The evaluation of the effects of two different functional appliances on airway volume in mandibular retrognathia patients with computed tomography

The aim of the present study, is evaluate the effects of Bionator and Forsus FRD EZ2 appliances on the airway volume with cone beam CT.Our study has 4 groups. Bionator group, Forsus group, Cephalometric control group (n=20) and Airway control group (n=30). Totally 90 patients were evaluated in this study. In the Bionator group (15 female, 5 male) mean chronological age was 12 years 1 month. In Forsus group (11 female, 9 male) mean chronological age was 12 years 9 months. All patients were Class II div 1 malocclusion with mandibular retrognathia and low angle growth pattern. Patients were at the peak pubertal growth period.In the Bionator group ,CBCT images were taken at the start of bionator application and after 6 months of appliance usage. In the Forsus group , CBCT images were taken after 0.017? x 0.025? SS archwire application and after the Forsus removal (mean 5,05 ± 1,6 months).Intragroup differences were evaluated with paired-samples ?t? test whileas intergroup differences were evaluated with one way analysis of variance (ANOVA). For determination of treatment group comparisons Tukey HSD statistical analysis was used. Dunnett test was used for the assessment of the differences between treatment and control groups.Cephalometric data revealed that both of the appliances increased sagital growth of the mandible, proclination of the lower incisors, mesialization of the lower molars, decreased the inclination of the upper incisors, overjet and overbite. Lower incisor intrusion, upper molar intrusion and upper incisor extrusion, lower molar extrusion were seen in the Forsus group. Both of the appliances increased the lower anterior face height. Soft and hard tissue pogonion were moved to anteriorly. In our study, airway volume was affected positively by both of the appliances. But Bionator group affected more than Forsus group. Oropharyngeal and nasopharyngeal airway volumes and minimum axial slice area were increased in the bionator group. C2, C3, Oropharynx-Nasopharynx border slice areas were increased in the both group. In bionator group, both anteroposterior and transversal measurements were increased, whileas in the Forsus group , primarily anteroposterior measurements were affected positively.Keywords: Bionator, Forsus FRD EZ2, Airway, CBCT, Class II malocclusion, Functional treatment