Smoking and Dental Implants: A Systematic Review and Meta-Analysis

Background and Objectives: Tobacco is today the single most preventable cause of death, being associated with countless diseases, including cancer and neurological, cardiovascular, and respiratory diseases. Smoking also brings negative consequences to oral health, potentially impairing treatment with dental implants. The present review aimed to evaluate the influence of smoking on dental implant failure rates and marginal bone loss (MBL). Materials and Methods: Electronic search was undertaken in three databases, plus a manual search of journals. Meta-analyses were performed, in addition to meta-regressions, in order to verify how the odds ratio (OR) and MBL were associated with follow-up time. Results: The review included 292 publications. Altogether, there were 35,511 and 114,597 implants placed in smokers and in non-smokers, respectively. Pairwise meta-analysis showed that implants in smokers had a higher failure risk in comparison with non-smokers (OR 2.402, p < 0.001). The difference in implant failure between the groups was statistically significant in the maxilla (OR 2.910, p < 0.001), as well as in the mandible (OR 2.866, p < 0.001). The MBL mean difference (MD) between the groups was 0.580 mm (p < 0.001). There was an estimated decrease of 0.001 in OR (p = 0.566) and increase of 0.004 mm (p = 0.279) in the MBL MD between groups for every additional month of follow-up, although without statistical significance. Therefore, there was no clear influence of the follow-up on the effect size (OR) and on MBL MD between groups. Conclusions: Implants placed in smokers present a 140.2% higher risk of failure than implants placed in non-smokers.