<p>Odontogenic diseases of the maxillary sinus are usually inflammatory; they are rarely cystic or neoplastic. In contrast to rhinogenic sinusitis, odontogenic sinusitis has a focal origin e.g., oroantral fistulae, apical infection, various foreign materials, and aspergillosis. The management of odontogenic maxillary sinusitis therefore requires simultaneous treatment of the odontogenetic origin with restoration of physiological mucociliary clearance of the sinus. The treatment goal is complete healing with maximal sparing of the structures and minimal stress for the patient. To ensure that a potential odontogenic cause is recognized, all cases of maxillary sinusitis must also be evaluated by an oral and maxillofacial surgeon. Regarding treatment, one can distinguish between measures targeting the odontogenic cause and measures aimed at restoring mucociliary clearance of the maxillary sinus, such that the following treatment algorithm results: restoration of the odontogenic origin with or without an osteoplastic approach via the anterior sinus wall as well as restoration of mucociliary clearance of the maxillary sinus according to the morphology of the ostiomeatal unit in CT scan. If the ostiomeatal unit is narrow, it is widened by functional endoscopic sinus surgery (FESS) in the middle meatus. In the case of a&#xa0;regular ostiomeatal unit, temporary drainage in the lower meatus may be adequate. While FESS is a&#xa0;minimally invasive approach and reduces morbidity for the patient, it requires special instruments and sufficient training.</p>