Abstract
Primary hyperparathyroidism causes hypercalcemia due to continuous secretion of parathyroid hormone. Most cases are caused by benign adenoma, and excision of the adenoma is the first choice of treatment. However, in non-surgical cases, bisphosphonate is used to decrease serum calcium level and improve osteoporosis. A 59-year-old female patient complained of right submandibular pain accompanied by an external dental fistula in the right submandibular region and intraoral bone exposure in the right lower premolar region. CT images revealed the sequestrum in the right mandible. The patient had been taking an intravenous bisphosphonate for a relatively long period to improve hypercalcemia and osteoporosis. Therefore, we diagnosed medication-related osteonecrosis of the jaw （MRONJ） Stage Ⅲ, and conservative treatment was started. Since her condition did not improve, surgery was performed under general anesthesia to remove the sequestrum to the extent that fresh bone with bleeding could be confirmed. Postoperatively, the external dental fistula of the right submandibular region was closed, and the exposed bone in the oral cavity was covered with healthy oral mucosa. The patient’s progress is good.
