The Effect Evaluation of Functional Appliance Used for Class II Patients With Temporomandibular Joint Anterior Disc Displacement

Orthopedic functional appliances are usually used to correct patients with retrognathic mandible. However, a part of cases have a trend of relapse after splint treatment. The aim of this study was to explore the role of temporomandibular joint disc position in functional appliance treatment. This study included 8 patients who had 1 joint anterior disc displacement with reduction (ADDWR) and the other joint anterior disc displacement without reduction (ADDWoR) confirmed by magnetic resonance imaging (MRI). Only the ADDWR joint could return to its normal position after wearing the anterior repositioning appliances (ARAs). Condylar morphology, condylar height, and disc length were evaluated 6 months after ARA treatment. The MRI showed that new bone appeared on 7 joints with ADDWR and on 1 joint with ADDWoR. The condylar height has increased 1.4 mm in the ADDWR group, while 0.1 mm shorter in the ADDWoR group. Disc length has increased from 8.5 to 8.7 mm in the ADDWR group and 0.4 mm shorter in the ADDWoR group after wearing the ARA. Our results suggested that it is noneffective of functional appliance used for class II malocclusion adolescents with ADDWoR and only a normal disc-condyle relationship benefits condyle growth by functional appliance. Thus it is important to reposition the disc as soon as possible. Address correspondence and reprint requests to Chi Yang, MD, Shanyong Zhang, MD, Department of Oral Surgery, Ninth People's Hospital, Collage of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai Research Institute of Stomatology, No 639, Zhi Zao Ju Rd, 200011 Shanghai, China; E-mail: yangchi63@hotmail.com, zhangshanyong@126.com Received 7 April, 2018 Accepted 9 July, 2018 PS and XL contributed equally to this work. This study was supported by the Youth Program of National Natural Science Foundation of China (81601915), Shanghai Municipal Hospital Emerging Frontier Technology United Key Project (SHDC12017101), and Science and Technology Commission of Shanghai Municipality Science Research Project (14DZ2294300). The authors report no conflicts of interest. © 2018 by Mutaz B. Habal, MD.

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