Current Evidence on Dental Implants Outcomes in Smokers and Nonsmokers: A Systematic Review and Meta-Analysis

This systematic review aims to answer the following PICO (Participants, Intervention, Comparison, and Outcome) question: "Does smoking increase the rates of implant failure and peri-implant marginal bone loss in patients with dental implants?" An extensive electronic search of the Cochrane Central Register of Controlled Trials, PubMed, Medline, Embase, and Web of Science databases and a subsequent hand search were performed. Only randomized controlled trial, controlled clinical trials, and prospective studies published up to January 2017 were included. For dichotomous outcomes, the effect estimates for smoking are expressed as odds ratios and 95% CIs. For continuous outcomes, weighted mean differences (WMDs) and 95% CIs are presented. Three randomized controlled trials and 7 prospective studies were included. The odds ratio for implant failure among smokers was 2.92 (95% CI, 1.76-4.83) ( P < .001). First-year marginal bone loss in smokers ranged from 0.02 to 0.45 mm. In the nonsmokers, bone loss ranged from -0.08 to 0.42 mm. Nonsmokers lost significantly less bone during the first year (WMD = 0.11 mm, 95% CI. 0.03-0.19) and subsequent years (WMD = 0.11 mm, 95% CI, 0.03-0.19, P = .009). The available scientific evidence suggests that smoking is associated with significantly increased rates of implant failure and marginal bone loss.