CBCT evaluation on the effect of two different functional appliances on the maxillary and mandibular bone volume

The aim of this study was to investigate the effects of Bionator and Forsus FRD EZ2 appliances on the maxillary and mandibular volumes using cone-beam computed tomography (CBCT). The study comprised 60 patients who were divided into three groups: Bionator (n=20), Forsus (n=20) and control group (n=20). Bionator group included 15 girls and 5 boys with a mean age of 12 years and 1 month, Forsus group included 11 girls and 9 boys with a mean age of 12 years and 9 months, and the control group included 9 girls and 11 boys with a mean age of 13 years and 8 months. Inclusion criteria were as follows: class II division 1 malocclusion, mandibular retrognathia, low-angle growth pattern, and peak growth period. In Bionator group, the CBCT images were obtained before and six months following the administration of the appliance, whereas the images in Forsus group were obtained when the 0.017"x0.025" SS arcwires were applied and the Forsus appliance was removed (mean period; 5.05±1.6 months). A paired t-test was used to compare the volume changes in the control group within the six months after the treatment and also to compare the mean differences between the pre- and post-treatment volume changes in the maxilla and mandible following the administration of Forsus and Bionator appliances. One-way ANOVA was used to make comparisons among the mean differences in the pre- and post-treatment periods and the follow-up period for the three groups, followed by Tukey's HSD test. The results showed an increase in the maxillary volume in Bionator and Forsus groups compared to the control group; however, the increase was not significant (p>0.05). Also, the volume increase in the Forsus group was higher than the one in the Bionator group, but no significance was observed (p>0.05). Key Words: Forsus FRD EZ2, Bionator, Maxillary Volume, Mandibular Volume, CBCT, Class II Division 1