Evaluation of the effects of myofunctional appliances on dentofacial structures and upper airway in individuals with class II division I malocclusion

Introduction: The aim of this study is to evaluate the effects of myofunctional appliances used in the treatment of patients with Class II division 1 malocclusion on skeletal, dental structures and upper airway compared to the control group. Methods: Thirty patients were included in the study. Myobrace, which is referred to as a myofunctional appliance, have been applied to 15 individuals with an average age of 9.3 ± 0.7 years presenting with Class II division 1 malocclusion was compared to a control group consisting of 15 individuals with an average age of 8.85 ± 0.7 years followed without treatment. Panoramic, lateral cephalometric, posteroanterior and hand-wrist films were taken before (T0) and after (T1) treatment for the Myobrace group and during the follow up period for the control group. Dental models were also obtained. Results: As a result of cephalometric evaluations, there was a decrease in SNA and ANS-PNS / SN angles and an increase in Co-Gn distance in the myobrace group compared to the control group. In the Myobrace group, overjet amount, ANB angle and Witts value were decreased compared to the control group. In the Myobrace group, retraction was detected for the upper incisors, whereas an extrusion was observed for the control group. As for the mandibular dentoalveolar results, an increase in L1-NB distance was detected in both groups. The changes for the facial growth direction measurements were similar for both groups. There was an increase in MAS and IAS distances in the Myobrace group, however no significance was found between the groups. An increase in C3-H distance was found in the Myobrace group, and an increase in PNS-H distance in the control group. Conclusions: As a result of our study, it was determined that the effects of myobrace appliances were more dentoalveolar for maxillary and mandibular regions and no statistically significant difference was observed in between the groups for the upper airway.