Functional orthopedic appliances have been proposed for the correction of Class II malocclusion due to a retrognathic mandible. The aim of using this appliance is to stimulate mandibular growth by forward positioning of the mandible in order to achieve normal jaw relationship. However, the modes of action using this appliance are still inconclusive. Also the effects of this therapy on the temporomandibular joint (TMJ) are still subject to doubts and discussion. Magnetic resonance imaging (MRI), the gold standard for assessing the soft tissue and position of the TMJ articular disc, therefore, was used to help clarify the effect of this appliance on the TMJ. The aims of this article are to provide a literature review of the methods that are used to assess changes in the TMJ, as seen on MRIs, from functional orthopedic appliances which include condylar and glenoid fossa remodelin assessment, condyle-fossa relationship assessment and articular disc assessment and to review clinical studies using MRI to investigate the effects of functional orthopedic treatment on the TMJ.

Keywords: Functional orthopedic appliance, Temporomandibular joint (TMJ), Magnetic resonance imaging (MRI)