Original Article
Comparison of double-plate appliance/facemask combination and facemask therapy in treating Class III malocclusions Deniz Gencera; Emine Kaygisizb; Sema Yu¨kselc; Tuba Tortopc ABSTRACT Objective: To compare the treatment effects of double-plate appliance/facemask (DPA-FM) combined therapy and facemask (FM) therapy in treating Class III malocclusions. Materials and Methods: The material consisted of lateral cephalometric radiographs of 45 children with skeletal and dental Class III malocclusion. The first treatment group comprised 15 patients (mean age 5 11 years) treated with FM. The second treatment group comprised 15 patients (mean age 510 years 9 months) treated with DPA-FM. The third group comprised 15 patients (mean age 5 10 years 5 months) used as controls. The paired t-test was used to evaluate the treatment effects and changes during the treatment and observation period in each group. Differences between the groups were determined by variance analysis and the Duncan test. Results: With the DPA-FM and FM appliances, the SNA and ANB angles increased significantly. These changes were statistically different compared with the control group. Lower facial height showed a greater increase in both treatment groups than in the control group. Molar relation showed a greater increase in the DPA-FM group than in the FM group. The increase in U6/ANSPNS angle in the FM group was significantly different from the DPA-FM and control groups. The L1/NB angle and Pg-T increased significantly only in the FM group, but no significant difference was found between the treatment groups. Conclusions: In the treatment of Class III malocclusion, both appliances were effective. The significant sagittal changes in the lower incisors and pogonion in the FM group compared with the nonsignificant changes in the DPA-FM group might be due to the restriction effect of acrylic blocks in the DPA-FM group. (Angle Orthod. 2015;85:278–283.) KEY WORDS: Class III malocclusion; Double-plate appliance; Facemask; Functional
orthopedic treatment approaches to the treatment of skeletal Class III malocclusions.1–6 These appliances are used in different ways, according to malocclusion patterns, skeletal age, patient compliance, and clinician’s experience in their use.4 For growing patients with skeletal problems, intraoral and extraoral appliances, such as the FR-3 appliance, 1 removable mandibular retractor,2 bionator,4 chincap,3 facemask (FM),5 or double-piece corrector,5,6 are indicated. Maxillary protraction is recommended for patients with skeletal Class III malocclusion and maxillary deficiency. For most patients with Class III malocclusion seen in the early mixed dentition or late deciduous dentition, FM is the authors’ customary choice.3 Petit7 introduced FM therapy with opposed angulated blocks of acrylic designed by Planas.8 The aim of the blocks is to alter the vertical components of the masticatory forces to the sagittal components. The double-plate appliance (DPA) was designed as intraoral opposed angulated acrylic blocks. Ucem et al.5
INTRODUCTION Skeletal Class III malocclusions in growing subjects are one of the most complex parts of the contemporary orthodontic practice. Skeletal Class III malocclusions can be due to mandibular prognathism or macrognathia, maxillary retrognathism or micrognathia, or a combination of mandibular and maxillary discrepancies. The literature describes many different orthodontic and Private Practice, Ankara, Turkey. Lecturer, Department of Orthodontics, Gazi University, Faculty of Dentistry, Ankara, Turkey. c Professor, Department of Orthodontics, Gazi University, Faculty of Dentistry, Ankara, Turkey. Corresponding author: Dr Emine Kaygisiz, Department of Orthodontics, Faculty of Dentistry, Gazi University Biskek Cd. (8.Cd.) 82.Sk. No:4 06510 Emek, Ankara, Turkey (e-mail: [email protected]) a b
Accepted: April 2014. Submitted: January 2014. Published Online: June 10, 2014 G 2015 by The EH Angle Education and Research Foundation, Inc. Angle Orthodontist, Vol 85, No 2, 2015
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DOI: 10.2319/013114-83.1
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compared the effects of DPA and FM therapy in Class III malocclusions and reported greater skeletal sagittal changes in the FM group. The dental contribution to Class III treatment seemed to be greater in the DPA group, but in this group vertical dental and skeletal changes were more satisfying. Gencer et al.6 reported that with DPA-FM combination therapy, skeletal and dental Class III malocclusion was treated by maxillary sagittal development while controlling vertical dimensions. In the literature, there are no studies comparing FM therapy with combined DPA-FM therapy. The aim of this study was to compare the treatment effects of DPA-FM and FM therapy in treating Class III malocclusions. The null hypothesis assumed that there are no differences between DPA-FM combined therapy and FM therapy on dentoalveolar and skeletal parameters. MATERIAL AND METHODS This study was approved by the Ethics Committee of Gazi University, Medical Faculty (ethical approval #177). This retrospective study was carried out using pretreatment (T1) and posttreatment (T2) lateral cephalograms of 45 patients with Angle Class III malocclusion characterized by an anterior crossbite and/or Class III molar relationship with skeletal Class III malocclusion (ANB angle # 0u) due to maxillary retrusion (SNA , 82u) or a combination of maxillary retrusion (SNA , 82u) and mandibular protrusion (SNB . 80u) and no congenital anomalies in the craniofacial region. In the first treatment group, 15 patients (7 girls and 8 boys; mean age 5 11 years) wore a Delaire type FM with removable intraoral appliances. The removable intraoral appliance had two Adams clasps at the molars and two F clasps between the upper lateral incisors and canines. The force of the protraction was 350–400 g per side, the angle between the occlusal plane and the direction force applied by the FM was approximately 20u, and the patients were instructed to wear the appliance 16 hours a day. The average treatment time was 9.6 months. The second treatment group of 15 patients (8 girls and 7 boys; mean age 5 10 years 9 months) was treated with DPA-FM. Construction bites for DPA were taken without sagittal activation and with a 5–6 mm vertical opening at the molar region. The appliances had modified Adams clasps at the molar region and F clasps between the upper lateral incisors and canines. Inclination between the acrylic blocks was 30u (Figure 1). The protraction elastics were attached to the F clasps, a force of 350–400 g was applied per side, and the patients were instructed to wear the mask approximately 16 hours a day. At the beginning of treatment
Figure 1. Schematic view of the double-plate appliance.
and every 3 weeks during treatment, 2 mm was trimmed from the posterior region of the lower angulated acrylic block and the anterior region of the upper angulated acrylic block. The aim of this trimming was to facilitate the free sliding of the upper and lower pieces of the appliance along the angulated surfaces. The average treatment time was 10.6 months. The treatment groups were compared with an untreated control group of 15 patients (9 girls and 6 boys; mean age 5 10 years 5 months). The observation period was 10.2 months. The first lateral cephalometric radiographs were taken before appliance insertion (T1), and the second lateral cephalometric radiographs were taken after achieving a positive overjet and a Class I molar occlusion (T2). Nine linear and 10 angular measurements were evaluated (Figure 2). Total superimpositions were made on the best fit of the anterior cranial base. For each superimposition, the pretreatment tracing T-W line (T 5 the most superior point of the anterior wall of the sella turcica at
Figure 2. Cephalometric measurements used in the study: 1 indicates SN; 2, SNA; 3, SNB; 4, ANB; 5, SN/GoGn; 6, ANS-PNS/ GoMe; 7, SN/ANS-PNS; 8, ANS-Me; 9, overbite; 10, overjet; 11, molar relation; 12, upper molar/ANS-PNS; 13, lower molar/GoMe; 14, upper incisor/NA; and 15, lower incisor/NB. Angle Orthodontist, Vol 85, No 2, 2015
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coefficients were calculated and found to be within acceptable limits (range, 0.98–1.00). Statistical analysis was done with SPSS for Windows version 16.0 package (SPSS Inc, Chicago, Ill). The sample size of 15 patients per group at a50.05 yields a statistical power very close to 0.80. A paired t-test was used to evaluate the treatment effects and changes during the treatment and observation period in each group. Differences between the groups were determined by variance analysis and the Duncan test. RESULTS
Figure 3. Measurements on total superimposition: 1 indicates point A-T; 2, point A-TW; 3, pogonion-T; and 4, pogonion-TW total superımposition.
the junction with tuberculum sella; W 5 the point where the middle cranial fossa is intersected by the sphenoid bone) was used as the horizontal reference line. A vertical line perpendicular to T-W at point T was used as the vertical reference plane. On the total superimposition, vertical and horizontal changes in point A and Pg were measured (Figure 3). The lateral cephalometric radiographs of 25 subjects were retraced, and superimpositions and measurements were repeated after 15 days. Method error Table 1.
Pretreatment/Preobservation Mean and Standard Error of the Mean (SEM) Values and Statistical Differences Between the Groupsa FM (Group 1) (n 5 15)
SN (mm) SNA (dg) SNB (dg) ANB (dg) SN/Go-Gn (dg) ANS-PNS/Go-Me (dg) SN/ANS-PNS (dg) ANS-Me (mm) Overbite (mm) Overjet (mm) Molar relation (mm) U6/ANS-PNS (dg) L6/Go-Me (dg) U1/NA (dg) L1/NB (dg) Chronological age a
Descriptive data and statistical comparisons for starting forms and cephalometric changes in groups from T1 to T2 are given in Tables 1 and 2, respectively. Analysis of the starting forms showed that the treated and control groups had no statistically significant differences in craniofacial characteristics at T1 (Table 1). In the FM group, a significant increase in SNA and ANB angles (P , .001) and a significant decrease in SNB angle (P , .01) were observed. During treatment, significant increases in ANS-Me distance and ANSPNS/Go-Me angle were observed (P, .001 and P , .05, respectively). Molar relationship and U6/ANS-PNS were increased significantly (P , .01). The increase in overjet and the decrease in overbite were found to be statistically significant (P , .001 and P , .01, respectively). Protrusion of the maxillary incisors (U1/ NA) and retrusion of the mandibular incisors (L1/NB) in the FM group were statistically significant. On total superimpositions, increases in A-T and Pg-TW dimensions were statistically significant (P , .01 and P , .001, respectively; Table 2).
DPA-FM (Group 2) (n 5 15)
Control (Group 3) (n 5 15)
p
Mean
SEM
Mean
SEM
Mean
SEM
1–2
1–3
2–3
68.3 77.9 80.6 22.7 31.6 25.7 8.1 62.9 3.4 22.6 23.0 103.0 99.3 25.1 20.4 11.0
0.96 0.82 0.87 0.30 1.16 1.43 0.70 1.59 0.48 0.55 0.90 1.31 1.40 2.00 1.45 0.36
67.6 77.2 79.9 22.7 32.3 26.9 8.0 64.1 2.5 22.5 24.7 100.5 94.2 23.6 20.5 10.9
0.91 0.81 0.87 0.52 0.98 1.19 0.76 1.81 0.49 0.4 0.59 1.02 0.93 1.23 1.33 0.35
67.8 77.1 78.9 21.9 34.6 26.7 9.8 62.5 2.2 22.4 23.4 98.5 95.5 21.5 21.1 10.5
0.78 0.81 0.79 0.39 1.18 1.11 0.60 1.09 0.67 0.39 0.57 2.18 2.71 1.80 1.73 0.27
NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS
NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS
NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS
FM indicates facemask; DPA-FM, Double-plate appliance/facemask combination; NS, non-significant.
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Table 2. Treatment Changes of Double-Plate Appliance/Facemask and Facemask Groups and Observation Period Changes of Control Group and Comparison Among Groupsa FM (Group 1) (n 5 15)
SN (mm) SNA (dg) SNB (dg) ANB (dg) SN/Go-Gn (dg) ANS-PNS/Go-Me (dg) SN/ANS-PNS (dg) ANS-Me(mm) Overbite (mm) Overjet (mm) Molar relation (mm) U6/ANS-PNS (dg) L6/Go-Me (dg) U1/NA (dg) L1/NB (dg) A-T A-TW Pg-T Pg-TW a
DPA-FM (Group 2) (n 5 15)
Control (Group 3) (n 5 15)
P
Mean Difference
SD
P
Mean Difference
SD
P
Mean Difference
SD
P
1–2
1–3
2–3
1.3 1.9 21.1 2.9 0.8 1.5 20.6 3.8 22.1 5.3 2.9 5.2 2.9 3.9 22.3 2.7 1.3 21.7 5.0
0.37 0.34 0.33 0.31 0.38 0.61 0.33 0.49 0.46 0.58 0.75 1.35 1.81 1.60 1.16 0.8 0.6 1 1
** *** ** *** NS * NS *** ** *** ** ** NS * * ** NS NS ***
1.4 2.6 20.4 3.0 0.6 1.4 21.5 2.7 21.2 5.3 4.7 21.6 20.5 2.9 20.5 2.8 1.4 20.1 2.8
0.39 0.21 0.31 0.28 0.37 0.49 0.37 0.56 0.38 0.63 0.42 1.27 1.28 0.88 0.91 0.43 0.50 0.83 0.65
** *** NS *** NS * ** *** ** *** *** NS NS ** NS *** * NS **
0.3 0.2 0.7 20.5 20.2 0.2 20.5 0.9 0.2 20.1 20.3 0.5 1.2 1.1 1.5 0.7 1.1 2.2 7.1
0.34 0.30 0.32 0.16 0.34 0.44 0.26 0.44 0.27 0.13 0.21 0.65 0.93 0.88 0.54 0.38 0.36 5.56 0.44
NS NS * ** NS NS NS NS NS NS NS NS NS NS * NS * *** NS
NS NS NS NS NS NS NS NS NS NS * * NS NS NS NS NS NS NS
NS * * * NS NS NS * * * * * NS NS * * NS * NS
NS * * * NS NS NS * * * * NS NS NS NS * NS NS NS
FM indicates facemask; DPA-FM, double-plate appliance/facemask combination; NS, nonsignificant; * P , .05; ** P , .01; *** P , .001.
In the DPA-FM group, increases in SNA and ANB angles were found to be statistically significant (P , .001). The U1/NA angle increased significantly during treatment (P , .01). The ANS-Me, overjet, and molar relationship also increased significantly (P , .001). A significant increase in ANS-PNS/GoMe angle was observed as well (P , .05). On total superimpositions, increases in A-T and Pg-TW were statistically significant (P , .001 and P , .01, respectively; Table 2). In the control group, there were a statistically significant increase in SNB angle (P , .05) and a decrease in ANB angle (P , .01). An increase in L1/ NB angle during the observation period was also statistically significant (P , .05). On total superimposition, Pg-T increased significantly (P , .001; Table 2). Comparisons Among the Groups Increases in the SNA and ANB angles and a decrease in the SNB angle in both treatment groups showed significant differences compared with the control group (P , .05). Changes for both treatment alternatives in ANS-Me distance, overbite, overjet, and molar relationship were significantly different compared with the control group (P , .05). The increase in molar relationship was significantly greater in the DPAFM group than in the FM group. In the FM group, the U6/ANS-PNS degree showed a significant increase compared with the DPA-FM and control groups. The decrease in L1/NB angle in the FM group showed a
significant difference compared with the control group (P , .05; Table 2). In total superimposition, the increase in A-T dimension was significantly different in the treatment groups compared with the control group (P , .05). The change in Pg-T dimension in the FM group was significantly different compared with the control group (P , .05; Table 2). DISCUSSION Ideal treatment in growing patients with skeletal Class III malocclusion aims to improve the horizontal jaw relationship. In clinical studies with FM therapy, forward movement of the maxilla and clockwise rotation of the mandible were reported as typical skeletal effects of the appliance.9–11 The main purpose of the DPA is to counteract the possible tendency toward posterior rotation of the mandible,5,6 which has been shown to be an unfavorable skeletal change in subjects with Class III malocclusion treated with FM and in untreated subjects with Class III malocclusion.12,13 In this study we aimed to evaluate the treatment effects of the combination of these two appliances (DPA-FM) and compare them with FM therapy alone. In this study, the significant increase in SNA and horizontal movement of point A showed that maxillary growth was achieved with both treatment alternatives. These findings are in accordance with FM studies,11,14–17 Angle Orthodontist, Vol 85, No 2, 2015
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282 a DPA study,5 and a DPA-FM study6 that demonstrated forward and downward movement of the maxilla. Cozza et al.18 reported that the craniofacial complex response to active orthopedic treatment of Class III malocclusion with an FM combined bite block appliance consisted of significant changes in maxillary growth and position. Ulgen and Firatli19 found that the increase in SNA angle was not statistically significant after Fra¨nkel III treatment. The amount of forward displacement of the maxilla with DPA-FM treatment was not significantly different compared with FM treatment. However, Cozza et al.18 reported that maxillary displacement was greater with FM and a bite block appliance, which might be due to the use of splints or prolonged time of FM wear. In the present study, SNB angle decreased significantly during FM therapy; however, the change in SNB angle was not significant during DPA-FM therapy. Both changes in SNB angle were significantly different compared with the control group. During FM treatment, change in the horizontal movement of pogonion was also different compared with the control group. A force exerted by the chincap effect of FM has helped redirect the mandibular downward and backward movement. It seemed that combined use of DPA and FM was less effective on the mandible compared with FM therapy alone. These findings were in accordance with other FM studies.20,21 In Class III malocclusion treatment with functional appliances, backward rotation associated with a reduction in mandibular growth was reported.4–6,17,18,22–26 Seehra et al.27 reported that FM therapy had a greater effect on SNB than reverse twin block therapy, indicating a greater downward and backward rotational effect. Changes in the maxilla and the mandible in the treatment groups resulted in increases in ANB (FM, 2.9u; DPA-FM, 3.0u). This result is in accordance with the results of previous studies that aimed to correct the skeletal Class III relation.6,12,18,24,26 Both treatment approaches could be accepted as effective appliances in treating subjects with Class III malocclusion, as these changes were significantly different compared with the control group. Increase in lower facial height (ANS-Me) and decrease in overbite were significantly greater in both treatment groups than in the control group. These changes did not seem to be related to maxillary and mandibular inclination as both showed no significant difference between treatment and control groups. In several FM studies, a backward rotation of the mandible and an increase in lower facial height were reported.11,27 However, some studies5,28 reported that the posterior/anterior face-height ratio remained unchanged; in accordance with this finding, a nonsignificant change was observed in the SN/GoGn angle. Angle Orthodontist, Vol 85, No 2, 2015
The significant decrease in overbite in the treatment groups might be due to maxillary incisor protrusion and changes in lower facial height. The decrease in overbite is in agreement with previous FM studies.5,20 The upper incisor labioversion in both treatment groups was significant but not significantly different compared with the control group. However, retrusion of the lower incisors in the FM group was different compared with the protrusion of lower incisors in the control group. In the DPA-FM group, DPA with the acrylic contacting the lingual surfaces of the mandibular incisors probably played a favorable role in preventing retraction of the mandibular incisors. In the FM group, lower incisor uprighting occurred as a result of the pressure by the chincap. Atalay and Tortop26 and Baik et al.29 reported similar results with different removable appliances. In several FM studies, proclination of the maxillary incisors and retroclination of the mandibular incisors were reported.5,12,17 Cozza et al.18 reported that with FM and a bite block appliance, the effect of maxillary protraction did not cause significant protraction of the maxillary incisors or retraction of the mandibular incisors. Because of the dental and skeletal sagittal changes described earlier, a positive overjet was obtained in both treatment groups, and a negative overjet remained without a significant change in the control group. Tortop et al.30 concluded that changes in upper incisors resulting from treatment with modified tandem traction bow appliance could be responsible for the overjet difference compared with FM treatment. Seehra et al.27 reported that both FM and reverse twin block therapies resulted in similar overjet changes. In molar relation, the significant increase was greater in the DPA-FM group than in the FM group. Increase in the U6/ANS-PNS angle in the FM group was significantly different compared with the DPA-FM and control groups. The removable appliance without the guidance of the angulated surfaces might cause upper molar tipping during FM therapy. CONCLUSIONS N The changes in molar relationship, overjet, and ANB angle in both treatment groups showed significant differences compared with the control group, so it could be concluded that both appliances are effective in treating subjects with Class III malocclusion. N The removable appliance without the guidance of the angulated surfaces might cause upper molar tipping during FM therapy. N Significant sagittal changes in lower incisors and pogonion in the FM group compared with the nonsignificant changes in the DPA-FM group might be due to the restriction effect of acrylic blocks in the DPA- FM group.
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N The null hypothesis partially failed to be rejected; vertical skeletal changes were similar between the DPA-FM and FM groups. REFERENCES 1. Frankel R. Maxillary retrusion in Class III and treatment with the function corrector III. Trans Eur Orthod Soc. 1970;46: 249–259. 2. Tollaro I, Baccetti T, Franchi L. Mandibular skeletal changes induced by early functional treatment of Class III malocclusion: a superimposition study. Am J Orthod Dentofacial Orthop. 1995;108:525–532. 3. Graber TM, Rakosi T, Petrovic AG. Dentofacial Orthopedics with Functional Appliances. 2nd ed. St Louis, MO: CV Mosby; 1997:468. 4. Garattini G, Levrini L, Crozzoli P, Levrini A. Skeletal and dental modifications produced by the Bionator III appliance. Am J Orthod Dentofacial Orthop. 1998;114:40–44. 5. Ucem TT, Ucuncu N, Yuksel S. Comparison of double-plate appliance and face mask therapy in treating Class III malocclusions. Am J Orthod Dentofacial Orthop. 2004;126: 672–679. 6. Gencer D, Hasanog˘lu Nalcı N, Yu¨ksel S, Tortop T. Ag˘ız ˙Ic¸i C ¸ ift Plak- Yu¨z Maskesi Kombinasyonunun Dentofasiyal ¨ niversitesi Dis¸ Yapılara Etkisi [abstract in English]. Gazi U Hekimlig˘i Faku¨ltesi Dergisi. 2009;3:163–170. 7. Petit H. Adaptation following accelerated facial-mask therapy. In: McNamara JA, Ribbens KA, Howe RP, eds. Clinical Alteration of the Growing Face. Monograph No 14. Craniofacial Growth Series. Ann Arbor: Center for Growth and Development, University of Michigan; 1983:253. 8. Planas P. Re´sultats en bouche de l’Orthope´die Fonctionnelle. Socie´te´ Franc¸aise d9Orthope´die Dento-Faciale. Volume des Rapports, pp. 1–24, 1962. Quoted by Petit H. Adaptation following accelerated facial-mask therapy. In: McNamara JA, Ribbens KA, Howe RP, eds. Clinical Alteration of the Growing Face. Monograph No 14. Craniofacial Growth Series. Ann Arbor: Center for Growth and Development, Ann Arbor, MI: University of Michigan; 1983:253. 9. Ishii H, Morita S, Takeuchi Y, Nakamura S. Treatment effect of combined maxillary protraction and chincap appliance in severe skeletal Class III cases. Am J Orthod Dentofacial Orthop. 1987;92:304–312. 10. Gallagher RW, Miranda F, Buschang PH. Maxillary protraction: treatment and posttreatment effects. Am J Orthod Dentofacial Orthop. 1998;113:612–619. 11. Nartallo-Turley PE, Turley PK. Cephalometric effects of combined palatal expansion and face mask therapy on Class III malocclusion. Angle Orthod. 1998;68:217–224. 12. Chong YH, Ive JC, Artun J. Changes following the use of protraction headgear for early correction of Class III malocclusion. Angle Orthod. 1996;66:351–362. 13. Deguchi T, Kanomi R, Ashizawa Y, Rosenstein SW. Very early face mask therapy in Class III children. Angle Orthod. 1999;69:349–355.
283 14. Pangrazio-Kulbersh V, Berger J, Kersten G. Effects of protraction mechanics on the midface. Am J Orthod Dentofacial Orthop. 1998;114:484–491. 15. Saadia M, Torres E. Sagittal changes after maxillary protraction with expansion in Class III patients in the primary, mixed, and late mixed dentitions: a longitudinal retrospective study. Am J Orthod Dentofacial Orthop. 2000; 117:669–680. 16. Suda N, Ishii-Suzuki M, Hirose K, Hiyama S, Suzuki S, Kuroda T. Effective treatment plan for maxillary protraction: is the bone age useful to determine the treatment plan? Am J Orthod Dentofacial Orthop. 2000;118:55–62. 17. Ucuncu N, Ucem TT, Yuksel S. A comparison of chincap and maxillary protraction appliances in the treatment of skeletal Class III malocclusions. Eur J Orthod. 2000;22:43–45. 18. Cozza P, Baccetti T, Mucedero M, Pavoni C, Franchi L. Treatment and posttreatment effects of a facial mask combined with a bite-block appliance in Class III malocclusion. Am J Orthod Dentofacial Orthop. 2010;138:300–310. 19. Ulgen M, Firatli S. The effects of the Fra¨nkel’s function regulator on the Class III malocclusion. Am J Orthod Dentofacial Orthop. 1994;105:561–567. 20. Merwin D, Ngan P, Ha¨gg U, Yiu C, Wei SHY. Timing for effective application of anteriorly directed orthopedic force to the maxilla. Am J Orthod Dentofacial Orthop. 1997;112: 292–299. 21. Baccetti T, Franchi L, McNamara JA. Treatment and posttreatment craniofacial changes after rapid maxillary expansion and face mask therapy. Am J Orthod Dentofacial Orthop. 2000;118:404–413. 22. Tollaro I, Baccetti T, Franchi L. Craniofacial changes induced by early functional treatment of Class III malocclusion. Am J Orthod Dentofacial Orthop. 1996;109:310–318. 23. Baccetti T, Tollaro I. A retrospective comparison of functional appliance treatment of Class III malocclusions in the deciduous and mixed dentitions. Eur J Orthod. 1998;20: 309–317. 24. Kidner G, DiBiase A, DiBiase D. Class III twin blocks: a case series. J Orthod. 2003;30:197–201. 25. Tuncer C, Uner O. Effects of a magnetic appliance in functional Class III patients. Angle Orthod. 2005;75: 768–777. 26. Atalay Z, Tortop T. Dentofacial effects of a modified tandem traction bow appliance. Eur J Orthod. 2010;32:655–661. 27. Seehra J, Fleming PS, Mandall N, DiBiase AT. A comparison of two different techniques for early correction of Class III malocclusion. Angle Orthod. 2012;82:96–101. 28. Mermigos J, Full CA, Andreasen G. Protraction of the maxillofacial complex. Am J Orthod Dentofacial Orthop. 1990;98:47–55. 29. Baik HS, Jee SH, Lee KJ, Oh TK. Treatment effects of Fra¨nkel functional regulator III in children with Class III malocclusions. Am J Orthod Dentofacial Orthop. 2004;125: 294–301. 30. Tortop T, Kaygisiz E, Gencer D, Yuksel S, Atalay Z. Modified tandem traction bow appliance compared with facemask therapy in treating Class III malocclusions. Angle Orthod. 2013 Nov 25. Epub ahead of print.
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Comparison of double-plate appliance/facemask combination and facemask therapy in treating Class III malocclusions Deniz Gencera; Emine Kaygisizb; Sema Yu¨kselc; Tuba Tortopc ABSTRACT Objective: To compare the treatment effects of double-plate appliance/facemask (DPA-FM) combined therapy and facemask (FM) therapy in treating Class III malocclusions. Materials and Methods: The material consisted of lateral cephalometric radiographs of 45 children with skeletal and dental Class III malocclusion. The first treatment group comprised 15 patients (mean age 5 11 years) treated with FM. The second treatment group comprised 15 patients (mean age 510 years 9 months) treated with DPA-FM. The third group comprised 15 patients (mean age 5 10 years 5 months) used as controls. The paired t-test was used to evaluate the treatment effects and changes during the treatment and observation period in each group. Differences between the groups were determined by variance analysis and the Duncan test. Results: With the DPA-FM and FM appliances, the SNA and ANB angles increased significantly. These changes were statistically different compared with the control group. Lower facial height showed a greater increase in both treatment groups than in the control group. Molar relation showed a greater increase in the DPA-FM group than in the FM group. The increase in U6/ANSPNS angle in the FM group was significantly different from the DPA-FM and control groups. The L1/NB angle and Pg-T increased significantly only in the FM group, but no significant difference was found between the treatment groups. Conclusions: In the treatment of Class III malocclusion, both appliances were effective. The significant sagittal changes in the lower incisors and pogonion in the FM group compared with the nonsignificant changes in the DPA-FM group might be due to the restriction effect of acrylic blocks in the DPA-FM group. (Angle Orthod. 2015;85:278–283.) KEY WORDS: Class III malocclusion; Double-plate appliance; Facemask; Functional
orthopedic treatment approaches to the treatment of skeletal Class III malocclusions.1–6 These appliances are used in different ways, according to malocclusion patterns, skeletal age, patient compliance, and clinician’s experience in their use.4 For growing patients with skeletal problems, intraoral and extraoral appliances, such as the FR-3 appliance, 1 removable mandibular retractor,2 bionator,4 chincap,3 facemask (FM),5 or double-piece corrector,5,6 are indicated. Maxillary protraction is recommended for patients with skeletal Class III malocclusion and maxillary deficiency. For most patients with Class III malocclusion seen in the early mixed dentition or late deciduous dentition, FM is the authors’ customary choice.3 Petit7 introduced FM therapy with opposed angulated blocks of acrylic designed by Planas.8 The aim of the blocks is to alter the vertical components of the masticatory forces to the sagittal components. The double-plate appliance (DPA) was designed as intraoral opposed angulated acrylic blocks. Ucem et al.5
INTRODUCTION Skeletal Class III malocclusions in growing subjects are one of the most complex parts of the contemporary orthodontic practice. Skeletal Class III malocclusions can be due to mandibular prognathism or macrognathia, maxillary retrognathism or micrognathia, or a combination of mandibular and maxillary discrepancies. The literature describes many different orthodontic and Private Practice, Ankara, Turkey. Lecturer, Department of Orthodontics, Gazi University, Faculty of Dentistry, Ankara, Turkey. c Professor, Department of Orthodontics, Gazi University, Faculty of Dentistry, Ankara, Turkey. Corresponding author: Dr Emine Kaygisiz, Department of Orthodontics, Faculty of Dentistry, Gazi University Biskek Cd. (8.Cd.) 82.Sk. No:4 06510 Emek, Ankara, Turkey (e-mail: [email protected]) a b
Accepted: April 2014. Submitted: January 2014. Published Online: June 10, 2014 G 2015 by The EH Angle Education and Research Foundation, Inc. Angle Orthodontist, Vol 85, No 2, 2015
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DOI: 10.2319/013114-83.1
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compared the effects of DPA and FM therapy in Class III malocclusions and reported greater skeletal sagittal changes in the FM group. The dental contribution to Class III treatment seemed to be greater in the DPA group, but in this group vertical dental and skeletal changes were more satisfying. Gencer et al.6 reported that with DPA-FM combination therapy, skeletal and dental Class III malocclusion was treated by maxillary sagittal development while controlling vertical dimensions. In the literature, there are no studies comparing FM therapy with combined DPA-FM therapy. The aim of this study was to compare the treatment effects of DPA-FM and FM therapy in treating Class III malocclusions. The null hypothesis assumed that there are no differences between DPA-FM combined therapy and FM therapy on dentoalveolar and skeletal parameters. MATERIAL AND METHODS This study was approved by the Ethics Committee of Gazi University, Medical Faculty (ethical approval #177). This retrospective study was carried out using pretreatment (T1) and posttreatment (T2) lateral cephalograms of 45 patients with Angle Class III malocclusion characterized by an anterior crossbite and/or Class III molar relationship with skeletal Class III malocclusion (ANB angle # 0u) due to maxillary retrusion (SNA , 82u) or a combination of maxillary retrusion (SNA , 82u) and mandibular protrusion (SNB . 80u) and no congenital anomalies in the craniofacial region. In the first treatment group, 15 patients (7 girls and 8 boys; mean age 5 11 years) wore a Delaire type FM with removable intraoral appliances. The removable intraoral appliance had two Adams clasps at the molars and two F clasps between the upper lateral incisors and canines. The force of the protraction was 350–400 g per side, the angle between the occlusal plane and the direction force applied by the FM was approximately 20u, and the patients were instructed to wear the appliance 16 hours a day. The average treatment time was 9.6 months. The second treatment group of 15 patients (8 girls and 7 boys; mean age 5 10 years 9 months) was treated with DPA-FM. Construction bites for DPA were taken without sagittal activation and with a 5–6 mm vertical opening at the molar region. The appliances had modified Adams clasps at the molar region and F clasps between the upper lateral incisors and canines. Inclination between the acrylic blocks was 30u (Figure 1). The protraction elastics were attached to the F clasps, a force of 350–400 g was applied per side, and the patients were instructed to wear the mask approximately 16 hours a day. At the beginning of treatment
Figure 1. Schematic view of the double-plate appliance.
and every 3 weeks during treatment, 2 mm was trimmed from the posterior region of the lower angulated acrylic block and the anterior region of the upper angulated acrylic block. The aim of this trimming was to facilitate the free sliding of the upper and lower pieces of the appliance along the angulated surfaces. The average treatment time was 10.6 months. The treatment groups were compared with an untreated control group of 15 patients (9 girls and 6 boys; mean age 5 10 years 5 months). The observation period was 10.2 months. The first lateral cephalometric radiographs were taken before appliance insertion (T1), and the second lateral cephalometric radiographs were taken after achieving a positive overjet and a Class I molar occlusion (T2). Nine linear and 10 angular measurements were evaluated (Figure 2). Total superimpositions were made on the best fit of the anterior cranial base. For each superimposition, the pretreatment tracing T-W line (T 5 the most superior point of the anterior wall of the sella turcica at
Figure 2. Cephalometric measurements used in the study: 1 indicates SN; 2, SNA; 3, SNB; 4, ANB; 5, SN/GoGn; 6, ANS-PNS/ GoMe; 7, SN/ANS-PNS; 8, ANS-Me; 9, overbite; 10, overjet; 11, molar relation; 12, upper molar/ANS-PNS; 13, lower molar/GoMe; 14, upper incisor/NA; and 15, lower incisor/NB. Angle Orthodontist, Vol 85, No 2, 2015
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coefficients were calculated and found to be within acceptable limits (range, 0.98–1.00). Statistical analysis was done with SPSS for Windows version 16.0 package (SPSS Inc, Chicago, Ill). The sample size of 15 patients per group at a50.05 yields a statistical power very close to 0.80. A paired t-test was used to evaluate the treatment effects and changes during the treatment and observation period in each group. Differences between the groups were determined by variance analysis and the Duncan test. RESULTS
Figure 3. Measurements on total superimposition: 1 indicates point A-T; 2, point A-TW; 3, pogonion-T; and 4, pogonion-TW total superımposition.
the junction with tuberculum sella; W 5 the point where the middle cranial fossa is intersected by the sphenoid bone) was used as the horizontal reference line. A vertical line perpendicular to T-W at point T was used as the vertical reference plane. On the total superimposition, vertical and horizontal changes in point A and Pg were measured (Figure 3). The lateral cephalometric radiographs of 25 subjects were retraced, and superimpositions and measurements were repeated after 15 days. Method error Table 1.
Pretreatment/Preobservation Mean and Standard Error of the Mean (SEM) Values and Statistical Differences Between the Groupsa FM (Group 1) (n 5 15)
SN (mm) SNA (dg) SNB (dg) ANB (dg) SN/Go-Gn (dg) ANS-PNS/Go-Me (dg) SN/ANS-PNS (dg) ANS-Me (mm) Overbite (mm) Overjet (mm) Molar relation (mm) U6/ANS-PNS (dg) L6/Go-Me (dg) U1/NA (dg) L1/NB (dg) Chronological age a
Descriptive data and statistical comparisons for starting forms and cephalometric changes in groups from T1 to T2 are given in Tables 1 and 2, respectively. Analysis of the starting forms showed that the treated and control groups had no statistically significant differences in craniofacial characteristics at T1 (Table 1). In the FM group, a significant increase in SNA and ANB angles (P , .001) and a significant decrease in SNB angle (P , .01) were observed. During treatment, significant increases in ANS-Me distance and ANSPNS/Go-Me angle were observed (P, .001 and P , .05, respectively). Molar relationship and U6/ANS-PNS were increased significantly (P , .01). The increase in overjet and the decrease in overbite were found to be statistically significant (P , .001 and P , .01, respectively). Protrusion of the maxillary incisors (U1/ NA) and retrusion of the mandibular incisors (L1/NB) in the FM group were statistically significant. On total superimpositions, increases in A-T and Pg-TW dimensions were statistically significant (P , .01 and P , .001, respectively; Table 2).
DPA-FM (Group 2) (n 5 15)
Control (Group 3) (n 5 15)
p
Mean
SEM
Mean
SEM
Mean
SEM
1–2
1–3
2–3
68.3 77.9 80.6 22.7 31.6 25.7 8.1 62.9 3.4 22.6 23.0 103.0 99.3 25.1 20.4 11.0
0.96 0.82 0.87 0.30 1.16 1.43 0.70 1.59 0.48 0.55 0.90 1.31 1.40 2.00 1.45 0.36
67.6 77.2 79.9 22.7 32.3 26.9 8.0 64.1 2.5 22.5 24.7 100.5 94.2 23.6 20.5 10.9
0.91 0.81 0.87 0.52 0.98 1.19 0.76 1.81 0.49 0.4 0.59 1.02 0.93 1.23 1.33 0.35
67.8 77.1 78.9 21.9 34.6 26.7 9.8 62.5 2.2 22.4 23.4 98.5 95.5 21.5 21.1 10.5
0.78 0.81 0.79 0.39 1.18 1.11 0.60 1.09 0.67 0.39 0.57 2.18 2.71 1.80 1.73 0.27
NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS
NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS
NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS
FM indicates facemask; DPA-FM, Double-plate appliance/facemask combination; NS, non-significant.
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Table 2. Treatment Changes of Double-Plate Appliance/Facemask and Facemask Groups and Observation Period Changes of Control Group and Comparison Among Groupsa FM (Group 1) (n 5 15)
SN (mm) SNA (dg) SNB (dg) ANB (dg) SN/Go-Gn (dg) ANS-PNS/Go-Me (dg) SN/ANS-PNS (dg) ANS-Me(mm) Overbite (mm) Overjet (mm) Molar relation (mm) U6/ANS-PNS (dg) L6/Go-Me (dg) U1/NA (dg) L1/NB (dg) A-T A-TW Pg-T Pg-TW a
DPA-FM (Group 2) (n 5 15)
Control (Group 3) (n 5 15)
P
Mean Difference
SD
P
Mean Difference
SD
P
Mean Difference
SD
P
1–2
1–3
2–3
1.3 1.9 21.1 2.9 0.8 1.5 20.6 3.8 22.1 5.3 2.9 5.2 2.9 3.9 22.3 2.7 1.3 21.7 5.0
0.37 0.34 0.33 0.31 0.38 0.61 0.33 0.49 0.46 0.58 0.75 1.35 1.81 1.60 1.16 0.8 0.6 1 1
** *** ** *** NS * NS *** ** *** ** ** NS * * ** NS NS ***
1.4 2.6 20.4 3.0 0.6 1.4 21.5 2.7 21.2 5.3 4.7 21.6 20.5 2.9 20.5 2.8 1.4 20.1 2.8
0.39 0.21 0.31 0.28 0.37 0.49 0.37 0.56 0.38 0.63 0.42 1.27 1.28 0.88 0.91 0.43 0.50 0.83 0.65
** *** NS *** NS * ** *** ** *** *** NS NS ** NS *** * NS **
0.3 0.2 0.7 20.5 20.2 0.2 20.5 0.9 0.2 20.1 20.3 0.5 1.2 1.1 1.5 0.7 1.1 2.2 7.1
0.34 0.30 0.32 0.16 0.34 0.44 0.26 0.44 0.27 0.13 0.21 0.65 0.93 0.88 0.54 0.38 0.36 5.56 0.44
NS NS * ** NS NS NS NS NS NS NS NS NS NS * NS * *** NS
NS NS NS NS NS NS NS NS NS NS * * NS NS NS NS NS NS NS
NS * * * NS NS NS * * * * * NS NS * * NS * NS
NS * * * NS NS NS * * * * NS NS NS NS * NS NS NS
FM indicates facemask; DPA-FM, double-plate appliance/facemask combination; NS, nonsignificant; * P , .05; ** P , .01; *** P , .001.
In the DPA-FM group, increases in SNA and ANB angles were found to be statistically significant (P , .001). The U1/NA angle increased significantly during treatment (P , .01). The ANS-Me, overjet, and molar relationship also increased significantly (P , .001). A significant increase in ANS-PNS/GoMe angle was observed as well (P , .05). On total superimpositions, increases in A-T and Pg-TW were statistically significant (P , .001 and P , .01, respectively; Table 2). In the control group, there were a statistically significant increase in SNB angle (P , .05) and a decrease in ANB angle (P , .01). An increase in L1/ NB angle during the observation period was also statistically significant (P , .05). On total superimposition, Pg-T increased significantly (P , .001; Table 2). Comparisons Among the Groups Increases in the SNA and ANB angles and a decrease in the SNB angle in both treatment groups showed significant differences compared with the control group (P , .05). Changes for both treatment alternatives in ANS-Me distance, overbite, overjet, and molar relationship were significantly different compared with the control group (P , .05). The increase in molar relationship was significantly greater in the DPAFM group than in the FM group. In the FM group, the U6/ANS-PNS degree showed a significant increase compared with the DPA-FM and control groups. The decrease in L1/NB angle in the FM group showed a
significant difference compared with the control group (P , .05; Table 2). In total superimposition, the increase in A-T dimension was significantly different in the treatment groups compared with the control group (P , .05). The change in Pg-T dimension in the FM group was significantly different compared with the control group (P , .05; Table 2). DISCUSSION Ideal treatment in growing patients with skeletal Class III malocclusion aims to improve the horizontal jaw relationship. In clinical studies with FM therapy, forward movement of the maxilla and clockwise rotation of the mandible were reported as typical skeletal effects of the appliance.9–11 The main purpose of the DPA is to counteract the possible tendency toward posterior rotation of the mandible,5,6 which has been shown to be an unfavorable skeletal change in subjects with Class III malocclusion treated with FM and in untreated subjects with Class III malocclusion.12,13 In this study we aimed to evaluate the treatment effects of the combination of these two appliances (DPA-FM) and compare them with FM therapy alone. In this study, the significant increase in SNA and horizontal movement of point A showed that maxillary growth was achieved with both treatment alternatives. These findings are in accordance with FM studies,11,14–17 Angle Orthodontist, Vol 85, No 2, 2015
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282 a DPA study,5 and a DPA-FM study6 that demonstrated forward and downward movement of the maxilla. Cozza et al.18 reported that the craniofacial complex response to active orthopedic treatment of Class III malocclusion with an FM combined bite block appliance consisted of significant changes in maxillary growth and position. Ulgen and Firatli19 found that the increase in SNA angle was not statistically significant after Fra¨nkel III treatment. The amount of forward displacement of the maxilla with DPA-FM treatment was not significantly different compared with FM treatment. However, Cozza et al.18 reported that maxillary displacement was greater with FM and a bite block appliance, which might be due to the use of splints or prolonged time of FM wear. In the present study, SNB angle decreased significantly during FM therapy; however, the change in SNB angle was not significant during DPA-FM therapy. Both changes in SNB angle were significantly different compared with the control group. During FM treatment, change in the horizontal movement of pogonion was also different compared with the control group. A force exerted by the chincap effect of FM has helped redirect the mandibular downward and backward movement. It seemed that combined use of DPA and FM was less effective on the mandible compared with FM therapy alone. These findings were in accordance with other FM studies.20,21 In Class III malocclusion treatment with functional appliances, backward rotation associated with a reduction in mandibular growth was reported.4–6,17,18,22–26 Seehra et al.27 reported that FM therapy had a greater effect on SNB than reverse twin block therapy, indicating a greater downward and backward rotational effect. Changes in the maxilla and the mandible in the treatment groups resulted in increases in ANB (FM, 2.9u; DPA-FM, 3.0u). This result is in accordance with the results of previous studies that aimed to correct the skeletal Class III relation.6,12,18,24,26 Both treatment approaches could be accepted as effective appliances in treating subjects with Class III malocclusion, as these changes were significantly different compared with the control group. Increase in lower facial height (ANS-Me) and decrease in overbite were significantly greater in both treatment groups than in the control group. These changes did not seem to be related to maxillary and mandibular inclination as both showed no significant difference between treatment and control groups. In several FM studies, a backward rotation of the mandible and an increase in lower facial height were reported.11,27 However, some studies5,28 reported that the posterior/anterior face-height ratio remained unchanged; in accordance with this finding, a nonsignificant change was observed in the SN/GoGn angle. Angle Orthodontist, Vol 85, No 2, 2015
The significant decrease in overbite in the treatment groups might be due to maxillary incisor protrusion and changes in lower facial height. The decrease in overbite is in agreement with previous FM studies.5,20 The upper incisor labioversion in both treatment groups was significant but not significantly different compared with the control group. However, retrusion of the lower incisors in the FM group was different compared with the protrusion of lower incisors in the control group. In the DPA-FM group, DPA with the acrylic contacting the lingual surfaces of the mandibular incisors probably played a favorable role in preventing retraction of the mandibular incisors. In the FM group, lower incisor uprighting occurred as a result of the pressure by the chincap. Atalay and Tortop26 and Baik et al.29 reported similar results with different removable appliances. In several FM studies, proclination of the maxillary incisors and retroclination of the mandibular incisors were reported.5,12,17 Cozza et al.18 reported that with FM and a bite block appliance, the effect of maxillary protraction did not cause significant protraction of the maxillary incisors or retraction of the mandibular incisors. Because of the dental and skeletal sagittal changes described earlier, a positive overjet was obtained in both treatment groups, and a negative overjet remained without a significant change in the control group. Tortop et al.30 concluded that changes in upper incisors resulting from treatment with modified tandem traction bow appliance could be responsible for the overjet difference compared with FM treatment. Seehra et al.27 reported that both FM and reverse twin block therapies resulted in similar overjet changes. In molar relation, the significant increase was greater in the DPA-FM group than in the FM group. Increase in the U6/ANS-PNS angle in the FM group was significantly different compared with the DPA-FM and control groups. The removable appliance without the guidance of the angulated surfaces might cause upper molar tipping during FM therapy. CONCLUSIONS N The changes in molar relationship, overjet, and ANB angle in both treatment groups showed significant differences compared with the control group, so it could be concluded that both appliances are effective in treating subjects with Class III malocclusion. N The removable appliance without the guidance of the angulated surfaces might cause upper molar tipping during FM therapy. N Significant sagittal changes in lower incisors and pogonion in the FM group compared with the nonsignificant changes in the DPA-FM group might be due to the restriction effect of acrylic blocks in the DPA- FM group.
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N The null hypothesis partially failed to be rejected; vertical skeletal changes were similar between the DPA-FM and FM groups. REFERENCES 1. Frankel R. Maxillary retrusion in Class III and treatment with the function corrector III. Trans Eur Orthod Soc. 1970;46: 249–259. 2. Tollaro I, Baccetti T, Franchi L. Mandibular skeletal changes induced by early functional treatment of Class III malocclusion: a superimposition study. Am J Orthod Dentofacial Orthop. 1995;108:525–532. 3. Graber TM, Rakosi T, Petrovic AG. Dentofacial Orthopedics with Functional Appliances. 2nd ed. St Louis, MO: CV Mosby; 1997:468. 4. Garattini G, Levrini L, Crozzoli P, Levrini A. Skeletal and dental modifications produced by the Bionator III appliance. Am J Orthod Dentofacial Orthop. 1998;114:40–44. 5. Ucem TT, Ucuncu N, Yuksel S. Comparison of double-plate appliance and face mask therapy in treating Class III malocclusions. Am J Orthod Dentofacial Orthop. 2004;126: 672–679. 6. Gencer D, Hasanog˘lu Nalcı N, Yu¨ksel S, Tortop T. Ag˘ız ˙Ic¸i C ¸ ift Plak- Yu¨z Maskesi Kombinasyonunun Dentofasiyal ¨ niversitesi Dis¸ Yapılara Etkisi [abstract in English]. Gazi U Hekimlig˘i Faku¨ltesi Dergisi. 2009;3:163–170. 7. Petit H. Adaptation following accelerated facial-mask therapy. In: McNamara JA, Ribbens KA, Howe RP, eds. Clinical Alteration of the Growing Face. Monograph No 14. Craniofacial Growth Series. Ann Arbor: Center for Growth and Development, University of Michigan; 1983:253. 8. Planas P. Re´sultats en bouche de l’Orthope´die Fonctionnelle. Socie´te´ Franc¸aise d9Orthope´die Dento-Faciale. Volume des Rapports, pp. 1–24, 1962. Quoted by Petit H. Adaptation following accelerated facial-mask therapy. In: McNamara JA, Ribbens KA, Howe RP, eds. Clinical Alteration of the Growing Face. Monograph No 14. Craniofacial Growth Series. Ann Arbor: Center for Growth and Development, Ann Arbor, MI: University of Michigan; 1983:253. 9. Ishii H, Morita S, Takeuchi Y, Nakamura S. Treatment effect of combined maxillary protraction and chincap appliance in severe skeletal Class III cases. Am J Orthod Dentofacial Orthop. 1987;92:304–312. 10. Gallagher RW, Miranda F, Buschang PH. Maxillary protraction: treatment and posttreatment effects. Am J Orthod Dentofacial Orthop. 1998;113:612–619. 11. Nartallo-Turley PE, Turley PK. Cephalometric effects of combined palatal expansion and face mask therapy on Class III malocclusion. Angle Orthod. 1998;68:217–224. 12. Chong YH, Ive JC, Artun J. Changes following the use of protraction headgear for early correction of Class III malocclusion. Angle Orthod. 1996;66:351–362. 13. Deguchi T, Kanomi R, Ashizawa Y, Rosenstein SW. Very early face mask therapy in Class III children. Angle Orthod. 1999;69:349–355.
283 14. Pangrazio-Kulbersh V, Berger J, Kersten G. Effects of protraction mechanics on the midface. Am J Orthod Dentofacial Orthop. 1998;114:484–491. 15. Saadia M, Torres E. Sagittal changes after maxillary protraction with expansion in Class III patients in the primary, mixed, and late mixed dentitions: a longitudinal retrospective study. Am J Orthod Dentofacial Orthop. 2000; 117:669–680. 16. Suda N, Ishii-Suzuki M, Hirose K, Hiyama S, Suzuki S, Kuroda T. Effective treatment plan for maxillary protraction: is the bone age useful to determine the treatment plan? Am J Orthod Dentofacial Orthop. 2000;118:55–62. 17. Ucuncu N, Ucem TT, Yuksel S. A comparison of chincap and maxillary protraction appliances in the treatment of skeletal Class III malocclusions. Eur J Orthod. 2000;22:43–45. 18. Cozza P, Baccetti T, Mucedero M, Pavoni C, Franchi L. Treatment and posttreatment effects of a facial mask combined with a bite-block appliance in Class III malocclusion. Am J Orthod Dentofacial Orthop. 2010;138:300–310. 19. Ulgen M, Firatli S. The effects of the Fra¨nkel’s function regulator on the Class III malocclusion. Am J Orthod Dentofacial Orthop. 1994;105:561–567. 20. Merwin D, Ngan P, Ha¨gg U, Yiu C, Wei SHY. Timing for effective application of anteriorly directed orthopedic force to the maxilla. Am J Orthod Dentofacial Orthop. 1997;112: 292–299. 21. Baccetti T, Franchi L, McNamara JA. Treatment and posttreatment craniofacial changes after rapid maxillary expansion and face mask therapy. Am J Orthod Dentofacial Orthop. 2000;118:404–413. 22. Tollaro I, Baccetti T, Franchi L. Craniofacial changes induced by early functional treatment of Class III malocclusion. Am J Orthod Dentofacial Orthop. 1996;109:310–318. 23. Baccetti T, Tollaro I. A retrospective comparison of functional appliance treatment of Class III malocclusions in the deciduous and mixed dentitions. Eur J Orthod. 1998;20: 309–317. 24. Kidner G, DiBiase A, DiBiase D. Class III twin blocks: a case series. J Orthod. 2003;30:197–201. 25. Tuncer C, Uner O. Effects of a magnetic appliance in functional Class III patients. Angle Orthod. 2005;75: 768–777. 26. Atalay Z, Tortop T. Dentofacial effects of a modified tandem traction bow appliance. Eur J Orthod. 2010;32:655–661. 27. Seehra J, Fleming PS, Mandall N, DiBiase AT. A comparison of two different techniques for early correction of Class III malocclusion. Angle Orthod. 2012;82:96–101. 28. Mermigos J, Full CA, Andreasen G. Protraction of the maxillofacial complex. Am J Orthod Dentofacial Orthop. 1990;98:47–55. 29. Baik HS, Jee SH, Lee KJ, Oh TK. Treatment effects of Fra¨nkel functional regulator III in children with Class III malocclusions. Am J Orthod Dentofacial Orthop. 2004;125: 294–301. 30. Tortop T, Kaygisiz E, Gencer D, Yuksel S, Atalay Z. Modified tandem traction bow appliance compared with facemask therapy in treating Class III malocclusions. Angle Orthod. 2013 Nov 25. Epub ahead of print.
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