Originally produced for the Consumer Product Recognition Committee, Canadian Dental Association
Abstract
MeSH Key Words: dentistry; periodontitis; smoking cessation, tobacco-use cessation
© J Can Dent Assoc 2001; 67:149
The provision of smoking cessation services by health professionals has received considerable recent attention. Research has clearly shown that physicians are effective in increasing the proportion of their patients who successfully quit smoking.5 As a result, public health organizations encourage physicians to provide smoking cessation services. Numerous prescription and over-the-counter products are now available to help medical practitioners and their patients to increase expected success rates.
With new awareness of the link between smoking and oral health, the dental profession has become more interested in cessation services for dental patients. The growing profes sional support for cessation services is reflected by the addition of cessation information to the undergraduate dental curriculum at Canadian dental faculties and by the Canadian Dental Association’s official policy on smoking cessation:
The Canadian Dental Association encourages the eradication of the use of tobacco products. Studies indicate that dental counselling is effective in influencing patients to quit using tobacco. The Canadian Dental Association urges dentists to inquire about their patient’s tobacco use and provide advice and encouragement to those interested in quitting.6
If smoking cessation products are effective, information about them should be incorporated into dental school tobacco-use cessation curricula and their use should be recommended and promoted within the dental profession.
This paper uses an evidence-based approach to determine whether the use of smoking cessation products should be promoted by dental offices. The evidence-based methodology is applied to each of the following 3 questions:
1. Does tobacco use affect periodontal health?
2. Are dentists effective smoking cessation counsellors?
3. Can smoking cessation products improve the effectiveness of cessation interventions?
If tobacco use affects oral health, if dentists are effective counsellors and if the adjunctive use of cessation products improves cessation effectiveness, then the use of smoking cessation products should be promoted by dental practitioners.
Methods Scientific evidence was gathered from searches of the 1980 to 2000 MEDLINE database. Relevant articles were identified by using MeSH headings such as “smoking cessation,” “tobacco-use cessation,” “dentistry” and “periodontitis,” and by using key words such as “bupropion,” “Zyban,” “nicotine,” “patch” and “gum.” All searches were limited to the English language, human studies, local holdings, adults over age 19 years and meta-analyses or randomized controlled trials (RCT). Study titles and abstracts were used to select the most appropriate studies for inclusion. For question 1, only adult periodontitis studies were considered. Due to ethical restrictions on performing clinical trials to address the subject of smoking and periodontal health, searches on this issue were not limited to meta-analyses or RCTs.
In addition to the MEDLINE searches, articles were identified by manual searching and by perusing bibliographies from appropriate sources. Selected studies were evaluated to determine whether the interventions were effective.
The study’s internal and external validity were also evalu ated. All selected papers were assessed for the quality of the study as reported in the article (i.e., sample size, study length, controls, blinding, randomization and use of placebo).
Each article selected was rated for the level of evidence provided according to the criteria developed by the Canadian Task Force on the Periodic Health Examination (see Table 1).7 Recommendations for or against each issue were classified as being based on good, fair or poor scientific evidence. Table 2 summarizes the resulting recommendations.
Results
Question 1 — Does Tobacco Use Affect Periodontal Health?
Direct Effect
Case-control studies have reported that smokers have significantly greater prevalence and severity of periodontitis.26,27 Overall, an estimated 40% of periodontitis can be attributed to tobacco use.30 In a recent cohort study, smokers were re ported to experience greater periodontal attachment loss and radiographic bone loss compared to non-smokers (odds ratio [OR] = 5.41; confidence interval [CI] = 1.5-19.5).31 Smokers’ cotinine level showed direct correlation with periodontal breakdown, suggesting a dose–response relationship between smoking and periodontal disease exhibited in a longitudinal study. Odds ratios for former smokers having moderate or advanced periodontitis are reported to be intermediate to those of current smokers and never smokers, again suggesting a dose–response relationship.27
Randomized clinical trials of the effect of smoking on perio dontitis are not possible due to ethical restrictions; however, strong evidence of the deleterious effect of smoking comes from a cohort study of Swedish twins who differed in smoking exposure.30 It was found that the degree of alveolar bone loss and the number of teeth lost were greater in twins with a high lifetime smoking exposure than in their twin partners with a low lifetime exposure.
The effect of smoking on alveolar bone loss has also been reported. A recent study reported that smokers had relative risks for attachment loss ranging from 2.05 for light smokers to 4.75 for heavy smokers when compared to non-smokers.8 Smokers also had greater odds for more severe bone loss compared to non-smokers, ranging from 3.25 to 7.28 for light and heavy smokers respectively.9 Approximately 56% of non-smokers were in the healthy group (< 2 mm bone loss) and 7.5% in the severe bone loss group, compared to 9.25% and 35.2% of smokers in these respective groups.
Response to Treatment The effect of smoking on the response to periodontal therapy has been investigated in several recent studies. In the first, the effect of scaling and root planing was examined on 57 adult patients with periodontitis.31 The authors reported that pockets initially Ž 4 mm showed significantly improved perio dontal health after therapy. These improvements occurred only in non-smokers and former smokers and were not observed in current smokers. Two more studies looked at the effect of adjunctive locally delivered antimicrobials in cases of refractory32 and severe33 periodontitis. The authors reported that, regardless of the type of treatment, the changes in probing depth and attachment gain were greater in non- smoker subjects than in smoker subjects. As well, there was a significant interaction between smoking status and baseline probing depth,32 suggesting that smoking plays an important role in the development of periodontitis as well as in the prognosis of periodontal treatment.
The clinical periodontal response to surgical and non- surgical therapy has been studied in 74 patients following maintenance for 6 years.34 The authors reported that smokers did not respond as favourably to therapy as non-smokers and were not maintained as well over the next 6 years. These results are also observed in another study of 60 smokers and 83 non-smokers.35 Preber and Bergstrom have studied the effect of smoking on non-surgical and surgical periodontal therapy.36,37 They reported a significant effect of smoking on the outcome obtained by surgical periodontal therapy.
Benefit of Quitting Evidence of the potential benefit to be gained by quitting smoking comes from cohort and cross-sectional studies that compare periodontal health in current smokers to that of former smokers and individuals who have never smoked. These studies have all reported that the periodontal health of former smokers is intermediate to that found in current smokers and never smokers.14,15,18,30 This relationship is suggestive of a dose–response relationship between smoking and periodontal health and indicates the potential benefit of quitting.
Conclusion Cohort, case-control and descriptive studies have consistently shown that tobacco use is associated with periodontitis. Ethical restrictions preclude the use of randomized controlled trials to assess this issue, leaving Level II research as the best possible evidence. Despite the lack of Level I evidence, the strong, consistent dose–response relationship seen between tobacco use and periodontitis suggests a cause–effect relationship. Overall, there is fair evidence that tobacco use is an important risk factor for periodontitis.
Question 2 — Are Dentists Effective Smoking Cessation Counsellors? Randomized clinical trials consistently report that routine smoking cessation counselling by dental professionals increases the proportion of patients who successfully quit smoking.38-43 An early trial of private dental office-based interventions reported test group quit rates of 16.9% compared to 7.7% for the control group.38 The efficacy of a brief dental office intervention has also been proven to be effective in helping patients quit using smokeless tobacco.39,40 A more recent trial of dental health advice as an aid to reducing cigarette smoking in a perio dontal specialty clinic setting reported a quit rate of 13.3% in the intervention group compared to 5.3% in control subjects.41
Several case series studies have also demonstrated the effectiveness of dental quit smoking interventions.44-46 Quit rates of 23%, 40% to 47%, and 45.3% have been reported by studies of different cessation interventions. In a recent meta-analysis performed for the U.S. Department of Health and Human Services, dentists are reported to be as effective as other health professionals (physicians and nurses) in helping patients quit.5
There is good evidence that oral health professionals are effective smoking cessation counsellors. Dental offices should provide smoking cessation services as a routine patient service (A-level recommendation).
Question 3 — Can Smoking Cessation Products Improve the Effectiveness of Cessation Interventions? Although there are many products available on the Canadian market to assist in the quitting process, the review in this area was limited to transdermal nicotine, nicotine gum and bupropion products.
Nicotine Replacement Products The adjunctive use of nicotine replacement products has been extensively studied in numerous randomized clinical trials and subsequent meta-analyses. For the purposes of this paper, only transdermal nicotine and nicotine gum were reviewed.
Nicotine Patch
Five published meta-analyses consistently report that the use of transdermal nicotine (the patch) as an adjunct to counselling is significantly more effective than the use of a placebo.47,48 Transdermal nicotine more than doubled the one-year quit rates obtained in control groups with combined ORs of different meta-analyses ranging from 2.07 to 2.6. These meta-analyses give good evidence to recommend the use of the transdermal nicotine patch as an adjunct to smoking cessation services (A-level recommendation).
Nicotine Gum
Three meta-analyses assessing the adjunctive use of nicotine chewing pieces report significantly increased cessation rates.48,51,52 These meta-analyses report that the use of nicotine gum increases one-year cessation success by approximately 50%, with combined ORs of different meta-analyses ranging from 1.4 to 1.6. These meta-analyses give good evidence to recommend the use of nicotine gum as an adjunct to smoking cessation services (A-level recommendation).
Bupropion Bupropion is a relatively new anti-smoking product. The drug is also prescribed for its antidepressive properties. If fact, initial interest in the use of bupropion for smoking cessation arose from anecdotal reports of successful quit attempts by smokers taking the drug as an antidepressant. A sustained-release formulation was subsequently developed specifically for use in smoking cessation.
Two randomized clinical trials on the adjunctive use of bupropion for tobacco-use cessation reported that bupropion significantly increases the proportion of people who successfully quit smoking.53,54 The adjunctive use of bupropion approximately doubled the quit rate obtained with placebo (23.1% vs. 12.4% and 30.3% vs. 15.6%). Minimal side effects were reported by both studies, with the most common adverse events being insomnia and headache. One of these studies looked at combination therapy using both bupropion and transdermal nicotine. While higher abstinence rates were reported with combination therapy than with bupropion alone, the difference was not statistically significant.54 These studies provide good evidence to recommend the use of bupropion as an adjunct to smoking cessation services (A-level recommendation).
Discussion Canadians who are interested in quitting smoking often obtain cessation products to decrease the side effects of quitting and thereby increase their chance of success. Many cessation products are currently available on the Canadian market, some by prescription and others as over-the-counter products. If effective, these products should be promoted for use by health professionals.
This review clearly shows that smoking is an important risk factor in the progression and management of periodontitis. It is associated with and shows a dose–response relationship with deteriorating periodontal health and it interferes with the outcome of periodontal therapy. Individuals who quit smoking have better periodontal health than do patients who continue to smoke.
The review also shows that oral health professionals are effective at increasing the number of patients who successfully quit smoking. Quit rates are nearly doubled when cessation services are offered. It is therefore appropriate for oral health professionals to provide smoking cessation services in the prevention and management of periodontal disease (A-level recommendation).
Finally, the review shows that transdermal nicotine and nicotine gum, both available as over-the-counter products in Canada, and bupropion are effective adjuncts to smoking cessation services (A-level recommendations). In view of the supporting evidence, the Canadian public would benefit from guidance in the selection of appropriate, effective smoking cessation methods. Dental offices should incorporate systematic smoking cessation services into routine patient care.
Dr. Brothwell is section head, community dentistry, faculty of dentistry, University of Manitoba.
Correspondence to: Dr. Douglas J. Brothwell, Section Head, Community Dentistry, Faculty of Dentistry, University of Manitoba, D108-780 Bannatyne Ave., Winnipeg, MB R3E 0W2.
E-mail: brothwel@ms.umanitoba.ca.
The author has no declared financial interest in any company manufacturing the types of products mentioned in this article.
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