Original Article

The Effects of Early Preorthodontic Trainer Treatment onClass II, Division 1 Patients
Serdar Usumez, DDS, PhDa; Tancan Uysal, DDS, PhDb; Zafer Sari, DDS, PhDa;
Faruk Ayhan Basciftci, DDS, MSa; Ali Ihya Karaman, DDS, MS, PhDc;
Enis Guray, DDS, PhDd
Abstract: The aim of this study was to clarify the dentoskeletal treatment effects induced by a preorthodontic trainer appliance treatment on Class II, division 1 cases. Twenty patients (10 girls and 10 boys,
mean age 9.6 6 1.3 years) with a Class II, division 1 malocclusion were treated with preorthodontic trainer
appliances (Myofunctional Research Co., Queensland, Australia). The patients were instructed to use thetrainer every day for one hour and overnight while they slept. A control group of 20 patients (mean age
10.2 6 0.8 years) with untreated Class II, division 1 malocclusions was used to eliminate possible growtheffects. Lateral cephalograms were taken at the start and end of treatment. Final cephalograms were taken
13.1 6 1.8 months after trainer application, compared with a mean of 11.2 6 2.4 months later for thecontrol group. The mean and standard deviations for cephalometric measurements were analyzed by pairedsamples t-test and independent-samples t-tests. At the end of the study period, the trainer group subjects
showed significant changes including anterior rotation and sagittal growth of the mandible, increased SNB
and facial height, reduced ANB, increased lower incisor proclination, retroclination of upper incisors, andoverjet reduction. However, only total facial height increase, lower incisor proclination, and overjet reduction were significantly higher when compared with the changes observed in the control group. This study
demonstrates that the preorthodontic trainer application induces basically dentoalveolar changes that resultin significant reduction of overjet and can be used with appropriate patient selection. (Angle Orthod 2004;
74:605–609.)
Key Words: Myofunctional treatment; Preorthodontic trainer; Class II, division 1

INTRODUCTION

Excessive dental protrusion and excessive overjet arecharacteristics of these cases, particularly in connection
with thumb or lip sucking and tongue thrusting.8 McNamara9 claimed that the most frequent skeletal problem inClass II malocclusions in preadolescents is mandibular retrognathia. This suggests that an appliance with the demonstrated ability to stimulate significant mandibular growthwould be an important part of the clinician’s armamentarium. Animal studies have shown that appliances that position the mandible anteriorly can stimulate significant mandibular growth, primarily by an enhanced remodeling response at the condyle.10–13
Myofunctional appliances have been used for many
years. There is a definite place for these appliances in orthodontics today because they are simple and economical,
but the cases need to be carefully selected, and the operator
needs to be well trained in their use.
Class II, division 1 malocclusions may be treated effectively in actively growing patients with any type of functional appliance.13,14 The principal aims of dentofacial orthopedic treatment of skeletal Class II, division 1 malocclusions with an activator are to correct the dental arch

Much attention has been paid to the problem of controlling dentofacial growth interferences caused by abnormal
lip and tongue function in the mixed dentition period. Various appliances have been presented for the treatment of
this problem.1–7 The main purpose of these appliances has
been to eliminate oral dysfunction, establish muscular balance, and correct or diminish maxillary incisor protrusion.8aAssistant Professor, Department of Orthodontics, School of Dentistry, Selcuk University, Konya, Turkey.
bResearch Assistant, Department of Orthodontics, School of Dentistry, Selcuk University, Konya, Turkey.
c
Associate Professor and Head, Department of Orthodontics,
School of Dentistry, Selcuk University, Konya, Turkey.
d
Associate Professor, Department of Orthodontics, School of Dentistry, Selcuk University, Konya, Turkey.
Corresponding author: Tancan Uysal, DDS, Orthodontics, Selcuk
Universitesi Dis Hekimligi Fakultesi, Ortodonti A. D., Konya 42079,
Turkey(e-mail: tancanuysal@selcuk.edu.tr).

Accepted: October 2003. Submitted: September 2003.
q 2004 by The EH Angle Education and Research Foundation, Inc.
605

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606

USUMEZ, UYSAL, SARI, BASCIFTCI, KARAMAN, GURAYTABLE 1. Intra- and Intergroup Values and Their Comparisons for the Control and Test Groups. Skeletal and Dental Measurements of thePre- and Posttreatment and Pre- and Postcontrol Lateral Cephalograms
Trainer Group (n 5 20)
Pretreatment,
0 mo

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

SNA (8)
SNB (8)ANB (8)
Sn-GoGn (8)FH-MP (8)PP-MP (8)Gn-Go-Ar (8)Ar-S-N (8)Me-Go-S (8)OP-SN (8)MaxP Angle (8)Ramus height (mm)Corpus length (mm)N-Me (mm)S-Go (mm)Go-Ar (mm)Go-Me (mm)Co-Gn (mm)Co-A (mm)Go-PC (mm)U1-NA (mm)U1-NA (8)U1-SN (8)L1-NB (mm)
L1-NB (8)IMPA (8)Interincisal angle
Overjet (mm)Overbite (mm)Posttreatment,
13.1 6 1.8 mo

Mean

SD

Mean

SD

Mean

SD

P-Value
Paired-Samples
t-Test

79.51
73.80
5.71
35.81
26.97
27.56
127.50124.19115.06
21.25
4.62
57.06
64.69
111.69
70.78
42.25
63.75
103.69
85.69
50.56
3.78
24.56
104.00
5.04
27.69
95.94
122.81
6.83
2.12

2.81
1.83
1.58
5.32
4.93
5.99
6.45
6.19
5.50
3.40
2.33
4.31
4.39
5.24
4.73
3.86
5.67
5.91
5.02
5.54
2.18
6.97
6.81
2.23
4.24
6.25
9.12
1.65
2.73

79.64
75.12
4.52
34.28
25.44
26.41
127.18124.41114.00
20.00
4.09
58.06
65.69
114.37
72.75
43.12
65.31
106.56
86.88
50.81
3.31
22.62
100.38
6.06
30.44
99.56
123.13
3.16
1.94

3.34
2.55
2.03
5.44
5.54
6.12
6.67
6.52
6.16
4.35
1.88
2.86
4.11
5.10
4.95
3.34
4.80
5.25
4.15
5.54
2.85
6.38
6.56
2.38
5.33
7.34
7.83
1.67
2.12

0.13
1.31
21.19
21.50
21.53
21.16
20.31
0.22
21.06
21.25
20.53
1.00
1.00
2.69
1.97
0.91
1.56
2.88
1.19
0.25
20.50
21.97
23.63
0.99
2.75
3.63
0.31
23.75
20.22

1.02
1.35
1.18
1.76
2.35
2.28
3.11
3.65
5.99
2.11
2.08
3.22
2.39
2.06
2.15
2.22
3.39
4.53
3.85
4.06
1.76
6.05
5.19
1.64
3.89
3.86
6.37
1.60
1.76

NSa
.001**.001**.003**
.020*
NS
NS
NS
NS
.032*
NS
NS
NS
.000***.002**
NS
NS
.023*
NS
NS
NS
NS
.014*
.025*
.013*
.002**
NS.000***
NS

DifferenceNS, not significant.
* P , .05.
** P , .01.
*** P , .001.
arelationship and to improve the patient’s facial profile bypromoting favorable mandibular growth changes.13,15
Bergersen16 stated that excessive overjet ideally should
be corrected before full eruption of the permanent incisors
so that the lingual surfaces of the upper incisors will provide stops to prevent increases in overbite. However, two
mm of overjet should remain after correction to ensure that
continued mandibular growth does not lead to prognathism.16
Tulloch et al17 identified 50 studies conducted between
1980 and 1987 that reported the treatment of young patientswith Class II malocclusion. Because of the various inherent
limitations of the different investigations, they were unable
to determine whether orthodontic treatment significantly influenced the growth potential of Class II patients.
Woodside et al18 indicated that mandibular growth isachieved by changes in the mode of breathing and that passive maxillary expansion plus bite opening was achieved
Angle Orthodontist, Vol 74, No 5, 2004

by changes in tongue position. Linder-Aronson et al19
claimed that a child passing from oral to nasal breathing
increases the horizontal growth of the mandible and normalizes incisor position.
To initiate Class II orthopedic therapy at an earlier age
and to correct functional problems of soft tissues such as
lingual malposition, the centripetal thrust of the lips andcheeks, oral respiration, and bruxism need to be part of thegoal. With this aim, our attention was drawn to the preorthodontic trainer (Figure 1), a functional device usable inchildren from the age of four to 10 years. Quadrelli etal20–22 recommended this appliance to correct the interposition of lips between dental arches, atypical swallowing,
and the centripetal thrust of cheeks upon the dental arches;to discourage oral respiration; to avoid bruxism; and to favor the action of the external pterygoid and thus encourage
the active push of the mandible.
The trainer and similar appliances are claimed to en-

607

EFFECT OF PREORTHODONTIC TRAINER APPLIANCE
TABLE 1. Extended
Control Group (n 5 20)

P-ValueFirst Observation,
0 moSecond Observation,
11.2 6 2.4 mo

Difference

Mean

SD

Mean

SD

Mean

SD

Paired-Samples
t-Test

80.46
74.58
5.86
35.63
26.44
28.63
124.34128.36108.62
16.98
22.20
60.76
65.14
117.15
75.64
45.62
67.86
109.55
85.02
50.26
5.70
22.65
78.00
5.15
24.70
94.65
126.75
8.47
3.05

3.06
3.08
1.40
5.85
5.04
5.81
5.80
4.23
5.76
4.76
2.73
5.24
3.78
7.41
5.07
2.94
4.16
6.15
3.70
3.43
2.25
7.41
7.20
1.90
5.50
5.71
9.29
3.52
2.00

80.35
74.99
5.36
35.29
26.25
28.06
124.62127.84108.92
16.49
21.83
61.51
65.57
117.67
76.68
46.52
68.74
111.01
85.47
50.80
5.90
24.00
7.10
5.00
24.40
94.20
126.25
8.33
3.11

3.11
3.36
1.51
6.09
5.73
5.87
6.60
4.84
5.82
4.77
2.87
4.88
3.33
7.39
4.91
3.15
3.92
6.27
4.21
3.55
2.47
7.53
6.73
1.97
5.74
6.51
8.10
3.12
2.07

20.11
0.41
20.50
20.34
20.20
20.57
0.29
20.52
0.31
20.49
0.38
0.75
0.43
0.50
1.04
0.90
0.88
1.47
0.45
0.54
0.20
1.35
20.90
20.15
20.30
20.45
20.50
20.13
0.06

1.70
1.64
1.24
1.90
3.19
2.40
2.12
2.65
1.32
1.57
2.88
2.54
0.99
0.31
0.63
1.59
1.57
2.60
2.48
1.69
1.40
3.87
3.09
1.56
3.74
4.36
5.41
0.78
0.39

NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
.004**.000***
.020*
.022*
.021*
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS

courage transverse bone growth by acting as a ‘‘shield’’ forthe cheeks and bringing about muscular relaxation and protection of the teeth and articulations from bruxism, by virtue of the ‘‘bite effect.’’23,24 The trainer is claimed to correcta skeletal Class II by an active mandibular force. By distancing the lower lips from the dental alveolar arch, thetrainer is claimed to prevent a malposition of the tongueand lower lip during swallowing, thus solving the associated dental open bite. It is also reported to promote nasal
respiration.25
Therefore, this study cephalometrically evaluates theoverall changes that occur during treatment with a preorthodontic trainer appliance and compares these changes
with an untreated Class II, division 1 control group.
MATERIALS AND METHODS
The study included 40 children with skeletal Class II,
division 1 malocclusions. Ten male and 10 female patients,
treated between 2000 and 2002, were selected as the treatment group. The ANB angles of all patients were greaterthan four degrees, and their overjets were greater than 4.5

IndependentSamples
t-Test
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
.000***
NS
NS
NS
NS
NS
NS
NS
NS
NS
.040*
.023*
.006**
NS.000***
NS

mm. None of the children in the test or control group hada thumb-sucking habit. All were Caucasian, and their ages
ranged from 8.3 to 10.9 years (9.6 6 1.3 years). All weretreated exclusively with the preorthodontic trainer appliance(Myofunctional Research Co., Queensland, Australia). The
patients were instructed to use the trainer every day for one
hour and overnight while they slept.
The remaining samples formed the untreated control
group to eliminate possible growth effects. This group consisted of 10 boys and 10 girls, with similar Class II, division
1 malocclusions (ANB . 48, and an overjet greater than
five mm). All were Caucasian with ages ranging from 9.6
to 11.0 years (10.2 6 0.8 years). The subjects in the control
group were informed about orthodontic treatment but refused treatment.
Lateral cephalograms were taken at the start and end oftreatment. Final cephalograms were taken after 13.1 6 1.8
months of trainer application and 11.2 6 2.4 months ofgrowth in the control group. The radiographs were traced
and measured by two investigators (Dr Usumez and Dr
Uysal). The landmarks were located according to the definition provided by Basçiftçi et al.13
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USUMEZ, UYSAL, SARI, BASCIFTCI, KARAMAN, GURAY

control group using the Student’s t-test for unpaired samples. The mean difference of the study group was larger
than that of the control group for only facial height, N-Me(mm), (P . .001).
Pre- and posttreatment dental differences

FIGURE 1. The preorthodontic trainer appliance.

All statistical analyses were performed using the SPSS
software package (SPSS for Windows, version 10.0.1,
SPSS Inc, Chicago, Ill). The mean differences between the
pretreatment and posttreatment measurements and the firstand second observation period measurements for the control group were evaluated using the paired t-test. Student’s
t-test was applied for comparison of the groups.
Two weeks after the first measurements, 30 radiographs
were selected at random and retraced. A paired-samples ttest was applied to the first and second measurements. It
was found that the difference between the first and second
measurements of the 30 radiographs was insignificant. Correlation analysis applied to the same measurements showedthat the highest r value was 0.99 for the interincisal angle
and the lowest r value 0.91 for FH-MP.26
RESULTS
The data from skeletal and dental measurements of thepre- and posttreatment and pre- and postcontrol lateralcephalograms are summarized in Table 1.
Pre- and posttreatment skeletal differences
Preorthodontic trainer group. In group I, treatment was
associated with increases in the mean values for N-Me
(2.69 6 2.06) (P . .001), SNB (1.31 6 1.35), S-Go (1.97
6 2.15) (P . .01), and Co-Gn (2.88 6 4.53) (P . .05).
In group I, treatment also was associated with decreases in
ANB (21.19 6 1.18), SN-GoGn (21.50 6 1.76) (P .
.01), FH-MP (21.53 6 2.35), and OP-SN (21.25 6 2.11)(P . .05) (Table 1).
Control group. In the control group, the means increased
for S-Go (1.04 6 0.63) (P . .001), N-Me (0.50 6 0.31)(P . .01), Go-Ar (0.90 6 1.59), Go-Me (0.88 6 1.57),
and Go-Me (1.47 6 2.60) (P . .05) (Table 1).
Intergroup comparisons. The mean differences in the
study group were compared with the mean differences inAngle Orthodontist, Vol 74, No 5, 2004

Preorthodontic trainer group. In group I, treatment resulted in decreases in U1-SN (deg) (23.63 6 5.19) (P .
.05) and overjet (mm) (23.75 6 1.60) (P . .001). The
means increased with treatment for L1-NB (mm) (0.99 6
1.64), L1-NB (deg) (2.75 6 3.89) (P . .05), and IMPA
(3.63 6 3.86) (P . .01).
Control group. No statistically significant differenceswere observed between the first and second measurementsof the control group.
Intergroup comparisons. The mean differences were significantly decreased more in the study group than in thecontrol group for U1-SN (deg) and L1-NB (P . .05),
IMPA (P . .01), and overjet (mm) (P . .001) (Table 1).
DISCUSSION
This study of a sample of 40 children with Class II, division
1 malocclusion was designed to study the effect of treatment
with the preorthodontic trainer appliance. The observedchanges during treatment reflect the combined effects of treatment and individual growth. Ideally, a matched or at least
comparable control group should be included for identifying
the changes due to growth.13,14,27–29 Therefore, a control groupconsisting of longitudinal growth data for untreated Class II,
division 1 malocclusion subjects was used in this investigation
to eliminate possible differences in growth pattern.
It was decided to initiate Class II orthopedic therapy at an
earlier age to correct functional problems in the soft tissues
such as lingual malposition, the centripetal thrust of lips andcheeks, oral respiration, and bruxism. A functional device, thepreorthodontic trainer appliance (Figure 1), was used in thisstudy for this purpose. Quadrelli et al20–22 indicated that thetrainer appliance can be used for children four to 10 years old
and recommended it to correct the interposition of lips between dental arches, atypical swallowing, and centripetal
thrust of cheeks upon the dental arches; to discourage oral
respiration; to avoid bruxism; and to favor the action of theexternal pterygoids and thus encourage the active push of themandible.
For patients with a Class II malocclusion, the preorthodontic trainer appliance is constructed with the mandible in alightly protruded position, similar to the therapeutic position
used in activator treatment. For oral screen treatment, Graber30
indicated that the construction bite cannot be as protrusive asthat with an activator, and a screen is of value mainly in casesof mild Class II malocclusions. Similarly, we thought thatmyofunctional appliances might be a reliable alternative forsagittal activation of the mandible in the early mixed dentition
period. A review of the literature presents no information on

EFFECT OF PREORTHODONTIC TRAINER APPLIANCE

whether the preorthodontic trainer appliance can actually improve a Class II skeletal relationship. Although the use of
myofunctional appliances such as the oral screen in the primary and mixed dentitions are mentioned in the literature,8,31
only one study has been published concerning the specificalterations induced by these procedures in the early occlusal
developmental stages.22 One study has been published concerning the trainer appliances combined with the straight wire
system.32
At the end of the study period, the myofunctional trainergroup subjects showed anterior rotation and sagittal growth ofthe mandible, increases in SNB, facial height, and lower incisor proclination, reductions of ANB and overjet, and retroclination of upper incisors. However, only total facial heightincrease, lower incisor proclination, and overjet reduction
were statistically significantly different when compared withthe changes in the control group. This implies that the skeletal
changes were not significant enough to be distinguished fromnormal growth, and the reduction of overjet was mainly related to the lower incisor proclination. These results are inaccordance with the works of Tallgren et al8 and Owman-Moll
and Ingerval,31 who reported similar changes with the use ofanother type of myofunctional appliance (oral shields).
CONCLUSIONSAt the end of the study period, in the trainer group, only
the total facial height increase, lower incisor proclination, andoverjet reduction were significantly higher compared with thechanges observed in the control group. This study demonstrates that preorthodontic trainer application induces basicallydentoalveolar changes that result in a significant reduction of
overjet and can be used with appropriate patient selection.
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Angle Orthodontist, Vol 74, No 5, 2004