Comparison of facial soft tissue changes after treatment with 3 different functional appliances

•Twin-block, mono-block, and Herbst appliance treatments can positively affect soft tissue profiles. •The effects were similar in all 3 groups. •Volumetric increases in the mandible were produced by all 3 appliances. Introduction This study aimed to evaluate the effects of 3 different fixed or removable functional appliances on the soft tissue changes in patients with Class II Division 1 malocclusion using 3-dimensional images. Methods A total of 60 patients with Class II Division 1 malocclusion (38 girls and 22 boys; mean age, 12.35 ± 1.01 years) were treated with 3 different functional appliances, namely, Twin-block (TB) (group TB, n = 20), mono-block (MB) (group MB, n = 20), or Herbst (H) (group H, n = 20) for 9.55 ± 1.46 months. Three-dimensional photographs of each patient were taken at the baseline and the end of the therapy with a 3dMD Face system (3dMD, Atlanta, Ga). Statistical analyses were performed using the dependent samples t test, 1-way analysis of variance, Kruskal-Wallis, Mann-Whitney U, and Wilcoxon signed rank tests. Results No statistically significant differences were detected for soft tissue changes except for the lower facial width found, at least in group H (P <0.05). Volumetric differences in the mandible were similar between the groups (P >0.05). A statistically significant decrease in total facial height and an increase in convexity angle and facial depth were detected in all groups after treatment compared with the baseline (P <0.05). The upper and lower facial height, lower lip height, and nasal width were statistically significantly increased in the TB and MB groups after treatment compared with the baseline (P <0.05) and similar to those in group H (P >0.05). Conclusions TB, MB, and H appliances may promote the facial soft tissue profile, including volumetric improvement, in the mandibular region.