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

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.

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.

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.

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.