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Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001 International Orthodontics 2020; //: ///
Original Article
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Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study Fernanda Pinelli Henriques Fontes, Silvio Augusto Bellini-Pereira, Aron Aliaga-Del-Castillo, Mayara Paim Patel, Marcos Roberto de Freitas, José Fernando Castanha Henriques, Guilherme Janson
Available online:
University of São Paulo, Bauru Dental School, Department of Orthodontics, Brazil
Correspondence: Fernanda Pinelli Henriques Fontes, University of São Paulo, Bauru Dental School, Department of Orthodontics, Alameda Octávio Pinheiro Brisolla 9-75, 1,7012-901 Bauru, São Paulo, Brazil. [email protected]
Keywords Malocclusion Angle Class II Extraoral Traction Appliances Orthodontics Corrective Cephalometry
Summary Objective > To retrospectively compare the dentoskeletal and soft tissue changes of patients with Class II malocclusion treated with cervical headgear and Jones Jig appliances, followed by fixed appliances. Material and methods > The sample comprised 46 Class II malocclusion patients divided into two groups. Patients with Class II malocclusion based on the ANB angle and plaster model analyses, needing non-extraction orthodontic treatment, absence of mandibular crowding and no previous orthodontic treatment were eligible to be selected. Group 1 consisted of 25 patients treated with cervical headgear (CH) followed by fixed appliances for a mean period of 3.26 years and group 2 consisted of 21 patients treated with the Jones Jig (JJ) appliance for a mean of 4.29 years. Lateral cephalograms were evaluated at the beginning and at the end of orthodontic treatment. For intergroup comparisons, t and Mann-Whitney tests were performed. Results > The cervical headgear group produced significantly greater maxillary anterior displacement restriction (SNA; CH: 0.978 1.33; JJ: 0.078 1.73; P = 0.025), apical base discrepancy improvement (ANB; CH: 1.528 1.25; JJ: 0.368 1.46; P = 0.006), FMA reduction (CH: 0.788 2.68; JJ: 1.078 2.84; P = 0.028) and distal mandibular molar angulation (Md6.PM; CH: 6.978 3.66; JJ: 2.778 6.87; P = 0.013) than the Jones Jig group. Conclusions > Both distalizers followed by fixed appliances were effective to correct Class II malocclusion. The cervical headgear group presented skeletal effects with less treatment time and there were no significant intergroup differences regarding soft tissue changes.
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ORTHO-468
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
Introduction Class II malocclusion is an anteroposterior discrepancy characterized not as a single clinical entity, but a result of dentoalveolar or skeletal components, or even the combination of both, of which mandibular retrusion is commonly observed [1]. There is a high prevalence of Class II malocclusion in the population, and due to the strong aesthetic impact on the face, depending on its severity, it is evident that a significant percentage of patients seek orthodontic treatment [2,3]. Non-extraction treatment for Class II malocclusion correction often requires distal movement of the maxillary molars through external force with cervical headgear appliance (CH) or intraoral force via distalizers, since these patients usually present a dentoalveolar compensation and/or maxillary protrusion [4]. The CH gained widespread acceptance as an effective treatment for Class II malocclusions, partly due to the dental changes in the sagittal and vertical plane provided and its important capacity to modify maxillary growth [5]. Despite its effects, the dependence on patient compliance is currently causing a decrease in the use of CH, associated with the development of efficient intraoral distalizing appliances with conventional [6–9] and skeletal anchorage [10–12]. However, the CH is still useful for specific Class II malocclusions, when maxillary protrusion is diagnosed. Intraoral distalizers correct Class II malocclusion without depending entirely on the patient. The Jones Jig (JJ) is an intraoral distalizing appliance with nitinol (NiTi) open coil springs; it exerts a force to the maxillary molars promoting their
distalization [13,14]. The appliance active unit is characterized by the NiTi coil springs applying a force from the buccal side of the molars. Therefore, in order to counteract the distalization force, the distalizer is anchored in the second premolars with a Nance button. Even though distalization is effective and anchorage is used, some minor undesirable effects such as the mesial displacement of premolars and the molars distal angulation have been demonstrated [13,15]. Thus, the purpose of this retrospective study was to compare the cephalometric changes of patients with Class II malocclusion treated with the cervical headgear and Jones Jig appliances, followed by fixed appliances.
Materials and methods This study was approved by the ethics in research committee of Bauru Dental School, University of São Paulo, Brazil. The sample size was calculated based on an alpha significance level of 5% and a beta of 20% to detect a mean difference of 1.40 mm with a standard deviation of 1.56 mm in maxillary molar anteroposterior position (Mx6-PTV) [4]. A minimum of 21 patients were required in each group based on the sample size calculation. In view of this, the sample comprised 46 patients (19 males, 27 female), treated at the Department of Orthodontics, Bauru Dental School, University of São Paulo, Brazil. The eligibility criteria were based on the following characteristics: 1) Presence of Class II malocclusion evaluated on the cephalometric analysis by the ANB angle and plaster models analysis regarding the Angle classification;
Figure 1
2
Flow chart regarding the sample collection
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To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
2) Patients needing non-extraction orthodontic treatment; 3) No severe mandibular crowding; 4) A history of acceptable oral hygiene and no damage to the appliance; 5) No previous orthodontic treatment. Sample selection is explained in the flowchart (figure 1). Group 1 consisted of 25 patients (8 males, 17 females) with a mean initial age of 13.00 years (SD, 1.30 years), treated with the cervical headgear (figure 2). The mean treatment time was 3.26 years (SD, 0.67 years). Group 2 comprised 21 patients (11 males, 10 females) with a mean initial age of 12.88 years (SD, 1.23 years), treated with the Jones Jig appliance (figure 3). The original stainless-steel coil
spring was changed to a NiTi coil spring (G&H Wire Co, Greenwood, Ind.) to exert continuous force. The mean treatment time was 4.29 years (SD, 0.76 years). In both groups, the appliances were used until the maxillary first molars were distalized to an overcorrected Class I relationship. Subsequently, pre-adjusted edgewise orthodontic appliances were placed to initiate levelling and aligning until 0.019 0.025-inch rectangular stainless-steel archwires were placed. At this stage, retraction of the premolars and anterior teeth was performed with elastic chains associated with Class II elastics, used 12 h/day, releasing an average force of 130 g/side. During the retraction stage, anchorage reinforcement was achieved with the CH with the outer bows tilted 158 to
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
Figure 2
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Treatment with the cervical headgear appliance: Cervical headgear appliance; maxillary molar distalization and final results
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
Figure 3 Treatment with the Jones Jig appliance: Jones Jig appliance; maxillary molar distalization and final results
208 upward from the occlusal plane to upright the distalized first molars [6,16]. After removal of the fixed appliances, a maxillary Hawley plate and a mandibular canine-to-canine bonded retainer were installed. The Hawley retainer was recommended to be used full-time for 6 months, followed by night-only use for an additional 6 months. The canine-to-canine bonded retainer was recommended to be used for 3 years.
Cephalometric analysis
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Pre-treatment (T1) and posttreatment (T2) cephalometric radiographs were taken for each patient. The radiographs
were traced, and landmark identifications were made on acetate paper by one investigator (F.P.H.F.) in a darkened room. The cephalometric landmarks off all traced radiographs were digitized and transferred to Dentofacial Planner 7.02 software (Dentofacial Planner Software Inc., Toronto, Ontario, Canada) which performed the cephalometric measurements. The cephalometric variables are described in table I and illustrated in figures 4, 5. The software corrected the magnification factor of the radiographic images that were between 6% and 9.8%. Treatment changes were calculated as T2-T1.
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To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
TABLE I Cephalometric measurements. SNA (8)
Angle formed by the intersection of SN line and NA line
SNB (8)
Angle formed by the intersection of SN line and NB line
ANB (8)
Angle formed by the intersection of NA line and NB line
FMA (8)
Angle formed by the intersection of Frankfurt plane and Go-Me
ANS-Me (mm)
Angle formed by the intersection of SN line and Go-Gn Linear measurement from anterior nasal spine to menton (Lower anterior face height)
Mx1.PP (8)
Angle formed by the maxillary incisor long axis and the palatal plane (ANS-PNS)
Mx1-PTV (mm)
Linear distance from the tip of the maxillary central incisor perpendicular to PTV
Mx6.PP (8) Mx6-PTV (mm) IMPA (8) Md1-PTV (mm) Md6.PM (8)
Angle formed by the maxillary molar long axis and the palatal plane Linear distance from the mesiovestibular cusp of the maxillary first molar perpendicular to PTV Angle formed by the mandibular incisor long axis and the mandibular plane (Go-Me) Linear distance from the tip of the mandibular central incisor perpendicular to PTV Angle formed by the mandibular molar long axis and the mandibular plane
Md6-PTV (mm)
Linear distance from the mesiovestibular cusp of the mandibular first molar perpendicular to PTV
Overbite (mm)
Linear vertical distance from the incisal of maxillary central incisor to incisal of the mandibular central incisor
Overjet (mm)
Linear horizontal distance from the incisal of maxillary central incisor to incisal of the mandibular central incisor
UL-Sn.Pg'
Linear distance from Upper Lip point to SnPg' line
LL-Sn.Pg'
Linear distance from Lower Lip point to SnPg' line
Error Study Two weeks after the first measurements, 28 randomly selected cephalometric radiographs were retraced and measured by the same investigator (F.P.H.F.). The random errors were estimated according to Dahlberg's formula [17], while the systematic errors were calculated with dependent t tests at P < 0.05 [18].
Statistical Analysis To evaluate the presence of normal distribution of the variables, Shapiro Wilk tests were performed in both groups and treatment stages for all variables.
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Intergroup comparability regarding sex and Class II molar relationship severity distributions were evaluated with Chi-square tests. Pre-treatment age and treatment time intergroup comparability were analysed with t tests. Intergroup initial cephalometric status and treatment changes were compared with t tests for the variables with normal distribution and with Mann Whitney tests for those without normal distribution. All the analyses were carried out using Statistica for Windows 7.0 (Copyright Stat Soft, Inc. Tulsa, Okla, USA 2001), with the level of significance set at P < 0.05.
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SN.GoGn (8)
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
Figure 4
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Skeletal and soft tissue cephalometric variables: (A) SNA; (B) SNB; (C) ANB; (D) FMA; (E) SN.GoGn; (F) ANS-Me; (G) UL-Sn.Pg'; (H) LL-Sn. Pg'
tome xx > 000 > xx 2020
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
Figure 5
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Dental Variables: (I) Mx1.PP; (J) Mx1-PTV; (K) Mx6.PP; (L) Mx6-PTV;(M) IMPA; (N) Md1-PTV; (O) Md6.PM; (P) Md6-PTV; (Q) Overbite; (R) Overjet
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
Results
TABLE III
The random errors ranged from 1.528 (IMPA) to 1.858 (Mx6.PP), considered within acceptable limits for clinical implication [19– 21]. Systematic errors were found statistically significant only for the variables Mx1-PTV and UL-Sn.Pg' (table II). The groups were comparable regarding sex and Class II molar relationship severity distributions, and pre-treatment age
Intergroup comparison of sex and Class II malocclusion severity distributions, pre- and posttreatment ages, and treatment times. Headgear Group n = 25 (%)
Jones Jig Group n = 21 (%)
P
Male
8 (32)
11 (52)
0.1621
Female
17 (68)
10 (48)
1
=4 Cusp Class II
8 (32)
8 (38)
½ Cusp Class II
8 (32)
8 (38)
¾ Cusp Class II
5 (20)
5 (24)
Variables
Sex
Occlusal malocclusion severity
TABLE II Random and systematic errors (Dahlberg and t tests). Variables
Measurement 1 Mean
S.D.
Measurement 2 Mean
P
Full-Cusp Class II Mean
4 (16) S.D. Mean
0 S.D.
Pretreatment age
13.00
1.30
12.88
1.23
0.7522
Posttreatment age
16.27
1.11
17.18
1.37
0.017*2
Treatment time
3.26
0.67
4.29
0.76
0.000*2
S.D. Dahlberg
Skeletal Variables SNA (8)
83.57
4.02
83.56
4.36
0.59
0.947
SNB (8)
79.78
3.47
79.82
3.61
0.46
0.732
ANB (8)
3.78
2.36
3.74
2.43
0.42
0.707
Vertical Skeletal Variables FMA (8)
28.59
4.44
28.28
4.57
0.68
0.088
SN.GoGn (8)
33.38
4.33
33.19
4.33
0.49
0.156
ANS-Me (mm)
65.12
6.94
65.01
6.74
0.39
0.316
0.2981
*Statistically significant difference (P < 0.05). 1 Chi-square tests. 2 T tests.
Maxillary Dental Variables Mx1.PP (8)
112.22
5.45
112.40 5.00
1.40
0.648
Mx1-PTV (mm)
55.09
5.38
55.47
5.48
0.65
0.025*
Mx6.PP (8)
98.59
6.35
98.36
5.98
1.85*
0.653
Mx6-PTV (mm)
24.47
4.52
24.75
4.63
0.62
0.091
Mandibular Dental Variables IMPA (8)
92.90
6.79
93.28
6.93
1.52*
0.362
Md1-PTV (mm)
52.14
2.06
52.21
2.13
0.30
0.411
Md6.PM (8)
99.71
5.40
99.60
5.88
1.53*
0.785
Md6-PTV (mm)
26.28
4.99
26.56
5.05
0.66
0.113
Overbite (mm)
3.60
1.52
3.63
1.43
0.49
0.789
Overjet (mm)
3.23
1.37
3.13
1.28
0.40
0.389
UL-Sn.Pg' (mm)
4.60
2.03
4.32
1.89
0.44
0.015*
LL-Sn.Pg' (mm)
4.10
2.07
4.05
2.08
0.38
0.656
Interdental Variables
Soft Tissue Variables
8
*Statistically significant difference (P < 0.05).
(table III). However, group 2 had a significantly greater posttreatment age and treatment time. Before treatment, the cervical headgear group presented a significantly retruded mandible, a horizontal growth pattern (FMA), the mandibular incisor with a significantly greater labial tipping and the mandibular molars with a significantly greater mesial angulation than the Jones Jig group (table IV). The headgear group produced significantly greater maxillary anterior displacement restriction (SNA; CH: 0.978 1.33; JJ: 0.078 1.73; P = 0.025), apical base discrepancy improvement (ANB; CH: 1.528 1.25; JJ: 0.368 1.46; P = 0.006), FMA reduction (CH: 0.788 2.68; JJ: 1.078 2.84; P = 0.028) and distal mandibular molar angulation (Md6.PM; CH: 6.978 3.66; JJ: 2.778 6.87; P = 0.013) than the Jones Jig group (table V).
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To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
TABLE IV
TABLE V
Pretreatment intergroup comparison (T and Mann Whitney tests).
Intergroup treatment changes comparison (T and Mann Whitney tests).
Variables
Headgear Group (n = 25) Mean
S.D.
Jones Jig Group (n = 21) Mean
P Variables
S.D.
Mean
Skeletal Variables SNA (8)
82.12
3.34
83.24
4.05
0.308
1 1
SNB (8)
77.42
3.32
79.49
3.36
0.042*
ANB (8)
4.70
2.01
3.73
3.00
0.1991
22.96
4.13
26.83
5.04
S.D.
SNB (8)
0.97 1.33 1.17
0.44 1.43 0.9561
1.52 1.25
0.36 1.46 0.006*1
0.54
1.07 2.84 0.028*1
0.59 1.37
0.15 1.70 0.1081
4.92
32.65
4.57
0.1482
ANS-Me (mm)
61.27
4.12
62.03
5.71
0.6051
SN.GoGn (8) ANS-Me (mm)
Maxillary Dental Variables
3.11
2.12
4.19 3.20 0.2842
2.02 5.17 0.4141
Mx1.PP (8)
112.98
8.16
114.72
5.56
0.4091
Maxillary Dentoalveolar Variables
Mx1-PTV (mm)
55.07
5.32
55.09
5.14
0.9881
Mx1.PP (8)
0.04 10.48
Mx6.PP (8)
98.10
7.56
100.24
5.78
0.2951
Mx1-PTV (mm)
0.26
Mx6-PTV (mm)
23.80
3.56
23.45
4.00
0.7601
Mx6.PP (8)
7.02
0.037*1 1
3.88
0.56 2.59 0.7322
5.94 5.67
3.05 4.36 0.0621
1.71
3.20
1.62 2.66 0.9201
IMPA (8)
1.42
4.36
1.54 4.63 0.9311
Mx6-PTV (mm)
Mandibular Dental Variables 92.82
0.07 1.73 0.025*1
0.78 2.68
31.05
6.46
Mean S.D.
Vertical Skeletal Variables
SN.GoGn (8)
97.08
P
0.006*1
FMA (8)
IMPA (8)
Jones Jig Group (n = 21)
Skeletal Variables SNA (8)
ANB (8)
Vertical Skeletal Variables FMA (8)
Headgear Group (n = 25)
Mandibular Dentoalveolar Variables
Md1-PTV (mm)
49.73
4.11
50.37
5.08
0.322
Md6.PM (8)
91.36
4.37
98.29
7.09
0.000*2
Md1-PTV (mm)
2.65
2.27
2.77 2.83 0.2991
Md6-PTV (mm)
23.42
3.76
24.54
4.38
0.3521
Md6.PM (8)
6.97
3.66
2.77 6.87 0.013*2
Md6-PTV (mm)
3.66
2.95
2.78 2.61 0.2951
Interdental Variables Overbite (mm)
5.34
3.07
4.71
1.66
0.8862
Interdental Variables
Overjet (mm)
3.33
1.58
3.97
1.45
0.1671
Overbite (mm)
0.92 1.47
1.16 1.06 0.5351
Overjet (mm)
2.38 2.84
1.60 1.32 0.6352
0.64 1.32
0.91 1.21 0.2082
Soft Tissue Variables UL-Sn.Pg' (mm)
4.48
1.92
5.01
2.20
0.3881
Soft Tissue Variables
LL-Sn.Pg' (mm)
3.06
2.50
4.33
2.00
0.0681
UL-Sn.Pg' (mm) LL-Sn.Pg' (mm)
*Statistically significant difference (P < 0.05. 1 T tests. 2 Mann Whitney tests.
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
0.04
1.33
0.48 1.16 0.1422
*Statistically significant difference (P < 0.05. 1 T tests. 2 Mann Whitney tests.
Discussion
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An extensive number of studies evaluating treatment effects from molar distal movement during the distalization phase can often be observed in the literature [4,22–24]. However, few studies evaluated the effects of these appliances when the orthodontic treatment is finished [14,15]. Two studies were found comparing the cervical headgear with Jones Jig directly [22,23], but only one evaluated the complete treatment, until
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
10
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
the removal of the fixed appliances [22]. In order to investigate the overall treatment effects between these two protocols, this study had the purpose of comparing the cephalometric changes of patients treated with cervical headgear and Jones Jig appliances followed by fixed appliances. It could be argued that the use of the CH in both groups might be a confounding factor in the present study and increase the risk of bias. Nonetheless, the use of the CH after distalization was necessary for the JJ group to upright the distalized first molars and to aid in the anchorage control, as previously performed in other studies [16,19,25]. Furthermore, the present study focused on evaluating the combination of the tested appliances followed by fixed orthodontics, since the comparison of the appliances separately was already performed [23]. This fact justifies the originality of the present study. Again, the retrospective design of this study may increase the possibility of bias. However, the presence of this inherent methodological limitation should be overcome by the great intergroup comparability and performance of annualization. There was good intergroup comparability regarding sex and Class II molar relationship severity distribution and pre-treatment age (table III). Nevertheless, intergroup treatment time was not statistically similar, with the Jones Jig group presenting a longer treatment time of 1.03 years. As the Jones Jig group had a greater posttreatment age and treatment time, the treatment changes were therefore annualized to the corresponding cervical headgear treatment time. All patients in the Jones Jig group had their treatment changes, for each variable, divided by their treatment time individually, and then multiplied by the mean treatment time of the cervical headgear group. This method permits a scientifically reliable comparison of each variable in both groups [19,26,27]. The difference observed was already expected since treatment with the JJ is performed in two phases. First, the distalization phase to obtain a Class I molar relationship and a second phase with the placement of fixed appliances. Furthermore, the JJ produces undesirable effects such as protrusion and labial tipping of the maxillary incisors and loss of anchorage of the premolars, which must be corrected during the second phase of treatment with fixed appliances [19,24,28], causing a probable treatment delay. In contrast, during maxillary molar distalization with the CH, due to its extraoral characteristic, no protrusive effects occurred at the maxillary incisors, canines, and premolars. These teeth usually follow the distalization by the action of transseptal fibers [24,29]. Additionally, the groups were pretty comparable at pretreatment regarding their skeletal and dentoalveolar characteristics (table IV). Even though the CH group presented a significantly retruded mandible and horizontal growth pattern at pretreatment when compared to the JJ group, these initial statuses showed no significant impact on the soft-tissue characteristics and treatment effects.
It could be assumed that the impact of these initial skeletal differences in the soft tissue was reduced because of the significant labial tipping of the mandibular incisors shown in the CH group when compared to the JJ group (table IV). Therefore, the expected initial lower lip retrusion in the CH group was compensated by the incisors, resulting in no significant differences between groups.
Skeletal Changes The cervical headgear promoted restriction of maxillary forward displacement, while in the Jones Jig group mild maxillary protrusion was observed (table V). This orthopaedic effect noticed with the cervical headgear group has been widely reported [23,30–32], and can be explained due to the action of highmagnitude forces in the maxilla (450–600 g/side). As a result, statistical improvement in apical base relationship could be achieved at the end of orthodontic treatment with the cervical headgear group when compared to the Jones Jig. Both appliances have their effects focused especially on the maxilla, thus similar mandibular effects were noticed (table V). The increase in mandibular sagittal dimensions in both groups is a probable result of normal mandibular growth [19,32]. Ideally, when non-extraction Class II treatment has the objective to promote significant effects in the mandible, fixed functional appliances can be used [33]. An increase in the growth pattern angles in both groups was expected due to the extrusion of the maxillary molars [4,22]. However, in the cervical headgear group a decrease in FMA and Sn.GoGn angles was noticed probably due to the inherent growth pattern of the patients [34], compensating the molar extrusion. The vertical components of the Jones Jig group showed a tendency to increase during treatment. In both groups, the lower anterior face height (ANS-Me) increased consequent to extrusion of the molars (table V). In the fixed appliances period this increased vertical development of the molars may benefit the overbite correction [35].
Dentoalveolar Changes The maxillary incisors and molars behaved similarly in the cervical headgear and Jones Jig groups during treatment (table V). The side effects that usually occur during the distalization phase with the JJ appliance, such as labial tipping of the incisors and distal inclination of the molars were corrected using fixed appliances [4,14]. Therefore, as this study evaluates the treatment changes with CH or JJ followed by fixed appliances, these side effects could not be noticed between the groups, agreeing with the findings of the study from Haydar et al. [23]. While these appliances mainly perform direct changes on the maxillary teeth, the mandibular dentoalveolar changes are primarily produced by the fixed appliances [14,15]. The mandibular incisors did not show significantly different changes between the groups, presenting mild labial tipping and protrusion probably due to the use of Class II elastics [36] (table V).
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To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
The mandibular molars on the CH group presented a significantly greater distal inclination when compared to the JJ group, and was the only dentoalveolar variable to present significant intergroup difference (table V). The greater use of Class II elastics in the JJ group, as verified in the patients clinical files, may have contributed to this difference [19,36]. Furthermore, the mandibular molars also presented mesialization in both groups (table V). Again, the use of Class II elastics probably contributed to these changes [36]. In addition, it is important to consider the anterior and vertical displacement of the molars during normal growth, which may have contributed to this change [19,29,37]. The overbite and overjet did not present significant intergroup differences (table V). Both appliances promoted similar anteroposterior effects in the incisors after the use of fixed appliances. These findings corroborate with the study of Brickman et al. [22] that also did not find significant differences in these variables.
Soft Tissue Changes The upper and lower lips presented similar changes during treatment (table V). As almost all dentoalveolar changes were not significantly different between the groups, there were no significant intergroup soft tissue change differences, as expected [15,38].
Clinical Relevance Although the treatment approaches evaluated in this study are classical, it could not be considered outdated. Contemporary and classical orthodontic approaches could be used depending on several factors such as patient need, simplicity, treatment efficiency, the clinician's ability, socioeconomic features and patient
cooperation among others. Orthodontists should consider all these features and provide the best possible individualized treatment. It is reasonable to state that contemporary alternatives with the use of mini-implants such as intraoral distalizers skeletally anchored or even total arch distalization directly supported in the mini-implants may be considered effective approaches that promote acceptable results with even fewer undesirable effects. Nonetheless, further research should be performed to fundament these treatment alternatives.
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
Conclusions
Both distalizers followed by fixed appliances were effective to correct Class II malocclusion. In general, the effects of these appliances are similar after the end of orthodontic treatment, with the cervical headgear appliance presenting mild skeletal changes and less treatment time when compared to the Jones Jig appliance. There were no significant intergroup differences regarding soft tissue changes. Author contributions: Fernanda Pinelli Henriques Fontes: data collection, statistical analyses and manuscript draft. Silvio Augusto Bellini-Pereira: article draft and critical revision. Aron Aliaga-Del Castillo: data checking and manuscript draft. Mayara Paim Patel: scientific and English revision. Marcos Roberto de Freitas: scientific revision. José Fernando Castanha Henriques: research supervision. Guilherme Janson: scientific and English revision. Acknowledgments: none to declare. Disclosure of interest: the authors declare that they have no competing interest.
References
[2]
[3]
[4]
McNamara Jr JA. Components of class II malocclusion in children 8–10 years of age. Angle Orthod 1981;51:177–202. Josefsson E, Bjerklin K, Lindsten R. Malocclusion frequency in Swedish and immigrant adolescents—influence of origin on orthodontic treatment need. Eur J Orthod 2007;29:79– 87. Tsiouli K, Topouzelis N, Papadopoulos MA, Gkantidis N. Perceived facial changes of Class II Division 1 patients with convex profiles after functional orthopedic treatment followed by fixed orthodontic appliances. Am J Orthod Dentofac Orthop 2017;152:80–91. Patel MP, Janson G, Henriques JF, et al. Comparative distalization effects of Jones jig
tome xx > 000 > xx 2020
[5]
[6]
[7]
[8]
and pendulum appliances. Am J Orthod Dentofacial Orthop 2009;135:336–42. Papageorgiou SN, Kutschera E, Memmert S, et al. Effectiveness of early orthopaedic treatment with headgear: a systematic review and meta-analysis. Eur J Orthod 2017;39:176–87. Carano A, Testa M. The distal jet for upper molar distalization. J Clin Orthod 1996;30:374– 80. Gianelly AA, Vaitas AS, Thomas WM. The use of magnets to move molars distally. Am J Orthod Dentofacial Orthop 1989;96:161–7. Muse DS, Fillman MJ, William JE, Mitchell RD. Molar and incisor changes with Wilson rapid molar distalization. Am J Orthod Dentofac Orthop 1993;104:556–65.
Reis RS, Henriques JF, Janson G, Freitas KMS, Moura W. Dental, skeletal and soft tissue effects of the Distal Jet appliance: a prospective clinical study. Dental Press J Orthod 2019;24:56–64. [10] Grec RHD, Janson G, Branco NC, Moura-Grec PG, Patel MP, Henriques JFC. Intraoral distalizer effects with conventional and skeletal anchorage: a meta-analysis. Am J Orthod Dentofac Orthop 2013;143:602–15. [11] Nur M, Bayram M, Pampu A. Zygoma-gear appliance for intraoral upper molar distalization. Korean J Orthod 2010;40:195–206. [12] Polat-Ozsoy O, Kircelli BH, Arman-Ozçirpici A, Pektas ZO, Uçkan S. Pendulum appliances with 2 anchorage designs: conventional
[9]
11
[1]
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
12
[21]
anchorage vs bone anchorage. Am J Orthod Dentofacial Orthop 2008;133. 339.e9-.e17. Jones R, White J. Rapid Class II molar correction with an open-coil jig. J Clin Orthod 1992;26:661. Patel MP, Henriques JFC, Freitas KM, Grec RH. Cephalometric effects of the Jones Jig appliance followed by fixed appliances in Class II malocclusion treatment. Dental Press J Orthod 2014;19:44–51. Vilanova L, Henriques JFC, Janson G, Patel MP, Reis RS, Castillo AA-D. Class II malocclusion treatment effects with Jones jig and distal jet followed by fixed appliances. Angle Orthod 2017;88:10–9. Mandurino M, Balducci L. Asymmetric distalization with a TMA transpalatal arch. J Clin Orthod 2001;35:174. Dahlberg G. Statistical methods for medical and biological students. Statistical methods for medical and biological students. London: George Allen & Unwin; 1940. Houston WJ. The analysis of errors in orthodontic measurements. Am J Orthod 1983;83: 382–90. Angelieri F, de Almeida RR, Janson G, Castanha Henriques JF, Pinzan A. Comparison of the effects produced by headgear and pendulum appliances followed by fixed orthodontic treatment. Eur J Orthod 2008;30:572–9. Artun J, Garol JD, Little RM. Long-term stability of mandibular incisors following successful treatment of Class II, Division 1, malocclusions. Angle Orthod 1996;66:229–38. Pollard LE, Mamandras AH. Male postpubertal facial growth in Class II malocclusions. Am J Orthod Dentofacial Orthop 1995;108:62–8.
[22] Brickman CD, Sinha PK, Nanda RS. Evaluation of the Jones jig appliance for distal molar movement. Am J Orthod Dentofacial Orthop 2000;118:526–34. [23] Haydar S, Uner O. Comparison of Jones jig molar distalization appliance with extraoral traction. Am J Orthod Dentofacial Orthop 2000;117:49–53. [24] Taner TU, Yukay F, Pehlivanoglu M, Cakirer B. A comparative analysis of maxillary tooth movement produced by cervical headgear and pend-x appliance. Angle Orthod 2003;73:686–91. [25] Ferguson DJ, Carano A, Bowman SJ, Davis EC, Gutierrez Vega ME, Lee SH. A comparison of two maxillary molar distalizing appliances with the distal jet. World J Orthod 2005;6 (4):382–90. [26] McNamara JA, Howe RP, Dischinger TG. A comparison of the Herbst and Fränkel appliances in the treatment of Class II malocclusion. Am J Orthod Dentofac Orthop 1990;98: 134–44. [27] Mills CM, McCulloch KJ. Posttreatment changes after successful correction of Class II malocclusions with the Twin Block appliance. Am J Orthod Dentofac Orthop 2000;118: 24–33. [28] Byloff FK, Darendeliler MA. Distal molar movement using the pendulum appliance .1. Clinical and radiological evaluation. Angle Orthod 1997;67:249–60. [29] Bowman S. Upper-molar distalization and the distal jet. J Clin Orthod 2016;50:159. [30] Gandini MREAS, Gandini LG, Martins JCR, Santo MD. Effects of cervical headgear and edgewise appliances on growing patients.
[31]
[32]
[33]
[34]
[35]
[36]
[37]
[38]
J Orthod Dentofacial Orthop Am 2001;119:531–9. King EW. Cervical anchorage in Class II, division 1 treatment, a cephalometric appraisal. Angle Orthod 1957;27:98–104. Klein P. An evaluation of cervical traction on the maxilla and the upper first permanent molar. Angle Orthod 1957;27:61–8. Jayachandran S, Wiltshire WA, Hayasaki SM, Pinheiro FH. Comparison of AdvanSync and intermaxillary elastics in the correction of Class II malocclusions: a retrospective clinical study. Am J Orthod Dentofac Orthop 2016;150:979–88. Kim K-R, Muhl ZF. Changes in mandibular growth direction during and after cervical headgear treatment. Am J Orthod Dentofac Orthop 2001;119:522–30. Bussick TJ, Mc Namara Jr JA. Dentoalveolar and skeletal changes associated with the pendulum appliance. Am J Orthod Dentofacial Orthop 2000;117:333–43. Janson G, Sathler R, Fernandes TMF, Branco NCC, de Freitas MR. Correction of Class II malocclusion with Class II elastics: a systematic review. Am J Orthod Dentofac Orthop 2013;143:383–92. Nelson B, Hansen K, Hägg U. Overjet reduction and molar correction in fixed appliance treatment of Class II, Division 1, malocclusions: Sagittal and vertical components. Am J Orthod Dentofac Orthop 1999;115:13–23. Chiu PP, McNamara Jr JA, Franchi L. A comparison of two intraoral molar distalization appliances: distal jet versus pendulum. Am J Orthod Dentofac Orthop 2005;128:353–65.
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Original Article
Websites: www.em-consulte.com www.sciencedirect.com
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study Fernanda Pinelli Henriques Fontes, Silvio Augusto Bellini-Pereira, Aron Aliaga-Del-Castillo, Mayara Paim Patel, Marcos Roberto de Freitas, José Fernando Castanha Henriques, Guilherme Janson
Available online:
University of São Paulo, Bauru Dental School, Department of Orthodontics, Brazil
Correspondence: Fernanda Pinelli Henriques Fontes, University of São Paulo, Bauru Dental School, Department of Orthodontics, Alameda Octávio Pinheiro Brisolla 9-75, 1,7012-901 Bauru, São Paulo, Brazil. [email protected]
Keywords Malocclusion Angle Class II Extraoral Traction Appliances Orthodontics Corrective Cephalometry
Summary Objective > To retrospectively compare the dentoskeletal and soft tissue changes of patients with Class II malocclusion treated with cervical headgear and Jones Jig appliances, followed by fixed appliances. Material and methods > The sample comprised 46 Class II malocclusion patients divided into two groups. Patients with Class II malocclusion based on the ANB angle and plaster model analyses, needing non-extraction orthodontic treatment, absence of mandibular crowding and no previous orthodontic treatment were eligible to be selected. Group 1 consisted of 25 patients treated with cervical headgear (CH) followed by fixed appliances for a mean period of 3.26 years and group 2 consisted of 21 patients treated with the Jones Jig (JJ) appliance for a mean of 4.29 years. Lateral cephalograms were evaluated at the beginning and at the end of orthodontic treatment. For intergroup comparisons, t and Mann-Whitney tests were performed. Results > The cervical headgear group produced significantly greater maxillary anterior displacement restriction (SNA; CH: 0.978 1.33; JJ: 0.078 1.73; P = 0.025), apical base discrepancy improvement (ANB; CH: 1.528 1.25; JJ: 0.368 1.46; P = 0.006), FMA reduction (CH: 0.788 2.68; JJ: 1.078 2.84; P = 0.028) and distal mandibular molar angulation (Md6.PM; CH: 6.978 3.66; JJ: 2.778 6.87; P = 0.013) than the Jones Jig group. Conclusions > Both distalizers followed by fixed appliances were effective to correct Class II malocclusion. The cervical headgear group presented skeletal effects with less treatment time and there were no significant intergroup differences regarding soft tissue changes.
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ORTHO-468
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
Introduction Class II malocclusion is an anteroposterior discrepancy characterized not as a single clinical entity, but a result of dentoalveolar or skeletal components, or even the combination of both, of which mandibular retrusion is commonly observed [1]. There is a high prevalence of Class II malocclusion in the population, and due to the strong aesthetic impact on the face, depending on its severity, it is evident that a significant percentage of patients seek orthodontic treatment [2,3]. Non-extraction treatment for Class II malocclusion correction often requires distal movement of the maxillary molars through external force with cervical headgear appliance (CH) or intraoral force via distalizers, since these patients usually present a dentoalveolar compensation and/or maxillary protrusion [4]. The CH gained widespread acceptance as an effective treatment for Class II malocclusions, partly due to the dental changes in the sagittal and vertical plane provided and its important capacity to modify maxillary growth [5]. Despite its effects, the dependence on patient compliance is currently causing a decrease in the use of CH, associated with the development of efficient intraoral distalizing appliances with conventional [6–9] and skeletal anchorage [10–12]. However, the CH is still useful for specific Class II malocclusions, when maxillary protrusion is diagnosed. Intraoral distalizers correct Class II malocclusion without depending entirely on the patient. The Jones Jig (JJ) is an intraoral distalizing appliance with nitinol (NiTi) open coil springs; it exerts a force to the maxillary molars promoting their
distalization [13,14]. The appliance active unit is characterized by the NiTi coil springs applying a force from the buccal side of the molars. Therefore, in order to counteract the distalization force, the distalizer is anchored in the second premolars with a Nance button. Even though distalization is effective and anchorage is used, some minor undesirable effects such as the mesial displacement of premolars and the molars distal angulation have been demonstrated [13,15]. Thus, the purpose of this retrospective study was to compare the cephalometric changes of patients with Class II malocclusion treated with the cervical headgear and Jones Jig appliances, followed by fixed appliances.
Materials and methods This study was approved by the ethics in research committee of Bauru Dental School, University of São Paulo, Brazil. The sample size was calculated based on an alpha significance level of 5% and a beta of 20% to detect a mean difference of 1.40 mm with a standard deviation of 1.56 mm in maxillary molar anteroposterior position (Mx6-PTV) [4]. A minimum of 21 patients were required in each group based on the sample size calculation. In view of this, the sample comprised 46 patients (19 males, 27 female), treated at the Department of Orthodontics, Bauru Dental School, University of São Paulo, Brazil. The eligibility criteria were based on the following characteristics: 1) Presence of Class II malocclusion evaluated on the cephalometric analysis by the ANB angle and plaster models analysis regarding the Angle classification;
Figure 1
2
Flow chart regarding the sample collection
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To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
2) Patients needing non-extraction orthodontic treatment; 3) No severe mandibular crowding; 4) A history of acceptable oral hygiene and no damage to the appliance; 5) No previous orthodontic treatment. Sample selection is explained in the flowchart (figure 1). Group 1 consisted of 25 patients (8 males, 17 females) with a mean initial age of 13.00 years (SD, 1.30 years), treated with the cervical headgear (figure 2). The mean treatment time was 3.26 years (SD, 0.67 years). Group 2 comprised 21 patients (11 males, 10 females) with a mean initial age of 12.88 years (SD, 1.23 years), treated with the Jones Jig appliance (figure 3). The original stainless-steel coil
spring was changed to a NiTi coil spring (G&H Wire Co, Greenwood, Ind.) to exert continuous force. The mean treatment time was 4.29 years (SD, 0.76 years). In both groups, the appliances were used until the maxillary first molars were distalized to an overcorrected Class I relationship. Subsequently, pre-adjusted edgewise orthodontic appliances were placed to initiate levelling and aligning until 0.019 0.025-inch rectangular stainless-steel archwires were placed. At this stage, retraction of the premolars and anterior teeth was performed with elastic chains associated with Class II elastics, used 12 h/day, releasing an average force of 130 g/side. During the retraction stage, anchorage reinforcement was achieved with the CH with the outer bows tilted 158 to
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
Figure 2
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3
Treatment with the cervical headgear appliance: Cervical headgear appliance; maxillary molar distalization and final results
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
Figure 3 Treatment with the Jones Jig appliance: Jones Jig appliance; maxillary molar distalization and final results
208 upward from the occlusal plane to upright the distalized first molars [6,16]. After removal of the fixed appliances, a maxillary Hawley plate and a mandibular canine-to-canine bonded retainer were installed. The Hawley retainer was recommended to be used full-time for 6 months, followed by night-only use for an additional 6 months. The canine-to-canine bonded retainer was recommended to be used for 3 years.
Cephalometric analysis
4
Pre-treatment (T1) and posttreatment (T2) cephalometric radiographs were taken for each patient. The radiographs
were traced, and landmark identifications were made on acetate paper by one investigator (F.P.H.F.) in a darkened room. The cephalometric landmarks off all traced radiographs were digitized and transferred to Dentofacial Planner 7.02 software (Dentofacial Planner Software Inc., Toronto, Ontario, Canada) which performed the cephalometric measurements. The cephalometric variables are described in table I and illustrated in figures 4, 5. The software corrected the magnification factor of the radiographic images that were between 6% and 9.8%. Treatment changes were calculated as T2-T1.
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To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
TABLE I Cephalometric measurements. SNA (8)
Angle formed by the intersection of SN line and NA line
SNB (8)
Angle formed by the intersection of SN line and NB line
ANB (8)
Angle formed by the intersection of NA line and NB line
FMA (8)
Angle formed by the intersection of Frankfurt plane and Go-Me
ANS-Me (mm)
Angle formed by the intersection of SN line and Go-Gn Linear measurement from anterior nasal spine to menton (Lower anterior face height)
Mx1.PP (8)
Angle formed by the maxillary incisor long axis and the palatal plane (ANS-PNS)
Mx1-PTV (mm)
Linear distance from the tip of the maxillary central incisor perpendicular to PTV
Mx6.PP (8) Mx6-PTV (mm) IMPA (8) Md1-PTV (mm) Md6.PM (8)
Angle formed by the maxillary molar long axis and the palatal plane Linear distance from the mesiovestibular cusp of the maxillary first molar perpendicular to PTV Angle formed by the mandibular incisor long axis and the mandibular plane (Go-Me) Linear distance from the tip of the mandibular central incisor perpendicular to PTV Angle formed by the mandibular molar long axis and the mandibular plane
Md6-PTV (mm)
Linear distance from the mesiovestibular cusp of the mandibular first molar perpendicular to PTV
Overbite (mm)
Linear vertical distance from the incisal of maxillary central incisor to incisal of the mandibular central incisor
Overjet (mm)
Linear horizontal distance from the incisal of maxillary central incisor to incisal of the mandibular central incisor
UL-Sn.Pg'
Linear distance from Upper Lip point to SnPg' line
LL-Sn.Pg'
Linear distance from Lower Lip point to SnPg' line
Error Study Two weeks after the first measurements, 28 randomly selected cephalometric radiographs were retraced and measured by the same investigator (F.P.H.F.). The random errors were estimated according to Dahlberg's formula [17], while the systematic errors were calculated with dependent t tests at P < 0.05 [18].
Statistical Analysis To evaluate the presence of normal distribution of the variables, Shapiro Wilk tests were performed in both groups and treatment stages for all variables.
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Intergroup comparability regarding sex and Class II molar relationship severity distributions were evaluated with Chi-square tests. Pre-treatment age and treatment time intergroup comparability were analysed with t tests. Intergroup initial cephalometric status and treatment changes were compared with t tests for the variables with normal distribution and with Mann Whitney tests for those without normal distribution. All the analyses were carried out using Statistica for Windows 7.0 (Copyright Stat Soft, Inc. Tulsa, Okla, USA 2001), with the level of significance set at P < 0.05.
5
SN.GoGn (8)
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
Figure 4
6
Skeletal and soft tissue cephalometric variables: (A) SNA; (B) SNB; (C) ANB; (D) FMA; (E) SN.GoGn; (F) ANS-Me; (G) UL-Sn.Pg'; (H) LL-Sn. Pg'
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To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
Figure 5
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7
Dental Variables: (I) Mx1.PP; (J) Mx1-PTV; (K) Mx6.PP; (L) Mx6-PTV;(M) IMPA; (N) Md1-PTV; (O) Md6.PM; (P) Md6-PTV; (Q) Overbite; (R) Overjet
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
Results
TABLE III
The random errors ranged from 1.528 (IMPA) to 1.858 (Mx6.PP), considered within acceptable limits for clinical implication [19– 21]. Systematic errors were found statistically significant only for the variables Mx1-PTV and UL-Sn.Pg' (table II). The groups were comparable regarding sex and Class II molar relationship severity distributions, and pre-treatment age
Intergroup comparison of sex and Class II malocclusion severity distributions, pre- and posttreatment ages, and treatment times. Headgear Group n = 25 (%)
Jones Jig Group n = 21 (%)
P
Male
8 (32)
11 (52)
0.1621
Female
17 (68)
10 (48)
1
=4 Cusp Class II
8 (32)
8 (38)
½ Cusp Class II
8 (32)
8 (38)
¾ Cusp Class II
5 (20)
5 (24)
Variables
Sex
Occlusal malocclusion severity
TABLE II Random and systematic errors (Dahlberg and t tests). Variables
Measurement 1 Mean
S.D.
Measurement 2 Mean
P
Full-Cusp Class II Mean
4 (16) S.D. Mean
0 S.D.
Pretreatment age
13.00
1.30
12.88
1.23
0.7522
Posttreatment age
16.27
1.11
17.18
1.37
0.017*2
Treatment time
3.26
0.67
4.29
0.76
0.000*2
S.D. Dahlberg
Skeletal Variables SNA (8)
83.57
4.02
83.56
4.36
0.59
0.947
SNB (8)
79.78
3.47
79.82
3.61
0.46
0.732
ANB (8)
3.78
2.36
3.74
2.43
0.42
0.707
Vertical Skeletal Variables FMA (8)
28.59
4.44
28.28
4.57
0.68
0.088
SN.GoGn (8)
33.38
4.33
33.19
4.33
0.49
0.156
ANS-Me (mm)
65.12
6.94
65.01
6.74
0.39
0.316
0.2981
*Statistically significant difference (P < 0.05). 1 Chi-square tests. 2 T tests.
Maxillary Dental Variables Mx1.PP (8)
112.22
5.45
112.40 5.00
1.40
0.648
Mx1-PTV (mm)
55.09
5.38
55.47
5.48
0.65
0.025*
Mx6.PP (8)
98.59
6.35
98.36
5.98
1.85*
0.653
Mx6-PTV (mm)
24.47
4.52
24.75
4.63
0.62
0.091
Mandibular Dental Variables IMPA (8)
92.90
6.79
93.28
6.93
1.52*
0.362
Md1-PTV (mm)
52.14
2.06
52.21
2.13
0.30
0.411
Md6.PM (8)
99.71
5.40
99.60
5.88
1.53*
0.785
Md6-PTV (mm)
26.28
4.99
26.56
5.05
0.66
0.113
Overbite (mm)
3.60
1.52
3.63
1.43
0.49
0.789
Overjet (mm)
3.23
1.37
3.13
1.28
0.40
0.389
UL-Sn.Pg' (mm)
4.60
2.03
4.32
1.89
0.44
0.015*
LL-Sn.Pg' (mm)
4.10
2.07
4.05
2.08
0.38
0.656
Interdental Variables
Soft Tissue Variables
8
*Statistically significant difference (P < 0.05).
(table III). However, group 2 had a significantly greater posttreatment age and treatment time. Before treatment, the cervical headgear group presented a significantly retruded mandible, a horizontal growth pattern (FMA), the mandibular incisor with a significantly greater labial tipping and the mandibular molars with a significantly greater mesial angulation than the Jones Jig group (table IV). The headgear group produced significantly greater maxillary anterior displacement restriction (SNA; CH: 0.978 1.33; JJ: 0.078 1.73; P = 0.025), apical base discrepancy improvement (ANB; CH: 1.528 1.25; JJ: 0.368 1.46; P = 0.006), FMA reduction (CH: 0.788 2.68; JJ: 1.078 2.84; P = 0.028) and distal mandibular molar angulation (Md6.PM; CH: 6.978 3.66; JJ: 2.778 6.87; P = 0.013) than the Jones Jig group (table V).
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To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
TABLE IV
TABLE V
Pretreatment intergroup comparison (T and Mann Whitney tests).
Intergroup treatment changes comparison (T and Mann Whitney tests).
Variables
Headgear Group (n = 25) Mean
S.D.
Jones Jig Group (n = 21) Mean
P Variables
S.D.
Mean
Skeletal Variables SNA (8)
82.12
3.34
83.24
4.05
0.308
1 1
SNB (8)
77.42
3.32
79.49
3.36
0.042*
ANB (8)
4.70
2.01
3.73
3.00
0.1991
22.96
4.13
26.83
5.04
S.D.
SNB (8)
0.97 1.33 1.17
0.44 1.43 0.9561
1.52 1.25
0.36 1.46 0.006*1
0.54
1.07 2.84 0.028*1
0.59 1.37
0.15 1.70 0.1081
4.92
32.65
4.57
0.1482
ANS-Me (mm)
61.27
4.12
62.03
5.71
0.6051
SN.GoGn (8) ANS-Me (mm)
Maxillary Dental Variables
3.11
2.12
4.19 3.20 0.2842
2.02 5.17 0.4141
Mx1.PP (8)
112.98
8.16
114.72
5.56
0.4091
Maxillary Dentoalveolar Variables
Mx1-PTV (mm)
55.07
5.32
55.09
5.14
0.9881
Mx1.PP (8)
0.04 10.48
Mx6.PP (8)
98.10
7.56
100.24
5.78
0.2951
Mx1-PTV (mm)
0.26
Mx6-PTV (mm)
23.80
3.56
23.45
4.00
0.7601
Mx6.PP (8)
7.02
0.037*1 1
3.88
0.56 2.59 0.7322
5.94 5.67
3.05 4.36 0.0621
1.71
3.20
1.62 2.66 0.9201
IMPA (8)
1.42
4.36
1.54 4.63 0.9311
Mx6-PTV (mm)
Mandibular Dental Variables 92.82
0.07 1.73 0.025*1
0.78 2.68
31.05
6.46
Mean S.D.
Vertical Skeletal Variables
SN.GoGn (8)
97.08
P
0.006*1
FMA (8)
IMPA (8)
Jones Jig Group (n = 21)
Skeletal Variables SNA (8)
ANB (8)
Vertical Skeletal Variables FMA (8)
Headgear Group (n = 25)
Mandibular Dentoalveolar Variables
Md1-PTV (mm)
49.73
4.11
50.37
5.08
0.322
Md6.PM (8)
91.36
4.37
98.29
7.09
0.000*2
Md1-PTV (mm)
2.65
2.27
2.77 2.83 0.2991
Md6-PTV (mm)
23.42
3.76
24.54
4.38
0.3521
Md6.PM (8)
6.97
3.66
2.77 6.87 0.013*2
Md6-PTV (mm)
3.66
2.95
2.78 2.61 0.2951
Interdental Variables Overbite (mm)
5.34
3.07
4.71
1.66
0.8862
Interdental Variables
Overjet (mm)
3.33
1.58
3.97
1.45
0.1671
Overbite (mm)
0.92 1.47
1.16 1.06 0.5351
Overjet (mm)
2.38 2.84
1.60 1.32 0.6352
0.64 1.32
0.91 1.21 0.2082
Soft Tissue Variables UL-Sn.Pg' (mm)
4.48
1.92
5.01
2.20
0.3881
Soft Tissue Variables
LL-Sn.Pg' (mm)
3.06
2.50
4.33
2.00
0.0681
UL-Sn.Pg' (mm) LL-Sn.Pg' (mm)
*Statistically significant difference (P < 0.05. 1 T tests. 2 Mann Whitney tests.
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
0.04
1.33
0.48 1.16 0.1422
*Statistically significant difference (P < 0.05. 1 T tests. 2 Mann Whitney tests.
Discussion
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9
An extensive number of studies evaluating treatment effects from molar distal movement during the distalization phase can often be observed in the literature [4,22–24]. However, few studies evaluated the effects of these appliances when the orthodontic treatment is finished [14,15]. Two studies were found comparing the cervical headgear with Jones Jig directly [22,23], but only one evaluated the complete treatment, until
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
10
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
the removal of the fixed appliances [22]. In order to investigate the overall treatment effects between these two protocols, this study had the purpose of comparing the cephalometric changes of patients treated with cervical headgear and Jones Jig appliances followed by fixed appliances. It could be argued that the use of the CH in both groups might be a confounding factor in the present study and increase the risk of bias. Nonetheless, the use of the CH after distalization was necessary for the JJ group to upright the distalized first molars and to aid in the anchorage control, as previously performed in other studies [16,19,25]. Furthermore, the present study focused on evaluating the combination of the tested appliances followed by fixed orthodontics, since the comparison of the appliances separately was already performed [23]. This fact justifies the originality of the present study. Again, the retrospective design of this study may increase the possibility of bias. However, the presence of this inherent methodological limitation should be overcome by the great intergroup comparability and performance of annualization. There was good intergroup comparability regarding sex and Class II molar relationship severity distribution and pre-treatment age (table III). Nevertheless, intergroup treatment time was not statistically similar, with the Jones Jig group presenting a longer treatment time of 1.03 years. As the Jones Jig group had a greater posttreatment age and treatment time, the treatment changes were therefore annualized to the corresponding cervical headgear treatment time. All patients in the Jones Jig group had their treatment changes, for each variable, divided by their treatment time individually, and then multiplied by the mean treatment time of the cervical headgear group. This method permits a scientifically reliable comparison of each variable in both groups [19,26,27]. The difference observed was already expected since treatment with the JJ is performed in two phases. First, the distalization phase to obtain a Class I molar relationship and a second phase with the placement of fixed appliances. Furthermore, the JJ produces undesirable effects such as protrusion and labial tipping of the maxillary incisors and loss of anchorage of the premolars, which must be corrected during the second phase of treatment with fixed appliances [19,24,28], causing a probable treatment delay. In contrast, during maxillary molar distalization with the CH, due to its extraoral characteristic, no protrusive effects occurred at the maxillary incisors, canines, and premolars. These teeth usually follow the distalization by the action of transseptal fibers [24,29]. Additionally, the groups were pretty comparable at pretreatment regarding their skeletal and dentoalveolar characteristics (table IV). Even though the CH group presented a significantly retruded mandible and horizontal growth pattern at pretreatment when compared to the JJ group, these initial statuses showed no significant impact on the soft-tissue characteristics and treatment effects.
It could be assumed that the impact of these initial skeletal differences in the soft tissue was reduced because of the significant labial tipping of the mandibular incisors shown in the CH group when compared to the JJ group (table IV). Therefore, the expected initial lower lip retrusion in the CH group was compensated by the incisors, resulting in no significant differences between groups.
Skeletal Changes The cervical headgear promoted restriction of maxillary forward displacement, while in the Jones Jig group mild maxillary protrusion was observed (table V). This orthopaedic effect noticed with the cervical headgear group has been widely reported [23,30–32], and can be explained due to the action of highmagnitude forces in the maxilla (450–600 g/side). As a result, statistical improvement in apical base relationship could be achieved at the end of orthodontic treatment with the cervical headgear group when compared to the Jones Jig. Both appliances have their effects focused especially on the maxilla, thus similar mandibular effects were noticed (table V). The increase in mandibular sagittal dimensions in both groups is a probable result of normal mandibular growth [19,32]. Ideally, when non-extraction Class II treatment has the objective to promote significant effects in the mandible, fixed functional appliances can be used [33]. An increase in the growth pattern angles in both groups was expected due to the extrusion of the maxillary molars [4,22]. However, in the cervical headgear group a decrease in FMA and Sn.GoGn angles was noticed probably due to the inherent growth pattern of the patients [34], compensating the molar extrusion. The vertical components of the Jones Jig group showed a tendency to increase during treatment. In both groups, the lower anterior face height (ANS-Me) increased consequent to extrusion of the molars (table V). In the fixed appliances period this increased vertical development of the molars may benefit the overbite correction [35].
Dentoalveolar Changes The maxillary incisors and molars behaved similarly in the cervical headgear and Jones Jig groups during treatment (table V). The side effects that usually occur during the distalization phase with the JJ appliance, such as labial tipping of the incisors and distal inclination of the molars were corrected using fixed appliances [4,14]. Therefore, as this study evaluates the treatment changes with CH or JJ followed by fixed appliances, these side effects could not be noticed between the groups, agreeing with the findings of the study from Haydar et al. [23]. While these appliances mainly perform direct changes on the maxillary teeth, the mandibular dentoalveolar changes are primarily produced by the fixed appliances [14,15]. The mandibular incisors did not show significantly different changes between the groups, presenting mild labial tipping and protrusion probably due to the use of Class II elastics [36] (table V).
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To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
The mandibular molars on the CH group presented a significantly greater distal inclination when compared to the JJ group, and was the only dentoalveolar variable to present significant intergroup difference (table V). The greater use of Class II elastics in the JJ group, as verified in the patients clinical files, may have contributed to this difference [19,36]. Furthermore, the mandibular molars also presented mesialization in both groups (table V). Again, the use of Class II elastics probably contributed to these changes [36]. In addition, it is important to consider the anterior and vertical displacement of the molars during normal growth, which may have contributed to this change [19,29,37]. The overbite and overjet did not present significant intergroup differences (table V). Both appliances promoted similar anteroposterior effects in the incisors after the use of fixed appliances. These findings corroborate with the study of Brickman et al. [22] that also did not find significant differences in these variables.
Soft Tissue Changes The upper and lower lips presented similar changes during treatment (table V). As almost all dentoalveolar changes were not significantly different between the groups, there were no significant intergroup soft tissue change differences, as expected [15,38].
Clinical Relevance Although the treatment approaches evaluated in this study are classical, it could not be considered outdated. Contemporary and classical orthodontic approaches could be used depending on several factors such as patient need, simplicity, treatment efficiency, the clinician's ability, socioeconomic features and patient
cooperation among others. Orthodontists should consider all these features and provide the best possible individualized treatment. It is reasonable to state that contemporary alternatives with the use of mini-implants such as intraoral distalizers skeletally anchored or even total arch distalization directly supported in the mini-implants may be considered effective approaches that promote acceptable results with even fewer undesirable effects. Nonetheless, further research should be performed to fundament these treatment alternatives.
Original Article
Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study
Conclusions
Both distalizers followed by fixed appliances were effective to correct Class II malocclusion. In general, the effects of these appliances are similar after the end of orthodontic treatment, with the cervical headgear appliance presenting mild skeletal changes and less treatment time when compared to the Jones Jig appliance. There were no significant intergroup differences regarding soft tissue changes. Author contributions: Fernanda Pinelli Henriques Fontes: data collection, statistical analyses and manuscript draft. Silvio Augusto Bellini-Pereira: article draft and critical revision. Aron Aliaga-Del Castillo: data checking and manuscript draft. Mayara Paim Patel: scientific and English revision. Marcos Roberto de Freitas: scientific revision. José Fernando Castanha Henriques: research supervision. Guilherme Janson: scientific and English revision. Acknowledgments: none to declare. Disclosure of interest: the authors declare that they have no competing interest.
References
[2]
[3]
[4]
McNamara Jr JA. Components of class II malocclusion in children 8–10 years of age. Angle Orthod 1981;51:177–202. Josefsson E, Bjerklin K, Lindsten R. Malocclusion frequency in Swedish and immigrant adolescents—influence of origin on orthodontic treatment need. Eur J Orthod 2007;29:79– 87. Tsiouli K, Topouzelis N, Papadopoulos MA, Gkantidis N. Perceived facial changes of Class II Division 1 patients with convex profiles after functional orthopedic treatment followed by fixed orthodontic appliances. Am J Orthod Dentofac Orthop 2017;152:80–91. Patel MP, Janson G, Henriques JF, et al. Comparative distalization effects of Jones jig
tome xx > 000 > xx 2020
[5]
[6]
[7]
[8]
and pendulum appliances. Am J Orthod Dentofacial Orthop 2009;135:336–42. Papageorgiou SN, Kutschera E, Memmert S, et al. Effectiveness of early orthopaedic treatment with headgear: a systematic review and meta-analysis. Eur J Orthod 2017;39:176–87. Carano A, Testa M. The distal jet for upper molar distalization. J Clin Orthod 1996;30:374– 80. Gianelly AA, Vaitas AS, Thomas WM. The use of magnets to move molars distally. Am J Orthod Dentofacial Orthop 1989;96:161–7. Muse DS, Fillman MJ, William JE, Mitchell RD. Molar and incisor changes with Wilson rapid molar distalization. Am J Orthod Dentofac Orthop 1993;104:556–65.
Reis RS, Henriques JF, Janson G, Freitas KMS, Moura W. Dental, skeletal and soft tissue effects of the Distal Jet appliance: a prospective clinical study. Dental Press J Orthod 2019;24:56–64. [10] Grec RHD, Janson G, Branco NC, Moura-Grec PG, Patel MP, Henriques JFC. Intraoral distalizer effects with conventional and skeletal anchorage: a meta-analysis. Am J Orthod Dentofac Orthop 2013;143:602–15. [11] Nur M, Bayram M, Pampu A. Zygoma-gear appliance for intraoral upper molar distalization. Korean J Orthod 2010;40:195–206. [12] Polat-Ozsoy O, Kircelli BH, Arman-Ozçirpici A, Pektas ZO, Uçkan S. Pendulum appliances with 2 anchorage designs: conventional
[9]
11
[1]
To cite this article: Fontes FPH, et al. Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study. International Orthodontics (2020), https://doi.org/10.1016/j.ortho.2020.03.001
Original Article
FPH. Fontes, S.A. Bellini-Pereira, A. Aliaga-Del-Castillo, M.P. Patel, M.R. Freitas, JFC. Henriques, et al.
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
12
[21]
anchorage vs bone anchorage. Am J Orthod Dentofacial Orthop 2008;133. 339.e9-.e17. Jones R, White J. Rapid Class II molar correction with an open-coil jig. J Clin Orthod 1992;26:661. Patel MP, Henriques JFC, Freitas KM, Grec RH. Cephalometric effects of the Jones Jig appliance followed by fixed appliances in Class II malocclusion treatment. Dental Press J Orthod 2014;19:44–51. Vilanova L, Henriques JFC, Janson G, Patel MP, Reis RS, Castillo AA-D. Class II malocclusion treatment effects with Jones jig and distal jet followed by fixed appliances. Angle Orthod 2017;88:10–9. Mandurino M, Balducci L. Asymmetric distalization with a TMA transpalatal arch. J Clin Orthod 2001;35:174. Dahlberg G. Statistical methods for medical and biological students. Statistical methods for medical and biological students. London: George Allen & Unwin; 1940. Houston WJ. The analysis of errors in orthodontic measurements. Am J Orthod 1983;83: 382–90. Angelieri F, de Almeida RR, Janson G, Castanha Henriques JF, Pinzan A. Comparison of the effects produced by headgear and pendulum appliances followed by fixed orthodontic treatment. Eur J Orthod 2008;30:572–9. Artun J, Garol JD, Little RM. Long-term stability of mandibular incisors following successful treatment of Class II, Division 1, malocclusions. Angle Orthod 1996;66:229–38. Pollard LE, Mamandras AH. Male postpubertal facial growth in Class II malocclusions. Am J Orthod Dentofacial Orthop 1995;108:62–8.
[22] Brickman CD, Sinha PK, Nanda RS. Evaluation of the Jones jig appliance for distal molar movement. Am J Orthod Dentofacial Orthop 2000;118:526–34. [23] Haydar S, Uner O. Comparison of Jones jig molar distalization appliance with extraoral traction. Am J Orthod Dentofacial Orthop 2000;117:49–53. [24] Taner TU, Yukay F, Pehlivanoglu M, Cakirer B. A comparative analysis of maxillary tooth movement produced by cervical headgear and pend-x appliance. Angle Orthod 2003;73:686–91. [25] Ferguson DJ, Carano A, Bowman SJ, Davis EC, Gutierrez Vega ME, Lee SH. A comparison of two maxillary molar distalizing appliances with the distal jet. World J Orthod 2005;6 (4):382–90. [26] McNamara JA, Howe RP, Dischinger TG. A comparison of the Herbst and Fränkel appliances in the treatment of Class II malocclusion. Am J Orthod Dentofac Orthop 1990;98: 134–44. [27] Mills CM, McCulloch KJ. Posttreatment changes after successful correction of Class II malocclusions with the Twin Block appliance. Am J Orthod Dentofac Orthop 2000;118: 24–33. [28] Byloff FK, Darendeliler MA. Distal molar movement using the pendulum appliance .1. Clinical and radiological evaluation. Angle Orthod 1997;67:249–60. [29] Bowman S. Upper-molar distalization and the distal jet. J Clin Orthod 2016;50:159. [30] Gandini MREAS, Gandini LG, Martins JCR, Santo MD. Effects of cervical headgear and edgewise appliances on growing patients.
[31]
[32]
[33]
[34]
[35]
[36]
[37]
[38]
J Orthod Dentofacial Orthop Am 2001;119:531–9. King EW. Cervical anchorage in Class II, division 1 treatment, a cephalometric appraisal. Angle Orthod 1957;27:98–104. Klein P. An evaluation of cervical traction on the maxilla and the upper first permanent molar. Angle Orthod 1957;27:61–8. Jayachandran S, Wiltshire WA, Hayasaki SM, Pinheiro FH. Comparison of AdvanSync and intermaxillary elastics in the correction of Class II malocclusions: a retrospective clinical study. Am J Orthod Dentofac Orthop 2016;150:979–88. Kim K-R, Muhl ZF. Changes in mandibular growth direction during and after cervical headgear treatment. Am J Orthod Dentofac Orthop 2001;119:522–30. Bussick TJ, Mc Namara Jr JA. Dentoalveolar and skeletal changes associated with the pendulum appliance. Am J Orthod Dentofacial Orthop 2000;117:333–43. Janson G, Sathler R, Fernandes TMF, Branco NCC, de Freitas MR. Correction of Class II malocclusion with Class II elastics: a systematic review. Am J Orthod Dentofac Orthop 2013;143:383–92. Nelson B, Hansen K, Hägg U. Overjet reduction and molar correction in fixed appliance treatment of Class II, Division 1, malocclusions: Sagittal and vertical components. Am J Orthod Dentofac Orthop 1999;115:13–23. Chiu PP, McNamara Jr JA, Franchi L. A comparison of two intraoral molar distalization appliances: distal jet versus pendulum. Am J Orthod Dentofac Orthop 2005;128:353–65.
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