Long term effects of orthodontic treatment /certified fixed orthodontic courses by Indian dental academy

LONG TERM EFFECTS OF ORTHODONTIC

TREATMENT

INDIAN DENTAL ACADEMY
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CLASS II CORRECTION

Orthopedic
appliances
CLASS III CORRECTION

Temporomandibular
joint

INTERNAL
DERANGEMENT
JOINT SOUNDS
CLICKING
Condyle fossa
relationship


•Orthognathic surgical
procedures
•Periodontal tissues
•Profile changes in
extraction and non
extraction cases

Single jaw surgery
Double jaw
surgery


Arch length

•Arch form
considerations

Arch perimeter
Arch width
Arch expansion

•Retention and stability


Long term periodontal changes
associated with orthodontic
treatment


• It is well established that orthodontic

therapy can produce a more esthetic
dentofacial complex and a superior
functional occlusion.
• However, it remains unclear as to whether
long-term periodontal health is better or
worse as a consequence of the patient
having undergone orthodontic therapy in
adolescence.


• The literature regarding the relationship

between crowding of teeth, plaque
accumulation, and degree of periodontal
disease is conflicting.
• Several studies report that there is a
positive relationship among these factors,
while other studies report no relationship.


• It is widely believed that an important rationale

•

for performing orthodontic treatment is to
promote the health of the periodontium, thereby
enhancing longevity of the dentition.1,2
It is therefore assumed that adults with
untreated malocclusions would be subject to a
greater prevalence of periodontal disease than if
their malocclusions had been corrected
orthodontically.


• Conversely, it has been maintained that

orthodontic treatment may have some
adverse effects on the gingival and
periodontal tissues which may hasten or
promote periodontal breakdown in later
life.


• Clinicians also differ in their opinions regarding

•

relationships between orthodontic treatment and
periodontal status; several investigators
maintain that there is no permanent damage to a
healthy periodontium as a result of orthodontic
treatment, whereas others believe that
orthodontic treatment may initiate the first stage
of marginal periodontitis.
In addition, the periodontal remodeling
associated with orthodontic therapy may
become a significant factor with age.


• A relationship may exist between orthodontic
•
•

therapy and conversion of gingivitis into
periodontitis— for example, orthodontic bands
may increase subgingival plaque retention.
Furthermore, orthodontic movement resulting in
tooth intrusion may shift supragingival plaque
into a subgingival location and predispose
toward destructive periodontitis.
In this respect small but statistically significant
loss of connective tissue attachment has been
reported shortly after completion of orthodontic
therapy

• Polson AM et al (ajo 1988) evaluated the
clinical periodontal status of persons who
had completed orthodontic therapy at
least 10 years previously (study) and
compared the findings to those of adults
with untreated malocclusions (control).


• Subjects in the study (n = 112; 63 female

subjects, 49 male subjects; mean age
29.3 ± 4.2 [SD] years) and control (n =
111; 62 female subjects, 49 male subjects;
mean age 32.9 ± 6.5 years) populations
underwent a comprehensive periodontal
examination


• periodontal examination consisted of
•
•
•
•
•
•

measurements taken at six points around the
circumference of each tooth:
(1) plaque,
(2) visual inflammation,
3) bleeding after probing,
(4) pocket depth,
(5) gingival recession, and
(6) loss of connective tissue attachment


Plaque and inflammation
• The degree of inflammation corresponded

with the distribution of plaque and
indicated that clinical signs of inflammation
(color changes and bleeding) related to
the presence or absence of plaque , rather
than a history of orthodontic treatment


Gingival margin
• Gingival margin location was measured as an

indication of gingival recession. Contrary to
expectations, the orthodontically treated group
consistently showed a more coronal gingival
margin location than the control group


• There are two possibilities that may be

responsible for the more coronal gingival
margin in the orthodontically treated
group.
• First, orthodontic appliances result in
gingival inflammation and enlargement,
independent of the presence of
supragingival plaque. Generally, however,
the gingiva returns to normal after bands
have been removed.


• The second possibility relates to the

gingival bunching that may occur with
orthodontic relocation of the teeth. The
incidence of gingival bunching and clefting
has been reported primarily in association
with orthodontic closure of extraction
spaces


Pocket depth
• Examination of pocket depths showed no

•

statistical difference between study and control
groups; however, the pocket depth values for all
tooth types and surface locations were always
greater in the orthodontically treated group.
Although one tends to associate deeper
periodontal pockets with destructive periodontal
disease, this is not necessarily the case since
the critical clinical variable relating to periodontal
destruction is the loss of connective tissue
attachment

• The lack of difference between the groups
regarding loss of attachment means that
the increased pocket depth tendency in
the study group did not represent greater
periodontal destruction.
• Consequently, the tendency for deeper
pocket depths in the study group resulted
from a more coronally positioned gingival
margin, rather than from increased
periodontal destruction at the. base of the
pocket.

• Residual tissue bunching would result in

coronal positioning of the gingival margin
and an associated increase in pocket
depth, and may have been responsible for
the greater pocket depth tendencies in the
study group


• It is reasonable, however, to consider that
gingival tissue bunching could also occur
in other locations where tooth position is
changed by orthodontic movement.
Although studies have indicated that
tissue bunching is transient and resolves
with time,


• the tendency for a more coronal gingival

margin location has been reported on a
long-term basis after tooth movement into
extraction spaces.
• A similar generalized effect throughout
the dentition would result in a tendency
toward the more coronal gingival margin in
the orthodontically treated group in this
present study.


Attachment loss
• It is probable that the connective tissue

•

attachment level is the single most important
variable when assessing the progression of
marginal periodontitis.
The lack of difference in attachment levels
between study and control groups in the present
study implies no adverse long-term effect after
orthodontic treatment in adolescence.


• . There was no correlation between

various incisal movements and the degree
of gingival recession.
• it was concluded that orthodontic
treatment during adolescence had no
discernible effect upon later periodontal
health.

• Trossello and Gianelly (J. Peridontol.

1979). also reported only minor
differences in the health of the periodontal
tissues and alveolar bone in a group of
thirty female patients between 18 and 25
years of age at least 2 years after
orthodontic treatment, as compared to a
similar group of subjects who had never
received orthodontic therapy

• In Zachrisson's study (AO 1973) however,
after 2 years of posttreatment follow-up,
the orthodontic group demonstrated a
slightly increased loss of periodontal
attachment and alveolar bone as
compared to the untreated control group,
but this was considered to be within
acceptable limits.


• However, approximately 10 percent of the
orthodontic patients demonstrated a more
significant amount of loss of attachment
and marginal alveolar bone loss.
• It should be realized that the cases
studied involved severe malocclusions
requiring extensive tooth movement


Long term changes on arch form
due to orthodontic treatment


• It is well established that increases in

dental arch length and width during
orthodontic treatment tend to return
toward pretreatment values after retention.
• These dimensional changes may affect
arch form as well. The majority of studies
pertaining to arch form have focused on
attempts to find the single shape that
would best describe the dental arches of a
particular sample.

• It is a commonly held view that minimal

alterations to the original arch form during
treatment may result in minimal
postretention changes.
• However, there are certain patients in
whom arch form is purposely changed
with treatment.


• Patients with Class II, Division 1

malocclusions maxillary arches with
tapered shapes, flared incisors, and
constricted intercanine widths are often
changed during treatment to coordinate it
with the mandibular arch. The long-term
consequences of this change in arch form
are not known


• Cruz R ,Paul Sampson, Robert M.

Little,et al (AJO 1995) did a study
to evaluate the long term changes
on arch form due to orthodontic
treatment


• Dental casts were evaluated before

treatment, after treatment, and a minimum of
10 years after retention for 45 patients with
Class I and 42 Class II, Division 1
malocclusions who received four first
premolar extraction treatment. Computer
generated arch forms were used to assess
changes in arch shape over time.
• Extraction patients were selected for the
study, since it was likely that their arch forms
were changed more during treatment than
nonextraction patients.

• Each patient had complete records

including dental casts and cephalometric
radiographs at three time periods
• pretreatment (T1),
• At the end of active treatment (T2), and
• A minimum of 10 years after removal of
retainers (T3).


• In the current study, a general pattern of

postretention relapse of the treatment
changes in arch form was exhibited by
patients with Class I and Class II
malocclusions. However, a high degree of
individual variability was prevalent.


• Results showed that changes in arch form that
occurred after retention were moderately
associated with changes that occurred as a
result of orthodontic treatment.
• This seems to indicate a tendency for small
treatment change to result in minimal
postretention change, whereas large
postretention change resulted in cases with
large treatment change.

• This would also seem to agree with claims
made by several investigators that
minimal changes in the dental arch form
may enhance long-term stability


• The Class II maxillary arches demonstrated

the highest mean change in shape during
orthodontic treatment. When compared with
the Class I sample,
• it was expected that the Class II sample
would have demonstrated more postretention
change. However, results did not support this
assumption. The Class II arches underwent a
similar variety of postretention change.


• Change in arch length, intermolar width, intercanine
•

width, and Irregularity Index were in agreement with
findings of Little et al (.AJO 1981)
In general, arch width and arch length decreased in
the postretention period and crowding increased,
irrespective of whether the original intercanine width
was maintained or increased during treatment.


• In the present study, the largest treatment
change in arch form was observed in the
Class II group, but no difference was
found in the magnitude of postretention
change when compared with the Class I
arches.


• This could suggest that the clinician

should not expect greater relapse when
altering the maxillary arch form of a patient
with Class II, Division 1 malocclusion.


• In fact, both Class I and Class II cases

had marked relapse, and Class II cases
did not respond with more relapse than
the Class I cases even though they were
changed more during treatment.
• Since the treatment versus postretention
correlation was low for the Class II cases,
another interpretation of the data is that
Class II maxillary arches had more
variation in response.

CLINICAL APPLICATION
• Arch form may be changed during

treatment if the clinician understands that
the change may or may not be stable.
Retention should certainly be an important
consideration when planning treatment for
these patients.


RAPID MAXILLARY EXPANSION
• I nterest in rapid maxillary expansion

(RME) has increased markedly during the
past 2 decades.
• The correction of transverse discrepancies
and the gain in arch perimeter as
potential nonextraction technique appear
to be the most important reasons
underlying this increased interest.

• There have been few well-designed

investigations of the long-term craniofacial
adaptations to RME therapy.


• the long-term effects of RME was performed by
Haas (AO 1980). The study presented longterm data from 10 subjects. After expansion,
the average increases initially were 9 mm in
apical base width and 4.5 mm in nasal cavity
width.
• None of the 10 subjects underwent a loss in
either dimension at the time of reevaluation (614 years postretention)


• In another long-term cephalometric study

that incorporated metallic implants, Krebs
examined 23 patients with bilateral cross
bites over a 7-year period after RME.
• He found that increments in both nasal
and maxillary width were relatively stable.
The width of the dental arch was
increased significantly by RME therapy,
but the gain in many instances was not
stable, with a steady decrease being
recorded up to 4 or 5 years after the
treatment.

• The findings of Cameron et al (AJO

2002)investigation revealed that, in the longterm (about 8 years after expansion), the
effects of RME with the Haas appliance
followed by fixed appliance therapy can
induce a normalization of both dental and
skeletal components of the craniofacial
complex.

• Therefore it can be concluded that on long
term results of RME are stable .


Extraction versus non extraction


• The extraction-nonextraction debate, ongoing
for almost 100 years, has often been based
more on supposition than fact.
• Those who favor nonextraction have often
presumed that extraction treatment tends to
dish in the face; those who favor extraction, on
the other hand, often presume the lips tend to
be “blown out” by excessive incisor flaring.


• The extraction-nonextraction debate has
also been based on suppositions about
what occurs after treatment.


• We now have good data showing only

small posttreatment differences between
extraction and nonextraction patients.
• Extraction patients tend to be 2 to 4 mm
flatter, on average, than nonextraction
patients at the end of treatment.


• Over the short term, it has been shown

that there is little or no difference in how
orthodontists and laypeople rate the
profiles of extraction and nonextraction
patients.
• However, these patients were followed for
only 2 years, and soft tissue changes take
longer to develop in subjects with reduced
growth potential.


Clear cut extraction vs non extraction


• Stephens,et al (AJO 2005) did a

study to evaluate long-term profile
changes in extraction and
nonextraction patients-


• Twenty extraction and 20 matched

nonextraction patients, with posttreatment
and long-term follow-up (average 15
years) records, were selected from a
single private orthodontic practice.
• Posttreatment and long-term follow-up
profile photos of the patients’ nose, lip,
and chin areas were evaluated by 105
orthodontists and 225 laypeople, who
indicated their preferences and the
amount of change they perceived among
the 40 profiles.

• The patients had similar dental protrusion,

soft tissue profile measurements, and
ages at the posttreatment observation
• The results clearly showed that the
extraction and nonextraction patients were
comparable at the end of treatment.


• Both groups had similar amounts of lip

protrusion in relation to the esthetic lines,
similar amounts of dental protrusion, and
similar soft tissue facial convexities.


• Bishara et al (AJO 1995) showed that

differences between extraction and non
extraction groups in lip position relative to
the E-line increased during their
posttreatment follow-up, but this was only
2 to 3 years later.


• Although they were not different, both groups

•

demonstrated significant changes over time.
Their lips became significantly more retruded in
relation to the E- and S-lines, and their facial
convexity decreased considerably over the long
term.
Similar posttreatment changes have been
reported for both extraction and nonextraction
patients .(Paquette DE et al AJO 1992, Zierhut
EC et al AO 2000, Finnoy JPet al EJO 1987,)


• Because there was no clear relation

between treatment modality and the profile
preferences of orthodontists and
laypeople, it cannot be concluded that one
type of treatment produces better, or
worse, long-term profiles than the other.


Clinical implication
• This simply demonstrates regardless of

the treatment modality that some profiles
changed for the better, and some changed
for the worse.
• Whether teeth were extracted had no
bearing on whether the profiles got better
or worse.

• We, as orthodontists, cannot determine

whether a patient will age for the better or
for the worse.
• The results also showed that just because
one’s appearance changes over time does
not necessarily mean that it will get worse
or better.


Borderline extraction vs non extraction


• Paquette, Beattie, and Johnston AJO

1992 compared the long term changes in
the borderline cases in class II patients


• The long-term effects of extraction and

nonextraction edgewise treatments were
compared in 63 patients with Class ll,
Division 1 malocclusions who were
identified by discriminant analysis as being
equally susceptible to the two strategies.


• A lateral cephalogram, study models, and
a self-evaluation of the esthetic impact of
treatment were obtained from each of the
33 extraction and 30 nonextraction
subjects.


• The average posttreatment interval was

14.5 years.
• Although the two strategies produced
significant, long-lived differences in the
convexity of the profile and the protrusion
of the dentition (the nonextraction patients
were about 2 mm "fuller"), half of the
nonextraction patients and three fourths of
the extraction patients ultimately
presented with less than 3.5 mm of lower
incisor irregularity.

• The two groups showed an essentially

identical pattern of posttreatment
relapse/settling that was related more to
the differential growth of the jaws than to
the posttreatment position and orientation
of the denture.


• it was noted that because the extraction
patients started out with slightly more
irregularity and ended up with slightly
less), the net change favors premolar
extraction


• Authors therefore suggested that it be

interpreted provisionally as an argument
against the single-sided hypothesis that
extraction treatments are generally
inferior. (mandibular distal
displacement/entrapment )


• In general, the pattern of relapse was

unrelated to the type of treatment or to the
posttreatment position and orientation of
the denture and, instead, appears to
constitute a dentoalveolar compensation
produced by the differential growth of the
jaws following treatment.


• the more the mandible outgrows the

maxilla, the greater the probability that the
upper molars and the upper incisors will
tip forward, that the lower incisors will tip
lingually, and that lower molar anchorage
will be preserved


Clinical implication
• several useful conclusions can be drawn .
• For example, if growth is the usual long-

term source of the molar and the overjet
corrections, a decision to extract upper
first premolars with an eye toward leaving
the molars in a Class II relationship would
seem an eminently logical approach to the
treatment of a nongrowing adult.

• Moreover, given that much of the relapse
seen here took the form of dentoalveolar
compensations for posttreatment jaw
growth, one might also infer the type and
the minimum duration of the retention
program required for the average
adolescent patient.


Long term effects on retention and
stability


• Retention for Life
• Based on extensive research conducted at the

•

University of Washington, Little and colleagues
concluded that orthodontic results are more likely
to be unstable than to be stable"
In these authors‘ opinion, the only way to ensure
continued satisfactory alignment after treatment
would be to provide retention for life.


• Essam A. Al Yami, AJO 1999; did a study
to evaluate stability of orthodontic
treatment on long term


• Dental casts of 1016 patients were evaluated

for the long-term treatment outcome using the
Peer Assessment Rating (PAR) index.
• The PAR index was measured at the
pretreatment stage (n = 1016), directly
posttreatment (n = 783), postretention (n =
942), 2 years postretention (n = 781), 5 years
postretention (n = 821), and 10 years
postretention (n = 564).


• The mean absolute change as well as the
percentage of change per year (relapse)
related to the postretention stage was
calculated.
• An analysis of variance was applied to
compare the mean change in the PAR
between cases with and without a fixed
retainer at the postretention stage and up
to 10 years postretention.


• The results indicate that 67% of the achieved
orthodontic treatment result was maintained
10 years postretention.
• About half of the total relapse (as measured
with the PAR index) takes place in the first 2
years after retention.


• All occlusal traits relapsed gradually over

time but remained stable from 5 years
postretention with the exception of the
lower anterior contact point displacement,
which showed a fast and continuous
increase even exceeding the initial score.


• The mean age at the posttreatment stage

was 15.6 ± 3.0 and at the postretention
stage 16.7 ± 3.1.
• This indicates that there were cases
reaching the postretention stage while
some potential growth was still present.
• This remnant of growth may influence the
stability of the result of the orthodontic
treatment.

• Sixty-seven percent of the achieved

orthodontic treatment result was
maintained 10 years postretention.
• Relapse should not be contributed to
orthodontic treatment alone but also of
physiologic and pathologic changes in the
dentition and surrounding tissues during
those years.


• It has been shown by Behrents Scholas and Van
•
•

der Linden that considerable craniofacial alteration
occurs beyond 17 years of age in human beings.
This is accompanied by compensatory changes in
the dentition. The orthodontist has little control over
these biologic processes
The results of this type of studies enable clinicians
to inform their patients before treatment about
treatment limitations in order to give them more
realistic expectations.

• In a recent, comprehensive review of the

orthodontic literature regarding relapse,
Shah (AJO 2003) found that postretention
relapse of the mandibular incisors was
often incorrectly attributed to
misdiagnosis, improper treatment, or
inappropriate treatment mechanics.'


• Mandibular incisor relapse is almost

inevitable, he pointed out, regardless of
the timing of orthodontic treatment and the
techniques employed.
• Even the extraction of premolars to
alleviate crowding does not appear to
make corrections any more stable.".


Factors affecting stability on long
term
•
•
•
•
•
•

Arch perimeter
Arch length
Inter canine width
Inter proximal force
Circumferential Supracrestal Fiberotomy
Bone morphology


• The main reason for a relapse of crowding is

the tendency for dental arch perimeter or length
and intercanine width to decrease and constrict
over time.
• This pattern has teen found in treated as well
as untreated normal subjects'; in fact, as early
as 1959, Moorrees demonstrated a reduction in
arch length from the mixed dentition through
the transitional dentition and into early
adulthood."

• Gianelly. and others ( AJO 2006) have

argued that the stability of orthodontic
treatment can be improved by preserving
mandibular intercanine width.
• This means that any increase in
mandibular intercanine dimension is
inherently unstable.


• Blake and Bibby (AJO 1998) listed six

major criteria for the stability of finished
orthodontic cases;
• I. The patient's pretreatment lower
archform should be maintained to the
extent possible.
• 2. The original lower intercanine width
should be maintained as much as
possible, because expansion of lower
intercanine width leads to the most
predictable of all orthodontic relapse

• 3. Mandibular arch length decreases with

time.
• 4. The most stable position of the lower
incisor is its pretreatment position;
advancing the lower incisors can seriously
compromise stability.


• 5. Fiberotomy is an effective means of

reducing rotational relapse. .
• 6. Lower incisor reproximation can
improve long-term post-treatment stability


Inter-proximal force
• A 'continuous, compressive inter proximal

force (IPF), originating in the periodontium
and acting on adjacent teeth at their
contact points, may be responsible for
some long-term arch constriction.


• Southard and colleagues (AJO 1990)

found a significant correlation between
mandibular anterior malalignment and IPF,
• It has been suggested that if IPF does
have an influence on dental alignment, it
probably acts in conjunction with lip and
cheek forces to collapse the arch.
• These forces are opposed by the tongue,
which tends to expand the arch.

• It follows that the influence of IPF should

be more evident in the anterior segment of
the arch, where the contact points are
narrower, the crowns more tapered, and
the expansive force of the tongue more
intermittent than in the posterior regions.
• Perhaps for this reason, lower incisor
reproximation can counteract‘ IPF by
slightly narrowing the teeth and by
broadening their contacts to resist contact
slippage.

circumferential supracrestal
fiberotomy (CSF)
• Reorganization of the periodontal ligament
occurs over a three-to-four month period,
whereas the gingival collagen fiber
network typically takes four to six months
to remodel, and the elastic supracrestal
fibers remain deviated for more than 232
days


• Edwards found circumferential supracrestal

fiberotomy (CSF) somewhat more effective in
preventing- pure rotational relapse than in
reducing labiolingual relapse over the long
term, and more successful in the maxillary
anterior segment than in the mandibular
anterior segment
• Significant and unpredictable individual tooth
movements were still observed after CSF.

Bone morphology
• The effect of the amount and structure of

•

mandibular bone on mandibular incisor stability
has recently been investigated in a case-control
study at the University of Washington.
After measuring trabecular bone structure and
cortical bone thickness in both relapsed and
stable subjects, Roth concluded that patients
with thinner mandibular cortices are at !
increased risk of dental relapse.

• Boese (AO 1980) found an improvement
in post-treatment stability of the
mandibular anterior segment, without
retention, when fiberotomy and
reproximation were used in combination
with overcorrection and selective root
paralleling.


Consequences of long term wear of
retainers


• The consequences of long-term fixed retainer

•

wear have been a concern. Over a six-month
retention Heier et al (AJO 1997) found limited
gingival inflammation with either. Hawley type
removable or bonded lingual retainers!'
Although they noted slightly more plaque and
calculus on the lingual surfaces in the fixed
retainer group, this did not result in more
significant gingival inflammation.


• In a longer-term study, Artun (AJO 1984 )

showed that the presence of a bonded
lingual retainer for as long as eight years
and the occasional accumulation of
plaque and calculus gingival to the
retainer wire caused no apparent damage
to the hard and soft tissues.


• Some authors have contended that a patient
•

•

with reduced periodontal support may be better
off with a fixed retainer.
A removable retainer may produce "jiggling"
forces that can compromise healing and bone
regeneration, whereas a fixed retainer can serve
as a periodontal splint.
In addition, there is no patient compliance issue
with a fixed retainer, and minor settling of the
posterior occlusion can occur.

Third molar and mandibular arch stability


• The justification often given for extraction
of third molars at age 18 to 22 is the
avoidance of mandibular incisor relapse
and irregularity.


• Bergstrom and Jensen (Dent Abstr 1961)

studied sixty subjects with unilateral molar
agenesis and noted greater crowding in
the quadrants in which third molars were
present than in those in which third molars
were missing.


• Sheneman In an investigation of 49 patients a
•

mean of 66 months after orthodontic therapy,
The sample included eleven patients with third
molars in bilateral occlusion, thirty-one patients
with bilateral third molar impaction, and seven
patients with bilateral third molar agenesis

• He concluded that patients with third molars

congenitally missing showed greater dental
stability than those in whom third molars were
present.

• Lindquist and Thilander (ajo 1982)

evaluated a sample of 23 males and 29
females with bilateral mandibular
impaction of third molars. The impacted
third molar was removed on one side, and
the contra lateral quadrant was used as a
control.


• Although they found evidence of less

crowding on the extraction side, in 70% of
the patients the investigators were not
able to use their analysis of variables to
predict which persons would react
favorably.


• In a longitudinal study of 61 pairs of twins

observed at 12 to 15 years of age and
again at the age of 26 to 30 years,
Lundstrom A (Dent Pract 1969 ) found a
reduction of spacing with an increase in
crowding with age, but he found no
relationship between third molar agenesis
and these observed changes in arch
dimension

• In 1973 Kaplan (AJO 1974) studied

postretention crowding in a group of 75
orthodontically treated patients.
• He found that, although some degree of
lower incisor crowding occurred in the
majority of patients, it was not significantly
different in subjects whose mandibular
third molars were bilaterally erupted,
impacted, or congenitally absent.

• In addition, he found that changes in

mandibular arch length, width, and molar
and incisor position were not significantly
different among the three groups.
• In conclusion, Kaplan stated that the
presence of third molars does not
influence postretention changes in arch
dimension, tooth position, or mandibular
incisor crowding.


CURRENT VIEWS( JCO 2007)
• The concept that mesial pressure exerted by
•

impacted or erupting third molars may alter
mandibular eruption patterns and cause
decreases in arch length is not substantiated
The clinician should make decisions relative to
the timing of third molar extraction on the basis
of potential development of pathosis, technical
considerations of the surgical procedure, and
long-term periodontal implications rather than
potential impact on mandibular incisor crowding.

CONCLUSION

• Usually, the goal of orthodontic treatment is to
•

•

produce a normal or so called ideal occlusion
that is morphologically stable and esthetically
and functionally well adjusted.
There is, however, a large variation in treatment
outcome because of the severity and type of
malocclusion, treatment approach, patient
cooperation, and growth and adaptability of the
hard and soft tissues.
Follow-up studies of treated cases have shown
that although ‘ideal’’ occlusion and dental
alignment have been achieved, there is a
tendency for relapse toward the original
malocclusion

REFERENCES:1. Polson AM, Subtelny JD, Meitner SW, Polson AP,

Sommers EW, Iker HP,-Long-term periodontal status
after orthodontic treatment. Am J Orthod Dentofacial
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