Comparison of the effects of Twin Block and activator treatment on the soft tissue profile
Department of Orthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey.The European Journal of Orthodontics (Impact Factor: 1.48). 05/2008; 30(2):128-34. DOI: 10.1093/ejo/cjm121
The aim of this study was to evaluate and compare the effects of activator and Twin Block (TB) appliances on the soft tissue profile. The study included 50 skeletal Class II patients (25 girls and 25 boys, mean age: 11.9 +/- 0.16 years) who were randomly allocated to one of two functional appliance treatment groups. The control group included 25 untreated skeletal Class II patients (13 boys and 12 girls, mean age: 10.11 +/- 0.91 years). Data were obtained from standardized lateral cephalograms taken at the beginning (T0) and end (T1) of appliance wear. The mean treatment time was 9 months for the activator group and 8 months for the TB group. The observation period of the control group was 8 months. Soft tissue profile changes were evaluated by means of 12 linear and five angular measurements. The groups were compared at T0 and T1 using analysis of variance, and treatment/observation differences (T1-T0) were evaluated with the Kruskal-Wallis test. Treatment changes in both appliance groups differed significantly (P < or = 0.001) from those in the control group, except for Ss-y, Ls-y, Li-E, and A-y measurements in the TB group and Ls-y, Li-E, nasolabial angle, and A-y measurements in the activator group. When the effects of the two appliances were compared, significant differences were observed only for SS-y (P < or = 0.05), Ss-E (P < or = 0.05), Si-E (P < or = 0.05), and nasolabial angle (P < or = 0.01). The effects of the activator and TB appliances on the soft tissue profile were similar; both significantly changed the soft tissue profile.
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ABSTRACT: To date, few studies have correlated the changes in muscle activity and specific soft tissue variables in adolescents with malocclusions. To determine associations between the soft tissue profile and electromyographic activities in temporalis, masseter and orbicularis oris muscles in children with Class II division 1 malocclusions treated with activators. For this prospective study, 25 subjects with Class II division 1 malocclusions were randomly assigned to either a Treatment group (N=15) or a Control group (N=10). The mean skeletal ages of the subjects in the Treatment and Control groups were 11.3 +/- 1.1 and 11.0 +/- 1.3 years, respectively. The subjects in the Treatment group were treated with activators and the subjects in the Control group were untreated. Lateral cephalometric radiographs and EMG recordings of the anterior temporalis and masseter muscles during clenching, chewing and swallowing and the orbicularis oris muscle during whistling were obtained at the start of the study and 12 months later. Changes in the soft tissue profile were correlated with changes in the EMG activities in anterior temporalis, superficial masseter and orbicularis oris muscles. The upper lip to E line distance (UL-E) decreased more in the Treatment group than the Control group (p < 0.05) and the H angle decreased in the Treatment group, but increased in the Control group (p < 0.01). The EMG activities of temporalis and masseter muscles increased significantly in both groups. All between-group EMG differences were statistically significant with the exception of the activities in the temporalis and masseter muscles during swallowing. In the Treatment group, a significant positive correlation (r = .57) was found between the changes in UL-E and anterior temporalis activity during swallowing, and significant negative correlations were observed between the EMG activity of masseter muscle during swallowing and changes in LL-E (r = -.54), OLp-UL (r = -.55) and OLp-LL (r = -.67). Activator therapy is accompanied by changes in the lips and temporalis and masseter activities during swallowing.
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ABSTRACT: The aim of this study was to determine the hard and soft tissue profile changes in Class III malocclusion subjects following functional regulator III (FR-3) treatment. The material comprised the cephalometric films of 15 patients (11 males and four females; mean ages 10.22 and 10.44 years, respectively) with a Class III malocclusion and a concave profile treated with the FR-3, and a control group of 15 subjects (11 males and four females; mean ages 10.39 and 10.27 years, respectively) with a Class I malocclusion matched for chronological age and observation period with the study group. Fourteen linear and seven angular measurements were measured on the cephalometric films taken before (T1) and after (T2) treatment/observation. The results of the Student's t-test showed that the treatment group had a concave facial profile when compared with the controls. At the end of treatment, the maxilla and surrounding soft tissues showed significant anterior movement (P < 0.001 and P < 0.01, respectively), whereas mandibular growth was restricted. The vertical dimensions increased, the upper incisors proclined, and the lower incisors retroclined significantly (P < 0.001). The FR-3 appliance produced significant improvements in the hard and soft tissues of Class III subjects with a concave profile.
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ABSTRACT: SUMMARY: The dentoskeletal effects of maxillary protraction (MP) therapy have been extensively investigated, while those relating to soft tissue profile changes are limited. Thus, the aim of this study was to determine the degree of soft tissue profile changes following MP therapy. The material consisted of the cephalometric films of 24 female subjects (12.69 +/- 1.08 years) with a Class III malocclusion who underwent MP therapy; these were compared with a control group of 15 females (12.13 +/- 0.63 years) with a Class I occlusion and matched for chronological age and observation period. Cephalometric films were available for all subjects before (T1) and after (T2) treatment/observation. The initial measurements and treatment/control changes were compared between the groups by means of a Student's t-test. The subjects in the MP group had a concave facial profile when compared with the controls. Comparison of the changes induced by MP therapy showed that the maxilla and surrounding soft tissues showed significant anterior movement (P < 0.001), whereas the mandible and surrounding soft tissues showed a backward and downward rotation. The improvement in facial profile predominantly resulted from maxillary soft tissue changes and mandibular hard tissue changes. The concave soft tissue profiles of the Class III subjects were corrected by anterior movement of the maxilla and a concomitant increase in the fullness of the upper lip. The concave skeletal profiles were, however, corrected mainly by backward and downward rotation of the mandible.
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