Background <p>Oroantral fistulas are challenging complications that often require surgical intervention for successful closure and long-term healing.</p> Purpose <p>To present a modified submucosal connective tissue flap technique that enhances closure stability and healing predictability in oroantral fistulas.</p> Methods <p>Following excision of the fistula and sinus debridement, a standard buccal advancement flap was elevated. A subepithelial connective tissue graft was harvested from the palatal mucosa using a partial-thickness dissection and stabilized using resorbable sutures anchored to bone perforations. The overlying buccal flap was then advanced and sutured to complete a bilayered closure.</p> Results <p>The technique allowed tension-free closure with improved flap stability and reduced donorsite morbidity. Postoperative healing was uneventful, and complete mucosal regeneration was observed within one month.</p> Conclusions <p>This bilayered closure technique, combining mechanical anchorage of a palatal graft with a buccal advancement flap, provides a reliable and predictable solution for oroantral fistula closure, particularly in edentulous or anatomically compromised cases.</p>