Effects of functional therapy on hyoid bone, pharyngeal airway and tongue position in class II patients

Aim: The aim of this study is to evaluate the change in the position of hyoid bone, pharyngeal airway, and tongue position in subjects with skeletal Class II malocclusion treated with Twin block therapy. Materials and Methods: This study was performed on pre and post treatment lateral cephalograms of 21 patients with class II malocclusion treated with Twin block appliance, (mean age of (12.24± 1.22). Paired-t test was used to compare the amount of differences of mean value before and after treatment. A value of P<0.05 was considered as significant. Result: Hard tissue result showed significant difference between pre-and post-treatment values of ANB, Hy-B, Hy-Me & Hy-CL. But no significant difference was seen between the pre-and post-treatment values of Hy-SN' & Hy-FHP. Soft tissue examination also found significant difference between pre-and post-treatment values of SPAS, but no significant difference was observed between the pre-and post-treatment values of MAS, IAS, PT-CL & PT-SNˈ. Conclusion: ANB angle was found to be significantly improved after functional treatment in skeletal class II group. The mandible has showed forward movement with respect to hyoid bone and the hyoid bone has been found to be shifted anteriorly and downward. Superior pharyngeal space was found to be significantly improved after functional therapy whereas there was no significant change with respect to tongue.