Soft- and hard-tissue changes following treatment of Class II division 1 malocclusion with Activator versus Trainer: a randomized controlled trial

Soft- and hard-tissue changes following treatment of Class II division 1 malocclusion with... Summary Background Increased awareness on the role of oral functions in the aetiology of Class II deformities has led to the wide spread of myofunctional training appliances as easy and possibly effective treatment for children with Class II malocclusion but their efficacy is yet to be proven. Objectives To evaluate soft- and hard-tissue changes following 12 months of Class II division 1 treatment in growing patients with a conventional functional appliance (a modified Activator) versus a myofunctional Trainer system (T4K®). Setting and sample population Department of Orthodontics, Dental School. Participants, study design, and methods: Sixty Class II division 1 children (8–12 years old) were recruited from primary schools and were distributed randomly into two equal groups. Randomization was based on a computer-generated sequence of random numbers. Data analysis included: the Activator group (28 patients, mean age = 10.6 ± 1.3 years); the T4K® group (26 patients, mean age = 10.3 ± 1.4 years). Skeletal, dentoalveolar, and soft tissues changes were assessed using standardized lateral cephalograms collected before and after 12 months of treatment. No blinding was applied in this trial. Results Improvement in the Class II skeletal and dentofacial characteristics were significantly greater in the Activator group when compared with the T4K® group. The improvement was evident in a significant decrease in the skeletal angle ANB with Activator ( x¯ = −1.89 ± 1.12) compared to T4K® ( x¯ = −0.9 ± 1.01) (P = 0.01), a significant greater increase in the facial convexity angle with Activator ( x¯ = 2.61 ± 3.71) more than T4K® ( x¯ = 0.2 ± 2.51) (P = 0.04), and a significant reduction in the overjet ( x¯ = −3.0 ± 2.3 mm) compared to ( x¯ = −1.5 ± 1.9 mm; P = 0.01) with Activator versus T4k®, respectively (P = 0.001). Limitations This study was a short-term study (12-month follow-up). Conclusions The results of the current study indicated that the Activator was more effective than the T4K® in treating Class II division 1 growing patients. Registration The trial was not registered in any major database of clinical trials. Protocol The protocol was not published before the commencement of the trial but can be given upon request. Introduction Since the early functional appliances have been introduced by Robin 1902 and Andresen 1908 to enhance mandibular growth in growing Class II patients, a wide range of functional appliances have been introduced to stimulate mandibular growth and correct the bite by forward positioning of the mandible (1–5). The available reports showed that short-term evidence indicates that the functional appliances are effective in correcting Class II malocclusion (5–7). The effects of abnormal lip and tongue functions and habits on craniofacial development have been well identified (8, 9), consequently much attention has been paid to control the dentofacial growth by correcting oral dysfunction and establishing oral muscular balance (10). Since the introduction of the oral screen by Newel in 1912 as a myofunctional appliance, various appliances have been developed such as the oral shield (11, 12), the double oral screen (13), Eruption Guidance Appliance (EGA) as a prefabricated elastomeric appliance (14), and recently the Positioner Trainer (Trainer For Kids: T4K®) by Farrell as a prefabricated treatment system in mixed dentition. Wearing these appliances should be accompanied by myofunctional exercise as a part of the treatment (15, 16). Studies about myofunctional appliances have reported positive changes in the lower dental arch and the maxillary incisors (16, 17). However, the effectiveness of orofacial myofunctional therapy in orthodontic patients is still questionable (18). A few studies have been published evaluating the efficacy of the T4K®. These studies reported a significant reduction of overjet in the treated subjects (15, 19, 20). The available studies have methodological flaws such as lack of a control group, absence of randomization, or absence of a cephalometric analysis. A study done by Quadrelli and colleagues in 2002 was a case series report of six participants distributed into two groups using T4K®: the soft T4K® type for the first group and the hard T4K® type for the second group. Another study was published by Usumez and colleagues in 2003 which was a non-randomized controlled trial. The control group comprised patients who refused to be treated by T4K® whereas patients in the experimental group were not obliged to wear both types of the appliance as recommended by the developers of the Trainer system. Although a recent study by Čirgić and colleagues 2015 was a randomized controlled trial, however the study did not evaluate soft- and hard-tissue changes by radiographic means. The only available data were based on clinical examinations. Functional appliances vary in their effects according to their design (21), therefore a raft of studies have been accomplished to compare different types of functional appliances. Furthermore, the Activator has been considered as the most common basic functional appliance to be compared with other appliances (22–28). With the increased awareness of the easiness and the possible positive effects of myofunctional training appliances in the early treatment of Class II deformities, the use of T4K® system has been claimed to spread worldwide as a simple treatment system (29). The efficacy of T4K® use is yet to be proven with a few available studies in the literature. Therefore, it seems reasonable that a comparison should be made between the traditional functional treatment (i.e. the Activator) which depends on a great extent on mandibular advancement and the myofunctional treatment (i.e. the T4K®) which depends mainly on correcting abnormal positioning of the lips and tongue. This randomized controlled trial aimed to evaluate soft and hard tissue changes after 12 months of applying functional treatment for growing Class II division 1 patients using two different methods: the modified Activator versus the Positioner Trainer (T4K®). Materials and methods Sample size estimation The G*Power software version 3.0.8 (Universität Kiel, Germany) was used for sample size calculation. In order to detect a difference of 1 degree in the ANB angle (5) using two-sample t test with a power of 95 per cent and an alpha of 0.05 with a reported variance of this variable in a previous study of 1 degree (19), 23 patients were required. We aimed to recruit 30 patients in each group to compensate for any possible dropouts. Participants The study was approved by the Local Ethics Committee in Al-Baath University Dental School (Ref 1165/Dent/MSc/022006). This research project was accomplished at the Department of Orthodontics, Dental School, Al-Baath University between June 2006 to August 2008. Two thousand two hundred and twenty-six children were screened in a randomly selected 13 schools out of the primary schools in two major cities in Syria (i.e. Homs and Hamah in the middle region of Syria). Children were screened in these schools using examination gloves and disposable plastic rulers to measure the overjet. Children who met the eligibility criteria (8–12 years old, Class II division 1 features with overjet >4 mm) were invited to participate in this study by sending letters of invitation to their parents. The responders were 188 children; all participants were provided with information sheets about the study and their informed consents were obtained. Patients’ recruitment and follow-up flow diagram is given in Figure 1. Figure 1. View largeDownload slide CONSORT Participants’ recruitment flow diagram in this trial. Figure 1. View largeDownload slide CONSORT Participants’ recruitment flow diagram in this trial. Randomization Sixty participants were selected randomly out of the 188 possible candidates using a computer-generated list of random numbers with the aid of SPSS (SPSS Inc. SPSS for Windows, Version 15.0. Chicago, SPSS Inc.). Chosen patients were randomly allocated to the two arms of this study with an allocation ratio of 1:1 (30 participants in each group). Randomization was performed by one of the academic staff at the Orthodontic Department who was not involved directly in this research project using a computer-generated random sequence of numbers. Allocation concealment was performed using opaque sealed envelopes which contained the assigned group for each patient and were not opened till the onset of the trial. The following inclusion criteria were applied: 8–12 years old patients and of a Syrian ancestry; Increased overjet >4 mm; Skeletal Class II relationship (ANB > 4 degree, Wits appraisal > 2 mm); Normal lower incisor/mandibular plane relationship (93° ± 5); No previous orthodontic treatment Patients with craniofacial syndromes were excluded. Skeletal age of the participants was determined based on hand-wrist radiographs analysed according to Bjork–Brown–Grace and the included patients were in one of these stages (PP2=, MP3=, S) (30, 31). The final sample consisted of 54 patients because six patients were lost to follow-up due to different reasons. There were 28 patients in the Activator group (14 males and 14 females; with an average age of 10.6 ± 1.3 years), 26 patients in the Trainer group (14 males and 12 females; with an average age of 10.3 ± 1.4 years). Baseline sample characteristics for each group are given in Table 1. Table 1. Baseline sample characteristic. Variable Activator Trainer (T4K®) Both groups P value Age/year (mean ± SD) 10.6 ± 1.3 10.3 ± 1.4 10.7 ± 1.3 0.700* Height/cm (mean ± SD) 148.1 ± 7.5 147.7 ± 6.3 147.9 ± 6.8 0.562* Sex n (%)  Male 14 (50%) 14 (53.8%) 28 (51.8%) 0.758†  Female 14 (50%) 12 (46.2%) 26 (48.2%) Skeletal age  PP2= 12 9 21 0.139†  MP3= 11 16 27  S 5 1 6 Variable Activator Trainer (T4K®) Both groups P value Age/year (mean ± SD) 10.6 ± 1.3 10.3 ± 1.4 10.7 ± 1.3 0.700* Height/cm (mean ± SD) 148.1 ± 7.5 147.7 ± 6.3 147.9 ± 6.8 0.562* Sex n (%)  Male 14 (50%) 14 (53.8%) 28 (51.8%) 0.758†  Female 14 (50%) 12 (46.2%) 26 (48.2%) Skeletal age  PP2= 12 9 21 0.139†  MP3= 11 16 27  S 5 1 6 *Two-sample t-test, level of differences set at 0.05. †Pearson’s chi-square test, level of significant set at 0.05; Biological age using hand and wrist radiograph stages: PP2= stage: the epiphysis of the proximal phalanx of the index finger has the same width as the diaphysis; MP3= stage: epiphysis of the middle phalanx of the middle finger is of the same width as the diaphysis; S stage: first mineralization of the sesamoid bone of the metacarpophalangeal joint of the hamular process of the hamatum. View Large Table 1. Baseline sample characteristic. Variable Activator Trainer (T4K®) Both groups P value Age/year (mean ± SD) 10.6 ± 1.3 10.3 ± 1.4 10.7 ± 1.3 0.700* Height/cm (mean ± SD) 148.1 ± 7.5 147.7 ± 6.3 147.9 ± 6.8 0.562* Sex n (%)  Male 14 (50%) 14 (53.8%) 28 (51.8%) 0.758†  Female 14 (50%) 12 (46.2%) 26 (48.2%) Skeletal age  PP2= 12 9 21 0.139†  MP3= 11 16 27  S 5 1 6 Variable Activator Trainer (T4K®) Both groups P value Age/year (mean ± SD) 10.6 ± 1.3 10.3 ± 1.4 10.7 ± 1.3 0.700* Height/cm (mean ± SD) 148.1 ± 7.5 147.7 ± 6.3 147.9 ± 6.8 0.562* Sex n (%)  Male 14 (50%) 14 (53.8%) 28 (51.8%) 0.758†  Female 14 (50%) 12 (46.2%) 26 (48.2%) Skeletal age  PP2= 12 9 21 0.139†  MP3= 11 16 27  S 5 1 6 *Two-sample t-test, level of differences set at 0.05. †Pearson’s chi-square test, level of significant set at 0.05; Biological age using hand and wrist radiograph stages: PP2= stage: the epiphysis of the proximal phalanx of the index finger has the same width as the diaphysis; MP3= stage: epiphysis of the middle phalanx of the middle finger is of the same width as the diaphysis; S stage: first mineralization of the sesamoid bone of the metacarpophalangeal joint of the hamular process of the hamatum. View Large Appliances used in the trial The modified Activator The Modified Activator used in the study was originally introduced by Schmuth in 1971 and consisted of acrylic body, two splints meeting each other in the occlusal plane, upper and lower labial bows, Coffin spring in the upper plate, and acrylic capping holding the lower incisors (Figure 2A) (1). The construction bite was taken by advancing the mandible to achieve a Class I or super Class I molar relationship with a 5–6-mm vertical opening in the premolars region. Patients were instructed to wear their appliances for 15 hours per day. At follow-up visits, the occlusal bite plane was gradually trimmed to guide the eruption of the posterior teeth, settling occlusion and Class I molar relation, and for occlusal plane levelling. Figure 2. View largeDownload slide (A) The modified Activator (Schmuth’s modification) consisted of acrylic body, labial bows, Coffin spring, and acrylic capping of the lower incisors. (B) The positioner trainer or trainer for kids (T4K®) consisting of tooth channels, labial bows, tongue tag, tongue guard, and lip bumpers. Figure 2. View largeDownload slide (A) The modified Activator (Schmuth’s modification) consisted of acrylic body, labial bows, Coffin spring, and acrylic capping of the lower incisors. (B) The positioner trainer or trainer for kids (T4K®) consisting of tooth channels, labial bows, tongue tag, tongue guard, and lip bumpers. The positioning trainer Trainer is a prefabricated appliance (Trainer For Kids T4K®, Myofunctional Research Co., Queensland, Australia), which is made of flexible material in a universal size for all children between 6 and 11 years of age. The Positioner Trainer consisted of tooth channels, labial bows, tongue tag, tongue guard, and lip bumpers (Figure 2B) (32). Patients were instructed to wear their appliance for 2 hours in the day and overnight while they sleep. During day-time, patients were asked to do simple myotherapy exercises: positioning the tongue tip on the tongue tag and swallowing while holding the appliance in place with closed lips; children were asked to repeat this exercise for three sets of 10 times. In addition, they were instructed to do another exercise by holding a small piece of paper between the lips and breathe through the nose with the tongue tip on the tongue tag; a child should do this exercise 3–5 minutes divided on three times during the day. These simple myofunctional exercises aimed to encourage breathing through the nose, to correct the tongue position, and to improve swallowing pattern. All participants had soft trainers for the first 6 months; thereafter hard trainers were used for the remaining period of the treatment. Cephalometric analysis and the primary outcome measures Standardized lateral cephalograms were collected before the commencement of treatment (T1) and at 12 months of treatment (T2). Cephalometric landmarks were determined on the lateral cephalograms by on-screen digitization and the measurements were accomplished by a special orthodontic software (AD-Orth Version1.0, ARAB-Dent.Co. Damascus, Syria). Pre- and post-treatment cephalograms were superimposed using the anterior cranial base line (S-N) as a reference line. Angular and linear measurements were used in evaluating dentoskeletal and soft tissue changes. These measurements are illustrated in Figures 3 and 4. Supplementary Table 1 provides the definition of cephalometric measurements used in the study. Cephalometric analysis results were exported in Excel format and statistically analysed using SPSS software (SPSS, IBM Corp. Version 22.0. Armonk, New York, USA). Figure 3. View largeDownload slide Angular skeletal measurements 1. SNA; 2. SNB; 3. ANB; 4. N.A.Pog; 5. S.N.Pog; 6. FH/MP; 7. MM; 8. YAxis; 9. GoMe/SN; 10. Me.Go.Ar; 11. SPP/SN; 12. overjet and dental measurements; 13. Overbite; 14. U1/SPP; 15. U1/SN; 16. L1Axis/MP; 17. U1/L1 (See Supplementary Table 1, available online, for variables’ definitions). Figure 3. View largeDownload slide Angular skeletal measurements 1. SNA; 2. SNB; 3. ANB; 4. N.A.Pog; 5. S.N.Pog; 6. FH/MP; 7. MM; 8. YAxis; 9. GoMe/SN; 10. Me.Go.Ar; 11. SPP/SN; 12. overjet and dental measurements; 13. Overbite; 14. U1/SPP; 15. U1/SN; 16. L1Axis/MP; 17. U1/L1 (See Supplementary Table 1, available online, for variables’ definitions). Figure 4. View largeDownload slide Soft tissues measurements: 18. Gla.Sn.Pog’; 19. Nasolabial angle; 20. Mentolabial angle; 21. Upper lip to Ricketts E line; 22. Lower lip to Ricketts E line. and Linear skeletal measurements: 23. Wits appraisal; 24. Cd-Gn; 25. Go-Pog; 26. Cd-Go. (See Supplementary Table 1, available online, for variables’ definitions). Figure 4. View largeDownload slide Soft tissues measurements: 18. Gla.Sn.Pog’; 19. Nasolabial angle; 20. Mentolabial angle; 21. Upper lip to Ricketts E line; 22. Lower lip to Ricketts E line. and Linear skeletal measurements: 23. Wits appraisal; 24. Cd-Gn; 25. Go-Pog; 26. Cd-Go. (See Supplementary Table 1, available online, for variables’ definitions). Error of the method Two weeks after the first digitization, 20 radiographs were selected randomly and cephalometric analysis was performed again. The error of the method was estimated according to Dahlberg’s formula (33) which ranged from 0.11 to 0.58 for the angular measurements and from 0.10 to 0.46 for the linear measurements. Furthermore, systematic error and interclass correlation coefficients (ICCs) showed that measurements used were highly reliable with no systematic error for all variables; Supplementary Table 2. The collected data were subjected to statistical analysis using SPSS software (SPSS, IBM Corp. Version 22.0. Armonk, New York, USA). Paired-sample t-test or Wilcoxon matched-pairs signed rank test according to normality test was used for intragroup comparisons. Differences between groups were evaluated using two-sample t tests or Mann–Whitney U tests according to the normality of distributions applying Kolmogorov–Smirnov tests. Results Standardized lateral cephalometric radiographs were taken before and after 12 months of the treatment. Skeletal measurements in both groups are demonstrated in Table 2. Improvement in the skeletal Class II features was detected in both groups, however the inter-group comparison showed significantly greater improvement with Activator when compared with T4k® treatment; SNB angle increased significantly in Activator ( x¯ = +1.30 ± 1.11) more than T4K®( x¯ = +0.34 ± 1.49) (P = 0.01); and a significantly greater decrease in the ANB angle was detected with Activator ( x¯ = −1.89 ± 1.12) compared to T4K ( x¯ = −0.9 ± 1.01) (P = 0.01); furthermore, the N.A.Pog angle increased significantly with Activator ( x¯ = +3.39 ± 2.49) more than T4K® ( x¯ = +1.91 ± 2.03) (P = 0.04). Ramus height showed a larger increase with Activator ( x¯ = +2.66 ± 0.71 mm) in compared to a slight change with T4K® ( x¯ = +0.48 ± 1.61 mm) (P < 0.001). The overall anterior facial height showed a significant larger increase with Activator ( x¯ = +3.99 ± 4.43 mm) more than T4K® ( x¯ = +0.64 ± 3.73 mm) (P = 0.004). Moreover, the lower anterior facial height (ANS-Me) increased significantly with the Activator ( x¯ = +2.05 ± 2.92 mm) compared to ( x¯ = +0.53 ± 2.43 mm) in T4k® group3 (P = 0.04). Table 2. Descriptive statistics of the assessed skeletal variables in the two groups as well as the associated P-values of significance tests. Variable Activator T4k P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P-value change over time Mean before SD Mean after SD Mean difference SD P value change over time SNA 80.33 3.32 79.74 3.15 −0.59 1.12 0.011* 81.86 5.37 81.30 5.30 −0.56 1.21 0.021* 0.814 SNB 73.91 3.19 75.21 2.83 1.30 1.11 <0.001**a 74.75 4.99 75.0.9 4.81 0.34 1.49 0.081 0.016** ANB 6.42 1.65 4.53 1.69 −1.89 1.12 <0.001**ab 7.11 1.89 6.21 2.04 −0.9 1.01 0.012*a 0.001**b N.A.Pog 167.58 4.27 170.97 4.30 3.39 2.49 <0.001** a b 166.31 4.95 168.22 5.46 1.91 2.03 <0.001**ab 0.041*b S.N.Pog 74.65 3.18 75.60 2.84 0.95 1.18 <0.001**a 75.48 4.87 75.82 4.62 0.34 1.26 0.195 0.087 FH.MP 28.95 5.38 28.80 4.92 −0.15 2.15 0.712 29.12 5.64 29.98 5.10 0.86 2.10 0.045* 0.085 MM 28.34 5.21 27.92 4.84 −0.42 2.43 0.353 29.79 6.49 29.88 5.89 0.09 2.08 0.821 0.599 Y-axis 67.81 3.33 67.66 3.13 −0.15 1.78 0.645 67.76 5.16 67.99 4.94 0.23 1.23 0.316b 0.357 GoMe/SN 36.97 5.02 36.99 4.60 0.02 2.01 0.964 37.57 6.85 37.79 6.81 0.22 1.62 0.625 0.607 Ar.Go.Me 129.27 5.63 129.83 5.46 0.56 1.75 0.09 130.41 6.49 130.51 6.63 0.1 1.98 0.437b 0.430 Wits app 3.93 2.03 1.57 1.44 −2.36 2.14 <0.001**ab 4.23 2.35 2.50 1.69 −1.73 2.04 <0.001a** 0.222b SPP/SN 7.98 3.15 7.54 3.50 −0.44 0.12 0.421 6.91 2.08 5.65 3.13 −1.26 0.19 0.082 0.890 Cd-Gn 106.03 7.35 108.92 7.5 2.89 5.14 0.014* 98.66 5.63 100.11 5.41 1.45 3.44 0.248b 0.194b Go-Pog 69.69 6.01 71.93 6.4 2.24 2.81 <0.001**a 65.45 5.03 66.42 5.40 0.97 2.69 0.062 0.084 Cd-Go 60.59 4.29 63.25 4.2 2.66 0.71 <0.001**a 58.66 4.30 59.14 3.21 0.48 1.61 0.357 <0.001**a N-Me 113.54 8.57 117.53 10.2 3.99 4.43 <0.001**a 106.27 6.79 106.91 7.66 0.64 3.73 0.263 0.004* Na-ANS 51.31 4.90 52.82 5.8 1.51 2.39 <0.001**a 47.75 3.39 48.28 3.57 0.53 1.67 0.131 0.094 ANS-Me 65.20 5.29 67.25 6.0 2.05 2.92 <0.001**a 61.39 5.21 61.92 5.21 0.53 2.43 0.179b 0.041* ANS-PNS 50.29 4.52 52.01 5.3 1.72 3.78 0.023* 48.47 3.90 49.63 3.24 1.16 2.81 0.041* 0.582 Variable Activator T4k P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P-value change over time Mean before SD Mean after SD Mean difference SD P value change over time SNA 80.33 3.32 79.74 3.15 −0.59 1.12 0.011* 81.86 5.37 81.30 5.30 −0.56 1.21 0.021* 0.814 SNB 73.91 3.19 75.21 2.83 1.30 1.11 <0.001**a 74.75 4.99 75.0.9 4.81 0.34 1.49 0.081 0.016** ANB 6.42 1.65 4.53 1.69 −1.89 1.12 <0.001**ab 7.11 1.89 6.21 2.04 −0.9 1.01 0.012*a 0.001**b N.A.Pog 167.58 4.27 170.97 4.30 3.39 2.49 <0.001** a b 166.31 4.95 168.22 5.46 1.91 2.03 <0.001**ab 0.041*b S.N.Pog 74.65 3.18 75.60 2.84 0.95 1.18 <0.001**a 75.48 4.87 75.82 4.62 0.34 1.26 0.195 0.087 FH.MP 28.95 5.38 28.80 4.92 −0.15 2.15 0.712 29.12 5.64 29.98 5.10 0.86 2.10 0.045* 0.085 MM 28.34 5.21 27.92 4.84 −0.42 2.43 0.353 29.79 6.49 29.88 5.89 0.09 2.08 0.821 0.599 Y-axis 67.81 3.33 67.66 3.13 −0.15 1.78 0.645 67.76 5.16 67.99 4.94 0.23 1.23 0.316b 0.357 GoMe/SN 36.97 5.02 36.99 4.60 0.02 2.01 0.964 37.57 6.85 37.79 6.81 0.22 1.62 0.625 0.607 Ar.Go.Me 129.27 5.63 129.83 5.46 0.56 1.75 0.09 130.41 6.49 130.51 6.63 0.1 1.98 0.437b 0.430 Wits app 3.93 2.03 1.57 1.44 −2.36 2.14 <0.001**ab 4.23 2.35 2.50 1.69 −1.73 2.04 <0.001a** 0.222b SPP/SN 7.98 3.15 7.54 3.50 −0.44 0.12 0.421 6.91 2.08 5.65 3.13 −1.26 0.19 0.082 0.890 Cd-Gn 106.03 7.35 108.92 7.5 2.89 5.14 0.014* 98.66 5.63 100.11 5.41 1.45 3.44 0.248b 0.194b Go-Pog 69.69 6.01 71.93 6.4 2.24 2.81 <0.001**a 65.45 5.03 66.42 5.40 0.97 2.69 0.062 0.084 Cd-Go 60.59 4.29 63.25 4.2 2.66 0.71 <0.001**a 58.66 4.30 59.14 3.21 0.48 1.61 0.357 <0.001**a N-Me 113.54 8.57 117.53 10.2 3.99 4.43 <0.001**a 106.27 6.79 106.91 7.66 0.64 3.73 0.263 0.004* Na-ANS 51.31 4.90 52.82 5.8 1.51 2.39 <0.001**a 47.75 3.39 48.28 3.57 0.53 1.67 0.131 0.094 ANS-Me 65.20 5.29 67.25 6.0 2.05 2.92 <0.001**a 61.39 5.21 61.92 5.21 0.53 2.43 0.179b 0.041* ANS-PNS 50.29 4.52 52.01 5.3 1.72 3.78 0.023* 48.47 3.90 49.63 3.24 1.16 2.81 0.041* 0.582 The definitions of the variables are given in Supplementary Table 1. Significant differences at *P < 0.05, Significant differences at **P < 0.01. aSignificant differences at the adjusted level according to Bonferroni P < 0.0025. bP values are obtained from Mann–Whitney U tests, other values are obtained from two-sample student t tests. View Large Table 2. Descriptive statistics of the assessed skeletal variables in the two groups as well as the associated P-values of significance tests. Variable Activator T4k P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P-value change over time Mean before SD Mean after SD Mean difference SD P value change over time SNA 80.33 3.32 79.74 3.15 −0.59 1.12 0.011* 81.86 5.37 81.30 5.30 −0.56 1.21 0.021* 0.814 SNB 73.91 3.19 75.21 2.83 1.30 1.11 <0.001**a 74.75 4.99 75.0.9 4.81 0.34 1.49 0.081 0.016** ANB 6.42 1.65 4.53 1.69 −1.89 1.12 <0.001**ab 7.11 1.89 6.21 2.04 −0.9 1.01 0.012*a 0.001**b N.A.Pog 167.58 4.27 170.97 4.30 3.39 2.49 <0.001** a b 166.31 4.95 168.22 5.46 1.91 2.03 <0.001**ab 0.041*b S.N.Pog 74.65 3.18 75.60 2.84 0.95 1.18 <0.001**a 75.48 4.87 75.82 4.62 0.34 1.26 0.195 0.087 FH.MP 28.95 5.38 28.80 4.92 −0.15 2.15 0.712 29.12 5.64 29.98 5.10 0.86 2.10 0.045* 0.085 MM 28.34 5.21 27.92 4.84 −0.42 2.43 0.353 29.79 6.49 29.88 5.89 0.09 2.08 0.821 0.599 Y-axis 67.81 3.33 67.66 3.13 −0.15 1.78 0.645 67.76 5.16 67.99 4.94 0.23 1.23 0.316b 0.357 GoMe/SN 36.97 5.02 36.99 4.60 0.02 2.01 0.964 37.57 6.85 37.79 6.81 0.22 1.62 0.625 0.607 Ar.Go.Me 129.27 5.63 129.83 5.46 0.56 1.75 0.09 130.41 6.49 130.51 6.63 0.1 1.98 0.437b 0.430 Wits app 3.93 2.03 1.57 1.44 −2.36 2.14 <0.001**ab 4.23 2.35 2.50 1.69 −1.73 2.04 <0.001a** 0.222b SPP/SN 7.98 3.15 7.54 3.50 −0.44 0.12 0.421 6.91 2.08 5.65 3.13 −1.26 0.19 0.082 0.890 Cd-Gn 106.03 7.35 108.92 7.5 2.89 5.14 0.014* 98.66 5.63 100.11 5.41 1.45 3.44 0.248b 0.194b Go-Pog 69.69 6.01 71.93 6.4 2.24 2.81 <0.001**a 65.45 5.03 66.42 5.40 0.97 2.69 0.062 0.084 Cd-Go 60.59 4.29 63.25 4.2 2.66 0.71 <0.001**a 58.66 4.30 59.14 3.21 0.48 1.61 0.357 <0.001**a N-Me 113.54 8.57 117.53 10.2 3.99 4.43 <0.001**a 106.27 6.79 106.91 7.66 0.64 3.73 0.263 0.004* Na-ANS 51.31 4.90 52.82 5.8 1.51 2.39 <0.001**a 47.75 3.39 48.28 3.57 0.53 1.67 0.131 0.094 ANS-Me 65.20 5.29 67.25 6.0 2.05 2.92 <0.001**a 61.39 5.21 61.92 5.21 0.53 2.43 0.179b 0.041* ANS-PNS 50.29 4.52 52.01 5.3 1.72 3.78 0.023* 48.47 3.90 49.63 3.24 1.16 2.81 0.041* 0.582 Variable Activator T4k P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P-value change over time Mean before SD Mean after SD Mean difference SD P value change over time SNA 80.33 3.32 79.74 3.15 −0.59 1.12 0.011* 81.86 5.37 81.30 5.30 −0.56 1.21 0.021* 0.814 SNB 73.91 3.19 75.21 2.83 1.30 1.11 <0.001**a 74.75 4.99 75.0.9 4.81 0.34 1.49 0.081 0.016** ANB 6.42 1.65 4.53 1.69 −1.89 1.12 <0.001**ab 7.11 1.89 6.21 2.04 −0.9 1.01 0.012*a 0.001**b N.A.Pog 167.58 4.27 170.97 4.30 3.39 2.49 <0.001** a b 166.31 4.95 168.22 5.46 1.91 2.03 <0.001**ab 0.041*b S.N.Pog 74.65 3.18 75.60 2.84 0.95 1.18 <0.001**a 75.48 4.87 75.82 4.62 0.34 1.26 0.195 0.087 FH.MP 28.95 5.38 28.80 4.92 −0.15 2.15 0.712 29.12 5.64 29.98 5.10 0.86 2.10 0.045* 0.085 MM 28.34 5.21 27.92 4.84 −0.42 2.43 0.353 29.79 6.49 29.88 5.89 0.09 2.08 0.821 0.599 Y-axis 67.81 3.33 67.66 3.13 −0.15 1.78 0.645 67.76 5.16 67.99 4.94 0.23 1.23 0.316b 0.357 GoMe/SN 36.97 5.02 36.99 4.60 0.02 2.01 0.964 37.57 6.85 37.79 6.81 0.22 1.62 0.625 0.607 Ar.Go.Me 129.27 5.63 129.83 5.46 0.56 1.75 0.09 130.41 6.49 130.51 6.63 0.1 1.98 0.437b 0.430 Wits app 3.93 2.03 1.57 1.44 −2.36 2.14 <0.001**ab 4.23 2.35 2.50 1.69 −1.73 2.04 <0.001a** 0.222b SPP/SN 7.98 3.15 7.54 3.50 −0.44 0.12 0.421 6.91 2.08 5.65 3.13 −1.26 0.19 0.082 0.890 Cd-Gn 106.03 7.35 108.92 7.5 2.89 5.14 0.014* 98.66 5.63 100.11 5.41 1.45 3.44 0.248b 0.194b Go-Pog 69.69 6.01 71.93 6.4 2.24 2.81 <0.001**a 65.45 5.03 66.42 5.40 0.97 2.69 0.062 0.084 Cd-Go 60.59 4.29 63.25 4.2 2.66 0.71 <0.001**a 58.66 4.30 59.14 3.21 0.48 1.61 0.357 <0.001**a N-Me 113.54 8.57 117.53 10.2 3.99 4.43 <0.001**a 106.27 6.79 106.91 7.66 0.64 3.73 0.263 0.004* Na-ANS 51.31 4.90 52.82 5.8 1.51 2.39 <0.001**a 47.75 3.39 48.28 3.57 0.53 1.67 0.131 0.094 ANS-Me 65.20 5.29 67.25 6.0 2.05 2.92 <0.001**a 61.39 5.21 61.92 5.21 0.53 2.43 0.179b 0.041* ANS-PNS 50.29 4.52 52.01 5.3 1.72 3.78 0.023* 48.47 3.90 49.63 3.24 1.16 2.81 0.041* 0.582 The definitions of the variables are given in Supplementary Table 1. Significant differences at *P < 0.05, Significant differences at **P < 0.01. aSignificant differences at the adjusted level according to Bonferroni P < 0.0025. bP values are obtained from Mann–Whitney U tests, other values are obtained from two-sample student t tests. View Large Dentoalveolar changes are presented in Table 3. The Activator group showed a greater significant decrease in overjet ( x¯ = −3.0 ± 2.3 mm) compared to ( x¯ = −1.5 ± 1.9 mm; P = 0.01) with T4k®. However, no significant differences were detected in other dentoalveolar variables. Table 3. Descriptive statistics of dentoalveolar variables assessed in the two groups as well as the associated P values of significance tests Variable Activator T4K P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P value change over time Mean before SD Mean after SD Mean difference SD P value change over time Overbite 4.13 1.62 3.44 1.7 −0.69 1.61 0.031* 3.02 1.88 2.89 1.40 −0.13 1.53 0.685 0.194 Overjet 7.23 2.12 4.20 2.1 −3.03 2.29 <0.001*ab 6.11 2.04 4.61 2.14 −1.5 1.91 <0.001*ab 0.010*b U1Axis/SPP 113.32 6.82 110.59 6.2 −2.73 1.53 0.049* 110.94 8.52 108.93 8.21 −2.01 1.10 0.041* 0.757 U1 Axis/SN 104.66 7.98 101.49 7.0 −3.17 7.32 0.021* 103.38 8.91 101.01 8.68 −2.37 1.72 0.025* 0.821 L1Axis/Mp 97.81 2.92 98.28 3.3 0.47 1.57 0.537a 97.40 3.01 98.47 3.71 1.07 3.59 0.132 0.522 b U1/1L Axis 119.54 7.96 122.21 6.8 2.67 7.01 0.052* 120.75 10.58 121.76 10.73 1.01 6.61 0.448 0.372 (gla.Sn.Pog`) 158.67 4.84 161.28 3.86 2.61 3.71 <0.001*ab 157.73 5.24 157.75 5.5 0.02 2.51 0.954 0.004**a (Cl.Sn. SLS) 113.35 10.00 109.33 8.97 −4.02 10.10 0.042* 113.05 10.90 114.82 10.8 1.77 8.50 0.678 0.027* (li.ils.Pog`) 112.73 13.69 124.69 15.44 11.96 12.57 <0.001*ab 115.34 17.31 121.78 10.7 6.44 14.77 0.021* 0.149 Ls to E 1.81 1.48 2.41 1.21 0.60 1.47 0.065b 1.71 1.40 2.01 1.5 0.30 1.46 0.781 b 0.585b Li to E 2.21 1.47 2.16 1.47 −0.05 1.43 0.854b 2.52 1.73 2.61 2.0 0.09 1.52 0.525 b 0.822b Variable Activator T4K P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P value change over time Mean before SD Mean after SD Mean difference SD P value change over time Overbite 4.13 1.62 3.44 1.7 −0.69 1.61 0.031* 3.02 1.88 2.89 1.40 −0.13 1.53 0.685 0.194 Overjet 7.23 2.12 4.20 2.1 −3.03 2.29 <0.001*ab 6.11 2.04 4.61 2.14 −1.5 1.91 <0.001*ab 0.010*b U1Axis/SPP 113.32 6.82 110.59 6.2 −2.73 1.53 0.049* 110.94 8.52 108.93 8.21 −2.01 1.10 0.041* 0.757 U1 Axis/SN 104.66 7.98 101.49 7.0 −3.17 7.32 0.021* 103.38 8.91 101.01 8.68 −2.37 1.72 0.025* 0.821 L1Axis/Mp 97.81 2.92 98.28 3.3 0.47 1.57 0.537a 97.40 3.01 98.47 3.71 1.07 3.59 0.132 0.522 b U1/1L Axis 119.54 7.96 122.21 6.8 2.67 7.01 0.052* 120.75 10.58 121.76 10.73 1.01 6.61 0.448 0.372 (gla.Sn.Pog`) 158.67 4.84 161.28 3.86 2.61 3.71 <0.001*ab 157.73 5.24 157.75 5.5 0.02 2.51 0.954 0.004**a (Cl.Sn. SLS) 113.35 10.00 109.33 8.97 −4.02 10.10 0.042* 113.05 10.90 114.82 10.8 1.77 8.50 0.678 0.027* (li.ils.Pog`) 112.73 13.69 124.69 15.44 11.96 12.57 <0.001*ab 115.34 17.31 121.78 10.7 6.44 14.77 0.021* 0.149 Ls to E 1.81 1.48 2.41 1.21 0.60 1.47 0.065b 1.71 1.40 2.01 1.5 0.30 1.46 0.781 b 0.585b Li to E 2.21 1.47 2.16 1.47 −0.05 1.43 0.854b 2.52 1.73 2.61 2.0 0.09 1.52 0.525 b 0.822b Variables’ definitions are given in Supplementary Table 1. The value is 0.000 for all of the italic values. Significant differences *P < 0.05, Significant differences **P < 0.01. aSignificant differences at the adjusted level according to Bonferroni P< 0.005. bP values are obtained from Mann–Whitney U tests, other values are resulted from two sample student t test. View Large Table 3. Descriptive statistics of dentoalveolar variables assessed in the two groups as well as the associated P values of significance tests Variable Activator T4K P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P value change over time Mean before SD Mean after SD Mean difference SD P value change over time Overbite 4.13 1.62 3.44 1.7 −0.69 1.61 0.031* 3.02 1.88 2.89 1.40 −0.13 1.53 0.685 0.194 Overjet 7.23 2.12 4.20 2.1 −3.03 2.29 <0.001*ab 6.11 2.04 4.61 2.14 −1.5 1.91 <0.001*ab 0.010*b U1Axis/SPP 113.32 6.82 110.59 6.2 −2.73 1.53 0.049* 110.94 8.52 108.93 8.21 −2.01 1.10 0.041* 0.757 U1 Axis/SN 104.66 7.98 101.49 7.0 −3.17 7.32 0.021* 103.38 8.91 101.01 8.68 −2.37 1.72 0.025* 0.821 L1Axis/Mp 97.81 2.92 98.28 3.3 0.47 1.57 0.537a 97.40 3.01 98.47 3.71 1.07 3.59 0.132 0.522 b U1/1L Axis 119.54 7.96 122.21 6.8 2.67 7.01 0.052* 120.75 10.58 121.76 10.73 1.01 6.61 0.448 0.372 (gla.Sn.Pog`) 158.67 4.84 161.28 3.86 2.61 3.71 <0.001*ab 157.73 5.24 157.75 5.5 0.02 2.51 0.954 0.004**a (Cl.Sn. SLS) 113.35 10.00 109.33 8.97 −4.02 10.10 0.042* 113.05 10.90 114.82 10.8 1.77 8.50 0.678 0.027* (li.ils.Pog`) 112.73 13.69 124.69 15.44 11.96 12.57 <0.001*ab 115.34 17.31 121.78 10.7 6.44 14.77 0.021* 0.149 Ls to E 1.81 1.48 2.41 1.21 0.60 1.47 0.065b 1.71 1.40 2.01 1.5 0.30 1.46 0.781 b 0.585b Li to E 2.21 1.47 2.16 1.47 −0.05 1.43 0.854b 2.52 1.73 2.61 2.0 0.09 1.52 0.525 b 0.822b Variable Activator T4K P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P value change over time Mean before SD Mean after SD Mean difference SD P value change over time Overbite 4.13 1.62 3.44 1.7 −0.69 1.61 0.031* 3.02 1.88 2.89 1.40 −0.13 1.53 0.685 0.194 Overjet 7.23 2.12 4.20 2.1 −3.03 2.29 <0.001*ab 6.11 2.04 4.61 2.14 −1.5 1.91 <0.001*ab 0.010*b U1Axis/SPP 113.32 6.82 110.59 6.2 −2.73 1.53 0.049* 110.94 8.52 108.93 8.21 −2.01 1.10 0.041* 0.757 U1 Axis/SN 104.66 7.98 101.49 7.0 −3.17 7.32 0.021* 103.38 8.91 101.01 8.68 −2.37 1.72 0.025* 0.821 L1Axis/Mp 97.81 2.92 98.28 3.3 0.47 1.57 0.537a 97.40 3.01 98.47 3.71 1.07 3.59 0.132 0.522 b U1/1L Axis 119.54 7.96 122.21 6.8 2.67 7.01 0.052* 120.75 10.58 121.76 10.73 1.01 6.61 0.448 0.372 (gla.Sn.Pog`) 158.67 4.84 161.28 3.86 2.61 3.71 <0.001*ab 157.73 5.24 157.75 5.5 0.02 2.51 0.954 0.004**a (Cl.Sn. SLS) 113.35 10.00 109.33 8.97 −4.02 10.10 0.042* 113.05 10.90 114.82 10.8 1.77 8.50 0.678 0.027* (li.ils.Pog`) 112.73 13.69 124.69 15.44 11.96 12.57 <0.001*ab 115.34 17.31 121.78 10.7 6.44 14.77 0.021* 0.149 Ls to E 1.81 1.48 2.41 1.21 0.60 1.47 0.065b 1.71 1.40 2.01 1.5 0.30 1.46 0.781 b 0.585b Li to E 2.21 1.47 2.16 1.47 −0.05 1.43 0.854b 2.52 1.73 2.61 2.0 0.09 1.52 0.525 b 0.822b Variables’ definitions are given in Supplementary Table 1. The value is 0.000 for all of the italic values. Significant differences *P < 0.05, Significant differences **P < 0.01. aSignificant differences at the adjusted level according to Bonferroni P< 0.005. bP values are obtained from Mann–Whitney U tests, other values are resulted from two sample student t test. View Large Table 3 describes the soft tissue changes. Facial convexity, nasolabial, and mentolabial angles showed significant changes in the Activator group (P ≤ 0.04; Table 3). In contrast, the T4k® group did not show significant changes in all soft tissue variables. When comparing the two groups, the facial convexity angle (gla.Sn.Pog`) showed significantly a larger increase with Activator ( x¯ = 2.61 ± 3.71) more than T4K® ( x¯ = 0.2 ± 2.51) (P = 0.004), in addition to significantly larger decrease in the nasolabial angle ( x¯= −4.02 ± 10.10) when compared with T4K® ( x¯ = 1.77 ± 8.50) (P = 0.02). Discussion This randomized controlled trial compared the efficacy of a traditional functional appliance for mandibular advancement (a modified Activator) with a myofunctional therapy using the Trainer of Kids appliance (T4K®) in growing Class II division 1 cases through evaluating soft and hard tissue changes in both groups using lateral cephalograms after 12 months of active treatment. The treatment groups were matched in age (biological and chronological), sex, and skeletal and dental cephalometric measurements. Biological age was assessed for all participants using hand and wrist radiograph which showed that some of the participants were (PP2=) stage which indicates that a child’s biological age has not reach the pubertal growth spurt yet; this may affect the response to functional treatment as suggested recently (34), at any rate the treatment groups were homogenous in the distribution of the participant in both groups regarding the biological age, thus it is not expected that including those participants in the study in the prepubertal stage would compromise the results of this study. Six participants withdrew from the study (four from the T4K® group, and two from the Activator group). This may reflect lower acceptance of T4K® treatment system which has been separately investigated and previously reported (35). Anatomical condylar point (Cd) was used instead of Articular point (Ar) in measuring mandibular length and ramus height to follow mandibular skeletal changes. Using Cd point is preferable as an anatomical point to the use of Ar which is a constructed point (5, 36, 37). Both groups showed significant skeletal changes but Activator was significantly more effective with greater increase in SNB angle and more reduction in ANB angle and Wits appraisal. Favourable skeletal changes with Activator therapy were referred to by many reports (36, 38–44). On the other hand, Usumez’ study about the T4K® appliance showed insignificant changes in mandibular measurements when compared with the control group which were consistent with the findings of the current study (19). The favourable skeletal changes seen with the Activator may due to the fact that Activator is a custom-made appliance which allows a precise anterior mandibular repositioning determined by the construction wax bite. Moreover, the Activator is made of acrylic material which is harder than that of the Trainer, specifically the starting appliance (i.e. the soft blue trainer). The high elasticity of the T4K® was an important flaw noted and reported by parents; this elasticity made it difficult for children to keep their mandibles in a forward position (i.e. in an edge-to-edge relationship at the incisors; Figure 5). This may give an indication that the use of the hard version of this appliance is important to attain better skeletal changes. An additional factor may play a role in the favourable skeletal changes is that the Activator was recommended to be worn for longer time per day than the Trainer as we followed the manufacturer instruction. Consequently, patients’ mandibles received higher force levels for longer period of time in the Activator group compared to the T4K® group. Figure 5. View largeDownload slide The Blue Trainer did not provide a stable forward positioning of the mandible. (a) Incisors at an edge-to-edge relationship immediately following Trainer’s wear and (b) the mandible moved to a backward position after few minutes of appliance wear. Figure 5. View largeDownload slide The Blue Trainer did not provide a stable forward positioning of the mandible. (a) Incisors at an edge-to-edge relationship immediately following Trainer’s wear and (b) the mandible moved to a backward position after few minutes of appliance wear. The significant increase in the lower facial height in the Activator group and the superior changes with Activator treatment in comparison with the T4K® appliance may due to Activator bite opening effect and the guided extrusion of the posterior teeth in the occlusal acrylic plate (37, 40–42, 44–46). However, a previous study about T4K® showed significant increase in the lower facial height (19), which was not seen in the current study. Insignificant changes in the lower incisors/mandibular plane angle may due to lower incisors acrylic capping used in the Activator design which may be useful in controlling the unfavourable labial movement of lower incisors. The seen dentoalveolar changes in the current study showed a greater decrease in overjet with Activator. These changes are coincident with previous studies regarding the Activator and the Trainer which reported favourable dentoalveolar changes (15, 19, 36, 37, 40–42, 44–46). Čirgić and colleagues compared the Trainer to Anderson Activator in Class II malocclusion and have reported that the Activator showed a greater reduction in overjet after 1 year treatment. However, after 6 months of completing the treatment a relapse in the overjet was detected in both groups which resulted in no significant differences in overjet (20). In the current study, there was no more cephalometric records were taken further to the 12 months follow-up to check for any possible relapse. Regarding soft-tissue changes, the facial-convexity-angle’s significant increase with the Activator therapy represented favourable facial changes and may be explained as a reflection of the significant underlying skeletal improvement. On the other hand, the Trainer system was not able to show such favourable changes in the soft-tissue drape. Limitations This trial had a relatively short-term follow-up (i.e. 12 months) and no further cephalometric follow-ups were made. Therefore, a study with a longer follow-up is required to confirm the current results. It is preferable to design the study including three arms (a control and two treatment groups) but considering the ethical flaw of such design leaving children without treatment made this design hard to apply in the study. Although not all of the participants were treated in the pubertal growth spurt, both groups were matched in both chronological and biological age. Conclusions - In the short-term, a 1-year treatment with the Activator appliance resulted in better skeletal changes compared to those of the T4K®, particularly the ANB angle decrease, the ramus height increase, and the greater lower facial height increase. - In the short-term, a 1-year Activator treatment was significantly more effective than the T4K® in correcting the increased overjet and normalizing soft-tissue appearance particularly the facial convexity angle and the nasolabial angle. Supplementary material Supplementary material is available at European Journal of Orthodontics online. Funding This research was funded by Postgraduate Research Budget in Al-Baath University (Ref 1165-2006-DEN). Conflict of Interest None to declare. References 1. Stockfisch , H . ( 1995 ) (ed.), The Principles and Practice of Dentofacial Orthopedics . Quintessence Puplishing Co, Inc ., New Malden, United Kingdom. 2. Fränkel , R . ( 1971 ) Possibilities of a late basal development of the mandible through the rearrangement of the bite by means of a functional regulator . Deutsche Stomatologie , 21 , 198 – 202 . Google Scholar PubMed 3. Clark , W.J . ( 1988 ) The twin block technique. A functional orthopedic appliance system . American Journal of Orthodontics and Dentofacial Orthopedics , 93 , 1 – 18 . Google Scholar CrossRef Search ADS PubMed 4. Pancherz , H . ( 1982 ) The mechanism of Class II correction in Herbst appliance treatment. A cephalometric investigation . American Journal of Orthodontics , 82 , 104 – 113 . Google Scholar CrossRef Search ADS PubMed 5. Cozza , P. , Baccetti , T. , Franchi , L. , De Toffol , L. and McNamara , J.A. , Jr . ( 2006 ) Mandibular changes produced by functional appliances in Class II malocclusion: a systematic review . American Journal of Orthodontics and Dentofacial Orthopedics , 129 , 599.e1 – 12 ; discussion e1. 6. Koretsi , V. , Zymperdikas , V.F. , Papageorgiou , S.N. and Papadopoulos , M.A . ( 2015 ) Treatment effects of removable functional appliances in patients with Class II malocclusion: a systematic review and meta-analysis . European Journal of Orthodontics , 37 , 418 – 434 . Google Scholar CrossRef Search ADS PubMed 7. Flores-Mir , C. and Major , P.W . ( 2006 ) A systematic review of cephalometric facial soft tissue changes with the Activator and Bionator appliances in Class II division 1 subjects . European Journal of Orthodontics , 28 , 586 – 593 . Google Scholar CrossRef Search ADS PubMed 8. Moss , M.L. and Rankow , R.M . ( 1968 ) The role of the functional matrix in mandibular growth . The Angle Orthodontist , 38 , 95 – 103 . Google Scholar PubMed 9. Moss , M.L . ( 1997 ) The functional matrix hypothesis revisited. 1. The role of mechanotransduction . American Journal of Orthodontics and Dentofacial Orthopedics , 112 , 8 – 11 . Google Scholar CrossRef Search ADS PubMed 10. Owman-Moll , P. and Ingervall , B . ( 1984 ) Effect of oral screen treatment on dentition, lip morphology, and function in children with incompetent lips . American Journal of Orthodontics , 85 , 37 – 46 . Google Scholar CrossRef Search ADS PubMed 11. Cheney , E.A . ( 1958 ) Factors in the early treatment and interception of malocclusion . American Journal of Orthodontics , 44 : 807 – 826 . Google Scholar CrossRef Search ADS 12. Cheney , E.A . ( 1963 ) Treatment planning and therapy in the mixed dentition . American Journal of Orthodontics , 49 : 568 – 580 . Google Scholar CrossRef Search ADS 13. Rossi , R. , Mortara , M.C. and Boccaccio , E . ( 1984 ) Preventive orthodontics and the use of oral screens. Parodontologia E Stomatologia (Nuova), 23(Suppl 3), 191–192 . 14. Bergersen , E.O . ( 1984 ) The eruption guidance myofunctional appliances: how it works, how to use it . The Functional Orthodontist , 1 , 28 – 29 . Google Scholar PubMed 15. Quadrelli , C. , Gheorgiu , M. , Marcheti , C. and Ghiglione , V . ( 2002 ) Early myofunctional approach to skeletal Class II . Mondo Ortodontico , 2, 109–122. 16. Tallgren , A. , Christiansen , R.L. , Ash , M. Jr and Miller , R.L . ( 1998 ) Effects of a myofunctional appliance on orofacial muscle activity and structures . The Angle Orthodontist , 68 , 249 – 258 . Google Scholar PubMed 17. Hashish , D.I. and Mostafa , Y.A . ( 2009 ) Effect of lip bumpers on mandibular arch dimensions . American Journal of Orthodontics and Dentofacial Orthopedics , 135 , 106 – 109 . Google Scholar CrossRef Search ADS PubMed 18. Homem , M.A. , Vieira-Andrade , R.G. , Falci , S.G. , Ramos-Jorge , M.L. and Marques , L.S . ( 2014 ) Effectiveness of orofacial myofunctional therapy in orthodontic patients: a systematic review . Dental Press Journal of Orthodontics , 19 , 94 – 99 . Google Scholar CrossRef Search ADS PubMed 19. Usumez , S. , Uysal , T. , Sari , Z. , Basciftci , F.A. , Karaman , A.I. and Guray , E . ( 2004 ) The effects of early preorthodontic trainer treatment on Class II, division 1 patients . The Angle Orthodontist , 74 , 605 – 609 . Google Scholar PubMed 20. Čirgić , E. , Kjellberg , H. and Hansen , K . ( 2016 ) Treatment of large overjet in Angle Class II: division 1 malocclusion with Andresen activators versus prefabricated functional appliances-a multicenter, randomized, controlled trial . European Journal of Orthodontics , 38 , 516 – 524 . Google Scholar CrossRef Search ADS PubMed 21. Bishara , S.E. and Ziaja , R.R . ( 1989 ) Functional appliances: a review . American Journal of Orthodontics and Dentofacial Orthopedics , 95 , 250 – 258 . Google Scholar CrossRef Search ADS PubMed 22. Stüber , P . ( 1989 ) Comparison of treatment of mandibular retrognathia by functional regulators and activators . Stomatologie Der DDR , 39 , 446 – 451 . Google Scholar PubMed 23. Sari , Z. , Goyenc , Y. , Doruk , C. and Usumez , S . ( 2003 ) Comparative evaluation of a new removable Jasper Jumper functional appliance vs an activator-headgear combination . The Angle Orthodontist , 73 , 286 – 293 . Google Scholar PubMed 24. Trenouth , M.J . ( 1992 ) A comparison of Twin Block, Andresen and removable appliances in the treatment of Class II Division 1 malocclusion . The Functional Orthodontist , 9 , 26 – 31 . Google Scholar PubMed 25. Tümer , N. and Gültan , A.S . ( 1999 ) Comparison of the effects of monoblock and twin-block appliances on the skeletal and dentoalveolar structures . American Journal of Orthodontics and Dentofacial Orthopedics , 116 , 460 – 468 . Google Scholar CrossRef Search ADS PubMed 26. Varlik , S.K. , Gültan , A. and Tümer , N . ( 2008 ) Comparison of the effects of Twin Block and activator treatment on the soft tissue profile . European Journal of Orthodontics , 30 , 128 – 134 . Google Scholar CrossRef Search ADS PubMed 27. Baltromejus , S. , Ruf , S. and Pancherz , H . ( 2002 ) Effective temporomandibular joint growth and chin position changes: Activator versus Herbst treatment. A cephalometric roentgenographic study . European Journal of Orthodontics , 24 , 627 – 637 . Google Scholar CrossRef Search ADS PubMed 28. Ulusoy , C. and Darendeliler , N . ( 2008 ) Effects of Class II activator and Class II activator high-pull headgear combination on the mandible: a 3-dimensional finite element stress analysis study . American Journal of Orthodontics and Dentofacial Orthopedics , 133 , 490.e9 – 490.15 . Google Scholar CrossRef Search ADS 29. Farell , C . ( 2017 ) How Successful are MRC’s Appliances? Do They Really Work? Myofunctional Research , Australia . http://smartertrack.myoresearch.com/KB/a24/how-successful-are-mrcs-appliances-do-they-really-work.aspx (13 December 2017, date last accessed). 30. Björk , A. and Helm , S . ( 1967 ) Prediction of the age of maximum puberal growth in body height . The Angle Orthodontist , 37 , 134 – 143 . Google Scholar PubMed 31. Grave , K.C. and Brown , T . ( 1976 ) Skeletal ossification and the adolescent growth spurt . American Journal of Orthodontics , 69 , 611 – 619 . Google Scholar CrossRef Search ADS PubMed 32. Farell , C . ( 2015 ) The Trainer system myoresearch.com: myoresearch . http://myoresearch.com/appliances/the_trainer_system/57 (1 August 2015, date last accessed). 33. Dahlburg , G ., (ed.) ( 1940 ) Statistical Methods for Medical and Biological Students . George Allen and Unwin Ltd , London . 34. Perinetti , G. , Primožič , J. , Franchi , L. and Contardo , L . ( 2015 ) Treatment effects of removable functional appliances in pre-pubertal and pubertal Class II patients: a systematic review and meta-analysis of controlled studies . PloS One , 10 , e0141198 . Google Scholar CrossRef Search ADS PubMed 35. Idris , G. , Hajeer , M.Y. and Al-Jundi , A . ( 2012 ) Acceptance and discomfort in growing patients during treatment with two functional appliances: a randomised controlled trial . European Journal of Paediatric Dentistry , 13 , 219 – 224 . Google Scholar PubMed 36. Chen , J.Y. , Will , L.A. and Niederman , R . ( 2002 ) Analysis of efficacy of functional appliances on mandibular growth . American Journal of Orthodontics and Dentofacial Orthopedics , 122 , 470 – 476 . Google Scholar CrossRef Search ADS PubMed 37. Nelson , C. , Harkness , M. and Herbison , P . ( 1993 ) Mandibular changes during functional appliance treatment . American Journal of Orthodontics and Dentofacial Orthopedics , 104 , 153 – 161 . Google Scholar CrossRef Search ADS PubMed 38. Aelbers , C.M. and Dermaut , L.R . ( 1996 ) Orthopedics in orthodontics: part I, fiction or reality–a review of the literature . American Journal of Orthodontics and Dentofacial Orthopedics , 110 , 513 – 519 . Google Scholar CrossRef Search ADS PubMed 39. Antonarakis , G.S. and Kiliaridis , S . ( 2007 ) Short-term anteroposterior treatment effects of functional appliances and extraoral traction on class II malocclusion. A meta-analysis . The Angle Orthodontist , 77 , 907 – 914 . Google Scholar CrossRef Search ADS PubMed 40. Basciftci , F.A. , Uysal , T. , Büyükerkmen , A. and Sari , Z . ( 2003 ) The effects of activator treatment on the craniofacial structures of Class II division 1 patients . European Journal of Orthodontics , 25 , 87 – 93 . Google Scholar CrossRef Search ADS PubMed 41. Cozza , P. , De Toffol , L. and Colagrossi , S . ( 2004 ) Dentoskeletal effects and facial profile changes during activator therapy . European Journal of Orthodontics , 26 , 293 – 302 . Google Scholar CrossRef Search ADS PubMed 42. Cozza , P. , De Toffol , L. and Iacopini , L . ( 2004 ) An analysis of the corrective contribution in activator treatment . The Angle Orthodontist , 74 , 741 – 748 . Google Scholar PubMed 43. Dolce , C. , Schader , R.E. , McGorray , S.P. and Wheeler , T.T . ( 2005 ) Centrographic analysis of 1-phase versus 2-phase treatment for Class II malocclusion . American Journal of Orthodontics and Dentofacial Orthopedics , 128 , 195 – 200 . Google Scholar CrossRef Search ADS PubMed 44. Türkkahraman , H. and Sayin , M.O . ( 2006 ) Effects of activator and activator headgear treatment: comparison with untreated Class II subjects . European Journal of Orthodontics , 28 , 27 – 34 . Google Scholar CrossRef Search ADS PubMed 45. Vargervik , K. and Harvold , E.P . ( 1985 ) Response to activator treatment in Class II malocclusions . American Journal of Orthodontics , 88 , 242 – 251 . Google Scholar CrossRef Search ADS PubMed 46. Luder , H.U . ( 1982 ) Skeletal profile changes related to two patterns of activator effects . American Journal of Orthodontics , 81 , 390 – 396 . Google Scholar CrossRef Search ADS PubMed © The Author(s) 2018. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The European Journal of Orthodontics Oxford University Press

Soft- and hard-tissue changes following treatment of Class II division 1 malocclusion with Activator versus Trainer: a randomized controlled trial

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© The Author(s) 2018. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com
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Abstract

Summary Background Increased awareness on the role of oral functions in the aetiology of Class II deformities has led to the wide spread of myofunctional training appliances as easy and possibly effective treatment for children with Class II malocclusion but their efficacy is yet to be proven. Objectives To evaluate soft- and hard-tissue changes following 12 months of Class II division 1 treatment in growing patients with a conventional functional appliance (a modified Activator) versus a myofunctional Trainer system (T4K®). Setting and sample population Department of Orthodontics, Dental School. Participants, study design, and methods: Sixty Class II division 1 children (8–12 years old) were recruited from primary schools and were distributed randomly into two equal groups. Randomization was based on a computer-generated sequence of random numbers. Data analysis included: the Activator group (28 patients, mean age = 10.6 ± 1.3 years); the T4K® group (26 patients, mean age = 10.3 ± 1.4 years). Skeletal, dentoalveolar, and soft tissues changes were assessed using standardized lateral cephalograms collected before and after 12 months of treatment. No blinding was applied in this trial. Results Improvement in the Class II skeletal and dentofacial characteristics were significantly greater in the Activator group when compared with the T4K® group. The improvement was evident in a significant decrease in the skeletal angle ANB with Activator ( x¯ = −1.89 ± 1.12) compared to T4K® ( x¯ = −0.9 ± 1.01) (P = 0.01), a significant greater increase in the facial convexity angle with Activator ( x¯ = 2.61 ± 3.71) more than T4K® ( x¯ = 0.2 ± 2.51) (P = 0.04), and a significant reduction in the overjet ( x¯ = −3.0 ± 2.3 mm) compared to ( x¯ = −1.5 ± 1.9 mm; P = 0.01) with Activator versus T4k®, respectively (P = 0.001). Limitations This study was a short-term study (12-month follow-up). Conclusions The results of the current study indicated that the Activator was more effective than the T4K® in treating Class II division 1 growing patients. Registration The trial was not registered in any major database of clinical trials. Protocol The protocol was not published before the commencement of the trial but can be given upon request. Introduction Since the early functional appliances have been introduced by Robin 1902 and Andresen 1908 to enhance mandibular growth in growing Class II patients, a wide range of functional appliances have been introduced to stimulate mandibular growth and correct the bite by forward positioning of the mandible (1–5). The available reports showed that short-term evidence indicates that the functional appliances are effective in correcting Class II malocclusion (5–7). The effects of abnormal lip and tongue functions and habits on craniofacial development have been well identified (8, 9), consequently much attention has been paid to control the dentofacial growth by correcting oral dysfunction and establishing oral muscular balance (10). Since the introduction of the oral screen by Newel in 1912 as a myofunctional appliance, various appliances have been developed such as the oral shield (11, 12), the double oral screen (13), Eruption Guidance Appliance (EGA) as a prefabricated elastomeric appliance (14), and recently the Positioner Trainer (Trainer For Kids: T4K®) by Farrell as a prefabricated treatment system in mixed dentition. Wearing these appliances should be accompanied by myofunctional exercise as a part of the treatment (15, 16). Studies about myofunctional appliances have reported positive changes in the lower dental arch and the maxillary incisors (16, 17). However, the effectiveness of orofacial myofunctional therapy in orthodontic patients is still questionable (18). A few studies have been published evaluating the efficacy of the T4K®. These studies reported a significant reduction of overjet in the treated subjects (15, 19, 20). The available studies have methodological flaws such as lack of a control group, absence of randomization, or absence of a cephalometric analysis. A study done by Quadrelli and colleagues in 2002 was a case series report of six participants distributed into two groups using T4K®: the soft T4K® type for the first group and the hard T4K® type for the second group. Another study was published by Usumez and colleagues in 2003 which was a non-randomized controlled trial. The control group comprised patients who refused to be treated by T4K® whereas patients in the experimental group were not obliged to wear both types of the appliance as recommended by the developers of the Trainer system. Although a recent study by Čirgić and colleagues 2015 was a randomized controlled trial, however the study did not evaluate soft- and hard-tissue changes by radiographic means. The only available data were based on clinical examinations. Functional appliances vary in their effects according to their design (21), therefore a raft of studies have been accomplished to compare different types of functional appliances. Furthermore, the Activator has been considered as the most common basic functional appliance to be compared with other appliances (22–28). With the increased awareness of the easiness and the possible positive effects of myofunctional training appliances in the early treatment of Class II deformities, the use of T4K® system has been claimed to spread worldwide as a simple treatment system (29). The efficacy of T4K® use is yet to be proven with a few available studies in the literature. Therefore, it seems reasonable that a comparison should be made between the traditional functional treatment (i.e. the Activator) which depends on a great extent on mandibular advancement and the myofunctional treatment (i.e. the T4K®) which depends mainly on correcting abnormal positioning of the lips and tongue. This randomized controlled trial aimed to evaluate soft and hard tissue changes after 12 months of applying functional treatment for growing Class II division 1 patients using two different methods: the modified Activator versus the Positioner Trainer (T4K®). Materials and methods Sample size estimation The G*Power software version 3.0.8 (Universität Kiel, Germany) was used for sample size calculation. In order to detect a difference of 1 degree in the ANB angle (5) using two-sample t test with a power of 95 per cent and an alpha of 0.05 with a reported variance of this variable in a previous study of 1 degree (19), 23 patients were required. We aimed to recruit 30 patients in each group to compensate for any possible dropouts. Participants The study was approved by the Local Ethics Committee in Al-Baath University Dental School (Ref 1165/Dent/MSc/022006). This research project was accomplished at the Department of Orthodontics, Dental School, Al-Baath University between June 2006 to August 2008. Two thousand two hundred and twenty-six children were screened in a randomly selected 13 schools out of the primary schools in two major cities in Syria (i.e. Homs and Hamah in the middle region of Syria). Children were screened in these schools using examination gloves and disposable plastic rulers to measure the overjet. Children who met the eligibility criteria (8–12 years old, Class II division 1 features with overjet >4 mm) were invited to participate in this study by sending letters of invitation to their parents. The responders were 188 children; all participants were provided with information sheets about the study and their informed consents were obtained. Patients’ recruitment and follow-up flow diagram is given in Figure 1. Figure 1. View largeDownload slide CONSORT Participants’ recruitment flow diagram in this trial. Figure 1. View largeDownload slide CONSORT Participants’ recruitment flow diagram in this trial. Randomization Sixty participants were selected randomly out of the 188 possible candidates using a computer-generated list of random numbers with the aid of SPSS (SPSS Inc. SPSS for Windows, Version 15.0. Chicago, SPSS Inc.). Chosen patients were randomly allocated to the two arms of this study with an allocation ratio of 1:1 (30 participants in each group). Randomization was performed by one of the academic staff at the Orthodontic Department who was not involved directly in this research project using a computer-generated random sequence of numbers. Allocation concealment was performed using opaque sealed envelopes which contained the assigned group for each patient and were not opened till the onset of the trial. The following inclusion criteria were applied: 8–12 years old patients and of a Syrian ancestry; Increased overjet >4 mm; Skeletal Class II relationship (ANB > 4 degree, Wits appraisal > 2 mm); Normal lower incisor/mandibular plane relationship (93° ± 5); No previous orthodontic treatment Patients with craniofacial syndromes were excluded. Skeletal age of the participants was determined based on hand-wrist radiographs analysed according to Bjork–Brown–Grace and the included patients were in one of these stages (PP2=, MP3=, S) (30, 31). The final sample consisted of 54 patients because six patients were lost to follow-up due to different reasons. There were 28 patients in the Activator group (14 males and 14 females; with an average age of 10.6 ± 1.3 years), 26 patients in the Trainer group (14 males and 12 females; with an average age of 10.3 ± 1.4 years). Baseline sample characteristics for each group are given in Table 1. Table 1. Baseline sample characteristic. Variable Activator Trainer (T4K®) Both groups P value Age/year (mean ± SD) 10.6 ± 1.3 10.3 ± 1.4 10.7 ± 1.3 0.700* Height/cm (mean ± SD) 148.1 ± 7.5 147.7 ± 6.3 147.9 ± 6.8 0.562* Sex n (%)  Male 14 (50%) 14 (53.8%) 28 (51.8%) 0.758†  Female 14 (50%) 12 (46.2%) 26 (48.2%) Skeletal age  PP2= 12 9 21 0.139†  MP3= 11 16 27  S 5 1 6 Variable Activator Trainer (T4K®) Both groups P value Age/year (mean ± SD) 10.6 ± 1.3 10.3 ± 1.4 10.7 ± 1.3 0.700* Height/cm (mean ± SD) 148.1 ± 7.5 147.7 ± 6.3 147.9 ± 6.8 0.562* Sex n (%)  Male 14 (50%) 14 (53.8%) 28 (51.8%) 0.758†  Female 14 (50%) 12 (46.2%) 26 (48.2%) Skeletal age  PP2= 12 9 21 0.139†  MP3= 11 16 27  S 5 1 6 *Two-sample t-test, level of differences set at 0.05. †Pearson’s chi-square test, level of significant set at 0.05; Biological age using hand and wrist radiograph stages: PP2= stage: the epiphysis of the proximal phalanx of the index finger has the same width as the diaphysis; MP3= stage: epiphysis of the middle phalanx of the middle finger is of the same width as the diaphysis; S stage: first mineralization of the sesamoid bone of the metacarpophalangeal joint of the hamular process of the hamatum. View Large Table 1. Baseline sample characteristic. Variable Activator Trainer (T4K®) Both groups P value Age/year (mean ± SD) 10.6 ± 1.3 10.3 ± 1.4 10.7 ± 1.3 0.700* Height/cm (mean ± SD) 148.1 ± 7.5 147.7 ± 6.3 147.9 ± 6.8 0.562* Sex n (%)  Male 14 (50%) 14 (53.8%) 28 (51.8%) 0.758†  Female 14 (50%) 12 (46.2%) 26 (48.2%) Skeletal age  PP2= 12 9 21 0.139†  MP3= 11 16 27  S 5 1 6 Variable Activator Trainer (T4K®) Both groups P value Age/year (mean ± SD) 10.6 ± 1.3 10.3 ± 1.4 10.7 ± 1.3 0.700* Height/cm (mean ± SD) 148.1 ± 7.5 147.7 ± 6.3 147.9 ± 6.8 0.562* Sex n (%)  Male 14 (50%) 14 (53.8%) 28 (51.8%) 0.758†  Female 14 (50%) 12 (46.2%) 26 (48.2%) Skeletal age  PP2= 12 9 21 0.139†  MP3= 11 16 27  S 5 1 6 *Two-sample t-test, level of differences set at 0.05. †Pearson’s chi-square test, level of significant set at 0.05; Biological age using hand and wrist radiograph stages: PP2= stage: the epiphysis of the proximal phalanx of the index finger has the same width as the diaphysis; MP3= stage: epiphysis of the middle phalanx of the middle finger is of the same width as the diaphysis; S stage: first mineralization of the sesamoid bone of the metacarpophalangeal joint of the hamular process of the hamatum. View Large Appliances used in the trial The modified Activator The Modified Activator used in the study was originally introduced by Schmuth in 1971 and consisted of acrylic body, two splints meeting each other in the occlusal plane, upper and lower labial bows, Coffin spring in the upper plate, and acrylic capping holding the lower incisors (Figure 2A) (1). The construction bite was taken by advancing the mandible to achieve a Class I or super Class I molar relationship with a 5–6-mm vertical opening in the premolars region. Patients were instructed to wear their appliances for 15 hours per day. At follow-up visits, the occlusal bite plane was gradually trimmed to guide the eruption of the posterior teeth, settling occlusion and Class I molar relation, and for occlusal plane levelling. Figure 2. View largeDownload slide (A) The modified Activator (Schmuth’s modification) consisted of acrylic body, labial bows, Coffin spring, and acrylic capping of the lower incisors. (B) The positioner trainer or trainer for kids (T4K®) consisting of tooth channels, labial bows, tongue tag, tongue guard, and lip bumpers. Figure 2. View largeDownload slide (A) The modified Activator (Schmuth’s modification) consisted of acrylic body, labial bows, Coffin spring, and acrylic capping of the lower incisors. (B) The positioner trainer or trainer for kids (T4K®) consisting of tooth channels, labial bows, tongue tag, tongue guard, and lip bumpers. The positioning trainer Trainer is a prefabricated appliance (Trainer For Kids T4K®, Myofunctional Research Co., Queensland, Australia), which is made of flexible material in a universal size for all children between 6 and 11 years of age. The Positioner Trainer consisted of tooth channels, labial bows, tongue tag, tongue guard, and lip bumpers (Figure 2B) (32). Patients were instructed to wear their appliance for 2 hours in the day and overnight while they sleep. During day-time, patients were asked to do simple myotherapy exercises: positioning the tongue tip on the tongue tag and swallowing while holding the appliance in place with closed lips; children were asked to repeat this exercise for three sets of 10 times. In addition, they were instructed to do another exercise by holding a small piece of paper between the lips and breathe through the nose with the tongue tip on the tongue tag; a child should do this exercise 3–5 minutes divided on three times during the day. These simple myofunctional exercises aimed to encourage breathing through the nose, to correct the tongue position, and to improve swallowing pattern. All participants had soft trainers for the first 6 months; thereafter hard trainers were used for the remaining period of the treatment. Cephalometric analysis and the primary outcome measures Standardized lateral cephalograms were collected before the commencement of treatment (T1) and at 12 months of treatment (T2). Cephalometric landmarks were determined on the lateral cephalograms by on-screen digitization and the measurements were accomplished by a special orthodontic software (AD-Orth Version1.0, ARAB-Dent.Co. Damascus, Syria). Pre- and post-treatment cephalograms were superimposed using the anterior cranial base line (S-N) as a reference line. Angular and linear measurements were used in evaluating dentoskeletal and soft tissue changes. These measurements are illustrated in Figures 3 and 4. Supplementary Table 1 provides the definition of cephalometric measurements used in the study. Cephalometric analysis results were exported in Excel format and statistically analysed using SPSS software (SPSS, IBM Corp. Version 22.0. Armonk, New York, USA). Figure 3. View largeDownload slide Angular skeletal measurements 1. SNA; 2. SNB; 3. ANB; 4. N.A.Pog; 5. S.N.Pog; 6. FH/MP; 7. MM; 8. YAxis; 9. GoMe/SN; 10. Me.Go.Ar; 11. SPP/SN; 12. overjet and dental measurements; 13. Overbite; 14. U1/SPP; 15. U1/SN; 16. L1Axis/MP; 17. U1/L1 (See Supplementary Table 1, available online, for variables’ definitions). Figure 3. View largeDownload slide Angular skeletal measurements 1. SNA; 2. SNB; 3. ANB; 4. N.A.Pog; 5. S.N.Pog; 6. FH/MP; 7. MM; 8. YAxis; 9. GoMe/SN; 10. Me.Go.Ar; 11. SPP/SN; 12. overjet and dental measurements; 13. Overbite; 14. U1/SPP; 15. U1/SN; 16. L1Axis/MP; 17. U1/L1 (See Supplementary Table 1, available online, for variables’ definitions). Figure 4. View largeDownload slide Soft tissues measurements: 18. Gla.Sn.Pog’; 19. Nasolabial angle; 20. Mentolabial angle; 21. Upper lip to Ricketts E line; 22. Lower lip to Ricketts E line. and Linear skeletal measurements: 23. Wits appraisal; 24. Cd-Gn; 25. Go-Pog; 26. Cd-Go. (See Supplementary Table 1, available online, for variables’ definitions). Figure 4. View largeDownload slide Soft tissues measurements: 18. Gla.Sn.Pog’; 19. Nasolabial angle; 20. Mentolabial angle; 21. Upper lip to Ricketts E line; 22. Lower lip to Ricketts E line. and Linear skeletal measurements: 23. Wits appraisal; 24. Cd-Gn; 25. Go-Pog; 26. Cd-Go. (See Supplementary Table 1, available online, for variables’ definitions). Error of the method Two weeks after the first digitization, 20 radiographs were selected randomly and cephalometric analysis was performed again. The error of the method was estimated according to Dahlberg’s formula (33) which ranged from 0.11 to 0.58 for the angular measurements and from 0.10 to 0.46 for the linear measurements. Furthermore, systematic error and interclass correlation coefficients (ICCs) showed that measurements used were highly reliable with no systematic error for all variables; Supplementary Table 2. The collected data were subjected to statistical analysis using SPSS software (SPSS, IBM Corp. Version 22.0. Armonk, New York, USA). Paired-sample t-test or Wilcoxon matched-pairs signed rank test according to normality test was used for intragroup comparisons. Differences between groups were evaluated using two-sample t tests or Mann–Whitney U tests according to the normality of distributions applying Kolmogorov–Smirnov tests. Results Standardized lateral cephalometric radiographs were taken before and after 12 months of the treatment. Skeletal measurements in both groups are demonstrated in Table 2. Improvement in the skeletal Class II features was detected in both groups, however the inter-group comparison showed significantly greater improvement with Activator when compared with T4k® treatment; SNB angle increased significantly in Activator ( x¯ = +1.30 ± 1.11) more than T4K®( x¯ = +0.34 ± 1.49) (P = 0.01); and a significantly greater decrease in the ANB angle was detected with Activator ( x¯ = −1.89 ± 1.12) compared to T4K ( x¯ = −0.9 ± 1.01) (P = 0.01); furthermore, the N.A.Pog angle increased significantly with Activator ( x¯ = +3.39 ± 2.49) more than T4K® ( x¯ = +1.91 ± 2.03) (P = 0.04). Ramus height showed a larger increase with Activator ( x¯ = +2.66 ± 0.71 mm) in compared to a slight change with T4K® ( x¯ = +0.48 ± 1.61 mm) (P < 0.001). The overall anterior facial height showed a significant larger increase with Activator ( x¯ = +3.99 ± 4.43 mm) more than T4K® ( x¯ = +0.64 ± 3.73 mm) (P = 0.004). Moreover, the lower anterior facial height (ANS-Me) increased significantly with the Activator ( x¯ = +2.05 ± 2.92 mm) compared to ( x¯ = +0.53 ± 2.43 mm) in T4k® group3 (P = 0.04). Table 2. Descriptive statistics of the assessed skeletal variables in the two groups as well as the associated P-values of significance tests. Variable Activator T4k P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P-value change over time Mean before SD Mean after SD Mean difference SD P value change over time SNA 80.33 3.32 79.74 3.15 −0.59 1.12 0.011* 81.86 5.37 81.30 5.30 −0.56 1.21 0.021* 0.814 SNB 73.91 3.19 75.21 2.83 1.30 1.11 <0.001**a 74.75 4.99 75.0.9 4.81 0.34 1.49 0.081 0.016** ANB 6.42 1.65 4.53 1.69 −1.89 1.12 <0.001**ab 7.11 1.89 6.21 2.04 −0.9 1.01 0.012*a 0.001**b N.A.Pog 167.58 4.27 170.97 4.30 3.39 2.49 <0.001** a b 166.31 4.95 168.22 5.46 1.91 2.03 <0.001**ab 0.041*b S.N.Pog 74.65 3.18 75.60 2.84 0.95 1.18 <0.001**a 75.48 4.87 75.82 4.62 0.34 1.26 0.195 0.087 FH.MP 28.95 5.38 28.80 4.92 −0.15 2.15 0.712 29.12 5.64 29.98 5.10 0.86 2.10 0.045* 0.085 MM 28.34 5.21 27.92 4.84 −0.42 2.43 0.353 29.79 6.49 29.88 5.89 0.09 2.08 0.821 0.599 Y-axis 67.81 3.33 67.66 3.13 −0.15 1.78 0.645 67.76 5.16 67.99 4.94 0.23 1.23 0.316b 0.357 GoMe/SN 36.97 5.02 36.99 4.60 0.02 2.01 0.964 37.57 6.85 37.79 6.81 0.22 1.62 0.625 0.607 Ar.Go.Me 129.27 5.63 129.83 5.46 0.56 1.75 0.09 130.41 6.49 130.51 6.63 0.1 1.98 0.437b 0.430 Wits app 3.93 2.03 1.57 1.44 −2.36 2.14 <0.001**ab 4.23 2.35 2.50 1.69 −1.73 2.04 <0.001a** 0.222b SPP/SN 7.98 3.15 7.54 3.50 −0.44 0.12 0.421 6.91 2.08 5.65 3.13 −1.26 0.19 0.082 0.890 Cd-Gn 106.03 7.35 108.92 7.5 2.89 5.14 0.014* 98.66 5.63 100.11 5.41 1.45 3.44 0.248b 0.194b Go-Pog 69.69 6.01 71.93 6.4 2.24 2.81 <0.001**a 65.45 5.03 66.42 5.40 0.97 2.69 0.062 0.084 Cd-Go 60.59 4.29 63.25 4.2 2.66 0.71 <0.001**a 58.66 4.30 59.14 3.21 0.48 1.61 0.357 <0.001**a N-Me 113.54 8.57 117.53 10.2 3.99 4.43 <0.001**a 106.27 6.79 106.91 7.66 0.64 3.73 0.263 0.004* Na-ANS 51.31 4.90 52.82 5.8 1.51 2.39 <0.001**a 47.75 3.39 48.28 3.57 0.53 1.67 0.131 0.094 ANS-Me 65.20 5.29 67.25 6.0 2.05 2.92 <0.001**a 61.39 5.21 61.92 5.21 0.53 2.43 0.179b 0.041* ANS-PNS 50.29 4.52 52.01 5.3 1.72 3.78 0.023* 48.47 3.90 49.63 3.24 1.16 2.81 0.041* 0.582 Variable Activator T4k P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P-value change over time Mean before SD Mean after SD Mean difference SD P value change over time SNA 80.33 3.32 79.74 3.15 −0.59 1.12 0.011* 81.86 5.37 81.30 5.30 −0.56 1.21 0.021* 0.814 SNB 73.91 3.19 75.21 2.83 1.30 1.11 <0.001**a 74.75 4.99 75.0.9 4.81 0.34 1.49 0.081 0.016** ANB 6.42 1.65 4.53 1.69 −1.89 1.12 <0.001**ab 7.11 1.89 6.21 2.04 −0.9 1.01 0.012*a 0.001**b N.A.Pog 167.58 4.27 170.97 4.30 3.39 2.49 <0.001** a b 166.31 4.95 168.22 5.46 1.91 2.03 <0.001**ab 0.041*b S.N.Pog 74.65 3.18 75.60 2.84 0.95 1.18 <0.001**a 75.48 4.87 75.82 4.62 0.34 1.26 0.195 0.087 FH.MP 28.95 5.38 28.80 4.92 −0.15 2.15 0.712 29.12 5.64 29.98 5.10 0.86 2.10 0.045* 0.085 MM 28.34 5.21 27.92 4.84 −0.42 2.43 0.353 29.79 6.49 29.88 5.89 0.09 2.08 0.821 0.599 Y-axis 67.81 3.33 67.66 3.13 −0.15 1.78 0.645 67.76 5.16 67.99 4.94 0.23 1.23 0.316b 0.357 GoMe/SN 36.97 5.02 36.99 4.60 0.02 2.01 0.964 37.57 6.85 37.79 6.81 0.22 1.62 0.625 0.607 Ar.Go.Me 129.27 5.63 129.83 5.46 0.56 1.75 0.09 130.41 6.49 130.51 6.63 0.1 1.98 0.437b 0.430 Wits app 3.93 2.03 1.57 1.44 −2.36 2.14 <0.001**ab 4.23 2.35 2.50 1.69 −1.73 2.04 <0.001a** 0.222b SPP/SN 7.98 3.15 7.54 3.50 −0.44 0.12 0.421 6.91 2.08 5.65 3.13 −1.26 0.19 0.082 0.890 Cd-Gn 106.03 7.35 108.92 7.5 2.89 5.14 0.014* 98.66 5.63 100.11 5.41 1.45 3.44 0.248b 0.194b Go-Pog 69.69 6.01 71.93 6.4 2.24 2.81 <0.001**a 65.45 5.03 66.42 5.40 0.97 2.69 0.062 0.084 Cd-Go 60.59 4.29 63.25 4.2 2.66 0.71 <0.001**a 58.66 4.30 59.14 3.21 0.48 1.61 0.357 <0.001**a N-Me 113.54 8.57 117.53 10.2 3.99 4.43 <0.001**a 106.27 6.79 106.91 7.66 0.64 3.73 0.263 0.004* Na-ANS 51.31 4.90 52.82 5.8 1.51 2.39 <0.001**a 47.75 3.39 48.28 3.57 0.53 1.67 0.131 0.094 ANS-Me 65.20 5.29 67.25 6.0 2.05 2.92 <0.001**a 61.39 5.21 61.92 5.21 0.53 2.43 0.179b 0.041* ANS-PNS 50.29 4.52 52.01 5.3 1.72 3.78 0.023* 48.47 3.90 49.63 3.24 1.16 2.81 0.041* 0.582 The definitions of the variables are given in Supplementary Table 1. Significant differences at *P < 0.05, Significant differences at **P < 0.01. aSignificant differences at the adjusted level according to Bonferroni P < 0.0025. bP values are obtained from Mann–Whitney U tests, other values are obtained from two-sample student t tests. View Large Table 2. Descriptive statistics of the assessed skeletal variables in the two groups as well as the associated P-values of significance tests. Variable Activator T4k P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P-value change over time Mean before SD Mean after SD Mean difference SD P value change over time SNA 80.33 3.32 79.74 3.15 −0.59 1.12 0.011* 81.86 5.37 81.30 5.30 −0.56 1.21 0.021* 0.814 SNB 73.91 3.19 75.21 2.83 1.30 1.11 <0.001**a 74.75 4.99 75.0.9 4.81 0.34 1.49 0.081 0.016** ANB 6.42 1.65 4.53 1.69 −1.89 1.12 <0.001**ab 7.11 1.89 6.21 2.04 −0.9 1.01 0.012*a 0.001**b N.A.Pog 167.58 4.27 170.97 4.30 3.39 2.49 <0.001** a b 166.31 4.95 168.22 5.46 1.91 2.03 <0.001**ab 0.041*b S.N.Pog 74.65 3.18 75.60 2.84 0.95 1.18 <0.001**a 75.48 4.87 75.82 4.62 0.34 1.26 0.195 0.087 FH.MP 28.95 5.38 28.80 4.92 −0.15 2.15 0.712 29.12 5.64 29.98 5.10 0.86 2.10 0.045* 0.085 MM 28.34 5.21 27.92 4.84 −0.42 2.43 0.353 29.79 6.49 29.88 5.89 0.09 2.08 0.821 0.599 Y-axis 67.81 3.33 67.66 3.13 −0.15 1.78 0.645 67.76 5.16 67.99 4.94 0.23 1.23 0.316b 0.357 GoMe/SN 36.97 5.02 36.99 4.60 0.02 2.01 0.964 37.57 6.85 37.79 6.81 0.22 1.62 0.625 0.607 Ar.Go.Me 129.27 5.63 129.83 5.46 0.56 1.75 0.09 130.41 6.49 130.51 6.63 0.1 1.98 0.437b 0.430 Wits app 3.93 2.03 1.57 1.44 −2.36 2.14 <0.001**ab 4.23 2.35 2.50 1.69 −1.73 2.04 <0.001a** 0.222b SPP/SN 7.98 3.15 7.54 3.50 −0.44 0.12 0.421 6.91 2.08 5.65 3.13 −1.26 0.19 0.082 0.890 Cd-Gn 106.03 7.35 108.92 7.5 2.89 5.14 0.014* 98.66 5.63 100.11 5.41 1.45 3.44 0.248b 0.194b Go-Pog 69.69 6.01 71.93 6.4 2.24 2.81 <0.001**a 65.45 5.03 66.42 5.40 0.97 2.69 0.062 0.084 Cd-Go 60.59 4.29 63.25 4.2 2.66 0.71 <0.001**a 58.66 4.30 59.14 3.21 0.48 1.61 0.357 <0.001**a N-Me 113.54 8.57 117.53 10.2 3.99 4.43 <0.001**a 106.27 6.79 106.91 7.66 0.64 3.73 0.263 0.004* Na-ANS 51.31 4.90 52.82 5.8 1.51 2.39 <0.001**a 47.75 3.39 48.28 3.57 0.53 1.67 0.131 0.094 ANS-Me 65.20 5.29 67.25 6.0 2.05 2.92 <0.001**a 61.39 5.21 61.92 5.21 0.53 2.43 0.179b 0.041* ANS-PNS 50.29 4.52 52.01 5.3 1.72 3.78 0.023* 48.47 3.90 49.63 3.24 1.16 2.81 0.041* 0.582 Variable Activator T4k P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P-value change over time Mean before SD Mean after SD Mean difference SD P value change over time SNA 80.33 3.32 79.74 3.15 −0.59 1.12 0.011* 81.86 5.37 81.30 5.30 −0.56 1.21 0.021* 0.814 SNB 73.91 3.19 75.21 2.83 1.30 1.11 <0.001**a 74.75 4.99 75.0.9 4.81 0.34 1.49 0.081 0.016** ANB 6.42 1.65 4.53 1.69 −1.89 1.12 <0.001**ab 7.11 1.89 6.21 2.04 −0.9 1.01 0.012*a 0.001**b N.A.Pog 167.58 4.27 170.97 4.30 3.39 2.49 <0.001** a b 166.31 4.95 168.22 5.46 1.91 2.03 <0.001**ab 0.041*b S.N.Pog 74.65 3.18 75.60 2.84 0.95 1.18 <0.001**a 75.48 4.87 75.82 4.62 0.34 1.26 0.195 0.087 FH.MP 28.95 5.38 28.80 4.92 −0.15 2.15 0.712 29.12 5.64 29.98 5.10 0.86 2.10 0.045* 0.085 MM 28.34 5.21 27.92 4.84 −0.42 2.43 0.353 29.79 6.49 29.88 5.89 0.09 2.08 0.821 0.599 Y-axis 67.81 3.33 67.66 3.13 −0.15 1.78 0.645 67.76 5.16 67.99 4.94 0.23 1.23 0.316b 0.357 GoMe/SN 36.97 5.02 36.99 4.60 0.02 2.01 0.964 37.57 6.85 37.79 6.81 0.22 1.62 0.625 0.607 Ar.Go.Me 129.27 5.63 129.83 5.46 0.56 1.75 0.09 130.41 6.49 130.51 6.63 0.1 1.98 0.437b 0.430 Wits app 3.93 2.03 1.57 1.44 −2.36 2.14 <0.001**ab 4.23 2.35 2.50 1.69 −1.73 2.04 <0.001a** 0.222b SPP/SN 7.98 3.15 7.54 3.50 −0.44 0.12 0.421 6.91 2.08 5.65 3.13 −1.26 0.19 0.082 0.890 Cd-Gn 106.03 7.35 108.92 7.5 2.89 5.14 0.014* 98.66 5.63 100.11 5.41 1.45 3.44 0.248b 0.194b Go-Pog 69.69 6.01 71.93 6.4 2.24 2.81 <0.001**a 65.45 5.03 66.42 5.40 0.97 2.69 0.062 0.084 Cd-Go 60.59 4.29 63.25 4.2 2.66 0.71 <0.001**a 58.66 4.30 59.14 3.21 0.48 1.61 0.357 <0.001**a N-Me 113.54 8.57 117.53 10.2 3.99 4.43 <0.001**a 106.27 6.79 106.91 7.66 0.64 3.73 0.263 0.004* Na-ANS 51.31 4.90 52.82 5.8 1.51 2.39 <0.001**a 47.75 3.39 48.28 3.57 0.53 1.67 0.131 0.094 ANS-Me 65.20 5.29 67.25 6.0 2.05 2.92 <0.001**a 61.39 5.21 61.92 5.21 0.53 2.43 0.179b 0.041* ANS-PNS 50.29 4.52 52.01 5.3 1.72 3.78 0.023* 48.47 3.90 49.63 3.24 1.16 2.81 0.041* 0.582 The definitions of the variables are given in Supplementary Table 1. Significant differences at *P < 0.05, Significant differences at **P < 0.01. aSignificant differences at the adjusted level according to Bonferroni P < 0.0025. bP values are obtained from Mann–Whitney U tests, other values are obtained from two-sample student t tests. View Large Dentoalveolar changes are presented in Table 3. The Activator group showed a greater significant decrease in overjet ( x¯ = −3.0 ± 2.3 mm) compared to ( x¯ = −1.5 ± 1.9 mm; P = 0.01) with T4k®. However, no significant differences were detected in other dentoalveolar variables. Table 3. Descriptive statistics of dentoalveolar variables assessed in the two groups as well as the associated P values of significance tests Variable Activator T4K P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P value change over time Mean before SD Mean after SD Mean difference SD P value change over time Overbite 4.13 1.62 3.44 1.7 −0.69 1.61 0.031* 3.02 1.88 2.89 1.40 −0.13 1.53 0.685 0.194 Overjet 7.23 2.12 4.20 2.1 −3.03 2.29 <0.001*ab 6.11 2.04 4.61 2.14 −1.5 1.91 <0.001*ab 0.010*b U1Axis/SPP 113.32 6.82 110.59 6.2 −2.73 1.53 0.049* 110.94 8.52 108.93 8.21 −2.01 1.10 0.041* 0.757 U1 Axis/SN 104.66 7.98 101.49 7.0 −3.17 7.32 0.021* 103.38 8.91 101.01 8.68 −2.37 1.72 0.025* 0.821 L1Axis/Mp 97.81 2.92 98.28 3.3 0.47 1.57 0.537a 97.40 3.01 98.47 3.71 1.07 3.59 0.132 0.522 b U1/1L Axis 119.54 7.96 122.21 6.8 2.67 7.01 0.052* 120.75 10.58 121.76 10.73 1.01 6.61 0.448 0.372 (gla.Sn.Pog`) 158.67 4.84 161.28 3.86 2.61 3.71 <0.001*ab 157.73 5.24 157.75 5.5 0.02 2.51 0.954 0.004**a (Cl.Sn. SLS) 113.35 10.00 109.33 8.97 −4.02 10.10 0.042* 113.05 10.90 114.82 10.8 1.77 8.50 0.678 0.027* (li.ils.Pog`) 112.73 13.69 124.69 15.44 11.96 12.57 <0.001*ab 115.34 17.31 121.78 10.7 6.44 14.77 0.021* 0.149 Ls to E 1.81 1.48 2.41 1.21 0.60 1.47 0.065b 1.71 1.40 2.01 1.5 0.30 1.46 0.781 b 0.585b Li to E 2.21 1.47 2.16 1.47 −0.05 1.43 0.854b 2.52 1.73 2.61 2.0 0.09 1.52 0.525 b 0.822b Variable Activator T4K P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P value change over time Mean before SD Mean after SD Mean difference SD P value change over time Overbite 4.13 1.62 3.44 1.7 −0.69 1.61 0.031* 3.02 1.88 2.89 1.40 −0.13 1.53 0.685 0.194 Overjet 7.23 2.12 4.20 2.1 −3.03 2.29 <0.001*ab 6.11 2.04 4.61 2.14 −1.5 1.91 <0.001*ab 0.010*b U1Axis/SPP 113.32 6.82 110.59 6.2 −2.73 1.53 0.049* 110.94 8.52 108.93 8.21 −2.01 1.10 0.041* 0.757 U1 Axis/SN 104.66 7.98 101.49 7.0 −3.17 7.32 0.021* 103.38 8.91 101.01 8.68 −2.37 1.72 0.025* 0.821 L1Axis/Mp 97.81 2.92 98.28 3.3 0.47 1.57 0.537a 97.40 3.01 98.47 3.71 1.07 3.59 0.132 0.522 b U1/1L Axis 119.54 7.96 122.21 6.8 2.67 7.01 0.052* 120.75 10.58 121.76 10.73 1.01 6.61 0.448 0.372 (gla.Sn.Pog`) 158.67 4.84 161.28 3.86 2.61 3.71 <0.001*ab 157.73 5.24 157.75 5.5 0.02 2.51 0.954 0.004**a (Cl.Sn. SLS) 113.35 10.00 109.33 8.97 −4.02 10.10 0.042* 113.05 10.90 114.82 10.8 1.77 8.50 0.678 0.027* (li.ils.Pog`) 112.73 13.69 124.69 15.44 11.96 12.57 <0.001*ab 115.34 17.31 121.78 10.7 6.44 14.77 0.021* 0.149 Ls to E 1.81 1.48 2.41 1.21 0.60 1.47 0.065b 1.71 1.40 2.01 1.5 0.30 1.46 0.781 b 0.585b Li to E 2.21 1.47 2.16 1.47 −0.05 1.43 0.854b 2.52 1.73 2.61 2.0 0.09 1.52 0.525 b 0.822b Variables’ definitions are given in Supplementary Table 1. The value is 0.000 for all of the italic values. Significant differences *P < 0.05, Significant differences **P < 0.01. aSignificant differences at the adjusted level according to Bonferroni P< 0.005. bP values are obtained from Mann–Whitney U tests, other values are resulted from two sample student t test. View Large Table 3. Descriptive statistics of dentoalveolar variables assessed in the two groups as well as the associated P values of significance tests Variable Activator T4K P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P value change over time Mean before SD Mean after SD Mean difference SD P value change over time Overbite 4.13 1.62 3.44 1.7 −0.69 1.61 0.031* 3.02 1.88 2.89 1.40 −0.13 1.53 0.685 0.194 Overjet 7.23 2.12 4.20 2.1 −3.03 2.29 <0.001*ab 6.11 2.04 4.61 2.14 −1.5 1.91 <0.001*ab 0.010*b U1Axis/SPP 113.32 6.82 110.59 6.2 −2.73 1.53 0.049* 110.94 8.52 108.93 8.21 −2.01 1.10 0.041* 0.757 U1 Axis/SN 104.66 7.98 101.49 7.0 −3.17 7.32 0.021* 103.38 8.91 101.01 8.68 −2.37 1.72 0.025* 0.821 L1Axis/Mp 97.81 2.92 98.28 3.3 0.47 1.57 0.537a 97.40 3.01 98.47 3.71 1.07 3.59 0.132 0.522 b U1/1L Axis 119.54 7.96 122.21 6.8 2.67 7.01 0.052* 120.75 10.58 121.76 10.73 1.01 6.61 0.448 0.372 (gla.Sn.Pog`) 158.67 4.84 161.28 3.86 2.61 3.71 <0.001*ab 157.73 5.24 157.75 5.5 0.02 2.51 0.954 0.004**a (Cl.Sn. SLS) 113.35 10.00 109.33 8.97 −4.02 10.10 0.042* 113.05 10.90 114.82 10.8 1.77 8.50 0.678 0.027* (li.ils.Pog`) 112.73 13.69 124.69 15.44 11.96 12.57 <0.001*ab 115.34 17.31 121.78 10.7 6.44 14.77 0.021* 0.149 Ls to E 1.81 1.48 2.41 1.21 0.60 1.47 0.065b 1.71 1.40 2.01 1.5 0.30 1.46 0.781 b 0.585b Li to E 2.21 1.47 2.16 1.47 −0.05 1.43 0.854b 2.52 1.73 2.61 2.0 0.09 1.52 0.525 b 0.822b Variable Activator T4K P value Activator versus T4K Mean before SD Mean after SD Mean difference SD P value change over time Mean before SD Mean after SD Mean difference SD P value change over time Overbite 4.13 1.62 3.44 1.7 −0.69 1.61 0.031* 3.02 1.88 2.89 1.40 −0.13 1.53 0.685 0.194 Overjet 7.23 2.12 4.20 2.1 −3.03 2.29 <0.001*ab 6.11 2.04 4.61 2.14 −1.5 1.91 <0.001*ab 0.010*b U1Axis/SPP 113.32 6.82 110.59 6.2 −2.73 1.53 0.049* 110.94 8.52 108.93 8.21 −2.01 1.10 0.041* 0.757 U1 Axis/SN 104.66 7.98 101.49 7.0 −3.17 7.32 0.021* 103.38 8.91 101.01 8.68 −2.37 1.72 0.025* 0.821 L1Axis/Mp 97.81 2.92 98.28 3.3 0.47 1.57 0.537a 97.40 3.01 98.47 3.71 1.07 3.59 0.132 0.522 b U1/1L Axis 119.54 7.96 122.21 6.8 2.67 7.01 0.052* 120.75 10.58 121.76 10.73 1.01 6.61 0.448 0.372 (gla.Sn.Pog`) 158.67 4.84 161.28 3.86 2.61 3.71 <0.001*ab 157.73 5.24 157.75 5.5 0.02 2.51 0.954 0.004**a (Cl.Sn. SLS) 113.35 10.00 109.33 8.97 −4.02 10.10 0.042* 113.05 10.90 114.82 10.8 1.77 8.50 0.678 0.027* (li.ils.Pog`) 112.73 13.69 124.69 15.44 11.96 12.57 <0.001*ab 115.34 17.31 121.78 10.7 6.44 14.77 0.021* 0.149 Ls to E 1.81 1.48 2.41 1.21 0.60 1.47 0.065b 1.71 1.40 2.01 1.5 0.30 1.46 0.781 b 0.585b Li to E 2.21 1.47 2.16 1.47 −0.05 1.43 0.854b 2.52 1.73 2.61 2.0 0.09 1.52 0.525 b 0.822b Variables’ definitions are given in Supplementary Table 1. The value is 0.000 for all of the italic values. Significant differences *P < 0.05, Significant differences **P < 0.01. aSignificant differences at the adjusted level according to Bonferroni P< 0.005. bP values are obtained from Mann–Whitney U tests, other values are resulted from two sample student t test. View Large Table 3 describes the soft tissue changes. Facial convexity, nasolabial, and mentolabial angles showed significant changes in the Activator group (P ≤ 0.04; Table 3). In contrast, the T4k® group did not show significant changes in all soft tissue variables. When comparing the two groups, the facial convexity angle (gla.Sn.Pog`) showed significantly a larger increase with Activator ( x¯ = 2.61 ± 3.71) more than T4K® ( x¯ = 0.2 ± 2.51) (P = 0.004), in addition to significantly larger decrease in the nasolabial angle ( x¯= −4.02 ± 10.10) when compared with T4K® ( x¯ = 1.77 ± 8.50) (P = 0.02). Discussion This randomized controlled trial compared the efficacy of a traditional functional appliance for mandibular advancement (a modified Activator) with a myofunctional therapy using the Trainer of Kids appliance (T4K®) in growing Class II division 1 cases through evaluating soft and hard tissue changes in both groups using lateral cephalograms after 12 months of active treatment. The treatment groups were matched in age (biological and chronological), sex, and skeletal and dental cephalometric measurements. Biological age was assessed for all participants using hand and wrist radiograph which showed that some of the participants were (PP2=) stage which indicates that a child’s biological age has not reach the pubertal growth spurt yet; this may affect the response to functional treatment as suggested recently (34), at any rate the treatment groups were homogenous in the distribution of the participant in both groups regarding the biological age, thus it is not expected that including those participants in the study in the prepubertal stage would compromise the results of this study. Six participants withdrew from the study (four from the T4K® group, and two from the Activator group). This may reflect lower acceptance of T4K® treatment system which has been separately investigated and previously reported (35). Anatomical condylar point (Cd) was used instead of Articular point (Ar) in measuring mandibular length and ramus height to follow mandibular skeletal changes. Using Cd point is preferable as an anatomical point to the use of Ar which is a constructed point (5, 36, 37). Both groups showed significant skeletal changes but Activator was significantly more effective with greater increase in SNB angle and more reduction in ANB angle and Wits appraisal. Favourable skeletal changes with Activator therapy were referred to by many reports (36, 38–44). On the other hand, Usumez’ study about the T4K® appliance showed insignificant changes in mandibular measurements when compared with the control group which were consistent with the findings of the current study (19). The favourable skeletal changes seen with the Activator may due to the fact that Activator is a custom-made appliance which allows a precise anterior mandibular repositioning determined by the construction wax bite. Moreover, the Activator is made of acrylic material which is harder than that of the Trainer, specifically the starting appliance (i.e. the soft blue trainer). The high elasticity of the T4K® was an important flaw noted and reported by parents; this elasticity made it difficult for children to keep their mandibles in a forward position (i.e. in an edge-to-edge relationship at the incisors; Figure 5). This may give an indication that the use of the hard version of this appliance is important to attain better skeletal changes. An additional factor may play a role in the favourable skeletal changes is that the Activator was recommended to be worn for longer time per day than the Trainer as we followed the manufacturer instruction. Consequently, patients’ mandibles received higher force levels for longer period of time in the Activator group compared to the T4K® group. Figure 5. View largeDownload slide The Blue Trainer did not provide a stable forward positioning of the mandible. (a) Incisors at an edge-to-edge relationship immediately following Trainer’s wear and (b) the mandible moved to a backward position after few minutes of appliance wear. Figure 5. View largeDownload slide The Blue Trainer did not provide a stable forward positioning of the mandible. (a) Incisors at an edge-to-edge relationship immediately following Trainer’s wear and (b) the mandible moved to a backward position after few minutes of appliance wear. The significant increase in the lower facial height in the Activator group and the superior changes with Activator treatment in comparison with the T4K® appliance may due to Activator bite opening effect and the guided extrusion of the posterior teeth in the occlusal acrylic plate (37, 40–42, 44–46). However, a previous study about T4K® showed significant increase in the lower facial height (19), which was not seen in the current study. Insignificant changes in the lower incisors/mandibular plane angle may due to lower incisors acrylic capping used in the Activator design which may be useful in controlling the unfavourable labial movement of lower incisors. The seen dentoalveolar changes in the current study showed a greater decrease in overjet with Activator. These changes are coincident with previous studies regarding the Activator and the Trainer which reported favourable dentoalveolar changes (15, 19, 36, 37, 40–42, 44–46). Čirgić and colleagues compared the Trainer to Anderson Activator in Class II malocclusion and have reported that the Activator showed a greater reduction in overjet after 1 year treatment. However, after 6 months of completing the treatment a relapse in the overjet was detected in both groups which resulted in no significant differences in overjet (20). In the current study, there was no more cephalometric records were taken further to the 12 months follow-up to check for any possible relapse. Regarding soft-tissue changes, the facial-convexity-angle’s significant increase with the Activator therapy represented favourable facial changes and may be explained as a reflection of the significant underlying skeletal improvement. On the other hand, the Trainer system was not able to show such favourable changes in the soft-tissue drape. Limitations This trial had a relatively short-term follow-up (i.e. 12 months) and no further cephalometric follow-ups were made. Therefore, a study with a longer follow-up is required to confirm the current results. It is preferable to design the study including three arms (a control and two treatment groups) but considering the ethical flaw of such design leaving children without treatment made this design hard to apply in the study. Although not all of the participants were treated in the pubertal growth spurt, both groups were matched in both chronological and biological age. Conclusions - In the short-term, a 1-year treatment with the Activator appliance resulted in better skeletal changes compared to those of the T4K®, particularly the ANB angle decrease, the ramus height increase, and the greater lower facial height increase. - In the short-term, a 1-year Activator treatment was significantly more effective than the T4K® in correcting the increased overjet and normalizing soft-tissue appearance particularly the facial convexity angle and the nasolabial angle. Supplementary material Supplementary material is available at European Journal of Orthodontics online. Funding This research was funded by Postgraduate Research Budget in Al-Baath University (Ref 1165-2006-DEN). Conflict of Interest None to declare. References 1. Stockfisch , H . ( 1995 ) (ed.), The Principles and Practice of Dentofacial Orthopedics . Quintessence Puplishing Co, Inc ., New Malden, United Kingdom. 2. Fränkel , R . ( 1971 ) Possibilities of a late basal development of the mandible through the rearrangement of the bite by means of a functional regulator . Deutsche Stomatologie , 21 , 198 – 202 . Google Scholar PubMed 3. Clark , W.J . ( 1988 ) The twin block technique. A functional orthopedic appliance system . American Journal of Orthodontics and Dentofacial Orthopedics , 93 , 1 – 18 . Google Scholar CrossRef Search ADS PubMed 4. Pancherz , H . ( 1982 ) The mechanism of Class II correction in Herbst appliance treatment. A cephalometric investigation . American Journal of Orthodontics , 82 , 104 – 113 . Google Scholar CrossRef Search ADS PubMed 5. Cozza , P. , Baccetti , T. , Franchi , L. , De Toffol , L. and McNamara , J.A. , Jr . ( 2006 ) Mandibular changes produced by functional appliances in Class II malocclusion: a systematic review . American Journal of Orthodontics and Dentofacial Orthopedics , 129 , 599.e1 – 12 ; discussion e1. 6. Koretsi , V. , Zymperdikas , V.F. , Papageorgiou , S.N. and Papadopoulos , M.A . ( 2015 ) Treatment effects of removable functional appliances in patients with Class II malocclusion: a systematic review and meta-analysis . European Journal of Orthodontics , 37 , 418 – 434 . Google Scholar CrossRef Search ADS PubMed 7. Flores-Mir , C. and Major , P.W . ( 2006 ) A systematic review of cephalometric facial soft tissue changes with the Activator and Bionator appliances in Class II division 1 subjects . European Journal of Orthodontics , 28 , 586 – 593 . Google Scholar CrossRef Search ADS PubMed 8. Moss , M.L. and Rankow , R.M . ( 1968 ) The role of the functional matrix in mandibular growth . The Angle Orthodontist , 38 , 95 – 103 . Google Scholar PubMed 9. Moss , M.L . ( 1997 ) The functional matrix hypothesis revisited. 1. The role of mechanotransduction . American Journal of Orthodontics and Dentofacial Orthopedics , 112 , 8 – 11 . Google Scholar CrossRef Search ADS PubMed 10. Owman-Moll , P. and Ingervall , B . ( 1984 ) Effect of oral screen treatment on dentition, lip morphology, and function in children with incompetent lips . American Journal of Orthodontics , 85 , 37 – 46 . Google Scholar CrossRef Search ADS PubMed 11. Cheney , E.A . ( 1958 ) Factors in the early treatment and interception of malocclusion . American Journal of Orthodontics , 44 : 807 – 826 . Google Scholar CrossRef Search ADS 12. Cheney , E.A . ( 1963 ) Treatment planning and therapy in the mixed dentition . American Journal of Orthodontics , 49 : 568 – 580 . Google Scholar CrossRef Search ADS 13. Rossi , R. , Mortara , M.C. and Boccaccio , E . ( 1984 ) Preventive orthodontics and the use of oral screens. Parodontologia E Stomatologia (Nuova), 23(Suppl 3), 191–192 . 14. Bergersen , E.O . ( 1984 ) The eruption guidance myofunctional appliances: how it works, how to use it . The Functional Orthodontist , 1 , 28 – 29 . Google Scholar PubMed 15. Quadrelli , C. , Gheorgiu , M. , Marcheti , C. and Ghiglione , V . ( 2002 ) Early myofunctional approach to skeletal Class II . Mondo Ortodontico , 2, 109–122. 16. Tallgren , A. , Christiansen , R.L. , Ash , M. Jr and Miller , R.L . ( 1998 ) Effects of a myofunctional appliance on orofacial muscle activity and structures . The Angle Orthodontist , 68 , 249 – 258 . Google Scholar PubMed 17. Hashish , D.I. and Mostafa , Y.A . ( 2009 ) Effect of lip bumpers on mandibular arch dimensions . American Journal of Orthodontics and Dentofacial Orthopedics , 135 , 106 – 109 . Google Scholar CrossRef Search ADS PubMed 18. Homem , M.A. , Vieira-Andrade , R.G. , Falci , S.G. , Ramos-Jorge , M.L. and Marques , L.S . ( 2014 ) Effectiveness of orofacial myofunctional therapy in orthodontic patients: a systematic review . Dental Press Journal of Orthodontics , 19 , 94 – 99 . Google Scholar CrossRef Search ADS PubMed 19. Usumez , S. , Uysal , T. , Sari , Z. , Basciftci , F.A. , Karaman , A.I. and Guray , E . ( 2004 ) The effects of early preorthodontic trainer treatment on Class II, division 1 patients . The Angle Orthodontist , 74 , 605 – 609 . Google Scholar PubMed 20. Čirgić , E. , Kjellberg , H. and Hansen , K . ( 2016 ) Treatment of large overjet in Angle Class II: division 1 malocclusion with Andresen activators versus prefabricated functional appliances-a multicenter, randomized, controlled trial . European Journal of Orthodontics , 38 , 516 – 524 . Google Scholar CrossRef Search ADS PubMed 21. Bishara , S.E. and Ziaja , R.R . ( 1989 ) Functional appliances: a review . American Journal of Orthodontics and Dentofacial Orthopedics , 95 , 250 – 258 . Google Scholar CrossRef Search ADS PubMed 22. Stüber , P . ( 1989 ) Comparison of treatment of mandibular retrognathia by functional regulators and activators . Stomatologie Der DDR , 39 , 446 – 451 . Google Scholar PubMed 23. Sari , Z. , Goyenc , Y. , Doruk , C. and Usumez , S . ( 2003 ) Comparative evaluation of a new removable Jasper Jumper functional appliance vs an activator-headgear combination . The Angle Orthodontist , 73 , 286 – 293 . Google Scholar PubMed 24. Trenouth , M.J . ( 1992 ) A comparison of Twin Block, Andresen and removable appliances in the treatment of Class II Division 1 malocclusion . The Functional Orthodontist , 9 , 26 – 31 . Google Scholar PubMed 25. Tümer , N. and Gültan , A.S . ( 1999 ) Comparison of the effects of monoblock and twin-block appliances on the skeletal and dentoalveolar structures . American Journal of Orthodontics and Dentofacial Orthopedics , 116 , 460 – 468 . Google Scholar CrossRef Search ADS PubMed 26. Varlik , S.K. , Gültan , A. and Tümer , N . ( 2008 ) Comparison of the effects of Twin Block and activator treatment on the soft tissue profile . European Journal of Orthodontics , 30 , 128 – 134 . Google Scholar CrossRef Search ADS PubMed 27. Baltromejus , S. , Ruf , S. and Pancherz , H . ( 2002 ) Effective temporomandibular joint growth and chin position changes: Activator versus Herbst treatment. A cephalometric roentgenographic study . European Journal of Orthodontics , 24 , 627 – 637 . Google Scholar CrossRef Search ADS PubMed 28. Ulusoy , C. and Darendeliler , N . ( 2008 ) Effects of Class II activator and Class II activator high-pull headgear combination on the mandible: a 3-dimensional finite element stress analysis study . American Journal of Orthodontics and Dentofacial Orthopedics , 133 , 490.e9 – 490.15 . Google Scholar CrossRef Search ADS 29. Farell , C . ( 2017 ) How Successful are MRC’s Appliances? Do They Really Work? Myofunctional Research , Australia . http://smartertrack.myoresearch.com/KB/a24/how-successful-are-mrcs-appliances-do-they-really-work.aspx (13 December 2017, date last accessed). 30. Björk , A. and Helm , S . ( 1967 ) Prediction of the age of maximum puberal growth in body height . The Angle Orthodontist , 37 , 134 – 143 . Google Scholar PubMed 31. Grave , K.C. and Brown , T . ( 1976 ) Skeletal ossification and the adolescent growth spurt . American Journal of Orthodontics , 69 , 611 – 619 . Google Scholar CrossRef Search ADS PubMed 32. Farell , C . ( 2015 ) The Trainer system myoresearch.com: myoresearch . http://myoresearch.com/appliances/the_trainer_system/57 (1 August 2015, date last accessed). 33. Dahlburg , G ., (ed.) ( 1940 ) Statistical Methods for Medical and Biological Students . George Allen and Unwin Ltd , London . 34. Perinetti , G. , Primožič , J. , Franchi , L. and Contardo , L . ( 2015 ) Treatment effects of removable functional appliances in pre-pubertal and pubertal Class II patients: a systematic review and meta-analysis of controlled studies . PloS One , 10 , e0141198 . Google Scholar CrossRef Search ADS PubMed 35. Idris , G. , Hajeer , M.Y. and Al-Jundi , A . ( 2012 ) Acceptance and discomfort in growing patients during treatment with two functional appliances: a randomised controlled trial . European Journal of Paediatric Dentistry , 13 , 219 – 224 . Google Scholar PubMed 36. Chen , J.Y. , Will , L.A. and Niederman , R . ( 2002 ) Analysis of efficacy of functional appliances on mandibular growth . American Journal of Orthodontics and Dentofacial Orthopedics , 122 , 470 – 476 . Google Scholar CrossRef Search ADS PubMed 37. Nelson , C. , Harkness , M. and Herbison , P . ( 1993 ) Mandibular changes during functional appliance treatment . American Journal of Orthodontics and Dentofacial Orthopedics , 104 , 153 – 161 . Google Scholar CrossRef Search ADS PubMed 38. Aelbers , C.M. and Dermaut , L.R . ( 1996 ) Orthopedics in orthodontics: part I, fiction or reality–a review of the literature . American Journal of Orthodontics and Dentofacial Orthopedics , 110 , 513 – 519 . Google Scholar CrossRef Search ADS PubMed 39. Antonarakis , G.S. and Kiliaridis , S . ( 2007 ) Short-term anteroposterior treatment effects of functional appliances and extraoral traction on class II malocclusion. A meta-analysis . The Angle Orthodontist , 77 , 907 – 914 . Google Scholar CrossRef Search ADS PubMed 40. Basciftci , F.A. , Uysal , T. , Büyükerkmen , A. and Sari , Z . ( 2003 ) The effects of activator treatment on the craniofacial structures of Class II division 1 patients . European Journal of Orthodontics , 25 , 87 – 93 . Google Scholar CrossRef Search ADS PubMed 41. Cozza , P. , De Toffol , L. and Colagrossi , S . ( 2004 ) Dentoskeletal effects and facial profile changes during activator therapy . European Journal of Orthodontics , 26 , 293 – 302 . Google Scholar CrossRef Search ADS PubMed 42. Cozza , P. , De Toffol , L. and Iacopini , L . ( 2004 ) An analysis of the corrective contribution in activator treatment . The Angle Orthodontist , 74 , 741 – 748 . Google Scholar PubMed 43. Dolce , C. , Schader , R.E. , McGorray , S.P. and Wheeler , T.T . ( 2005 ) Centrographic analysis of 1-phase versus 2-phase treatment for Class II malocclusion . American Journal of Orthodontics and Dentofacial Orthopedics , 128 , 195 – 200 . Google Scholar CrossRef Search ADS PubMed 44. Türkkahraman , H. and Sayin , M.O . ( 2006 ) Effects of activator and activator headgear treatment: comparison with untreated Class II subjects . European Journal of Orthodontics , 28 , 27 – 34 . Google Scholar CrossRef Search ADS PubMed 45. Vargervik , K. and Harvold , E.P . ( 1985 ) Response to activator treatment in Class II malocclusions . American Journal of Orthodontics , 88 , 242 – 251 . Google Scholar CrossRef Search ADS PubMed 46. Luder , H.U . ( 1982 ) Skeletal profile changes related to two patterns of activator effects . American Journal of Orthodontics , 81 , 390 – 396 . Google Scholar CrossRef Search ADS PubMed © The Author(s) 2018. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)

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The European Journal of OrthodonticsOxford University Press

Published: Apr 3, 2018

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