Although most fistulae are not problematic, surgeons occasionally encounter recurrent and/or refractory fistulae in the field of oral and maxillofacial surgery. In this case report, the authors describe a case in which a patient experienced a recurrent and refractory fistula or perforation at his oral floor through the submandible, with heterotopic bone formation arising on both sides of the mylohyoid line. These heterotopic bones were connected to each other, forming a bone bridge at the center of the oral floor. A fistulectomy and wound closure with a tongue flap was successful. The perforation has not recurred after over four years of follow-up, and the bone bridge is still present.