Design, manufacture and clinical evaluation of a new TMJ exerciser

Temporomandibular joint (TMJ) ankylosis or hypomobility is a major clinical problem that affects many patients suffering from facial trauma, infection, TMJ dysfunction, inflammatory diseases and tumors. Postoperative physiotherapy is recognized as essential for the prevention or treatment of TMJ hypomobility or ankylosis. Traditional methods using stacked tongue depressors and the reported TMJ opening exercisers all have disadvantages and cannot achieve clinical requires. This study employed CAD/CAM techniques to develop a new TMJ exerciser that would be user-friendly and performed clinical trails to test the efficacy of the device. A power screw was used to overcome the small force control difficulty, allowing gradually increased TMJ opening performance. The front end of the device was designed as U-shape platform that could be inserted into the patient's mouth to allow easy TMJ exercise performance. A streamlined handle also designed to be held by the patients to decrease the mouth loading. This device is convenient for long-term physiotherapy. The clinical trail results indicated that the improvements of the incisor opening range could increase from 108% to 258% within one mouth after postoperative physiotherapy. The developed TMJ exerciser is effective, convenient, easy to use, light weight and has long-term durability for postoperative physiotherapy.