Early orthodontic treatment for Class II malocclusion reduces the chance of incisal trauma: Results of a Cochrane systematic review

Abstract

In this article, we summarize the most clinically relevant findings of our recently updated Cochrane systematic review into the treatment of Class II Division 1 malocclusion.
A systematic review of the databases was performed to identify all randomized controlled trials evaluating early treatment with functional appliances to correct Class II Division 1 malocclusion.
Three early treatment studies with data from 353 participants were included in this review. The results showed no significant difference for any outcomes, except new incidence of incisor trauma, which was significantly less for the early treatment group. The risk ratio analysis for new incisor trauma showed that providing early treatment reduced the risk of trauma by 33% and 41% in the functional and headgear groups, respectively. However, when the numbers needed to treat were calculated, early treatment with functional appliances prevents 1 incidence of incisal trauma for every 10 patients (95% CI, 5-174), and headgear treatment prevents 1 incidence of incisal trauma for every 6 patients (95% CI, 3-23).
Orthodontic treatment for young children, followed by a later phase of treatment when the child is in early adolescence, appears to reduce the incidence of new incisal trauma significantly compared with treatment that is provided in 1 phase when the child is in early adolescence. However, these data should be interpreted with caution because of the high degree of uncertainty. There are no other advantages in providing 2-phase treatment compared with 1 phase in early adolescence.
Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Full text

Early orthodontic treatment for Class II
malocclusion reduces the chance of incisal
trauma: Results of a Cochrane systematic review
Badri Thiruvenkatachari,
a
Jayne Harrison,
b
Helen Worthington,
c
and Kevin O'Brien
d
Manchester and Liverpool, United Kingdom
In this article, we summarize the most clinically relevant findings of our recently updated Cochrane systematic
review into the treatment of Class II Division 1 malocclusion. Methods: A systematic review of the databases
was performed to identify all randomized controlled trials evaluating early treatment with functional appliances
to correct Class II Division 1 malocclusion. Results: Three early treatment studies with data from 353 partici-
pants were included in this review. The results showed no significant difference for any outcomes, except
new incidence of incisor trauma, which was significantly less for the early treatment group. The risk ratio analysis
for new incisor trauma showed that providing early treatment reduced the risk of trauma by 33% and 41% in the
functional and headgear groups, respectively. However, when the numbers needed to treat were calculated,
early treatment with functional appliances prevents 1 incidence of incisal trauma for every 10 patients (95%
CI, 5-174), and headgear treatment prevents 1 incidence of incisal trauma for every 6 patients (95% CI, 3-
23). Conclusions: Orthodontic treatment for young children, followed by a later phase of treatment when
the child is in early adolescence, appears to reduce the incidence of new incisal trauma significantly compared
with treatment that is provided in 1 phase when the child is in early adolescence. However, these data should
be interpreted with caution because of the high degree of uncertainty. There are no other advantages in
providing 2-phase treatment compared with 1 phase in early adolescence. (Am J Orthod Dentofacial
Orthop 2015;148:47-59)
In this article, we outline and discuss the most clini-
cally relevant findings of our recently updated
Cochrane systematic review into the treatment of
Class II malocclusion.
1
This form of malocclusion affects
nearly a quarter of 12-year-olds in the United Kingdom
2
and 15% of 12- to 15-year-olds in the United States.
3
As
a result, correcting Class II malocclusion is a common
treatment performed by orthodontists.
There has been extensive research into Class II treat-
ment, and this was summarized in the previous version
of our Cochrane review, when we concluded that “early
treatment of Class II malocclusion resulted in limited
advantage when compared to providing treatment in
one stage during adolescence.”Despite this high level
of evidence, these conclusions are still thought to be
controversial because the results of nonrandomized
investigations do not always agree with the results of
the trials.
4-10
Our review was originally published in 2008, and we
have updated it to ensure that additional research is
included so that the conclusions remain contempo-
rary.
11
In this article, we outline the most important out-
comes that are relevent to the timing of treatment.
MATERIAL AND METHODS
We identified studies using the Cochrane Oral Health
Group's Trials Register (to April 17, 2013), the Cochrane
Central Register of Controlled Trials (Cochrane Library
2013, Issue 3), MEDLINE via OVID (1946 to April 17,
2013), and EMBASE via OVID (1980 to April 17, 2013).
Articles that were identified as part of the Cochrane
a
National Institute of Health Research (NIHR) Academic Clinical Lecturer in or-
thodontics, School of Dentistry, University of Manchester, Manchester, United
Kingdom.
b
Honorary senior lecturer/consultant orthodontist, Orthodontic Department,
Liverpool University Dental Hospital, Liverpool, United Kingdom.
c
Professor, Cochrane Oral Health Group, School of Dentistry, University of
Manchester, Manchester, United Kingdom.
d
Professor, School of Dentistry, University of Manchester, Manchester, United
Kingdom.
All authors have completed and submitted the ICMJE Form for Disclosure of
Potential Conflicts of Interest, and none were reported.
Address correspondence to: Badri Thiruvenkatachari, JR Moore Bldg, School of
Dentistry, University of Manchester, Oxford Rd, Manchester, United Kingdom
M13 9PL; e-mail, Badri.T@manchester.ac.uk.
Submitted, August 2014; revised and accepted, January 2015.
0889-5406/$36.00
Copyright Ó2015 by the American Association of Orthodontists.
http://dx.doi.org/10.1016/j.ajodo.2015.01.030
47
SYSTEMATIC REVIEW

Oral Health Group's hand searching program were
obtained from the following journals: American Journal
of Orthodontics and Dentofacial Orthopedics,Angle
Orthodontist,European Journal of Orthodontics,Jour-
nal of Orthodontics,andBritish Journal of Orthodon-
tics. An example of the search strategy is shown in the
Appendix. We included randomized controlled trials
that looked at children or adolescents, or both, receiving
orthodontic treatment to correct prominent maxillary
front teeth. The participants had to be 16 years of age
or younger. We excluded trials that included participants
with cleft lip or palate or other craniofacial deformities or
syndromes. No language restrictions were placed on the
studies considered for inclusion in this review, and pub-
lished or unpublished sources were considered. For
unpublished studies, an attempt was made to identify
them by contacting the first-named author of the trial re-
ports. The study eligibility was assessed by 2 review au-
thors (B.T. and K.O'B.) independently and in duplicate,
and disagreements were resolved by discussions or clari-
fications from the authors. Further details of the method-
ology that we used are included in the original review.
1
For the purposes of this article, we reported on only
the most clinically relevant subset of outcomes from
the original review.
1
The primary outcome measure was the prominence
of the maxillary front teeth (overjet).
The secondary outcome measures were the relationship
between the maxillary and mandibular jaws (cephalo-
metric measurements), self-esteem and patient satisfac-
tion (Piers Harris questionnaire), and incidence of incisal
trauma.
The risk of bias was evaluated according to the
Cochrane Collaboration's tool for assessing the risk of
bias, as described in the Cochrane Handbook for Sys-
tematic Reviews of Interventions.
12
This was assessed
independently by 2 authors (B.T. and another) against
the following key criteria.
1. Sequence generation: This evaluation was based on
examination of the method used to generate the
allocation sequence: eg, computer-generated
random numbers or random number tables.
2. Allocation concealment: These are the methods of
concealing the allocation sequence from those
assigning participants to the intervention groups.
Did they use sealed envelopes, or was this done
remotely via an Internet site or telephone
allocation? These steps are taken so that the oper-
ator in the study cannot influence the treatment
allocation.
3. Blinding of participants, personnel, and outcome
assessors: This ensures that the participants, clini-
cians, and assessors are unaware of the intervention
allocations. This is carried out to reduce the chances
that the operators and the data handlers could
influence the results of the study. In orthodontic
studies, it is often difficult to conceal the treatment
allocation from participants and clinicians, but it is
usually possible to blind the outcome assessors for
data collection and analysis.
4. Incomplete outcome data: This is an assessment of
the possible effects of missing data caused by attri-
tion or exclusion from analysis: eg, postrandomiza-
tion dropouts. If there are many dropouts in a
treatment group, this can introduce bias. This may
be an issue in orthodontic studies because of
relatively high dropout rates as a result of the long
duration of the studies.
5. Selective outcome reporting: Selectively reporting
outcomes: eg, chasing significance or not reporting
harms. This is assessed to make sure that all data are
reported, not just the outcomes that are considered
significant to the investigators.
6. Other sources of bias: Biases not covered elsewhere.
We summarized the overall risk of bias for each study
as low, unclear, or high.
Statistical analysis
The statistical analysis was performed according to
the statistical guidelines referenced in the Cochrane
Handbook for Systematic Reviews of Interventions
and facilitated by RevMan.
12
Mean differences and 95% confidence intervals (CIs)
were calculated for continuous data. Dichotomous out-
comes were expressed as odds ratios (ORs) together with
95% CIs. Any heterogeneity between trials was assessed
with the Cochran test and the I
2
statistic. A meta-analysis
was performed on studies with similar comparisons that
reported the same outcome measures. We would have
used the random-effects models if there had been
more than 3 studies in the meta-analysis and used
fixed-effect models if there were only 2 or 3 studies.
When relevant, we calculated the numbers needed to
treat and the risk ratio (RR).
13
RESULTS
In our literature search, we initially identified a total
of 1572 records, of which 117 full-text records were
assessed. Of these, we excluded 57 articles; 10 additional
studies were considered not relevant to this review.
Seventeen trials were identified (published in 50 articles)
(Fig 1); these included 3 early treatment trials and 14 late
treatment studies. The 3 early treatment trials are
48 Thiruvenkatachari et al
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included in this review. These studies were reported in
several articles, so for ease of description, we have com-
bined them into 3 broad descriptors: Florida,
14-22
North
Carolina,
23-34
and United Kingdom mixed.
35-38
Assessment of the risk of bias revealed the following
for each study.
In the Florida studies, there was a high risk of bias in 2
categories: bias in randomization method because the
authors used a stratified randomization procedure, but
after 3 years, the method was modified by allocation
to groups (23% of the sample) because of the slow
recruitment rate; and attrition bias, since the dropout
rate was significantly higher for minority ethnic groups.
In the North Carolina studies, there was a high risk of
bias for blinding of the outcome assessment. The molar
bands were left in place at the end of phase 1 data collec-
tion, allowing the technician to identify these patients'
treatment groups.
In the United Kingdom mixed studies, there was a low
risk of bias.
Further more detailed information on the risks of bias
for each study is given in Table I and Figure 2.
Fig 1. Study flow diagram.
Thiruvenkatachari et al 49
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Three trials reported on early treatment for Class II Di-
vision 1 malocclusion, and all were included in the meta-
analyses. Detailed characteristics are described in Table II.
We looked at the outcomes of early (2-phase) inter-
vention vs adolescent (1-phase) treatment at the conclu-
sion of treatment.
Table I. Methodologic quality summary
Bias Authors' judgment Support for judgment
Florida
14-22
Random sequence generation (selection bias) High risk A stratified block randomization procedure was used
“Subjects initially were selected in blocks of 6 and randomized to the
treatment protocols. This procedure of assigning subjects to
groups only after a block had filled was modified in year 3, after we
recognized slow entry rate and many partially filled blocks (23% of
the sample) were randomized to groups”
Allocation concealment (selection bias) Unclear risk Not described
Blinding of outcome assessment (detection bias) Low risk “All cephalometric radiographs were encoded by the staff assistant
and then decoded for analysis”
Incomplete outcome data (attrition bias) High risk Clear information on withdrawals. Dropouts, 24%. Number of
dropouts was approximately equal in each group, but the rate of
withdrawal was significantly higher for subjects who were not
white.
Selective reporting (reporting bias) Low risk All variables reported
Other biases Low risk No other sources of bias identified
North Carolina
23-34
Random sequence generation (selection bias) Low risk “Randomization was performed within gender in blocks of six
patients with Proc Plan in SAS”
Allocation concealment (selection bias) Unclear risk Not described
Blinding of outcome assessment (detection bias) High risk Because the molar bands were not removed at the end of phase 1, the
technician was not masked as to these patients' treatment group
Incomplete outcome data (attrition bias) Unclear risk Number of patients randomized in different groups not reported
192 randomized; 175 started, 166 finished phase 1; and 137 finished
phase 2
Dropout rates of 13.5% (low risk) for phase 1 and 28.6% (high risk)
for phase 2. Reasons for dropouts reported, but not for each
treatment group
Selective reporting (reporting bias) Low risk All variables reported
Other biases Low risk No other bias found
United Kingdom mixed
35-38
Random sequence generation (selection bias) Low risk “The randomization was made at the start of the study with pre-
prepared random number tables with a block stratification on
centre and sex”
Allocation concealment (selection bias) Low risk Randomization was carried out by using a central telephone line and
minimization software
Blinding of outcome assessment (detection bias) Low risk Assessor blinded to outcomes. “The cephalograms and the study
casts were scored with the examiner unaware of the patient's
group”
Incomplete outcome data (attrition bias) Low risk Clear information on withdrawals, but rates different in each group:
22/89 (25%) in the Twin-block group and 12/85 (14%) in the
control group.
Reasons for exclusion specified (unpublished data)
Control group: 4 refused to consent to phase 2 treatment, 1 withdrew
due to illness, 3 had multiple DNAs with no final records, 1 moved
away or lost contact, 2 had Twin-blocks fitted in phase 1 in error, 1
had a sore mouth and required treatment in phase 1
Treatment group: 2 moved away or lost contact, 9 had multiple DNAs
with no follow-up records, 4 did not start because eligibility
criteria were not met, 5 refused to continue, 1 had poor oral health,
1 was removed from study because of health problems
Selective reporting (reporting bias) Low risk All variables reported
Other biases Low risk Groups appeared similar at baseline
DNA, Did not attend.
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Three trials with data from 343 participants
compared treatment for younger children with a func-
tional appliance vs treatment for adolescents.
14-38
When we evaluated the effects of treatment at a
young age with a functional appliance (phase 1)
followed by further treatment during adolescence
(phase 2), at the conclusion of all treatment, we
found no statistically significant differences in final
overjet (P50.18), final ANB (P50.92), peer
assessment rating (PAR) score (P50.34), and
self-concept score (P50.60) (Fig 3). However, the
incidence of new incisal trauma showed statistically
significant results in favor of early treatment with a
functional appliance (P50.04) compared with 1-
phase treatment during adolescence only (OR, 0.59;
95% CI, 0.35-0.99) (Fig 4). When the risk of trauma
was evaluated, 29% (54 of 185) of patients who had
1 course of treatment in adolescence had new trauma
compared with only 20% (34 of 172) of patients hav-
ing incisal trauma in the early treatment group. The
difference in the risk was 9.7%. The RR analysis
showed that providing early treatment reduced the
risk of new trauma by 33% of what it was when treat-
ment was delayed and provided in 1 course in adoles-
cence (RR, 0.67; 95% CI, 0.46-0.98). Importantly,
calculating the measure of treatment impact—ie, the
number needed to treat—showed that early treatment
with a functional appliance prevents 1 incidence of
new incisal trauma for every 10 patients treated
(95% CI, 5.4-175).
Two trials, with data from 285 children, compared
treatment for young children who used headgear with
adolescent (1-phase) treatment.
14-34
There were no
statistically significant effects of an early course of
headgear treatment at a young age followed by
treatment in adolescence with respect to final overjet
(P50.20), final ANB (P50.32), and PAR score
(P50.16) (Fig 5) compared with treatment in adoles-
cence only. However, the incidence of new incisal
trauma showed a statistically significant reduction in
the early treatment group (P50.009), with an OR
of 0.47 (95% CI, 0.27-0.83) (Fig 6). The adolescent
treatment group showed nearly twice the incidence of
new incisal trauma, with 39% (47 of 120) compared
with 23% (27 of 117) for the young group with early
headgear treatment. The RR showed a risk reduction
of 41% for patients having early headgear treatment
(RR, 0.59; 95% CI, 0.39-0.87). When we considered
the numbers needed to treat, we found that early treat-
ment with headgear prevented 1 incidence of incisal
trauma for every 6 patients treated (95% CI, 3.64-
23.22).
When we evaluated any effect of early treatment with
either a functional appliance or headgear, we found no
significant differences in final overjet (Fig 7), final ANB
(Fig 5), PAR score (Fig 5), or the incidence of incisal
trauma (Fig 8) between the 2 interventions.
14-38
DISCUSSION
The results of this updated review showed that for
overjet reduction, PAR score, and skeletal change,
there are no benefits of early treatment, and the results
of the original systematic review have not changed.
However, the addition of new data showed that early
treatment, with either a functional appliance or head-
gear, resulted in a reduction in incisal trauma. This
illustrates the value of continuously updating system-
atic reviews.
It is worthwhile to consider the important outcomes
in which early treatment had an effect in terms of their
ability to reduce treatment uncertainty.
For the psychosocial impact, the United Kingdom
study was the only one that reported in sufficient detail
on self-concept.
35,37
The results from this study
suggested that although self-concept and self-esteem
improved initially for patients having treatment early,
at the end of phase 1 treatment, this effect was not
maintained to the end of phase 2 treatment in
Fig 2. Risk of bias summary for each included study.
Thiruvenkatachari et al 51
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Table II. Characteristics of studies
Study Characteristics
Florida
14-22
Methods Location: University of Florida
Number of centers: 1
Recruitment period: not stated
Funding source: funded by NIH (DE08715)
Trial design: randomized parallel group study over 10 years
Participants Inclusion criteria: third or fourth grade at school, at least bilateral 1/2 cusp Class II molars or 1 side\1/2 cusp Class II if other side was greater than 1/2 cusp Class II. Fully
erupted permanent first molars, emergence of not more than 3 permanent canines or premolars, and positive overbite and overjet
Exclusion criteria: not willing to undergo orthodontic treatment or to be randomly allocated to treatment type. Poor general health, active dental or periodontal pathology
Age at baseline: mean, 9.6 years
Screened child population (360) then referred to clinic for treatment
Number randomized: 325 randomized; 277 started treatment: 95, 100, and 82 in bionator, headgear, and control groups, respectively
Number evaluated: end of treatment phase (1), 79/95, 92/100, and 78/82; end of retention phase, 75/95, 85/100, and 75/82; and end of follow-up (II), 70/95, 81/100,
and 74/82 in bionator, headgear, and control groups, respectively
Interventions Group A: bionator appliance
Group B: cervical pull headgear with removable biteplane
Group C: delayed treatment control
3 phases of treatment: 2 years of early treatment plus 6 months retention plus further 6 months follow-up
Outcomes Overjet
Skeletal discrepancy
Dental alignment measured with the PAR index
Notes Duration of randomized treatment: 2 years initially
Sample size calculation not reported
North Carolina
23-34
Methods Location: North Carolina
Number of centers: 1
Recruitment period: August 1988 to November 1993
Funding source: grants from NIH, and Orthodontic Fund, Dental Foundation of North Carolina
Trial design: parallel group randomized controlled trial with 2 treatment phases
Participants Inclusion criteria: children with mixed dentition, with all permanent teeth developing, with growth potential throughout phase 1 of treatment. Overjet .7 mm, all incisors
erupted, second molars not erupted
Exclusion criteria: clinically obvious facial asymmetry, cleft or syndrome, more than 2 SD from normal vertical proportionality, and prior orthodontic treatment
Age group: mean, 9.4 years (SD, 1.0 year)
Screened child population (2164) then referred to clinic for treatment
Numbers randomized: 192 randomized, 175 started treatment
Numbers evaluated: 53, 52, and 61 at the end of phase 1, and 39, 47, and 51 at the end of phase 2 for bionator, headgear, and control groups, respectively
Interventions Group A (n 553): functional appliance—modified bionator with the bite taken with 4-6 mm of protrusion and minimal vertical opening. Reactivation of appliance when
necessary was by construction of a new appliance
Group B (n 552): headgear—combination headgear with supershort outer bow, adjusted to deliver 8-10 oz to the head cap, with neck strap force just sufficient to prevent
buccal flaring of maxillary molars
All appliances delivered within 1 month of patients' initial records being taken
Group C (n 561): control (observation only)
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Table II. Continued
Study Characteristics
Outcomes Skeletal growth changes; maxilla, mandible, skeletal relationship, dental relationship
Notes Duration of intervention: phase 1, 15 months, and phase 2, 25.5, 30.1, and 34.5 months for functional, headgear, and control groups, respectively
Frequency of treatment visits: every 6-8 weeks for active treatment groups and every 6 months for control group
Sample size calculation: sample size of 40 per group was calculated as necessary to detect a mean difference between any 2 groups equivalent to the doubling in
annualized change of SNPg (with alpha 50.01 and power of 0.90)
Patients were rerandomized at the end of phase 2 for different clinicians
United Kingdom
35-38
Methods Location: United Kingdom
Number of centers: 13
Recruitment period: March 1997 to June 1998.
Funding source: Medical Research Council (99410454)
Trial design: randomized parallel group trial
Participants Inclusion criteria: children in the mixed dentition with overjet greater than 7 mm and willingness of the patient and a parent to participate in the study. The patients had to
be in the mixed dentition with at least the permanent incisors and first molars erupted, but there was no age criterion
Exclusion criteria: craniofacial syndromes
Age at baseline: average ages were 9.7 (SD, 0.98) years for the treatment group and 9.8 (SD 0.94) years for the control group
Number randomized: 174
Number evaluated: 127
Interventions Comparison
Group A: Twin-block early treatment: randomized, 89; completed, 67
Group B: Twin-block delayed treatment: randomized, 85; completed, 73
Outcomes (trauma not
noted)
Overjet
Skeletal discrepancy measured by the Pancherz analysis
Dental alignment measured with the PAR index
Duration of treatment
Notes Duration of intervention: phase 1, 15 months; phase 2, early treatment group, 14 months (435 days), late treatment group, 24 months (744 days).
Sample size calculation: “This showed that the mean duration of treatment for patients who had later treatment after early treatment was 25 months (SD, 11). It was
decided that a meaningful difference between the treatment duration for children who did, or did not, receive early treatment was 6 months. To give a study a power of
80% and an alpha of 0.05, the sample size needed to be 60 in each group”
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adolescence. We can, therefore, conclude that providing
treatment did not make a positive impact in the long
term. Unfortunately, it appears that the effect of early
orthodontic treatment diminishes with time. Neverthe-
less, we do not know the effect of the increase in
self-esteem that occurred after early intervention; this
may have clinical importance, particularly if a child is
subjected to excessive teasing or bullying.
All 3 early treatment studies reported on the inci-
dence of new incisal trauma.
14,27,36
The Florida
study used the modified Ellis classification with the
help of study models, photographs, and x-rays.
27
In
the North Carolina study, the authors used the modi-
fied National Health and Nutritional Examination Sur-
vey (NHANES III), which was clinically assessed at each
stage of the study.
14
Although the scores ranged from
Fig 4. Forest plot representing the incidence of new incisal trauma in patients receiving early treat-
ment with a functional appliance compared with 1-phase treatment during adolescence only. M-H,
Mantel-Haenszel.
Fig 3. Forest plot representing the effects of treatment at a young age with a functional appliance
(phase 1) followed by a further treatment during adolescence (phase 2) and final overjet, final ANB,
PAR score, and self-concept. IV, Instrumental variables.
54 Thiruvenkatachari et al
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0 to 7 for both studies, the scoring criteria were
different. In the United Kingdom study, the incidence
of trauma was simply recorded as “yes”or “no,”with
no information on the severity of the injury.
36
In all
these studies, a reliability assessment was performed
for the assessors.
The meta-analyses showed a statistically and clini-
cally significant reduction in incisal trauma after early
treatment with both functional appliances and head-
gear. However, we need to interpret this finding with
caution and consider all the data, particularly the RRs
and the numbers needed to treat.
The RR is a measure of an event happening in one
group compared with the risk of the event happening
in another group. For example, the RR of 0.67 that we
reported for early treatment with a functional appliance
means that the risk of incisal trauma is reduced by 33%
in the early treatment group, when compared with the
adolescent treatment group. This suggests that
providing treatment early is likely to have a benefit.
However, when we examined the confidence intervals,
these were wide (0.46-0.98). This means that the risk
reduction could be as high as 54% or as low as 2%. As
a result, there is a high degree of uncertainty about
this finding.
Another useful way to interpret these data is to
consider the numbers needed to treat. This is the number
of patients that one needs to treat to prevent 1 addi-
tional adverse outcome: in this case, 1 episode of
trauma. When this was calculated for early treatment
with a functional appliance, it showed that we needed
to treat 10 patients to prevent 1 episode of trauma.
The 95% CIs (5-175) again showed a high degree of
uncertainty.
Fig 6. Forest plot representing new incisal trauma in the early treatment and adolescent treatment
groups. M-H, Mantel-Haenszel.
Fig 5. Forest plot representing effects of an early headgear treatment at a young age followed by treat-
ment in adolescence with respect to final overjet, final ANB, and PAR score. IV, Instrumental variables.
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Similar data were found for the effect of early
treatment with headgear; the risk reduction was
41% (RR, 0.59; 95% CI, 0.39-0.87), with numbers
needed to treat of 6 (95% CI, 3-23). Although these
figuresshowalowerdegreeofuncertainty,itisstill
considerable.
In 2 of the 3 studies, the majority of the injuries were
scored as minor fractures involving the enamel only.
14,27
In the Florida study, 80% of the patients had enamel-
only fractures, 19% had enamel and dentin fractures,
and 1 patient had pupal involvement.
27
In the North
Carolina study, at the end of phase 2, most new injuries
were craze lines or enamel-only fractures.
14
One patient
had enamel and dentin fracture that required resin resto-
ration, and another patient required endodontic treat-
ment for a pulpal injury. In the United Kingdom trial,
the authors reported only the presence or absence of
incisor trauma. However, all 3 studies reported a signif-
icant number of patients with incisor trauma before the
start of the trial.
It is interesting that in the North Carolina and
the Florida studies, the incidences of trauma were not
statistically significantly different between boys and
girls.
14,27
In the North Carolina study, the difference
was statistically significant for the control group, with
significantly more boys having incisal trauma.
14
Fig 8. Forest plot representing effect of early treatment with either a functional appliance or headgear
and the incidence of incisal trauma. M-H, Mantel-Haenszel.
Fig 7. Forest plot representing effect of early treatment with either a functional appliance or headgear
and final overjet, final ANB, and PAR score. IV, Instrumental variables.
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However, no study provided data on sex, and so a meta-
analysis was not possible in this review.
It would have been useful to have additional infor-
mation on the sporting activities of the patients
involved in the trials, but none of the 3 studies re-
ported on this and also whether mouthguards were rec-
ommended.
It is also relevant to consider that although the re-
view showed that early treatment may reduce trauma,
other factors such as cost, patient compliance, and
risks associated with lengthy treatment should be
considered before deciding on treatment timing. The
cost savings of preventing incisor trauma must be
balanced against the greater cost of providing
treatment in 2 phases.
Whereas the findings on the reduction of trauma are
encouraging, it is clear that they should be interpreted in
relation to the high level of uncertainty. As a result, we
suggest that the prevention of trauma should not be
the only reason for routinely providing early treatment
for Class II malocclusion. This decision should be taken
as part of a risk evaluation that considers the size of
overjet and the child's engagement in activities that in-
crease the risk of trauma.
For the dental and skeletal outcomes, analyses of
the PAR scores, cephalometric measurements, and
overjet reduction showed no statistically or clinically
significant effect of providing early orthodontic treat-
ment. This was not surprising because this was the
conclusion of the 3 large-scale randomized trials, and
these findings have not changed since the original re-
view. It is therefore clear that in terms of morphologic
outcomes of orthodontic treatment, there are no ad-
vantages to early treatment.
The result of the assessment of the risk of bias is
important because it showed that the quality of 2 of
the 3 long-term (2-phase) studies were classified as hav-
ing a higher risk of bias.
14-34
This may be a concern, but
these studies were planned and completed some years
ago, and the Cochrane tool reflects current research
practices. Furthermore, these were long-term (10 years)
studies; as a consequence, subject dropout was unavoid-
able. These results should be accepted but interpreted in
the light of this classification.
The results from this systematic review do not sup-
port the widespread provision of early orthodontic treat-
ment for children with Class II malocclusion in terms of
dentoskeletal outcomes. However, they do provide data
that should be used to inform discussions on whether
parents wish their children to have early orthodontic
treatment with the aim of reducing the chances of incisal
trauma, particularly in groups that may be vulnerable to
this problem.
CONCLUSIONS
1. There are no advantages in providing a 2-phase
treatment compared with 1 phase in early adoles-
cence except for a potential reduction in the inci-
dence of new incisal trauma.
2. Orthodontic treatment for young children, followed
by a later phase of treatment when the child is in
early adolescence, appears to reduce the incidence
of new incisal trauma significantly compared with
treatment in 1 phase when the child is in early
adolescence. However, these data should be inter-
preted with caution because of the high degree of
uncertainty.
REFERENCES
1. Thiruvenkatachari B, Harrison JE, Worthington HV, O'Brien KD.
Orthodontic treatment for prominent upper front teeth (Class II
malocclusion) in children. Cochrane Database Syst Rev 2013;
(11):CD003452.
2. Office for National Statistics. National children's dental health
survey; 2003. Available at: http://www.ons.gov.uk/ons/
guide-method/method-quality/specific/health-methodology/
dental-health/dental-health-of-children/index.html. Accessed
July 1, 2014.
3. Proffit WR, Fields HW Jr, Moray LJ. Prevalence of malocclusion
and orthodontic treatment need in the United States: estimates
from the NHANES III survey. Int J Adult Orthod Orthognath Surg
1998;13:97-106.
4. Baccetti T, Franchi L, Kim LH. Effect of timing on the outcomes of
1-phase nonextraction therapy of Class II malocclusion. Am J Or-
thod Dentofacial Orthop 2009;136:501-9.
5. Bailleau A, Aknin JJ, Gebeile-Chauty S. One phase or two-
phase orthodontic treatment: comparisons. Orthod Fr 2012;
83:289-96.
6. Bollen AM. Interceptive orthodontic treatment of Class II mal-
occlusions is slightly more successful with headgear/biteplane
than with bionator treatment. J Evid Based Dent Pract 2011;
11:58-9.
7. Franchi L, Pavoni C, Faltin K Jr, McNamara JA Jr, Cozza P. Re:
response to: Long-term skeletal and dental effects and treatment
timing for functional appliances in Class II malocclusion. Angle Or-
thod 2013;83:933.
8. Ghislanzoni LT, Toll DE, Defraia E, Baccetti T, Franchi L. Treatment
and posttreatment outcomes induced by the mandibular advance-
ment repositioning appliance; a controlled clinical study. Angle
Orthod 2011;81:684-91.
9. Silvestrini-Biavati A, Alberti G, Silvestrini Biavati F, Signori A,
Castaldo A, Migliorati M. Early functional treatment in Class II di-
vision 1 subjects with mandibular retrognathia using Frankel II
appliance. A prospective controlled study. Eur J Paediatr Dent
2012;13:301-6.
10. Wigal TG, Dischinger T, Martin C, Razmus T, Gunel E, Ngan P. Sta-
bility of Class II treatment with an edgewise crowned Herbst appli-
ance in the early mixed dentition: skeletal and dental changes. Am
J Orthod Dentofacial Orthop 2011;140:210-23.
11. Harrison JE, O'Brien KD, Worthington HV. Orthodontic treatment
for prominent upper front teeth in children. Cochrane Database
Syst Rev 2007;CD003452.
Thiruvenkatachari et al 57
American Journal of Orthodontics and Dentofacial Orthopedics July 2015 Vol 148 Issue 1

12. Higgins JP, Altman DG, Gotzsche PC, Juni P, Moher D, Oxman AD,
et al. The Cochrane Collaboration's tool for assessing risk of bias in
randomised trials. BMJ 2011;343:d5928.
13. Pandis N. The effect size. Am J Orthod Dentofacial Orthop 2012;
142:739-40.
14. Chen DR, McGorray SP, Dolce C, Wheeler TT. Effect of early Class II
treatment on the incidence of incisor trauma. Am J Orthod Dento-
facial Orthop 2011;140:e155-60.
15. Dolce C, McGorray SP, Brazeau L, King GJ, Wheeler TT. Timing of
Class II treatment: skeletal changes comparing 1-phase and 2-
phase treatment. Am J Orthod Dentofacial Orthop 2007;132:481-9.
16. Johnson PD, Cohen DA, Aiosa L, McGorray S, Wheeler T. Attitudes
and compliance of pre-adolescent children during early treatment
of Class II malocclusion. Clin Orthod Res 1998;1:20-8.
17. Keeling SD, Garvan CW, King GJ, Wheeler TT, McGorray S. Tempo-
romandibular disorders after early Class II treatment with bionators
and headgears: results from a randomized controlled trial. Semin
Orthod 1995;1:149-64.
18. Keeling SD, Wheeler TT, King GJ, Garvan CW, Cohen DA,
Cabassa S, et al. Anteroposterior skeletal and dental changes after
early Class II treatment with bionators and headgear. Am J Orthod
Dentofacial Orthop 1998;113:40-50.
19. King GJ, McGorray SP, Wheeler TT, Dolce C, Taylor M. Comparison
of peer assessment ratings (PAR) from 1-phase and 2-phase treat-
ment protocols for Class II malocclusions. Am J Orthod Dentofacial
Orthop 2003;123:489-96.
20. King GJ, Wheeler TT, McGorray SP. Randomised prospective clin-
ical trial evaluating early treatment of Class II malocclusions [ab-
stract]. Eur J Orthod 1999;21:445.
21. Wheeler TT, McGorray SP, Dolce C, Taylor MG, King GJ. Effective-
ness of early treatment of Class II malocclusion. Am J Orthod Den-
tofacial Orthop 2002;121:9-17.
22. Wortham JR, McGorray S, Taylor M, Dolce C, King DJ,
Wheeler TT. Arch dimension changes following phase I and
phase II orthodontic class II treatment [abstract 1131]. J
Dent Res 2001;80:177.
23. Almeida MA, Phillips C, Kula K, Tulloch C. Stability of the palatal
rugae as landmarks for analysis of dental casts. Angle Orthod
1995;65:43-8.
24. Brin I, Tulloch JF, Koroluk L, Philips C. External apical root resorp-
tion in Class II malocclusion: a retrospective review of 1- versus 2-
phase treatment. Am J Orthod Dentofacial Orthop 2003;124:151-6.
25. Dann C 4th, Phillips C, Broder HL, Tulloch JF. Self-concept,
Class II malocclusion, and early treatment. Angle Orthod
1995;65:411-6.
26. Ehmer U, Tulloch CJ, Proffit WR, Phillips C. An international com-
parison of early treatment of angle Class-II/1 cases. Skeletal effects
of the first phase of a prospective clinical trial. J Orofac Orthop
1999;60:392-408.
27. Koroluk LD, Tulloch JF, Phillips C. Incisor trauma and early treat-
ment for Class II Division 1 malocclusion. Am J Orthod Dentofacial
Orthop 2003;123:117-26.
28. Proffit WR, Tulloch JF. Preadolescent Class II problems: treat now
or wait? Am J Orthod Dentofacial Orthop 2002;121:560-2.
29. Tulloch JF. Early versus late treatment for Class II malocclusions
[abstract]. Eur J Orthod 1999;21:453.
30. Tulloch JF, Phillips C, Koch G, Proffit WR. The effect of early
intervention on skeletal pattern in Class II malocclusion: a ran-
domized clinical trial. Am J Orthod Dentofacial Orthop 1997;
111:391-400.
31. Tulloch JF, Phillips C, Proffit WR. Benefit of early Class II treat-
ment: progress report of a two-phase randomized clinical trial.
Am J Orthod Dentofacial Orthop 1998;113:62-72.
32. Tulloch JF, Proffit WR, Phillips C. Influences on the outcome of
early treatment for Class II malocclusion. Am J Orthod Dentofacial
Orthop 1997;111:533-42.
33. Tulloch JF, Proffit WR, Phillips C. Outcomes in a 2-phase random-
ized clinical trial of early Class II treatment. Am J Orthod Dentofa-
cial Orthop 2004;125:657-67.
34. Tulloch JF, Rogers L, Phillips C. Early results from a randomized
clinical trial of growth modification in Class II malocclusion [ab-
stract]. J Dent Res 1992;72:523.
35. O'Brien K, Macfarlane T, Wright J, Conboy F, Appelbe P, Birnie D,
et al. Early treatment for Class II malocclusion and perceived im-
provements in facial profile. Am J Orthod Dentofacial Orthop
2009;135:580-5.
36. O'Brien K, Wright J, Conboy F, Appelbe P, Davies L, Connolly I,
et al. Early treatment for Class II Division 1 malocclusion with
the Twin-block appliance: a multi-center, randomized, controlled
trial. Am J Orthod Dentofacial Orthop 2009;135:573-9.
37. O'Brien K, Wright J, Conboy F, Chadwick S, Connolly I, Cook P,
et al. Effectiveness of early orthodontic treatment with the
Twin-block appliance: a multicenter, randomized, controlled trial.
Part 2: psychosocial effects. Am J Orthod Dentofacial Orthop
2003;124:488-95.
38. O'Brien K, Wright J, Conboy F, Sanjie Y, Mandall N, Chadwick S,
et al. Effectiveness of early orthodontic treatment with the
Twin-block appliance: a multicenter, randomized, controlled trial.
Part 1: dental and skeletal effects. Am J Orthod Dentofacial Orthop
2003;124:234-43.
58 Thiruvenkatachari et al
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APPENDIX
SEARCH STRATEGY FOR MEDLINE (OVID)
1. exp Orthodontics/
2. (appliance$ adj5 (function$ or remova$ or
fix$)).mp.
3. (orthodontic$ and (brace$ or band$ or
wire$)).mp.
4. (orthodontic$ and (extract$ or remov$)).mp.
5. (orthodontic$ and (headgear$ or “head gear$”or
head-gear$)).mp.
6. (device$ adj5 (function$ or remova$ or fix$)).mp.
7. ((appliance$ or device$) adj5 (intraoral or “intra
oral”or intra-oral or extraoral or “extra oral”or ex-
tra-oral)).mp.
8. (activator adj appliance$).mp.
9. (Frankel or “twin$ block$”or FR-II).mp.
10. ((growth adj3 modif$) and (jaw$ or maxilla$ or
mandible$ or mandibular)).mp.
11. (two-phase and (treatment or therapy) and (ortho-
dontic$ or malocclusion$)).mp.
12. ((orthopedic$ or orthopaedic$) and (dental or or-
thodontic$ or facial)).mp.
13. or/1-12
14. Malocclusion, Angle Class II/
15. Retrognathism/
16. ((“class II”or “class 2”) adj3 malocclusion$).mp.
17. (posterior adj3 occlusion$).mp.
18. (distoclusion$ or disto-occlusion$ or distocclu-
sion$).mp.
19. retrognath$.mp.
20. (prominent adj3 upper adj3 teeth).mp.
21. (overjet$ or “over jet$”or over-jet$).mp.
22. or/14-21
23. 13 and 22
Thiruvenkatachari et al 59
American Journal of Orthodontics and Dentofacial Orthopedics July 2015 Vol 148 Issue 1