Background: Little is known about the long-term outcome of oxidized surface oral implants, especially in periodontitis-susceptible smokers. The aim of this study is to determine implant survival and marginal bone loss at turned and oxidized implants in smokers and never-smokers with periodontitis.

Methods: Forty smokers and 40 never-smokers with experience of advanced periodontal disease, treated with implants 5 years previously, are included in this study. Groups were matched for sex, oral hygiene, and implant distribution, and patients were subgrouped by implant surface type (turned or oxidized).

Results: The overall implant survival rate was 96.9% in never-smokers and 89.6% in smokers. Compared with oxidized implants, turned implants failed more frequently in smokers. In smokers, mean (standard error of the mean) marginal bone loss at 5 years was 1.54 (0.21) mm at turned and 1.16 (0.24) mm at oxidized implants. In never-smokers, significantly greater bone loss was found at oxidized implants, 1.26 (0.15) mm, than at turned implants, 0.84 (0.14) mm. Oxidized implants demonstrated similar bone loss for both groups. Turned implants lost significantly more bone in smokers. Compared with never-smokers, the smokers' likelihood ratio for implant failure was 4.68, 6.40 for turned and 0.00 for oxidized implants.

Conclusions: The results of the study underscore the need for prevention and cessation of smoking. Turned implants failed more frequently and lost more marginal bone in smokers. In contrast, oxidized implants showed similar failure rates and bone loss in smokers and never-smokers. Turned implants displayed less bone loss than oxidized implants in never-smokers. Oxidized surface implants are more suitable for patients susceptible to periodontitis who smoke.