Myofunctional appliances are valuable tools in the armamentarium of orthodontics for the correction of altered form and function. Their mode of action on different sites of orofacial skeleton can control and modify the growth of mandible. Skeletal class II malocclusion being a prevalent condition can be corrected by these functional appliances in growing patients. Among these appliances Twin Block is the choice of appliance due to its versatility.

   The tongue is the most active muscular structure of the oropharyngeal system and is directly influenced by any modification in the dentoskeletal environment. After skeletal discrepancy is corrected, the tongue adapts within the altered position of the dental arches and can enhance post-functional stability.

         The tongue is a muscular organ that may be posteriorly positioned in a retrognathic mandible. With the use of a functional appliance such as Twin Block, posture of tongue can be improved, resulting in increased dimensions of the airways.

To our knowledge, there is limited literature evidence regarding changes in the posture of tongue after functional appliance therapy.  Most of the studies are retrospective studies with two-dimensional imaging modality, which is not reliable due to magnification errors. There is no prospective study demonstrating the changes in tongue posture, using a three-dimensional (3D) imaging modality. Hence this study is designed to evaluate changes in tongue posture and airway volumes after twin block appliance therapy in growing skeletal class II patients using Cone Beam Computed Tomography.