Dental implant displacement into the maxillary sinus is a rare complication. Maxillary sinus displacement of the implants is often associated with incorrect surgical planning or inadequate surgical technique. Dental implants often result in foreign body reactions in the sinuses and should be removed in order to avoid the development of sinus complications. A careful preoperative clinical and radiological evaluations and surgical foresight regarding anatomical formations should be done correctly and atraumatic technique should be performed in order to prevent these complications. In this study, a retrospective case series was presented to discuss the necessity of removing the sinus dental implant even if it is biocompatible.