the study evaluated the one stage endoscopic middle meatal antrostomy (EMMA) technique with the application of a platelet rich fibrin membrane (PRF) for Oroantral Fistula (OAF) closure and relief of maxillary sinusitis.

This study was conducted on nine eligible patients who complained of OAF with odontogenic sinusitis. Oral fistulectomy was done with proper curettage. Then, EMMA was performed with simultaneous closure of the OAF by application of PRF membrane and covering it with an acrylic splint. Patients were clinically evaluated for closure of the OAF after 14th days postoperatively, relief of the symptoms, and assessment of the pain level. Also, measurement of the size of the bone defect with the aid of computed tomography (CT) preoperatively and 24th weeks postoperatively.

Inclusion Criteria:

1 - Adult patients between the ages of 20-60 years. 2- Patients who were suffering from chronic fistula that occurred after the extraction of upper posterior teeth

Exclusion Criteria:

1. patients who have any systemic disease that contraindicates any intervention under general anesthesia (e.g., coronary artery disease).
2. OAF that occurred as a result of other causes (e.g., cyst,and trauma)