A device for temporomandibular joint exercise and trismus correction: design and clinical application

Temporomandibular joint (TMJ) hypomobility and trismus is a frequently seen clinical condition, and rehabilitation with mouth-opening exercises is mandatory for fast and successful recovery. As conventional methods and available devices are not without disadvantages, a new TMJ exerciser has been developed and clinically tested. Materials and methods: The new device was designed and made using a computer-aided design/computer-aided manufacture program. The mouthpiece is opened using a power screw technique. The device was revised until it became acceptable for clinical trials. Nineteen patients with TMJ hypomobility or trismus used the new device: five after surgical release of TMJ ankylosis, five after facial fracture reduction and intermaxillary fixation, three after blunt facial trauma, five following orthognathic surgery, and one following facial bone-contouring surgery. The outcome was evaluated. Results: The new TMJ exercise appliance was convenient, durable and easy to use. The maximal incisor opening was 16.3 ± 7.1 mm before use of the device, and 34.2 ± 6.3 mm after the treatment period (P < 0.05). Fourteen patients (74%), i.e. all except the five with release of ankylosis, recovered to normal range of mouth opening at longitudinal follow up. There was no mechanical failure and no complications from using the device, and the patients were satisfied. Conclusion: The new exerciser is a satisfactory device for physiotherapy of TMJ hypomobility and trismus.