Inserting a foreign body into an anatomical structure is a rare situation in which the maxillary sinus is most commonly involved. The latter results in developing sinusitis or, more rarely an asymptomatic situation. The present case report describes an event in which a dental bur was found into the right maxillary sinus of a female patient, because of an event that took place while extracting a molar. Grafting material was also found except for the dental bur. The dental bur and grafting material were removed by performing a 'Caldwell-Luc' surgery, the patient was covered with antibiotics and the therapeutic effects were quite satisfactory. The report discusses the possible causes of the event and the possible therapeutic approaches.