An excessive coronoid hyperplasia with suspected traumatic etiology resulting in mandibular hypomobility.

There are multiple theories as to the causes of coronoid process hyperplasia of the mandible, including trauma, temporalis muscle hyperactivity, hormonal stimulus, and genetic inheritance. The excess growth of the coronoid process can cause impingement on the zygomatic processes and may result in mandibular hypomobility. A case of an excessive unilateral coronoid hyperplasia with suspected traumatic etiology, which was successfully treated by coronoidectomy and postoperative physiotherapy, is presented. The patient was a 21-year-old man whose maximum mouth opening was 23 mm. The attachments of the temporalis muscle were stripped and the coronoid process was accessed using the Al-Kayat and Bramley approach. The coronoid process was then resected via an intraoral pathway. One week after surgery, physiotherapy was started and the maximum mouth opening had increased to 38 mm. In the case presented, a coronoidectomy with postoperative physiotherapy for treatment of coronoid process hyperplasia produced satisfactory results in the correction of coronoid-malar interference.