Increasing levels of smoking may increase the relative risk of dental implant failure

Summary Subjects or Study Selection The authors searched PubMed, Embase, Web of Science and Scopus databases for randomly controlled clinical trials, cohort studies, case control studies and case series of subjects with dental implants who smoked, who also reported implant failures and the number of cigarettes they smoked. Two authors graded the quality of the studies using the nine-point Newcastle-Ottawa scale, and they retained studies that scored greater than six points. The initial search identified 5,035 studies, 23 of which met the criteria for inclusion in the meta-analysis, with 1 clinical trial, 6 prospective studies, and 16 retrospective studies, and a total of 31,129 implants. Though not reported in the paper, the number of subjects (10,902) was calculated from the online supplemental Table S2A; however, the actual number of subjects was higher because one paper in the table did not report the number of subjects. Key Study Factor Systematic review and meta-analysis of 23 studies comparing the effects of smoking on failure rates of dental implants; all studies had to include the level of smoking expressed as numbers of cigarettes smoked, and at least two categories, such as light versus heavy smoking. Main Outcome Measure The main outcome measure was a statistically significant increase (P 10 cigarettes; 2) none, 15 cigarettes; 3) none, 20 cigarettes; and, 4) none, 20 cigarettes. They also performed separate meta-analyses based on implant-related and patient-related data (each implant was considered as a separate subject). Finally, separate sub-group meta-analyses were performed based on implant surface type (rough vs. smooth), and on implants placed in grafted sinuses. Main Results Subjects who smoked >20 cigarettes per day, compared to non-smokers, had a relative risk of 2.48 (C.I. 1.46-4.22, p= 0.001) for implant failure on an implant-level basis, and 4.0 (C.I., 2.72-5.89, p Funnel plot inspections and Egger’s tests for all meta-analyses performed detected no evidence of publication bias. Conclusions The authors concluded that the risks of implant failure increased as the number of cigarettes smoked increased, and that smoking more than a pack of cigarettes per day can be considered a risk for implant failure.