasal obstruction in monkeys, for a prolonged time 
malocclusion.
Placing a block on the roof of the mouth, forcing the tongue
to a more downward position  variety of malocclusion.
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Because total nasal obstruction in humans is so rare:
whether partial nasal-obstruction is a risk factor in causing
malocclusion?



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Primates do not have same naso respiratory mechanism
as humans.
Total nasal obstruction  not seen in humans.
Type of malocclusion is determined by individual
animal’s pattern of adaptation.

Does nasal obstruction equates  mouth breathing + lip-apart
posture.



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Ballard and Gwynne-Evans (1958)

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Lip incompetence not necessarily associated with mouth
breathing.
Nose breathers, who have a lip - apart posture, usually have
post seal with tongue against soft palate as an adaptive
mechanism.

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Contemporary view:
2 opposing principles, leaving large gray area between them:
Total nasal obstruction is highly likely to alter pattern of
growth and lead to malocclusion & individuals with high
percentage of oral respiratory is over-represented in longface population.
Majority of individuals with long-face deformity have no
evidence of nasal obstruction because some other etiological
factor as principal cause.

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Tongue-thrust as etiologic factor:
Profitt (72) –the term tongue-thrust is a misnomer, since it
implies that the tongue is forcefully thrust forward.
Laboratory studies
Forces is less in tongue thrust than with normal
Swallowing - controlled physiologically - hence cannot be
considered a habit.
Cannot blame tongue-thrust as a cause for open bite
useful physiologic adaptation, if you have an open bite


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Individual with an open bite also has a tongue-trust swallow.
The reverse is not true.
Role of tongue in etiology of malocclusion???
“Equilibrium theory” : Light but sustained pressure by tongue
against the teeth
A typical swallow is < 1 seconds.
swallows 800 times in a day, while awake
Total/ day is < 1000 times, & thus 1000 seconds of pressure
has little/no effect.


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Current view point:
Tongue –thrust is primarily seen in 2 circumstances:
 In young children with normal occlusion –
transitional stage in normal physiologic
maturation.
 In individuals of any age with displaced
anterior teeth – adaptive.
 Hence it is more a “Result” than a “cause”
 However tongue posture and size is more
important.



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Light continuous pressure for more duration  change in
tooth position.

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Spacing – large & forwardly placed tongue
Crowding – small tongue

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If posture is normal, tongue-thrust swallow has no clinical
significance.


Dr. Ashish Singh


Studies related to nasal obstruction &
malooclusion


Studies related to nasal obstruction & malooclusion

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Research leads to 2 opposing principles:
Total nasal obstruction – highly likely to alter the pattern of
growth & lead to malocclusion.
Majority of individuals with long face pattern of deformity
have no evidence of nasal obstruction & must have some
other etiological factor as the principle cause.


Studies showing direct correlation between
pattern of respiration and malocclusion


Experimental Studies Of Respiratory Obstruction:
a.

James Mc Namara-

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caused complete nasal obstruction in primates using silicon
plugs.

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Found downward & backward rotation of mandible &
increased lower facial height.


Experimental Studies Of Respiratory Obstruction
b. Harvold
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Miller – Classical studies in young rhesus monkey.
Latex plugs inserted into the nasal passages – forcing to
breathe through the mouth.
Gradual adaptation from nasal to oral respiration.
Some animals positioned mandibles downward & backward.
Some, rhythmically lowered and raised the mandibles.
Some positioned the mandible downward & forward.


i.

Soft tissue changes occurred first – notching of upper lip &
grooving of the tongue.

i.

Moderate skeletal changes in animals who lowered
mandible for each breath.


iii.

Dramatic changes

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In mandibular morphology –at the gonial region and chin in
animals which maintained lowered mandibular posture.

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Distance from nasion to chin increased- lowering of
mandible.

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Distance from nasion to hard palate increased –downward
displacement of maxilla.


Clinical Studies Of Respiratory Obstruction
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Linder – Aronson & Backstrom compared facial types & type
of occlusion in nose breathers and mouth breathers.
Found :
Greater nasal resistance – children with long narrow faces &
high narrow palate.
No direct correlation between mouth breathing & type of
occlusion - particularly overbite / jet.


Studies which conclude that Individuals with
long face pattern of deformity have no
evidence of nasal obstruction


Studies which conclude that Individuals with long face pattern of
deformity have no evidence of nasal obstruction

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Bushey-Compared lateral cephalograms –pre and post
surgically.

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Found no relationship between linear measurements of the
adenoids and nasal respiration.


Studies which are not univocal about the
results


Studies which are not univocal about the results
Fields et alcompared respiratory modes of normal and long-faced subjects
using respirometer.
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1/3rd of the long-faced individuals have less than 50% nasal
respiration and none of the normal-faced individuals have
such low values.
Most of the long faced individuals are predominantly nasal
breathers.


Studies which are not univocal about the results
Clinical study by James A. McNamara Jr. –
Preliminary analysis of skeletal & dental characteristics of 40
patients.
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Results indicate craniofacial relationships with mouth
breathing are variable & associated with number of facial
patterns.


Controversies in Functional Appliances


Changing trends of Class II treatment
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Early treatment methods:
Late 1800s – head gear
Early 1900s – Angle era
Use of head gear abandoned
Same result with Class II elastics
Also Kingsley
Antr. Inclined plane – “jumping the bite”
Mode of correction of both was supposed to promote Mblar
growth.


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Advent of ceph:

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Both Class II elastics / antr. Bite plane
Correction mainly by forward movement of lower arch

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Head gear – more of skeletal effect (Weislander)
Head gear – again mainstay of Class II treatment in USA.
Overlook the forward movement of lower arch – results were
unstable

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In Europe
Removable functional appliance
Early app.: Monobloc of Pierre Robins (1907) – not very
popular
Andressen’s activator – loose fitting retainer
Correction of Class II by forward Mblar growth.
Andressen associated with Haupl – “ Functional Jaw
Orthopedics”
Very popular in Europe in mid 20th century – largely
unaccepted in USA


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1970 – 1980s - popular in USA
Graber , Woodside, Mc Namara, Harvold etc.
Use of head gear & functional app. in orthodontics sparked 3
main controversy:
Which is superior????
Are they effective????
Are they needed????( early vs. late treatment)


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Proffit and Tulloch – RCTs 1998 UNC AJO - DO
Comparison of effect of head gear / bionator or activator with
controls
Results:
Both are useful
HG – Max. Restriction
Func. Appl – Mb growth
Some didn’t show good result – unfavorable growth pattern


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Univ of Pennsylvania (Ghafari) 1998 AJO - DO
Comparison Head Gear and Functional Regulator
Found no difference in effect.
Both appl. are equally effective.

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Univ of Florida RCTs 1998 AJO - DO
Keeling, Wheeler et al.
Bionator / HG & bite plate
Both appl. are effective.

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Class II correction in patients treated with Class II elastics
and with fixed functional appliances : a comparative
study.
Birgitta Nelson et al AJO – DO 2000
Quantitative evaluation of skeletal & dental changes
Both type of changes were seen with both app..
More skeletal with Herbst treated group.


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Are they effective????

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Do func app. & Head Gear work?

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Long term studies of HG – very effective in shorter duration
Melson – during treat. with cervical pull HG  Maxilla grew
downward and backward
8 years post treat follow up – Maxilla resumed its forward
growth

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Melson 2003
Head gear – restricting growth of maxilla
distalizing 1st molar
Follow up – on removal
Mx. continued to grow downward & forward
1st molar returned to normal position
Similar finding – Derringer
After discontinuing HG – Mx. continued to grow downward
& forward


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Studies of functional appliances:

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Short term results of various appliances

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Activator , Herbst, activator with HG, Herbst with HG

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Esp Herbst with HG (Der mout & Aelbos)


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Studies of functional appliances:

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Long term results – all the effect by the functional appl
seemed to be lost over the long term.

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Pancherz (1981) Europ J ortho– although Herbst appliance
resulted in good growth of Mb during treat period.
Long term – no difference b/w grp treated with Herbst
appliance & untreated controls.

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De Vincenzo (1998)

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Acceleration of growth - functional app.
Reduction in rate of growth after functional app. therapy
So that after 3 -4years it was increasingly difficult to
distinguish b/w 2 groups

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Studies of Frankel app.:
Mc Namara popularized FR-2
There was increase in growth – retrospective study
Almeida et al AJO – DO (2002)
Increase of about only 1.1mm after wearing FR-2 for 17
months


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Studies of Twin Block:
Retrospective studies of Lund et al
Correction of Class II by proclination of lower incisors
Uprighting of upper incisors
Review of literature of Chun – Meta Analysis
No advantage of functional app. on long term


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Studies that indicate functional appl can result in growth:

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Rabie et al 2003 AJO-DO

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Growth of condyle & glenoid fossa

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Findings are:


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The expression of Sox 9 and type II collagen are accelerated
and enhanced when the mandible is positioned forward.

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The amount of new bone formation during mandibular
advancement and after the removal of bite-jumping

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No significant difference in new bone formation could be
found after the appliance was removed when compared with
natural growth


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Functional appliance therapy accelerates and enhances
condylar growth by accelerating the differentiation of
mesenchymal cells into chondrocytesmore cartilage matrix.

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This enhancement of growth did not result in a subsequent
pattern of subnormal growth for most of the growth period;

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This indicates that functional appliance therapy can truly
enhance condylar growth.


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Mills CM, Mc Culloch KJ (2000) reported the long-term
treatment effects of Twin Block appliance:

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To ascertain if any residual increase in the mandibular length
remained at the end of the follow-up period, that is, three
years after phase I Twin Block treatment.


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However, there was a slight reduction in the mandibular
growth (0.7 mm) after treatment.

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Much of the significant increase in the mandibular length
achieved during the active phase of the treatment with the
Twin Block appliance was still present 3 years later when the
subjects had matured into the permanent dentition phase.


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Are functional appliance needed?
Early vs. late treatment
RCTs of Univ. of North Carolina
Tulloch, Phillips, Proffit
Compared pts treated in 2 phases.
1st phase – functional app. / head gear
2nd phase – fixed app.
Controls – only fixed app. therapy


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Findings

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No difference in need for extraction
No diff. in need of complexity of orthog. surgery
Difficulty of treatment with fixed appl. were similar
Same no. of success & failures

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No advantage of early treatment in:

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Reducing treatment complexity
Reducing need for extraction
Reducing need for orthognathic surgery
Reducing time of treatment with fixed appl.

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Advantages of early treatment:
Reduced risk of trauma to antr. Teeth
Proved by – RCTs by Tulloch
Better psychological development and self image
Shown by – ‘O’ Brien et al.AJO-DO 2003

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Proffit disagrees

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“psychological development and self esteem occurs at
adolescence, therefore early treatment before adolescence will
have no advantage over late treatment with regards to
psychological improvement”

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RCT in Univ of Florida

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Functional app. corrected malocclusion

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But no diff b/w treated grp. & control grp. before starting
phase II

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Even when functional app. & HG were used part time as
retainer – no advantage was seen.


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Disadvantages of early treatment:

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Increased cost of treatment
Increased demand of patient cooperation
Increased risk of iatrogenic tendency – caries root resorption
e.g.
Impacted canine – due to uprighting of lat. incisor

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Controversies of timing of treatment in class II div1

i.

Intervention in pri dentition
Early mixed dentition
Mid mixed dentition( intertransitional period before the emergence of 1 st
pm & perm. Mb. canine)
Late mixed dentition (before the emergence of 2 nd pm & perm. Mx.
canine)
Anthony D. Viazis AJO-DO 1995
HG/ Func appl. – late mixed dentition

ii.
iii.
iv.
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Prospective RCTs in Univ of Pennsylvania
Ghafari in 1998

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Treatment in late childhood was as effective as that in mid
childhood

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Timing of treatment in developing malocclusion may be
optimal in late mixed dentition thus avoiding a retention
phase before a later stage of ortho treat. with fixed appl.


Resolution of functional appl. controversies
The current rationale


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i.
ii.
iii.
iv.

Taken from EDITORIAL of AJO-DO Jan 1998
Donald G. Woodside
dentoalveolar changes
restriction of forward growth of the midface
stimulation of mandibular growth beyond that which would
normally occur in growing children
redirection of condylar growth from an upward and
forward–directed growth to a posterior


v.

deflection of ramal form

v.

horizontal expression of mandibular growth from downward
and forward to horizontal

v.

changes in neuromuscular anatomy and function that would
induce bone remodeling

v.

adaptive changes in glenoid fossa location to a more
anterior and vertical position.

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Validity of research is sometimes questionable???

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Problems with ceph studies:

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Too small sample
SNA, SNB Angle – change with incisors position
Landmarks are difficult to locate
Condyle is often positioned antrly.
Radiographic images are often obscured by other cranial structure
Small amount of statistical significance – may not clinically signi.

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Problems of Histologic Studies:
Voudoris (1998), Angelopoulos (1991)
Increased activity of bone by using tritiated thymidine 
increase in Mb length
Only reflect increased metabolic activity.
Individual variation occurs in the TMJ.
Anatomical variation in sections.










Miscellaneous problems:
Patient cooperation.
Anatomic physiologic difference b/w animal models & human
subjects.
Age variation – juveniles are compared with adolescents or
young adults.
Difficulty in finding untreated controls, so results are often
compared with untreated normal subjects.










Variation in appliance design – act dissimilar ways
Variation in appliance action –
Amount of Mblar advancement
Type of construction bite
Prescribed time of wear
Duration of treatment varies
Homogeneity in sex, age, and control b/w study groups is
lacking


“Truth itself is often concealed in such a way
that the harder you look for it, the harder it
is to find.”
Singer’s Yentl


Extraction vs. Non- Extraction




i.
ii.





“To extract or not to extract”
2 main reasons for extraction
Space – crowding
Allow teeth to move – skeletal Class II / Class III
camouflaged.
History
Late 1800’s – early 1920’s
From 1930’s – 1970’s
Between 1970’s – 1990’s









Late 1800 – early 1920’s
Late 1800 saw a casual attitude towards extraction
1902 Edward H. Angle
Facial esthetics/ stability of results
Rousseau – perfectibility of man
Wolff – biologic concept “Wolff's law of bone”
“Bone trabeculae were arranged in response to stress lines
on the bone”











Angle propose 2 key concepts
Skeletal growth  influenced readily by external forces
Proper function of dentition would be the key for maintaining
teeth in their correct position
Proper occlusion  favorable force direction  bone growth
 increase stability
Bodily movement of teeth
Edgewise Appl. – “Bone growing appl.”











Relapse:
Adequate occlusion not reached
“If correct occlusion is produced  result is stable, if results
not stable it was the fault of the orthodontist & not the theory.”
Dentofacial esthetics:
Devoted much time in search of ideal facial form
Prof. Wuerpel – “tremendous variety in human faces makes it
impossible to specify any one facial form as the ideal.”









Ideal facial esthetics  teeth are in ideal occlusion  arch
expansion is necessary
Angle’s Dogma:
Alignment of teeth - Expansion of dental arches
Use of elastics – bring teeth into occlusion
Extraction was not necessary for stability & esthetics
Calvin Case – argued that neither stability nor esthetics
would be satisfactory in the long term for many patients after
alignment from expansion.









Controversy culminated in a widely publicized debate:
Dewey and Case in the dental literature of 1920s.
Angle’s follower won – extraction disappeared b/w World
War I & II.
South Americans – did not agree with Angle’s appl sys.
Removable (Crozat) or partially banded appl. ( twin wire)
were used  accepted non extraction philosophy.



 From 1930 – 1970’s
 Charles Tweed re – treated with extraction
 Extraction was reintroduced by the late 1940’s
 Raymond Begg – Begg appl.
 Further strengthened by Prof. Stockard’s – breeding exp.




Malocclusion could be inherited
Genetically determined disparities b/w tooth size & jaw size
Lack of proximal wear – modern man



Between 1970 – 1990’s – revival of non extraction











Why the decline in extraction rates more recently?

Premolar extraction does not guarantee stability of tooth
alignment.
Little, Wallen and Riedel – 1981 AJO.
MC Reynolds and Little – 1991 Angle Orthod.
Argument
“If result not stable either way, why sacrifice teeth at all”.
v/s.
“If extraction cases are unstable, non-extraction would be
worse”.



Changing views of esthetics – fuller and more prominent
lips, than the orthodontic standards of 1950s & 1960s.



Change from fully banded to largely bonded appliances
made it easier to expand arches – border line case
generally treated better without extraction.











Both Tweed’s and Begg’s rational for extraction, lost some
of their validity.
The contemporary Perspective:
Majority of patients can be treated without extraction, but by
no means all.
Extraction can be undertaken to compensate for:
Crowding.
Incisor protrusion.
Camouflage skeletal discrepancies
For surgery


Extraction vs. Non- Extraction (The contemporary
Perspective)


Treatment modalities converting borderline cases into non –
extraction cases:
 Early intervention:



Use of ‘E’ space.
Proximal stripping of primary teeth.
Space regainers with space maintainers.
Arch expansion.
Use of functional appliances.
Molar distalization.
Bonded attachments rather than banded ones.









Perspective)







Treatment modalities converting borderline cases into non
–extraction cases:

Adults:
Molar distalization.
Inter-proximal reduction.
Arch expansion.
Surgery for skeletal discrepancies.


Perspective)








Recommendations for expansion V/S extraction:
Esthetic considerations:
Expansion makes teeth more prominent
Extraction makes teeth less prominent
Facial esthetics – unacceptable on either too-protrusive or
too-retrusive.
Acceptable range of protrusion and biologic limitations –
expand
Control space closure - extraction

Perspective)


Perspective)











Size of the nose and chin – relative lip prominence
Large nose and/ or a large chin:
Non extraction – move incisor forward ( but doesn’t
diminish the labiomental sulcus too much).
Extraction – controlled space closure
Lack of well defined mentolabial sulcus/ lip strain:
Increase lower facial height/ protrusion of antrs
Extraction is choice

Perspective)






Thin lips
Proclining incisors fuller lips & more vermilion show –
more attractive
Retraction in thin lips – aged face appearance


Perspective)

Poorly defined mentolabial sulcus


Perspective)



Incisor position determine the extraction /non- extraction
decision



No esthetic liability:
Extraction space – less retraction
Non- Extraction – w/o protruding incisors





Perspective)


Stability consideration:



How much can arches be expanded??
Lower arch
Upper arch





Perspective)
Lower arch:
 More constrained than upper – limited expansion
 Lower incisor  2mm
 Lip pressure limiting factor in forward mov. of lower antrs.
 Lingually tipped lower incisors – can be moved further
forward than upright lower antrs.
 Expansion transverse > anteroposterior (except in canine area)
 Canine – relatively high lip pressure
 Pre molar & molar – relatively low cheek pressure



Perspective)


Upper arch expansion:



Opening mid palatal suture
Sutural expansion – 50 % skeletal & 50 % dental
Limiting factors - Cheeks pressure
12 mm total expansion
- Buccal cortical bone – fenestration (> 3mm)







Perspective)


Summary
For Class I crowding / protrusion:
< 4mm of arch length discrepancy with no vertical
discrepancy: non-extraction.









Arch length discrepancy – 5-9mm
Non-extraction – transverse expansion of premolar segment.
Extraction – any pattern depending on hard and soft tissues.


Perspective)


> 10mm : of arch length discrepancy



Extract

 1st choice – all 1st pre molars or
 Upper 1st pre molars & lower lat. Incisors
 Rarely - all 2nd pre molars or all 1st molars




Indications for extraction of 1st premolars (Tweed and
Begg):
 Maximum anterior retraction and camouflage of Class
II div I.
 Maximum anchorage – Less taxing of anchorage.
 Eruptive sequence – space for canines.
 Space discrepancy > 10mm for Class I M.O. –
crowding.
 Class I bimax cases




When the term "orthodontic extraction" arises, the tooth that
immediately comes to mind is the first premolar.



(1) it usually erupts before any of the other posterior teeth with the
exception of the first permanent molar;





(2) its extraction allows eruption of the permanent canine; and
(3) it is in the center of each half of the arch and therefore the space
provided by its extraction can alleviate anterior and/or posterior crowding.




Indications for 2nd premolar extraction: Nance, Carey,
Dewey and Thompson (Begg)
 Good profile and mild crowding.
 Straight profile and moderate crowding.
 Class II div. 1 dental on Class I skeletal with mild
mandibular crowding.
 Case of maxillary set back surgery.
 Crowded and out of arch.
 Correction of molar relation.





Indications for Incisor extraction:
Lower Incisor


Severely crowded mandibular arch – Reidel – increased
stability – 1940 Jacobson – extracted mandibular
incisors.

 Severe

protrusion.
 Periodontal breakdown /periapical lesion.
 Severely fractured.
 Bolton discrepancy.












Reidel  extraction of mandibular incisors decreases
treatment time – 2 laterals instead of 2 premolars
Kokich and Shapiro – 4 successfully treated cases with single
mandibular incisor extraction.
Maxillary central incisors:
Caries.
Fracture.
Dilacerated.
Badly impacted.




Maxillary lateral incisor:



a. Crowding in incisor region with mesial displacement of root apices of
canines - Gardiner.



Indications for 1st molar extractions (Wilkinson):



Carious / endo treated/ multifilled.
Esthetic considerations with properly developed 2nd and 3rd molars –
large nose and chin – pre molars dished face.
Open bite cases?
Supraerupted teeth.
Crowding in premolar region and incisors in good relation.









Indications for canine extractions: (Creekmore):



Periodontally involved.
Horizontally impacted – tooth movement?
Distally tipped/ severely rotated / grossly displaced
buccally/palatally.







controversy within the extraction of second molars



Liddle (AJO 1977) believes that many malocclusions develop
because of the eruption forces of the permanent second
molars and that extracting premolars is treating the "effects"
rather than the "cause" of the malocclusion.



Samir E. Bishara and Paul S. Burkey, AJO-DO 1986 May




Samir E. Bishara and Paul S. Burkey, AJO-DO 1986 May



Facilitation of treatment using removable appliances
Reduction in the amount and duration of appliance therapy
Disimpaction of third molars
Faster eruption of third molars
Prevention of "late" incisor imbrication
Facilitation of first molar distal movement
















Distal movement of the dentition only as needed to correct the
overjet
Prevention of "dished-in'' appearance of the face at the end of
facial growth
Fewer "residual" spaces at the end of orthodontic treatment
Less likelihood of relapse
Good functional occlusion
Good mandibular arch form
Reduction in incisal overbite











Indications for 2nd molar extraction:
Chipman AJO 1961
Mild –moderate arch length discrepancy with good esthetics.
Distalization of first molar.
Relieve lower incisor crowding.
Relieve impaction of 2nd premolar.
Severely carious / ectopically erupted / rotated.


Perspective)


Present understanding



Non extraction treat.:
Fuller profile & less stability
Extraction treat.:
Flattening of profile & more stability








Decision is based upon:
Soft tissue profile
Growth – size of nose & chin increases, lips – flatter & thin

Perspective)


Borderline cases – non extraction



Imp. Consideration





Lip separation – increases with tooth prominence.
Thick, full lips – can afford prominent incisors.
Cephalometric readings can serve as guidelines.
Nasolabial angle
Lip incompetence
Size of nose & chin



Johnston – with extraction – about 2 mm flatter
















Drobocky and Smith: AJO-DO 1989 March
Soft-tissue profiles were examined in 160 orthodontic patients
treated with removal of four first premolars.
Records of 10- to 30-year-old patients were selected at
random from five sources:
Tweed foundation
Kesling Rocke group
From 2 practioners – PEA
Pre molars enucleated at an early age


Results :
 extraction of four first premolars generally did not result in a
"dished-in" profile.
 Approximately 10% to 15% of cases could be defined as
excessively flat alter treatment
 80 % - 90% of patients treated by extraction of four first
premolars had soft-tissue measurements that suggested the
profile was improved by treatment or remained satisfactory
throughout treatment.







Paquette, Beattie, and Johnston - AJO-DO 1992 Jul
Borderline extraction and nonextraction comparison



63 patients with Class II, Division 1 malocclusions – 33
extracn & 30 non extracn

Data provide little support for the claims that premolar

extraction — as opposed to expansion and bite-jumping —
must flatten the profile enough to ruin the face.



 Faruk Ayhan et al Angle Orthod 2003
 “Effects of extraction & non extraction treatment on Class I
& Class II subjects”



Successfully treated cases, whether by extraction or non
extraction, same soft and hard tissue profile were seen.

 Extraction means a more retrusive profile or dished – in
profile seems to be unacceptable.


 Faruk Ayhan et al Angle Orthod 2004
 Influence of extraction treatment on Holdway Soft – tissue
Measurements



Generalization concerning the negative effects of extraction
of four 1st pre molars on the profile are not true.


THIRD MOLARS:A DILEMMA!
OR IS IT?


The greatest enemy of truth is very often not
the lie – deliberate, contrived, and dishonest,
but the myth – persistent, persuasive and
unrealistic.
John F. Kennedy
Yale Univ. June 11, 1962


THIRD MOLARS:A DILEMMA! OR IS IT?



The present controversy
In 1859, Robinson wrote “the dens sapientiae is frequently
the immediate cause of irregularity of the teeth”.



In a survey of more than 600 orthodontists and 700 oral
surgeons



Laskin found, that 65% were of the opinion that third molars
sometimes produce crowding of the mandibular anterior teeth.




Removal versus the preservation of third molars



Third molars should be removed even on a prophylactic
basis, because they are frequently associated with future
orthodontic and periodontal complications as well as
other pathologic conditions.


There is no scientific evidence of a cause and effect
relationship between the presence of third molars and
orthodontic and periodontal problems.




What is the relationship b/w 3rd molars & lower incisor
crowding?



Are 3rd molars impaction predictable?



Is there rationale on how to handle 3rd molars at the end of
ortho Tx ?









Relationship between 3rd molars and incisor crowding:
The changes in Lower incisor that occur with time in both
untreated and orthodontic treatment populations.
Untreated normal:
Bishara et al (1989AJO and 1996 AO):
Evaluated changes in lower incisor between 12 and 25 years
and again at 45 years – findings indicated :










Increase in tooth size arch length discrepancy with age
– consistent decrease in arch length.
Average changes 2.7mm in males; 3.5mm in females.
Similar findings by
Lundstrom (1968)
Sinclair and Little (1983 AJO):




Orthodontically treated patients:



Fastlicht (1970 AJO) found that in orthodontically treated
subject- 11% had 3rd molars, but 86% had crowding.



Little et al (1981AJO) observed that 90% of extraction cases
that were well treated orthodontically ended up with an
unacceptable lower incisor crowding.





Long term studies :



Incidence as well as the severity of mandibular
incisor crowding increased during adolescents and
adulthood in both the normal untreated individuals
as well as orthodontic treated patients, after all
retention is discontinued.




Bramante (1990) observed that many clinicians consider
some form of indefinite retention to avoid crowding in later
stages of maturation.



Studies relating 3rd molar to crowding of dentition



Studies indicating lack of correlation between mandibular 3rd
molar and post retention crowding
Retrospective / prospective studies


Studies relating 3rd molar to crowding of dentition:









Two studies which are most widely quoted
Bergstrom and Jensen (1961)
Vego (1962 AO)
Bergstrom and Jensen (1961)
To determine the extent to which 3rd molars are responsible
for secondary tooth crowding
Cross-sectional study, 30 dental students - unilateral
agenesis of upper 3rd molar
27 had agenesis of one lower 3rd molar.




On plaster cast they performed left-to-right comparisons of
space conditions of both sides of each arch.


More crowding in the quadrant with 3rd molar present than in the
quadrant with the third molar missing.



Mesial displacement of lateral dental segments on the side with 3rd
molar present in the mandibular arch not in the maxillary arch.



The unilateral presence of a third molar did not have an effect on the
midline.









Vego (1962 AO)
Longitudinal study – 40 with 3rd molars and 25 with an
congenitally missing 3rd molar.
2 time intervals –
1st :13 years- 2nd molar eruption;
2nd: average age of 19 years.
 All 65 cases – decrease in arch perimeter between the 2
intervals.
 But arch perimeter decrease was less noticeable in persons
without lower 3rd molars.


 Schwarze (1975):


Compared a group of 56 patients with third molar
germectomy to 49 subjects with third molars present.



significantly greater forward movement of first molars
associated with increased lower arch crowding in the non
extraction group.


 Lindquist and Thilander (1982)


Extracted third molar unilaterally in 52 patients



found more stable space conditions (less increase in
crowding) on the extraction side compared with the control
side in 70% of cases.










Belfast third molar study – Richardson M.E. (82-87).
Produce further evidence “Pressure from behind” theory:
Group of 51 subjects with intact lower arches and bilateral
third molar present were examined at ages 13 and 18 years.
On average these cases had an increase in lower arch crowding of
slightly more than 1mm on each side during the 5 year observation
period.
In some quadrants the crowding increased by as much as 4mm and only
16% of quadrants demonstrated no change in crowding.




The cause of this kind of crowding is controversial and often
confused with the causes of post treatment relapse, which may
be quite different.



Whether this pressure results from:
Dev. 3rd molar.
Physiologic mesial movement / drift.
Anterior component of force derived from forces of occlusion
on mesially inclined teeth.








Another school of thought is (Graber, Woodside, SelmerOlsen):



“In absence of 3rd molar, the dentition has room to settle
distally under anterior pressures caused by late growth or soft
tissue changes”.


Studies indicating lack of correlation between mandibular
3rd molar and post retention crowding:







A] Retrospective studies:
Kaplan (1974AJO): investigated whether mandibular third
molars have a significant influence on post treatment
changes in the mandibular arch, specifically on anterior
crowding relapse.
75 orthodontically treated patients – pre and, post treatment
and 10 years post treatment study models and lateral ceph
3 groups




1st group - 30 persons with both third molars erupted to the occlusal
plane, in good alignment buccolingually, and of normal size and form.



2nd group - 20 persons with bilaterally impacted third molars. All were
candidates for surgical removal of the third molars on the basis of
postretention periapical radiographs.



3rd group - 25 patients with bilateral agenesis of the mandibular third
molars.



Presence of 3rd molar does not produce a greater degree of lower
anterior crowding or rotational relapse after cessation of retention.




Ades et al (1990AJO-DO), in a cephalometric study on a
similar sample found :


No significant differences in mandibular growth
patterns between various 3rd molar groups – erupted,
impacted or agenesis.



Majority of cases have incisal crowding, but no
correlation with 3rd molars.




Lifshitz (1982)



evaluated the effect of lower premolar extraction versus non
extraction as well as the presence of absence of lower third
molars, on mandibular incisor crowding.



In all groups evaluated, there is a significant decrease in
arch length and a significant increase in crowding.



But there were no significant difference between the groups
that did or did not have premolar extractions or whether
third molars were present or missing.








B] Prospective studies:
Lindquist and Thilander (1982AJO):
To determine the effect of the prophylactic removal of
mandibular third molars on lower incisors.
3rd molar on one side were extracted at an average of 15.5
years and the other side left as a control.
Study casts and cephl on these patients 3 years
postoperatively.
Unable to predict which patients benefit from prophylactic
extraction – both side similar changes




Southhard (1991AJO-DO) et al



Measured proximal contact tightness between the mandibular
teeth in cases with bilaterally unerupted third molars.
The measurements were taken before and after the unilateral
removal of one third molar.





Surgical removal of 3rd molar – no significant effect on
contact tightness.







Pirttiniemi et al (1994)
evaluated the effect of removal of impacted third molars on
24 individuals at 3rd decade of life
Dental casts were evaluated before & 1 year after extraction.
Extraction of 3rd molar allowed for slight distal drift of 2nd
molar but no significant change in incisal area.
Summary :
3rd molars do not play a significant, i.e., quantifiable, role in
mand. antr. crowding.


Third Molar Impactions:


Clinical problem in managing adolescent ortho patients.



Are there any morphologic factors hat may affect the eruption
or impaction of 3rd molars?



Should we enucleate 3rd molars at an early age if we think
they will be impacted?



How predictable is the ultimate 3rd molar position, from
earlier observations of its inclination?


Morphologic factors that can influence space available for
3rd molar:



Bjork et al (1956):



examined 243 cases to estimate the relationship between
various cephalometric parameters and the space available for
mandibular third molars.



Identified three skeletal factors that may influence third molar
impaction:


3rd molar:



Vertical direction of condylar growth as indicated by
mandibular base – ramus angle (Gonial angle).



Decreased mandibular length – Cd-Pog.



Backward – directed eruption of mandibular dentition as
determined by degree of alveolar inclination.


3rd molar:











Capelli (1991 AO)
60patients of four 1st premolar extraction
Findings of pre & post Tx. Ceph suggested
3rd molar impactions – predominant vertical Mb growth
Other indicators:
A long ascending ramus
Short Mb length
Greater mesial crown inclinations of 3rd molars

Summary – some morphologic factors that are related to
greater incidence of 3rd molar impaction.


Enucleation of 3rd molars & their prophylactic extractions









Bjork et al (1956) found 20-25% risk of impaction of third
molars in Scandinavian males.
Dachi and Howell (1961) – found similar ratio in U.S.
Dichotomy b/w proponents & opponents of extraction
Opponents of extraction
the risk of complications during surgery.
there are three major areas of economic concern in the third
molar extraction:


i.

Can the cost of the “routine” removal of third molars as a
preventive procedure be justified for the 80% who will not
have impacted third molars?

ii.

What are the added costs of such a procedure on the cost of
health insurance?

iii.

What are the risks involved with the procedure and the use
of GA?




Proponents of the removal of third molars
young adults between the ages of 18 and 22 years experience
problems with their third molars



Anchorage preparation - distal movement of the first and
second molars may be required.



Ricketts et al further indicated that removal of third molar
buds at the age of 7 to 10 years is surprisingly simple and
relatively atraumatic.


Consensus Development Conferences On Removal Of 3rd
Molars:








2 consensus –
National Institution of Dental Research (1979)
American Association of OMFS (1993).
When and what condition – extraction of 3rd molar advised.
1. Lower incisor crowding – multifactorial etiology.
If adequate room is available – every effort should be made
to bring these teeth into functional occlusion.


Molars:


Orthodontic treatment – distalization of molar ( tipping/
translation) – if causes impaction extract.



No evidence – 3rd molars needed for development of basal
skeletal component of maxillary or mandibular.



Post-operative pain, swelling, infection etc. decreased if
patients are young and roots 2/3rd developed.



If extraction is indicated – early extraction beneficial.


Molars:


Enucleation at 7-9 years not acceptable – present predictive
techniques  not highly reliable



Inform patients about possible complications of extraction
pain, swelling, trismus, nerve damage etc.


Why are 3rd molars extracted








Lysell & Rhlin 1988
Records of 870 Swedish patients treated in 23 clinics in
Sweden.
Indication of 3rd molar removal:
27% - prophylactic, 25% - pericoronitis
14% - orthodontics, 25% - caries/pulpitis
3% - cysts, tumours etc. , 18%- other factors


Conclusion


Incisor crowding is multifactorial – no evidence that 3rd molar
is only or major etiologic factor



Only relationship – both occur approx same stage of dev. i.e.
in adolescence & early adulthood



But this is not a cause and effect relationship


Conclusion


The clinician has to have a justifiable reason to recommend
the extraction of any tooth.



Has to consider the impact of the extraction decision on any
future Tx plan from an orthodontic, periodontic, or
prosthodontic aspect.



If extraction is indicated – remove in young adulthood rather
than older age.


REFERENCES








Proffit “Contemporary orthodontics” 3rd ed.
Birte Melson “Current controversies in orthodontics”
Samir E. Bishara “Third molars: A dilemma! Or is it?”
AJO-DO 1999; 115: 628-33.
Margaret E. Richardson “The role of the third molars
in the cause of late lower arch crowding: A review.”
AJO-DO 1989; 95 : 79-83.
Faruk Ahyan – The influence of extraction treatment on
Holdway soft-tissue measurements AO – 2004; 74: 167173


REFERENCES







Faruk Ahyan – Effects of extraction and non extraction
treatment on Class I and Class II subjects AO – 2003; 73: 3642.
Donald G. Woodside – Do functional appliances have an
orthopedic effect? AJO-DO Jan 1988.
Aelbers & Dermaut - Orthopedics in orthodontics: Part I,
fiction or reality – a review of the literature AJO-DO 1996
110: 513-9
Aelbers & Dermaut - Orthopedics in orthodontics: Part II,
fiction or reality – a review of the literature AJO-DO 1996
110: 667-71


REFERENCES








Gianelly – One phase versus two phase treatment AJO-DO
1995 vol 108 No 5
Camilla Tulloch – Outcome in a 2-phase randomized clinical
trial of early Class II treatment AJO-DO 2004;125:657-67
Robert M. Ricketts – A statement regarding early treatment
AJO-DO Vol 117 No.5
Birgitta Nelson – Class II correction in patients treated with
Class II elastics and with fixed functional appliances: A
comparative study AJO-DO 2000;118:142-9


REFERENCES


Anthony D. Viazis – Efficient orthodontic treatment timing
AJO-DO 1995;108:560-1


I can’t
believe,
so
many
types!!!


Well, it
looks
alien


I
think,
it is
edible
!


Dad says
his is
optical


food
pattern
s


I ‘ll
get a
bag


Thank
you !!


Dad
thinks
he’s big
Brain!!


Son,cheese
roll looks
good!!!




I would like to leave you with an inspirational saying

“Coming together is a beginning
Keeping together is progress
Growing together is success”.


Leader in continuing dental education


Controversies in orthodontics /certified fixed orthodontic courses by Indian dental academy

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