Impact of peri-implantitis on adjacent dental implants: A retrospective analysis

Although peri‑implantitis is known to affect adjacent natural teeth, its site‑specific influence on neighboring implants remains poorly characterized. The purpose of this retrospective study was to evaluate whether peri‑implantitis exerts localized, site‑specific detrimental effects on adjacent dental implants and to determine whether these effects differ between mesial and distal adjacent implants.

A retrospective chart review was conducted on patients with two or more adjacent implants in function for ≥1 year, in which at least one implant was diagnosed with peri-implantitis. Clinical parameters such as probing depth (PD), relative probing depth (RPD), free mucosal margin (FMM), bleeding on probing (BOP) and radiographic bone levels were recorded and analyzed using linear and generalized linear mixed-effects models, accounting for patient-level clustering.

Fifty-three patients contributed to 78 peri-implantitis affected main implants and 100 adjacent implants. Overall, RPD was significantly greater at near sites than far sites (p = 0.0237), and FMM was more apical at near sites than far sites (p = 0.007). Distal adjacent implants showed significantly deeper PD (p = 0.037) and greater RPD (p = 0.034) at near sites, whereas mesial adjacent implants exhibited only increased recession (p = 0.012) compared to far sites. Marginal bone loss differences were small and not statistically significant. Notably, 53% of adjacent implants developed peri-implantitis.

Peri-implantitis exerts localized, site-specific effects on adjacent implants, with more pronounced soft-tissue breakdown at near surfaces, particularly affecting distal neighbors. These findings underscore the need for close monitoring of implants adjacent to peri-implantitis sites.