Download Are orthodontic distalizers reinforced with the temporary skeletal

SYSTEMATIC REVIEW
Are orthodontic distalizers reinforced with the
temporary skeletal anchorage devices effective?
Piotr Fudaleja and Joanna Antoszewskab
Nijmegen, The Netherlands, and Wroclaw, Poland
Introduction: Our objective was to perform a systematic review of studies pertaining to the distalization of
teeth with appliances reinforced with temporary skeletal anchorage devices. Methods: PubMed, Embase,
Cochrane Central Register of Controlled Trials, Web of Knowledge, Ovid, and Scopus were searched until
the second week of August 2010 to identify all articles reporting on the use of orthodontic implants or miniplates
in distalization of teeth. The quality of the relevant studies was ranked on an 11-point scale, from low to high
quality. Results: Twelve relevant articles were identified. The distal movement of the maxillary molars was
from 3.3 to 6.4 mm; the concomitant molar distal tipping was from 0.80 to 12.20 . The maxillary incisors remained stable during molar distalization. The assessment of study quality showed that 8 studies were of low
and 4 of medium quality. Conclusions: Molar distalizers reinforced with the temporary skeletal anchorage
devices seem to effectively move molars distally without unwanted mesial incisor tipping. Because of the lack
of high-quality studies, however, the findings of this study should be interpreted with caution. (Am J Orthod
Dentofacial Orthop 2011;139:722-9)
D
istalization of the molars has become a popular
nonextraction treatment alternative in some
patients with Class II malocclusions. There are numerous methods to move teeth distally; some techniques
require a patient’s active compliance, whereas others do
not. Because patients’ cooperation during orthodontic
treatment is frequently problematic, the appliances that
eliminate the need for compliance are usually deemed superior to those demanding cooperation. Although popular noncompliance appliances, such as the pendulum1
and the distal jet,2 are effective in distalizing molars, the
distalization process is associated with the concomitant
loss of anterior anchorage. Sfondrini et al3 critically evaluated various appliances used for molar distalization and
found that most noncompliant appliances were associated with mesial movement or tipping of the incisors,
a
Assistant professor, Department of Orthodontics and Oral Biology, Radboud
University Nijmegen Medical Centre, Nijmegen, The Netherlands; Assistant
professor, Department of Orthodontics, Palacky University, Olomouc, Czech
Republic.
b
Assisstant professor, Department of Dentofacial Orthopedics and Orthodontics, Wroclaw Medical University, Wroclaw, Poland.
The authors report no commercial, proprietary, or commercial interest in the
products of companies described in this article.
Reprint requests to: Piotr Fudalej, Department of Orthodontics and Craniofacial
Biology, Radboud University Nijmegen Medical Centre, 309 Dentistry, PO Box
9101, 6500 HB Nijmegen, The Netherlands; e-mail, [email protected].
Submitted, August 2010; revised, December 2010; accepted, January 2011.
0889-5406/$36.00
Copyright Ó 2011 by the American Association of Orthodontists.
doi:10.1016/j.ajodo.2011.01.019
722
synonymous with loss of anchorage. Similar conclusions
were made by Antonarakis and Kiliaridis,4 who systematically reviewed the effects of noncompliance tooth-borne
distalizers. They found that distalization of molars is related to unavoidable loss of anchorage, which was
observed as premolar mesial movement and incisor mesial
crown and tipping movements.
To reinforce anchorage and reduce unwanted movement of the incisors and premolars, a temporary skeletal anchorage device (TSAD) can be used. The TSAD is
defined as a device that is temporarily fixed in bone for
reinforcement of orthodontic anchorage.5 Because
a TSAD is stable, it provides absolute anchorage. To
date, many distalization appliance designs incorporating TSADs have been developed. They range from the
skeletal anchorage system (SAS) with miniplates placed
in the zygomatic region in the maxilla6 or retromolar
region of the mandible7 to appliances supported by
a single orthodontic implant in the anterior palate.8 Although the current studies suggest that these appliances might be effective in moving molars distally, an
in-depth analysis is needed to investigate also other aspects of distalization, such as a rate and duration of
molar movement. Therefore, the objectives of this systematic review were to evaluate the effectiveness of the
distalization of molars with distalizers supported with
TSADs and to compare the effectiveness of TSADreinforced distalizers with tooth-borne noncompliance
distalization appliances.
Fudalej and Antoszewska
MATERIAL AND METHODS
PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Knowledge, Ovid, and Scopus were
searched until the second week of August of 2010 to
identify all articles reporting on the use of TSADs in distalization of molars. The search strategy used in this
review is shown in Table I.
Based on the data from titles and abstracts of the
retrieved studies, both authors independently selected
articles that met the following inclusion criteria.
1.
2.
3.
4.
Studies on human subjects, published in English.
Studies that included clear descriptions of the distalization appliance and the technique.
Prospective or retrospective original studies (case
reports and review and summary articles were
excluded).
Studies with minimum 10 subjects in the sample.
The reference lists of these articles were perused, and
references related to the articles were followed up. If
there was disagreement between the authors, inclusion
of the study was confirmed by mutual agreement.
From the identified articles, the authors independently extracted data referring to year of publication,
type of study, sample size, site of implant or miniplate
placement, type of distalizing appliance, magnitude of
force exerted on the teeth, duration of treatment, age
at the start of treatment, presence of second molars, calculation of the method error, amounts of molar retraction and tipping, and changes of the position of the
central incisors (Table II).
According to the Centre for Reviews and Dissemination, evaluation of methodologic quality gives an indication of the strength of evidence provided by the study
because flaws in the design or conduct of a study can result in bias.9 However, no single approach for assessing
methodologic soundness is appropriate to all systematic
reviews. The best approach should be determined by
contextual, pragmatic, and methodologic considerations. Therefore, quality assessment performed independently by the authors comprised evaluation of the
selection process (including information about whether
the sample consisted of consecutively treated patients),
sample size estimation, adequacy of outcome measures,
adequacy of method error estimation, and adequacy of
statistical analysis (Table III). If there was disagreement
between the authors, consensus was reached after discussion. The quality of the studies was ranked on an
11-point scale and assessed accordingly: high, with a total score of 11 points; medium high, with a total score 9
or 10 points; medium, with a total score 7 or 8 points;
and low, with a total score below 7 points.
723
Table I. Search strategy
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
orthodontic*
micro-implant* OR microimplant* OR “micro implant*”
mini-implant* OR “mini implant*”
“orthodontic implant*”
“mini-plate*” OR “mini plate*”
“palatal implant*” OR “midpalatal implant*”
“buccal implant*”
miniscrew* OR mini-screw* OR “mini screw*”
microscrew* OR micro-screw* OR “micro screw*”
2 OR 3 OR 4 OR 5 OR 6 OR 7 OR 8 OR 9
1 AND 10
Statistical analysis
A meta-analysis of the results of the studies that used
comparable techniques of distalization was planned
with the aid of the RevMan software (version 5.0, The
Nordic Cochrane Centre, Copenhagen, Denmark).10 Heterogeneity of the studies was assessed first by calculating
the I2 index.11 According to the recommendation of
the Cochrane Collaboration, if heterogeneity is high
(I2, .75%), a meta-analysis might produce misleading
results, and omitting it from a systematic review
should be considered.10
RESULTS
The search of PubMed yielded 357 publications;
Embase, 272; Cochrane Central, 45; ISI Web of Knowledge, 802; Ovid, 919; and the Scopus, 518; there was
overlap among the databases. Application of the inclusion and exclusion criteria and follow-up on the referred
studies allowed identification of 12 relevant publications
(Fig, Table II).
Heterogenity of the results of the investigation
with a similar technique of distalization was high
(.85%).8,12-18 A meta-analysis was not performed for
this reason.
In total, 223 subjects (78 male, 145 female) were examined. However, 2 studies most likely evaluated the
outcome in the same samples.8,12 The mean age at the
start of molar distalization in the evaluated samples
ranged from 13 years13 to 27.3 years.19 Overall, in 6
studies, the samples comprised teenagers; in 3 studies,
adults; and in 1 study, the sample included teenagers
g et al16 did not report on the mean
and adults.20 Onça
age at the start of treatment, and Gelg€
or et al8 gave
only the age range at the start of distalization.
In 6 studies (153 subjects), an area adjacent to the
median suture in the anterior region of the hard palate
was chosen as the site for placement of the orthodontic
implant; the anchorage devices were also placed in the
infrazygomatic crest region (2 studies, 42 subjects) and
the anterior margin of the mandibular ramus (1 study,
American Journal of Orthodontics and Dentofacial Orthopedics
June 2011 Vol 139 Issue 6
Fudalej and Antoszewska
724
Table II. Characteristics of the samples, distalization techniques, and outcomes in the included studies.
Study
Type of
study;
consecutive
patients (Y, N);
control group
(Y, N)
Sample
size
Age at
start
of
treatment
in years
(SD)
Site of
placement
of the TSAD
TSAD
diameter,
length
Osseointegration
(Y or N)
Distalization
appliance
Elastics attached
to maxillary
fixed appliance
Modified
pendulum
appliance
Transpalatal bar
between
premolars
supported by
implant and
nickel-titanium
open coil between
premolar
and molar on the
buccal side
Transpalatal bar
between
premolars
supported by
implant and
nickel-titanium
open coil
between premolar
and molar
on the buccal side
Appliance
consisting
of acrylic
palatal button
attached to
implant,
premolar rests,
and nickeltitanium
open coils on the
lingual side
Distal jet
Magnitude
of force
150 g
27.3 (NR)
Infrazygomatic crest
Miniplate
N
13 (2.1)
Anterior palate
2 implants:
2.0 mm,
11 mm
1.8 mm,
14 mm
N
Anterior palate
1.8 mm,
14 mm
N
20 (11 girls, NR (NR);
9 boys)
range,
12.315.4
Anterior palate
1.8 mm,
14 mm
N
Retrospective;
N; N
10 (8 girls,
2 boys)
12.1 (NR)
Anterior palate
1.6 mm,
8-9 mm
N
Prospective;
NR; N
10 (9 girls,
1 boy)
13.5 (1.8)
Anterior palate
2.0 mm,
8 mm
N
Pendulum
appliance
NR
Prospective;
NR; N
16 (4 girls, 14.3 (NR)
12 boys)
Anterior palate
N
Dual–force
distalizer
250-300 g
Oncag
et al,
200716
Retrospective;
Y; Y
15 (9 girls,
6 boys)
NR (NR)
Anterior palate
2 implants:
2.0 mm,
11 mm
3.8 mm;
9 mm
Y
300 g
Park et al,
200520
Retrospective;
Y; N
13 (8 girls,
5 boys)
17.9 (5.7)
Polat-Ozsoy
et al,
200818
Retrospective;
N; Y
22 (15 girls, 13.6 (2.0)
7 boys)
various
9 patients: Mn implants
distal to second molars
or in retromolar area; 2
patients: Mx implants in
buccal alveolar bone
between second
premolars and first
molars; 2 patients: both
Mn and Mx implants
Anterior palate
2.0 mm, 8 mm
Pendulum springs
made of beta
nickel-titanium
wire
Nickel-titanium
coils and
elastomeric
thread
Pendulum appliance
230 g
Cornelis and Retrospective;
De Clerck,
Y; N
200719
Escobar
Retrospective;
et al,
Y; N
200713
Gelg€
or et al, Prospective;
200412
NR; N
17 (15
female,
2 male)
15 (6 girls,
9 boys)
25 (18 girls, 13.8 (NR)
7 boys)
Anterior palate
Gelg€
or et al,
20078*
Retrospective;
N; Y
20 (8 girls, NR (NR);
12 boys)
range,
11.615.1
Gelg€
or et al,
20078y
Retrospective;
N; Y
Kinzinger
et al,
200914
Kircelli
et al,
200615
Oberti et al,
200917
June 2011 Vol 139 Issue 6
N
NR
N
250 g
250 g
250 g
250 g
200 g
200 g
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725
Table II. Continued
Type of
study;
consecutive
patients (Y, N);
control group
Sample
Study
(Y, N)
size
Retrospective;
15 (12
Sugawara
N; N
female, 3
et al, 20047
male)
Sugawara
Retrospective;
25 (22
et al.,
N; N
female, 3
20066
male)
Age at start
of
treatment
Site of
in years
placement
(SD)
of the TSAD
26.9 (NR) Anterior margin
of mandibular
ramus
23.9 (NR) Infrazygomatic
crest
Treatment
duration
in months (SD)
7.0 (2.0)
Presence of
second molars
100%
7.8 (NR)
NR
4.6 (NR)
88%
4.6 (NR)
90%
Gelg€
or et al,
20078y
5.4 (NR)
85%
Kinzinger et al,
200914
6.7 (NR)
Study
Cornelis and
De Clerck,
200719
Escobar et al,
200713
Gelg€
or et al,
200412
Gelg€
or et al,
20078*
Kircelli et al,
200615
7 (1.8)
Oberti et al,
200917
5 (NR)
Oncag et al,
200716
Park et al, 200520
6.2 (NR)
12.3 (5.7)
TSAD
diameter,
length
Titanium
plates
Osseointegration
(Y or N)
N
Distalization
appliance
SAS
Magnitude
of force
NR
N
SAS
NR
Amount
of molar
distal
movement/
tipping (mm/ )
3.3/1.8
Monthly
rate of molar
movement
(mm)
0.5
Amount of
central incisor
mesial movement/
tipping (mm/ );
negative value for
distal movement/
tipping
1.4/NR
Success
rate
100%
6.0/11.2
0.8
–0.5/–2.5
Unclear
3.9/8.8
0.8
0.5/1.0
NR
4.0/9.1
0.7
–0.5/–1.1
NR
3.9/0.8
0.7
–0.1/–0.1
NR
3.8/3.0
0.6
–0.4/–0.6
NR
6.4/10.9
0.9
–0.2/–0.6
NR
5.9/5.6
1.2
–0.5/–0.8
NR
4.0/12.2
0.6
Mn first
molars, 2.9/5
4.8/9.1
*
Titanium
plates
Method
error
N
Intraclass
correlation
coefficient
Dahlberg’s
method
Dahlberg’s
method 1
correlational
analysis
Dahlberg’s
method 1
correlational
analysis
N
20% fully
erupted,
25% erupting
NR
Spearman
correlation
coefficient
between
repeated
measurements
Intraclass
Unerupted
correlation
or just
coefficient
recently
erupted
NR
ANOVA test
Mostly
present
13.6%
Paired t test
Polat-Ozsoy
et al, 200818
6.8 (1.7)
Sugawara
et al, 20047
28.9 (NR)
100%
Spearman
correlation
coefficient
between repeated
measurements
Unclear
Sugawara
et al, 20066
19 (NR)
100%
Unclear
3.5/NR;
tipping ratio,
46.3%
3.8 mm crown,
3.2 mm root
0.7
Right side, 0.1/1.0
Left side, –2/–0.6
Mn central
incisors, NR
–0.1/–1.7
NR
0.1
NR
NR
0.2
NR
NR
90%
Unclear
Y, yes; N, no; NR, not reported; Mn, mandibular; Mx, maxillary.
or et al.8
*Group 1 evaluated by Gelg€
or et al8; ygroup 2 evaluated by Gelg€
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726
Table III. Assessment of the study quality
Study
Points
Cornelis and
De Clerck,
200719
Escobar et al,
200713
Gelg€
or et al,
200412
Gelg€
or et al,
20078
Kinzinger
et al,
200914
Kircelli et al,
200615
Oberti et al,
200917
Oncag et al,
200716
Park et al,
200520
Polat-Ozsoy
et al,
200818
Sugawara
et al,
20047
Sugawara
et al,
20066
A.
Description of
B.
C.
D.
selection
Prospective or Consecutive Sample
process
retrospective
cases
size
0, 1, or 2
0 or 2
0 or 1
0 or 1
2
0
1
0
E.
Choice of
outcome
measure
0, 1, or 2
1
F.
Adequacy of
method error
analysis
0, 1, or 2
0
G.
Adequacy of
statistical
analysis
0 or 1
1
Quality
score
Judged
quality
standard
5
Low
1
0
1
0
2
1
1
6
Low
1
2
1
1
2
1
0
8
Medium
1
0
0
1
2
1
1
6
Low
0
0
0
0
2
0
1
3
Low
1
2
1
0
2
0
1
7
Medium
2
2
0
0
2
1
1
8
Medium
1
0
0
0
2
1
1
5
Low
2
0
1
0
2
1
1
7
Medium
1
0
0
1
2
0
1
5
Low
2
0
0
0
1
0
0
3
Low
2
0
0
1
1
0
0
4
Low
Description of quality score assignment:
A: 0, if inadequate description; 1, if some details of sample selection missing; 2, if in-depth description of sample selection.
B: 0, if retrospective; 2, if prospective.
C: 0, if sample comprised unconsecutive patients or no information regarding this was included; 1, if sample comprised consecutive patients.
D: 0, if \20 subjects; 1, if $20 subjects.
E: 0, if inadequate outcome measure; 1, if partially adequate outcome measure; 2, if adequate outcome measure.
F: 0, if method error not evaluated; 1, if partially adequate method error analysis; 2, if adequate method error.
G: 0, if inadequate; 1, if adequate.
15 subjects). The pendulum appliance was used most
frequently to distalize the molars. In subjects in whom
miniplates were placed, elastomeric power chains
attached to the fixed orthodontic appliance were used.
The duration of treatment ranged from 4.6 to 28.9
months. However, in most studies, distalization of molars did not last more than 8 months. In the studies
that reported treatment time exceeding 8 months, enmasse retraction of the whole dentition was carried out.
The mean distal movement (Table II) of the maxillary
molars ranged from 3.5 to 6.4 mm. Concomitant distal
tipping ranged from 0.80 to 12.20 (Table II). The position of the central incisors was largely stable; only Cornelis
and De Clerck19 found a statistically significant retraction
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by 1.4 mm (P \0.05), and Oberti et al17 detected 0.5 mm
of retraction of the central incisors (P \0.05).
The assessment of the quality showed that 8 studies
were of low quality, and 4 studies demonstrated medium
quality. In general, the methodologic soundness of the
studies was compromised by retrospective designs without inclusion of consecutively treated patients, inadequate sample sizes, and lack of analysis of method errors.
DISCUSSION
In this study, we aimed to review articles that had
evaluated the effectiveness of orthodontic distalizers reinforced with TSADs. A systematic review seemed the
most appropriate, because its methodology makes
American Journal of Orthodontics and Dentofacial Orthopedics
Fudalej and Antoszewska
727
QUOROM Flow Diagram
Manual search; relevant
articles
(n = 3)
Potentially relevant articles
after search of the electronic
databases
(n = 1215)
Excluded articles, nonEnglish (n= 85)
Articles retrieved for more
detailed evaluation (n = 1130)
Articles retrieved for more
detailed evaluation (n = 888)
Included articles (n = 9)
Excluded articles, nonhuman studies, reviews
(n= 242)
Excluded articles, not
relevant to the subject of
the present study, case
reports, description of
technique, < 10 subjects
in sample (n = 879)
Total number of included
articles (n = 12)
Fig. Flowchart illustrating the selection of relevant articles.
possible identification, appraisal, and synthesis of most
available evidence. Depending on the quality of the included studies, a systematic review can provide various
levels of scientific evidence ranging from the highest,
if only randomized clinical trials are included, to the lowest, if only retrospective investigations are reviewed.21 In
the latter case, a systematic review summarizes what is
already known, indicates the weaknesses of the studies,
and highlights the areas requiring further research.
This systematic review included only nonrandomized
prospective and retrospective studies. The methodologies of these investigations were generally of low and
medium quality (Table III). Consequentially, our findings
should be interpreted with caution, and conclusions that
can be drawn from them are necessarily tentative.
These results suggest that the TSADs used as anchors
supporting distalizing appliances reduce the unwanted
side effects of tooth-borne appliances. Antonarakis
and Kiliaridis4 found in their systematic review that
tooth-borne distalizers could move maxillary molars distally on average 2.9 mm; however, the associated undesirable incisor mesial movement was 1.8 mm. Our
findings indicate that reinforcement of anchorage with
orthodontic implants or miniplates increased the
amount of molar distalization. The distal movements of
the maxillary molars in the studies with comparable distalization techniques were from 3.9 to 6.4 mm.8,12-18 At
the same time, the maxillary incisors remained stable.
This implies better outcomes produced by TSADreinforced distalization devices than by tooth-borne
appliances.
A distal movement of the molars is the effect of
bodily tooth movement and tipping, which is usually
not desired clinically. The findings of the studies that
used similar techniques of distalization showed that
the distalization of molars was associated with 3.0 to
12.20 of distal tipping.8,12-18 Only Gelg€or et al8 found
minimal molar tipping (0.80 ) in 1 of their 2 study
groups. This was also found by Antonarakis and Kiliaridis,4 who reported 5.40 of molar distal tipping after the
use of tooth-borne distalizing appliances. The greater
molar distal tipping observed in patients with the TSADs
might have resulted from excessive pressure exerted on
the molars by the distalizers. Assuming that the force
values generated by the tooth-borne and TSADssupported appliances were comparable, less pressure
was applied to the molars in subjects with the toothborne appliances than in those with the TSADs because,
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Fudalej and Antoszewska
728
in the former group, the force was dissipated also in the
anterior direction, causing mesial movement or tipping
of the maxillary incisors. In subjects with TSADs, this
was not possible because of the stability of the implants.
Nonintegrated TSADs placed in the paramedian region of the anterior palate were used to reinforce distalization appliances in most studies in this review. In
comparison with osseointegrated TSADs, nonintegrated
TSADs offer several advantages to the clinician, such as
immediate loading, simpler surgery, lower cost, and less
discomfort to the patient. Our results suggest that nonintegrated TSADs were successful in anchorage reinforcement during distalization. However, few data
regarding failure rates limit the strength of this conclusion. Only the authors of 2 studies showed the proportions of successfully and unsuccessfully treated
patients.13,18 Escobar et al13 reported that the treatment
of 2 patients was unsuccessful (success rate, 87%) because of tissue inflammation and failure of the screw.
They, however, used a modified pendulum appliance attached to the palate with 2 screws. It is unclear whether
all TSADs in the remaining subjects were stable. PolatOzsoy et al18 reported the lack of stability of 4 TSADs
in 3 subjects. Because most patients wore distalization
appliances supported by 2 TSADs, instability of the
TSADs was noticed during accidental damage of the distalizing spring or at the appliance removal. Although the
clinical success rate in the study by Polat-Ozsoy et al was
100%, it is difficult to generalize these data because
other investigators used distalization appliances supported by a single palatal implant. It is possible, then,
that loosening of the implant in such cases could lead
to clinical failure. Therefore, conclusions regarding the
effectiveness of the nonintegrated TSADs can be made
only after more data concerning rates of successful
and unsuccessful outcomes are obtained.
The rates of molar distalization achieved with different devices, calculated as millimeters of molar distal
movement per month, can be an important factor for
a clinician during selection of the distalization appliance. The results of this review showed that the mean
distal movement of the maxillary molars was 0.7 mm
(SD, 0.3 mm) per month (range, 0.2-1.2 mm). The slowest rate was observed for the SAS system described
by Sugawara et al6; a similar technique was used by
Cornelis and De Clerck,19 and the fastest was when the
dual-force distalizer was used.17 The slowest distalization rate found for the SAS was most likely because
the whole maxillary dentition was distalized simultaneously, since the distal force was applied to the fixed
appliances worn by the patient. Conversely, the fastest
rate of distalization was achieved when the force was
applied to the molars only. The use of the dual-force
June 2011 Vol 139 Issue 6
distalizer allowed obtaining the highest rate of molar
distal movement from 2 force systems: 1 from the palatal
and 1 from the buccal side, exerting pressure on the molars. The difference in the rate of distalization, however,
might be clinically meaningless because distalization is
usually followed by a phase of comprehensive treatment,
which can cancel the effects of rapid distalization.
Therefore, it is possible that a comparable overall treatment outcome can be achieved faster with the SAS rather
than with the dual-force distalizer.
Erupted second maxillary molars might affect the
rate of distalization. According to Kinzinger et al22 and
Karlsson and Bondemark,23 efficiency of distalization
is greater if it is started before the eruption of the second
molars. The results of this study, however, do not support this claim unambiguously. Although the greatest
monthly distal movement of maxillary first molars was
noted in the patients treated with the dual-force distalizer whose maxillary second molars were unerupted or
just recently erupted, other groups differing in the number of erupted second molars showed comparable rates
of distalization.17 For example, in the samples investigated by Gelg€
or et al8,12 and Polat-Ozsoy et al,18 the
maxillary first molars were moved distally by 0.7 to 0.8
mm per month despite considerable differences in the
percentages of erupted second molars. In the groups examined by Gelg€
or et al,8,12 approximately 90% of the
second molars were erupted, whereas in the sample of
Polat-Ozsoy et al18 only 13.6% of second molars were
present. These findings suggest that presence or absence
of second molars might play a smaller role when implant- or miniplate-supported distalization appliances
are used.
The molars are usually distalized early during orthodontic therapy, and it is followed by other stages of comprehensive treatment. The position of the molars or the
inclination of the incisors achieved during distalization
might be affected during later stages of treatment.
Therefore, 2 important issues should be considered before
making conclusions regarding the effectiveness of TSADsupported distalizers. First, are the end-of-treatment
outcomes with TSADs better than those obtained with alternative tooth-borne anchorage? Second, are outcomes
with TSADs more stable than conventional methods? Unfortunately, no studies included in our review addressed
these questions. All of them were focused on the shortterm effects of distalization. The lack of long-term evaluations necessarily weakened the conclusions.
CONCLUSIONS
On the basis of this systematic review, the following
can be concluded.
American Journal of Orthodontics and Dentofacial Orthopedics
Fudalej and Antoszewska
1.
2.
3.
Orthodontic distalizers reinforced with the TSADs
seem to be effective in molar distalization. They
also appear to produce fewer unwanted side effects.
The methodologic soundness of the reviewed studies was relatively low.
The long-term effectiveness of TSAD-reinforced
molar distalization should be studied.
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American Journal of Orthodontics and Dentofacial Orthopedics
June 2011 Vol 139 Issue 6