Objectives: Implant displacement into the maxillary sinus often results from features specific to the posterior maxillary teeth, including poor bone quality and insufficient remaining bone. This study reviews implants displaced into the maxillary sinus, the causes and complications of displacement, and how to remove them, according to when the displacement occurs.
Materials and methods: The PubMed, Ovid (MEDLINE), and EMBASE databases were searched using the keywords "displacement," "implant," "maxillary sinus," and "removal" for articles published between January 2000 and July 2013.
Results: Twenty-two journal articles were selected; these discussed 49 displaced implants. Most of the implants were displaced into the maxillary sinus during implantation, but resulted in a low incidence of complications, such as maxillary sinusitis. The displaced implants were removed using the Caldwell-Luc approach or a transoral or transnasal endoscopic approach.
Conclusion: Implants displaced into the maxillary sinus have various causes according to when they are displaced. As displaced implants can cause several complications, transnasal endoscopy is recommended to remove them; however, the implants should be examined thoroughly before selecting the removal method.