2013 Volume 25 Issue 2 Pages 92-96
Objective: We report a case in which a mandibular exercise device developed by Yamagata University was tested for postoperative jaw exercise in a patient with bilateral coronoid hyperplasia following bilateral coronoidectomy.
Case: The patient was a 32-year-old woman who had been examined for trismus at our facility in June 2011. X-ray/computed tomography was performed again, leading to a diagnosis of bilateral coronoid hyperplasia. Bilateral coronoidectomy was performed at our facility in September 2011. The patient's mouth opening immediately before surgery was 32 mm, compared to 46 mm immediately after surgery. Jaw exercises using the mandibular exercise device were started in postoperative week 1. The exercise consisted of maintaining maximum mouth opening for 10 s, three times (one set). The patient performed five sets per day. Starting in postoperative month 2, the three repetitions were increased to five repetitions, with the addition of three protrusive excursions.
Results: Mouth opening at discharge was 20 mm prior to exercise and 25 mm after exercise. In postoperative month 3, mouth opening was 32 mm before and after exercise. In postoperative month 19, mouth opening was 38 mm before and after exercise.
Conclusion: This device is characterized by the stable point of action and the average transmission of power, because the anterior 16 teeth of the maxilla and mandible always remain in contact with the device. Furthermore, bilateral or unilateral mandibular exercise is enabled by regulating the grip of the user. Our tests showed this device is suitable for postoperative jaw exercise following bilateral coronoidectomy.
