Management of restricted mouth opening caused by radiation: A clinical report.

Trismus, a commonly observed sequela in patients who have undergone radiation therapy to treat malignancies of the head and neck, causes a loss of function that reduces patients' overall quality of life. Radiation can cause intense fibrosis in the masticatory muscles, and this fibrosis may lead to trismus. This clinical report describes the management of a patient with radiation-induced trismus who was treated with a custom-made mouth-opening device. The device had maxillary and mandibular sections, was made of a thermoactive acrylic resin material, and was connected with 2 vertical screws in the right and left canine regions. The screws were adjusted daily to increase the oral opening, such that each turn of the screws increased the opening by 0.25 mm. With the help of this device, at the end of a 4-month follow-up period, the patient's maximal interdental distance had increased from 7.16 mm to 19.50 mm. The intraoral opening device described in this study is useful for achieving a vertical opening sufficient to perform dental treatment.