Oroantral communication is an unnatural space that connects the oral cavity and the maxillary sinus. In dental practice, it most often occurs after an extraction of the upper distal teeth, especially molars with extremely divergent and long roots. Communication can be of iatrogenic nature which usually occurs during apicoectomy, implant therapy, cyst enucleation. Other causes are trauma and pathological processes, such as osteomyelitis. After unsuccessful treatment, the communication epithelializes and forms an oroantral fistula. Oroantral fistula is a pathological pathway covered with epithelium that connects the sinus with the oral cavity. The fistula cannot close spontaneously and bacteria easily enter into the sinus and cause inflammation known as maxillary sinusitis. Clinical tests, X-rays and medical history are required for diagnosis. Patients most often complain about bad breath, penetration of fluids into the nasal cavity during drinking and the flow of air through the fistula. Patients may as well give us information about possible extractions or previous surgeries. During treatment, it is necessary to pay attention to possible inflammation in the sinuses, which should be taken care of before surgical fistula closure. The surgical technique should be selected individually according to patients’ needs and status.