Causes of Implant Failure and Subsequent Removal: A Retrospective Study in a Hospital setting.

Despite high rates of success for dental implants, implant failure due to several causes may require explantation. In the present retrospective study, implants removed between 2000 and 2022 have been registered and the cause of removal has been established. All implants were removed by a single operator (PPM) in the department of Oral Surgery of the George Eastman Dental Hospital in Rome, Italy. Characteristics of removed implants such as implant surface, morphology (bone versus tissue level implants), type of restoration (fixed versus removable), in the case of fixed restorations, mode of retention (cement versus screw-retained), location of the implant (maxillary versus mandibular arch) were recorded. Furthermore, patient-level characteristics were also recorded (systemic health conditions and medications taken, smoking habits and previous history of periodontitis). In total, 381 implants in 381 patients were removed in the 20-year time-span. The most frequent cause of removal was peri-implantitis (82.4% of implants), followed by implant malposition and loss of osteointegration. The survival time was not affected by the cause of removal, while bone level implants had a longer survival time versus tissue level implants. Maxillary implants had a higher prevalence of peri-implantitis compared to mandibular implants.