title: Displacement of a dental implant into the maxillary sinus after internal sinus floor elevation: report of a case and review of literature.
abstract: BACKGROUND
  Dental implant placement in the posterior maxilla may be complicated by implant migration into the maxillary sinus.
  
  
  OBJECTIVE
  To report the clinical and radiological characteristics of a patient who experienced dental implant displacement into the maxillary sinus following sinus floor elevation, and to compare our findings with those of other published reports of the displacement of dental implants.
  
  
  METHODS
  Implant placement and maxillary sinus elevation were performed simultaneously. The location of the displaced implant was monitored for 8 years, until the ectopic implant was surgically removed using the lateral window approach. The contributing factors, treatment modality, and clinical outcome for our patient were compared with those of patients reported in the literature.
  
  
  RESULTS
  The clinical characteristics of our case were similar to those of patients with displaced implants who were also asymptomatic for long periods. The clinical outcome of our case was consistent with that of patients who underwent similar surgeries.
  
  
  CONCLUSIONS
  Transnasal endoscopic removal of an ectopic implant may be suitable in cases in which the ectopic implant is accessible. Transoral direct approaches are adequate in most cases in which endoscopic approaches may be confounded. The bony-window transoral technique may allow the removal of large implants.
authors.affiliation: Department of Stomatology, Zhongshan Hospital, Shanghai Medical School, Fudan University Shanghai 200032, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Ding
authors.affiliation: Department of Stomatology, Zhongshan Hospital, Shanghai Medical School, Fudan University Shanghai 200032, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Stomatology, Zhongshan Hospital, Shanghai Medical School, Fudan University Shanghai 200032, China.
authors.forename: Xuehua
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Stomatology, Zhongshan Hospital, Shanghai Medical School, Fudan University Shanghai 200032, China.
authors.forename: Youcheng
authors.initials: Y
authors.lastname: Yu
keywords: Maxillary sinus; bony-window transoral technique; dental implant placement; sinus floor elevation