DOI: 10.11607/prd.3694, PubMed ID (PMID): 29889912Pages 489-493, Language: EnglishSimion, Massimo / Nevins, Myron / Rasperini, Giulio / Tironi, FrancescoThe goal of this retrospective investigation was to provide evidence of the longevity of machine-surfaced implants placed in native bone and treated with the original two-stage surgical protocol. The observation times of this study covered periods of 13 to 32 years. Consecutive cases were impossible; the patients' ages when treated reduced the number of available people as a result of death, relocation, being impossible to find, or refusal to cooperate. Mean marginal bone loss after 13 to 32 years was 1.9 ± 0.9 mm, survival rate was 97.7%, and success rate was 92.7%. Peri-implantitis occurred in a limited number of cases, with a prevalence of 1.8%. This study demonstrates long-term reliability of machined implants as a therapeutic choice.