Comparative study of the treatment effects of bionator and bite jumping appliances on Class II malocclusions

Purpose: The purpose of this investigation was to compare and evaluate the treatment effects of two commonly used removable functional appliances. Materials and methods: The subjects, 12 children, were all diagnosed as having maxillary protrusion. They were divided into two treatment groups: the bionator group, comprising 3 boys and 3 girls, mean age 11.3 years at the start of treatment; and the bite jumping appliance (BJA) group, comprising 5 boys and one girl, mean age 10.9 years at the start of treatment. Lateral cephalograms in the intercuspal position were taken both at the beginning and at the end of use of each appliance. Results: In comparison of treatment effects between both groups, the BJA group showed greater lingual inclination of the maxillary incisors and labial inclination of the mandibular incisors compared with the bionator group. Also, the BJA group showed a significantly greater forward and downward change in the inclination of the occlusal plane than did the bionator group. Conclusions: In terms of treatment mechanics, the bionator and BJA are quite different. Therefore, the proper use of each depends on symptoms, sequence of use, and time of initiation of therapy in order to provide the most effective treatment of Class II malocclusions. (C) 2015 Elsevier Ltd and the Japanese Orthodontic Society. All rights reserved.