Double-layer versus conventional mucoperiosteal flap closure in the surgical treatment of medication-related osteonecrosis of the jaw: A combined Retrospective-Prospective cohort study.

Medication-related osteonecrosis of the jaw (MRONJ) remains surgically challenging, as wound dehiscence after conventional mucoperiosteal flap (MPF) closure is common. Recent studies suggest that double-layer closure using a pedicled buccal fat pad flap (BFF) in the maxilla and a mylohyoid muscle flap (MMF) in the mandible may improve early mucosal healing. We performed a single-center combined retrospective-prospective cohort study (2019-2024). Patients treated with MPF (retrospective cohort) were compared with those receiving double-layer closure (prospective cohort). The primary endpoint was complete mucosal integrity at 8 weeks postoperatively, defined as intact mucosal coverage of the treated site without clinically visible dehiscence, fistula, or bone exposure on postoperative examination. A total of 104 patients were included (prospective n = 38; retrospective n = 66), with 80 evaluable for the primary endpoint. Complete mucosal integrity at 8 weeks was achieved in 68.4% of patients treated with double-layer closure compared with 26.2% after MPF (p < 0.001). Double-layer closure independently reduced non-healing (OR 0.15, 95% CI 0.025-0.88), while larger lesion size negatively affected healing. Complications occurred more frequently with double-layer closure (34.2% vs. 18.2%), mainly transient neurosensory disturbances. Double-layer closure significantly improves early mucosal integrity after MRONJ surgery. Despite more frequent but mostly temporary complications, the overall clinical benefit supports its use with appropriate patient counseling.