This randomized controlled clinical study will evaluate the effectiveness of the inverted buccal periosteal flap in closing recent post-extraction oroantral communications and compare it with the conventional buccal advancement flap. The study will include 24 patients who develop an oroantral communication measuring 3-6 mm after non-surgical extraction of maxillary posterior teeth. Participants will be randomly allocated into two groups: the test group treated with the inverted buccal periosteal flap, and the control group treated with the buccal advancement flap. The primary outcome will be successful clinical closure of the communication, assessed by absence of oroantral fistula, nasal fluid leakage, and air leakage during the Valsalva test. Secondary outcomes will include postoperative pain, facial edema. Patients will be followed for up to 45 days after surgery.