An oroantral fistula (OAF) can be defined as an epithelialized pathological unnatural communication between the oral cavity and the maxillary sinus [1]. The term oroantral fistula is used to indicate a canal lined by epithelium that may be filled with granulation tissue or polyposis of the sinus membrane [2]. They can arise as late sequelae from perforation and last at least 48–72 h. An oroantral fistula (OAF) may develop as a complication of maxillary molar or premolar extraction due to the proximity of the bicuspid apices and molars to the antrum [3]. Furthermore, oroantral fistula might originate following the removal of maxillary cysts or tumors, facial trauma, dentoalveolar or implant surgery, and infection or may even be iatrogenic in nature. Oroantral fistulas are common between the ages of 30 and 60 [1]. Apparently, studies reported sexual dimorphism in oroantral fistula, with males showing more frequency than females [1, 4]. This difference can be explained by a higher overall frequency of traumatic tooth extraction in men [5].

Clinically, the patient may experience one or more disturbances which draw attention to the oroantral fistula. Symptoms and signs comprise, pain, foul or salty taste, alteration in voice resonance, inability to blow out the cheeks, air shooting from the fistula into the mouth when blowing the nose, and escape of liquids from the mouth through the nose [5].

At a later stage, the formation of an antral polyp, which is visible through the defect intraorally, is possible. The establishment of oroantral communication can be confirmed by the Valsalva method. The patient is instructed to expel air against closed nostrils, while the clinician checks if air hisses from the fistula into the mouth. A hissing noise from air leakage through the maxillary sinus and nose indicates a positive test. In some cases, the test of blowing through the nose or mouth does not provide a positive answer, particularly when the fistular canal is filled with inflammatory changed nasal mucous membrane. Additionally, a test with a blunt probe will confirm the existence of an oroantral fistular canal. However, to confirm clinical findings, the clinician needs to radiologically inspect the site via a panoramic radiograph or a computed tomography (CT).