Crestal Bone Loss and Peri‐Implant Conditions at Tissue‐Level Implants: Influence of Prosthesis Type After 25 Years

OBJECTIVE: To evaluate long-term crestal bone level changes (ΔCBL) and prevalence of peri-implant conditions according to the type of implant-supported fixed dental prosthesis (IFDP), and to identify implant-, prosthetic-, and patient-related factors associated with ΔCBL. MATERIALS AND METHODS: This single-center observational study evaluated patients rehabilitated with single crowns (SCs), splinted crowns (SPs), or bridges (BRs) on tissue-level implants after 10 and 25 years of function. Standardized clinical and radiographic evaluations were performed, and peri-implant conditions were diagnosed according to established consensus definitions. RESULTS: A total of 147 patients with 233 implants were included. The prevalence of peri-implantitis (PI) increased from 10 to 25 years, from 2.3% to 7.8% for SC, from 1.6% to 6.3% for SP, and from 0% to 4.9% for BR, with no significant differences between IFDP types at either time point (p ≥ 0.95). SP tended to have higher peri-implant mucositis (PM) rates at 25 years (87.3%), compared to SC (74.4%) and BR (80.5%). Mean ΔCBL was -0.37 ± 0.91 mm for SC, -0.25 ± 0.85 mm for SP, and -0.70 ± 1.0 mm for BR, with no significant differences between IFDP types (p = 0.37). Multivariate analyses demonstrated that greater ΔCBL was significantly associated with incisor region location (-0.74 mm), increased probing depth (-0.16 mm per mm), and suppuration on probing (-0.97 mm), all p ≤ 0.05. In contrast, prosthetic retention, marginal misfit, and prosthet emergence geometry were not significantly associated with ΔCBL. CONCLUSIONS: Over 25 years, the type of IFDP did not significantly affect ΔCBL or the prevalence of PM and PI around tissue-level implants. Long-term bone stability was primarily influenced by implant location in the incisor region, increased probing depths, and the presence of suppuration.