Oroantral communication is an unnatural connection between the maxillary sinus and the oral cavity. It can result from the extraction of upper premolar and molar teeth, and if not treated, it can develop into an oroantral fistula or chronic maxillary sinusitis. Therefore, it is necessary to be acquainted with diagnostic methods and early treatment procedures to prevent further complications. There are certain predisposing factors for the occurrence of oroantral communication, such as pneumatized maxillary sinuses, long and divergent roots, and an inadequate and rough tooth extraction technique. The appearance of the communication is possible even when preventive measures are taken. The most common diagnostic method is the nose blowing test, known as the Valsalva test. Persistent and untreated communication leads to the formation of a fistula. The fistula allows the food and bacteria to pass from the oral cavity to the maxillary sinus, thus causing maxillary sinusitis. The symptoms of the oroantral fistula include fluids and food passing from the oral cavity to the nose, difficulties while using a straw, unpleasant taste in the mouth and a whistling sound that may be present whilst speaking. Treatment should be carried out as soon as the diagnosis is determined in order to prevent the complications. Selecting the type of treatment depends significantly on the size of the communication, the time elapsed since the formation, and the presence of maxillary sinusitis. Blood clot formation and maintenance in the alveolus is the basic form of treatment for smaller communications, while larger communications require surgical procedures.