Timing and extent of Peri-Implant bone loss for dental implant removal: A retrospective Cross-Sectional analysis

OBJECTIVES: The occurrence of dental implant loss has not been systematically investigated. This study assessed the extent of radiological crestal bone loss at time of dental implant removal and the timing of dental implant removal. MATERIALS AND METHODS: Patients transferred to the Department of Oral- and Craniomaxillofacial Surgery of the University clinic of Freiburg, Germany, between 2014 and 2024 for dental implant removal were retrospectively analyzed. Radiological bone loss was determined using panoramic and intraoral radiographs. Further data included patient demographics, implant characteristics, bone defect morphology, and specific reasons for removal. RESULTS: 738 implant removals in 462 patients were included. Peri-implant inflammation accounted for 71% of implant removals, with 83% of late implant losses attributed to this cause. The mean radiological bone loss at time of implant removal was 51% (SD: 28%) and was significantly higher in the mandible than in the maxilla (p < 0.001). Most implants were lost three years after placement. At later time points, less implants were removed. Average bone loss levels at the time of implant removal increased over time, ranging from 36% in the first three years to 60% in years 8 to 10 (p = 0.002). Complete loss of osseointegration was observed more frequently over time. CONCLUSION: This study provides the first large-scale systematic assessment of dental implant loss. Peri-implant bone loss was confirmed as the leading cause of dental implant failure. Within this monocentric clinical setting, dental implant removal was closely associated with a radiographic bone loss threshold of around 50%, underscoring its potential value for clinical decision-making in advanced peri-implant disease. CLINICAL RELEVANCE: A radiographic bone loss level of approximately 50 % may serve as a pragmatic threshold to escalate from salvage concepts towards the decision of implant removal in advanced peri-implant disease. The high proportion of implant removals occurring in the early years after placement highlights the importance of early clinical surveillance.