Smokers have less reductions in probing depth than non-smokers following nonsurgical periodontal therapy

Abstract

0.05). For sites with an initial PD of 5.00 mm (eight studies), a random-effects meta-analysis indicated a weighted mean difference in PD reduction of 0.43 mm favouring nonsmokers (95% confidence interval (CI), 0.24-0.63; P<0.001). Because of significant heterogeneity between studies, only a cautious observation can be made but, with one exception, all studies produced a summary estimate favouring nonsmokers. Meta-analysis of the two studies that compared the change in clinical attachment level between nonsmokers and ex-smokers, who had given up their habit, in sites with an initial PD of +/-5.00 mm, showed a difference in clinical attachment level gain of 1.34 mm favouring the nonsmokers (95% CI, 0.65-2.03; P<0.001; chi(2) test for heterogeneity, 7.47 with 1 degree of freedom; P=0.006). In both of these analyses, the degree of heterogeneity is a cause for concern. Bleeding was assessed after therapy in seven studies but meta-analysis was not performed because of great heterogeneity in the methods used to assess bleeding. No statistically significant differences in bleeding were found between smokers and nonsmokers either at baseline or after therapy in most of the studies. One study found significantly less bleeding in smokers than in nonsmokers at baseline and another found a reduced response in terms of bleeding in smokers than in nonsmokers. Two studies evaluating the change in bleeding in ex-smokers found no statistically significant difference after treatment. No data were reported for any of the included studies on patient-centred outcomes such as quality of life, ease of maintenance, changes in aesthetic appearance, or patient experience. CONCLUSIONS: Following nonsurgical periodontal therapy, people who smoke will experience less reduction in PD than nonsmokers. There is no evidence of a difference in gain in clinical attachment between smokers and nonsmokers or a reduction of bleeding on probing between smokers and nonsmokers. Differences in study design and lack of data precluded an adequate and complete pooling of data for a more comprehensive analysis. In short-term studies, it is unclear whether people who stop smoking will respond as favourably to nonsurgical therapy as those who have never been smokers. Progress in understanding the effects of smoking on periodontal therapy will require the evaluation of objective measures of smoking such as nicotine exposure and exhaled carbon monoxide in place of sole reliance on patient-reported information.