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Nonsmokers fare better than smokers for most surgical root-coverage procedures Critical Summary Prepared by: Scott Tomar DMD, DrPH; Matthew Palermo DMD; Laurie MacPhail DMD 

OVERVIEW

  • Systematic Review Conclusion:

    Root coverage surgeries successfully treated recession in nonsmokers and smokers, but subepithelial connective tissue grafts worked best in nonsmokers.

  • Critical Summary Assessment:

    This well-conducted systematic review and meta-analysis of limited evidence found that surgical root-coverage procedures led to improvements in gingival recession and clinical attachment level for smokers and nonsmokers, but nonsmokers generally had more favorable outcomes.

  • Evidence Quality Rating:

    Limited

A Critical Summary of:

The influence of tobacco smoking on the outcomes achieved by root-coverage procedures: a systematic review

Chambrone L, Chambrone D, Pustiglioni FE, Chambrone LA, Lima LA. Journal of the American Dental Association. 2009;140(3):294-306

  • Clinical Questions:

    In adults with Miller class I and II gingival recessions being treated by surgical root-coverage procedures, do nonsmokers have more favorable clinical outcomes than smokers?

  • Review Methods:

    The authors searched four databases through June 2008 for randomized controlled trials, controlled trials or case series that compared periodontal surgical results, with at least a six month follow-up, for nonsmokers versus smokers (= 10 cigarettes/day) . They noted changes in gingival recession (GR), clinical attachment level (CAL), and keratinized tissue (KT); percentage of sites with complete root coverage; and mean root coverage. They also hand-searched pertinent journals and contacted authors as necessary.

  • Main Results:

    The authors identified 632 articles and excluded 535 on review of title/abstract. Two independent reviewers read the remaining 97 studies and selected seven for analysis: two of the seven comprised the same patients and were combined to yield six articles. The authors analyzed four controlled clinical trials and two case series (107 nonsmokers, 64 smokers,). Three studies used subepithelial connective tissue grafts (SCTG) (35 nonsmokers, 34 smokers), two used coronally advanced flaps (CAF) (59 nonsmokers, 21 smokers) and one used guided tissue regeneration (GTR) (13 nonsmokers, 9 smokers). All CAF and SCTG studies reported improvements in GR and CAL measures for nonsmokers and smokers at 6 months. For CAF, meta-analyses comparing nonsmokers to smokers found no significant difference for any of the review outcomes. For SCTG however, meta-analyses results [weighted mean difference in millimeters (95 percentconfidence interval)] found that nonsmokers had significantly more improvement than smokers for GR [-0.78 (-1.06 to -0.51) p=<0.0001] and CAL [-0.75 (-1.13 to 0.38) p=<0.0001]. Nonsmokers also had a greater percentage of sites with complete coverage [Risk Ratio 0.24 (0.10 - 0.58) p=0.001]. For GTR, the one case-series found significantly (p=0.032) more improvement in mean GR in nonsmokers (3.6±1.1) than smokers (2.5±1.2), but no significant difference in other clinical outcomes.

  • Conclusion:

    The authors reported statistically significant improvements in GR and CAL measures for nonsmokers and smokers for CAF and SCTG surgical techniques. Meta-analysis found no significant differences between nonsmokers and smokers for CAF whereas nonsmokers had significantly more improvement in GR and CAL measures than smokers for SCTG. The only statistically significant difference for GTR was more improvement in GR in nonsmokers. Overall, nonsmokers had better outcomes.

  • Source of funding:

    Not reported

Commentary:

  • Importance and Context:

    Tobacco smoking is a risk factor for periodontal disease, (1) and patients with gingival recession from periodontal disease may experience dental hypersensitivity (2) and poor esthetics.(3) Knowing whether tobacco smoking negatively influences the outcome of a surgical treatment for gingival recession could be valuable in selecting which surgical procedure to use for a patient who smokes. Prior systematic reviews of root-coverage surgical procedures did not directly address the effect of smoking vs. not smoking on clinical outcomes. Strengths and Weaknesses of the Systematic review: The authors followed standard protocols for systematic reviews, reporting the search methods, analysis methods, and results completely. They assessed the quality of the studies and tabulated the data. The authors performed meta-analyses on pooled data for studies with SCTG and CAF surgical techniques despite the differences among the studies as to surgical techniques, examiner blinding, follow-up period, operator's level of experience, recession localization and gingival anatomy.

  • Strengths and Weaknesses of the Systematic Review:

    Standard protocols for systematic reviews were followed and the search and analysis methods and results were completely reported. The quality of the studies was assessed and data were tabulated. Meta-analyses were performed on pooled data for studies with SCTG and CAF surgical techniques despite the differences among the studies as to surgical techniques, examiner blinding, follow-up period, operator’s level of experience, recession localization and gingival anatomy.

  • Strengths and Weaknesses of the Evidence:

    Available literature was sparse: the authors found only four controlled clinical trials, two case series and no randomized controlled clinical trials. Sample sizes were small: controlled trials included 30 subjects total and, although one case series was larger (n=60), it had few smokers (n=11). The authors identified only one small (n=22) case series for GTR. Although pooled data used in meta-analysis came from studies of different designs and follow-up periods, the overall findings favored nonsmokers. Only one study (SCTG, n=9 smokers) verified reported smoking rates by measuring cotinine levels. For SCTG, there was little evidence for heterogeneity, and the tests for overall effect were significant for GR, CAL and number of sites with complete root coverage. The review reported the risk difference (the difference between the proportions of subjects exhibiting complete root coverage in nonsmokers and smokers) and number needed to treat (NNT) for this comparison; the results were -0.41 (95 percent CI, 0.59 to 0.24; p < 0.001) and 3.00, respectively. Because risk difference is typically calculated as the risk in the control group minus the risk in the exposed group, the negative value for risk difference in that analysis implies a lower proportion of subjects in the non-smoking group had complete root coverage. As reported, the NNT calculation implies that three smokers would need to be treated to obtain one patient with complete root coverage. No study directly compared surgical techniques or addressed patient-oriented outcome measures such as morbidity, symptom improvement, cost reduction, or quality of life.

  • Implications for Dental Practice:

    Current limited evidence suggests that, overall, nonsmokers fare better than smokers from root coverage procedures for Miller class I and II gingival recessions, and that smokers may have better results with coronally advanced flaps or guided tissue regeneration than with subepithelial connective tissue grafts.

    References
    1. Bergstrom J. Periodontitis and smoking: an evidence-based appraisal. J Evid Based Dent Pract 2006;6(1):33-41.
    2. Canadian Advisory Board on Dentin Hypersensitivity. Consensus-based recommendations for the diagnosis and management of dentin hypersensitivity. J Can Dent Assoc 2003;69(4):221-6.
    3. Cairo F, Rotundo R, Miller PD, Pini Prato GP. Root coverage esthetic score: a system to evaluate the esthetic outcome of the treatment of gingival recession through evaluation of clinical cases. J Periodontol 2009;80(4):705-10.

  • Critical Summary Publication Date: 3/28/2012

These summaries are not intended to, and do not, express, imply, or summarize standards of care, but rather provide a concise reference for dentists to aid in understanding and applying evidence from the referenced systematic review in making clinically sound decisions as guided by their clinical judgment and by patient needs. American Dental Association ©

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