Changes in soft tissue profile using functional appliances in the treatment of skeletal class II malocclusion

Abstract

Introduction The effects of orthodontic treatment are considered to be successful if the facial harmony is achieved, while the structures of soft tissue profile are in harmony with skeletal structures of neuro-cranium and viscerocranium. In patients with skeletal distal bite caused by mandibular retrognathism, facial esthetics is disturbed often, in terms of pronounced convexity of the profile and change in the position and relationship of the lips. Objective The aim of this study was to determine the extent of soft tissue profile changes in patients with skeletal Class II malocclusion treated with three different orthodontic appliances: Frankel functional regulator type I (FR-I), Balters' Bionator type I and Hotz appliance. Methods The study included 60 patients diagnosed with skeletal Class II malocclusion caused by man¬dibular retrognathism, in the period of early mixed dentition. Each subgroup of 20 patients was treated with a variety of orthodontic appliances. On the lateral cephalogram, before and after treatment, the fol¬lowing parameters were analyzed: T angle, H angle, the height of the upper lip, the position of the upper and lower lip in relation to the esthetic line. Within the statistical analysis the mean, maximum, minimum, standard deviation, coefficient of variation, two-factor analysis of variance with repeated measures and the factor analysis of variance were calculated using ANOVA, Bonferroni test and Student's t-test. Results A significant decrease of angles T and H was noticed in the application of FR-I, from 21.60° to 17.15°, and from 16.45° to 13.40° (p<0.001). FR-I decreased the height of the upper lip from 26.15 mm to 25.85 mm, while Hotz appliance and Balters' Bionator type I increased the height of the upper lip, thereby deteriorating esthetics of the patient. Conclusion All used orthodontic appliances lead to changes in soft tissue profile in terms of improving facial esthetics, with the most distinctive changes in the application of Frankel's functional regulator type I, which is the most successful appliance for achieving the overall facial harmony of the patient.