Assessment of the role of coronoid in restrictive jaw disorders and physiologic mandibular movements.

Introduction: Restricted mouth opening has major health implications, such as malnutrition, difficulty in speech, and poor oral hygiene resulting in a functional shortage of the masticatory system. Reduced mouth opening can occur due to trismus, as in the oral submucous fibrosis (OSMF) condition. Excision of fibrous bands in OSMF leads to reestablishment of the mouth opening. Other than trismus, temporomandibular joint (TMJ) ankylosis is another common condition that causes fibrosis or bony ankylosis between articular surfaces. Coronoidectomy is a useful procedure that various authors nowadays apply. It is the most popular surgical procedure used as a conventional method of treatment, which includes the detachment of temporalis muscle.

Materials and methods: A group of 15 patients with OSMF and TMJ ankylosis with written informed consent were selected for the study and were operated on under general anesthesia. Preoperative and postoperative assessment was done for bite force management, measuring and comparing mandibular movements, and the electromyography (EMG) study.

Results: Statistical analysis shows the increase in maximum mouth opening and lateral excursions in OSMF and TMJ ankylosis patients on the seventh, 15^th, 90^th days, and six months postoperatively treated either without coronoidectomy and with coronoidectomy; however, there was no significant difference was found in mean EMG and bite force readings in both groups.

Conclusion: The present study concludes that the coronoidectomy not only increases the mouth opening, but masticatory efficacy is also improved with an increase in mandibular movements postoperatively in patients with OSMF and TMJ ankylosis.