Case Description: A 74 year old caucasian male patient was referred to the implantology and Oral Rehabilitation consult at the ISCSEM University clinic due to loss of osseointegration and migration of a dental implant into the left maxillary sinus. An ortopantomography was taken. A Computerized Tomography (CT) using Dentascan technique with 1mm cross-sectioning was prescribed. For the surgical removal of the implant, an external sinus access was performed and a collagen membrane was used. Discussion: The migration of dental fragments, endodontics material and dental implants into the maxillary sinus is described. The poor density bone of the posterior maxilla may cause loss of osseointegration. Inadequate bone preparation, perforation of the sinuses floor and/or Schneiderian membrane, as well as the lack of primary stability of dental implants placed in close range of the sinuses can be considered as possible causes of implant migration into the sinus cavities. The non removal of the migrated dental implants may cause its displacement into craniofacial structures, which can provoque further complications due to foreign body reactions, infections and tissue necrosis and collapse if sinus clearance. Conclusion: Dental implant migration into the maxillary sinuses must be swiftly and carefully managed. Schlagwörter: Migration, dental implant, maxillary sinus, complication