Assessment of Residual Bone Level Around Explanted Implants and Description of the Systemic and Local Characteristics. A Retrospective Study.

The study aimed to evaluate the residual bone level of explanted implants and to report local and systemic characteristics observed in patients who underwent implant explantation. A total of 494 administrative records were initially retrieved from the database. After elimination of duplicates, 464 medical records of patients who underwent implant explantation between 2005 and 2021 in thirteen private clinics in Switzerland were screened. Information regarding implant history, local (oral health, periodontal and prosthetic status) and systemic (systemic diseases, medication, and smoking) characteristics was assessed through the medical records and the radiographic data. ISRCTN registry (ISRCTN10631004). In total, 399 patients and 521 implants were included in the analysis. Peri-implantitis was the most frequent reason for explantation (62%). Explantation was mainly performed in cases of advanced peri-implantitis with a mean bone loss of 62.92% of the implant length. Most patients had radiographic bone loss around the remaining dentition with a bone loss/age ratio of 0.74, presented compromised oral health, and 47.80% of them were smokers. Moreover, only 56.12% of patients reported being in good systemic health. Implant explantations were typically performed once bone loss reached approximately 60% of the implant length. They were most often observed in advanced cases of peri-implantitis and in patients with high-risk profiles for periodontal breakdown, such as a history of periodontal disease or heavy smoking habits.