Paget's disease of bone involving the mandible may causes temporomandibular joint ankylosis: A case report

Paget's disease of bone (PDB) is a rare metabolic disorder characterized by focal acceleration of bone remodeling. Herein, we report a case of PDB in the mandible complicated by temporomandibular joint (TMJ) ankylosis. A 38-year-old man with a chief complaint of trismus was referred to our department. He had previously presented to our department at the age of 22 years with pain and swelling of the left mandible. At that time, curettage and closed irrigation-suction treatments were performed based on the clinical diagnosis of chronic osteomyelitis of the left mandible. After symptom relief, the patient was lost to follow-up for 15 years. He visited our department again at the age of 38 years with immobility of the mandible, reduced mouth opening, and multiple severe carious lesions in the teeth. Plain radiography and computed tomography of the mandible revealed a cotton-wool appearance with osseous ankylosis of the TMJ bilaterally. PDB with ankylosis of the TMJ was diagnosed, and gap arthroplasty was performed after risedronate administration. Although mobility of the mandible was achieved, the maximum mouth opening (the interridge distance between the upper gingiva and lower incisal edges of the central incisors) remained at 14 mm for 3 years following surgery. Follow-up is necessary in cases of PDB of the mandible to check for recurrence or development of sarcoma. In addition, mouth opening training is highly recommended to prevent re-ankylosis.