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Tobacco use has significant adverse effects on oral health. Oral health professionals in the dental office or community setting have a unique opportunity to increase tobacco abstinence rates among tobacco users.
This review assesses the effectiveness of interventions for tobacco cessation delivered by oral health professionals and offered to cigarette smokers and smokeless tobacco users in the dental office or community setting.
We searched the Cochrane Tobacco Addiction Group Specialized Register (CENTRAL), MEDLINE (1966-November 2011), EMBASE (1988-November 2011), CINAHL (1982-November 2011), Healthstar (1975-November 2011), ERIC (1967-November 2011), PsycINFO (1984-November 2011), National Technical Information Service database (NTIS, 1964-November 2011), Dissertation Abstracts Online (1861-November 2011), Database of Abstract of Reviews of Effectiveness (DARE, 1995-November 2011), and Web of Science (1993-November 2011).
We included randomized and pseudo-randomized clinical trials assessing tobacco cessation interventions conducted by oral health professionals in the dental office or community setting with at least six months of follow-up.
Two authors independently reviewed abstracts for potential inclusion and abstracted data from included trials. Disagreements were resolved by consensus. The primary outcome was abstinence from smoking or all tobacco use (for users of smokeless tobacco) at the longest follow-up, using the strictest definition of abstinence reported. The effect was summarised as an odds ratio, with correction for clustering where appropriate. Heterogeneity was assessed using the I2 statistic and where appropriate a pooled effect was estimated using an inverse variance fixed-effect model.
Fourteen clinical trials met the criteria for inclusion in this review. Included studies assessed the efficacy of interventions in the dental office or in a community school or college setting. Six studies evaluated the effectiveness of interventions among smokeless tobacco (ST) users, and eight studies evaluated interventions among cigarette smokers, six of which involved adult smokers in dental practice settings. All studies employed behavioral interventions and only one required pharmacotherapy as an interventional component. All studies included an oral examination component. Pooling all 14 studies suggested that interventions conducted by oral health professionals can increase tobacco abstinence rates (odds ratio [OR] 1.71, 95% confidence interval [CI] 1.44 to 2.03) at six months or longer, but there was evidence of heterogeneity (I2 = 61%). Within the subgroup of interventions for smokers, heterogeneity was smaller (I2 = 51%), but was largely attributable to a large study showing no evidence of benefit. Within this subgroup there were five studies which involved adult smokers in dental practice settings. Pooling these showed clear evidence of benefit and minimal heterogeneity (OR 2.38, 95% CI 1.70 to 3.35, 5 studies, I2 = 3%) but this was a posthoc subgroup analysis. Amongst the studies in smokeless tobacco users the heterogeneity was also attributable to a large study showing no sign of benefit, possibly due to intervention spillover to control colleges; the other five studies indicated that interventions for ST users were effective (OR 1.70; 95% CI 1.36 to 2.11).
Available evidence suggests that behavioral interventions for tobacco cessation conducted by oral health professionals incorporating an oral examination component in the dental office or community setting may increase tobacco abstinence rates among both cigarette smokers and smokeless tobacco users. Differences between the studies limit the ability to make conclusive recommendations regarding the intervention components that should be incorporated into clinical practice, however, behavioral counselling (typically brief) in conjunction with an oral examination was a consistent intervention component that was also provided in some control groups.
In addition to the well-known harmful effects of smoking on respiratory and cardiovascular systems, tobacco use has significant adverse effects on oral health (Warnakulasuriya 2010). Cigarette smoking is associated with an increased risk for oral disease (Gelskey 1999; Mecklenburg 1998; Salvi 2000). Tobacco exposes the oral cavity to toxic carcinogens that may have a role in initiation and promotion of cancer (Mirbod 2000). Tobacco is the major inducer of oral squamous cell carcinoma (SCC) and is considered to be responsible for 50% to 90% of oral cancer cases worldwide (Epstein 1992; Holleb 1996). The incidence of oral SCC is four to seven times greater in smokers than non-smokers (Piyathilake 1995). Oral cancer and pre-cancer occurs more frequently in smokers, and quitting smoking decreases the risk for oral cancer within 5 to 10 years (EU Working Group 1998). Tobacco exposure is also harmful to periodontal health, and smoking status is an important factor in the prognosis for periodontal therapy, oral wound healing, implant therapy, and cosmetic dentistry (Mecklenburg 1998). Smoking results in discoloration of both teeth and dental restorations, and is associated with halitosis, diminished taste, and an increased prevalence and severity of periodontal disease (EU Working Group 1998). Cigarette smoking is causally associated with an increased prevalence and severity of periodontitis (Gelskey 1999), even when adequate oral hygiene is practiced (Kerdvongbundit 2002). Cessation of smoking may halt disease progression and improve outcomes of periodontal therapy (EU Working Group 1998).
Smokeless tobacco use has been reported to cause tooth decay (Tomar 1999) and discoloration of dental restorations (Walsh 2000). Chewing tobacco, in particular, is associated with an increased risk for dental caries due to high sugar content and increased gingival recession. Abrasive particles in chewing tobacco may contribute to significant dental attrition which may require dental restorations in advanced cases (Bowles 1995; Milosevic 1996). Cross-sectional studies have suggested that smokeless tobacco users with co-existing gingivitis have high rates of gingival recession, mucosal pathology, and dental caries (Offenbacher 1985). Smokeless tobacco use has also been associated with irreversible gingival attachment loss resulting in root exposure (Ernster 1990). Effects of smokeless tobacco use are typically observed at anatomical locations where the tobacco contacts the mucosa, such as the labial vestibule and adjacent periodontium. Both the prevalence and severity of tobacco-related oral lesions demonstrate a dose-response relationship with the amount, frequency and duration of smokeless tobacco exposure (Little 1992a). Chronic exposure can lead to leukoplakia (Hirsch 1982), a premalignant condition (Silverman 1984; Silverman 1976). Smokeless tobacco use in the United States has been associated with an increased risk for oral cancer in a dose-response fashion (Stockwell 1986; Williams 1977; Winn 1981). Risk may vary depending upon the type of smokeless tobacco used, as the highest rates of oral cancer are observed in countries where smokeless tobacco is consumed with additives (e.g., areca nut) (Critchley 2003).
The dental practice setting provides a unique opportunity to assist tobacco users in achieving tobacco abstinence (Christen 1990; Needleman 2010; Ramseier 2010). Widespread acceptance of tobacco use interventions in the dental setting have been lacking and limitations in primary care resources have curtailed further efforts (Warnakulasuriya 2002). Compared to other health care providers, dentists more accurately estimate patient tobacco use (Block 1999). However, dental practitioners are less consistent with and supportive of intervention, less likely to report having strong knowledge or skill levels regarding tobacco cessation, and more likely to perceive barriers to tobacco intervention (Block 1999). More than 40% of dentists do not routinely ask about tobacco use and 60% do not routinely advise tobacco users to quit (Tomar 2001).
While 61.5% of dentists believe their patients do not expect tobacco cessation services, 58.5% of their patients felt such services should be provided (Campbell 1999). Barriers to providing tobacco cessation service include concern for patient resistance (Campbell 1994), lack of knowledge, lack of time (Dolan 1997), lack of financial reimbursement (Fried 1992), and a concern for poor co-ordination of care between dentistry and tobacco cessation services (Campbell 1994).
We assess the effectiveness of interventions for tobacco cessation offered by oral health professionals to cigarette smokers and smokeless tobacco users in the dental office or community setting. We were interested in testing the following hypotheses in regards to increasing tobacco abstinence rates among tobacco users:
All randomized and pseudo-randomized (i.e., by patient number, date of birth, day of attendance) controlled trials with at least six months follow-up were included. The unit of randomization was the dentist or practice for the studies in the dental office setting, and college or high school for the studies in the community setting.
Patients or subjects of any age reporting tobacco use and receiving oral health interventions by dental professionals were included. Subject recruitment and participation included both those actively seeking treatment and those who did not express an interest in quitting. All tobacco users (cigarette, cigar, and pipe smokers, and smokeless tobacco users) were included.
We included any intervention to promote tobacco use cessation (intervention versus usual care or placebo, and/or intervention versus other intervention) which included a component delivered by a dentist, dental hygienist, dental assistant or office staff in the dental practice setting and any combination of these, as well as the same individuals providing intervention as part of a community effort. Interventions could include brief advice to quit, provision of self-help materials, counselling, pharmacotherapy or any combination of these, or referral to other sources of support. Interventions that were directed at both smokers and smokeless tobacco users were included, as were interventions aimed at the training of dental health professionals.
The outcome measure was smoking and tobacco use cessation, assessed at least six months from the delivery of the intervention. Trials which did not report tobacco use outcomes or did not have sufficiently long follow-up were excluded. Biochemical validation of self-reported cessation was not required but was recorded and used where available.
The Specialized Registers of the Cochrane Tobacco Addiction Group (most recent search November 2011) and the Cochrane Oral Health Group (Cochrane Central Register of Controlled Trials, Cochrane Library 2011) were searched for references to tobacco use interventions by dental health professionals, in the dental practice setting or otherwise. We also searched the following electronic retrieval systems and databases:
The following terms were used to describe the participants: smokers; smoking; cigarettes; smokeless tobacco; chewing tobacco; oral tobacco; spit tobacco; snuff; quid; chew; plug; tobacco use(rs). The following terms described the interventions: randomized; dentists; dental; hygienists; dental-patient relations; behavior modification; conditioning therapy; therapy; behavior; conditioning; group therapy; cognitive therapy; counselling; behavioral intervention; pharmacotherapy; drug; patient education; health promotion. The following terms were used to describe the outcomes: tobacco use cessation; smoking abstinence; tobacco abstinence. The following terms described the intervention environment: dentists; dental; hygienists; dental-patient relations; oral health.
The Medical Subject Headings (MeSH) used in MEDLINE and CINAHL were also used to focus on the dental environment: limit retrieval to the dentistry journals subset; or subject headings Oral Health/or exp Dentistry/or exp Dental Staff/or exp DENTISTS/or DENTIST’S PRACTICE PATTERNS/or exp dental auxiliaries/or dental hygienists. Keywords of the various oral specialties orthodont$, periodont$ and endodont$ were also searched. There were no language restrictions. In general, records were searched by conducting searches the following way: (participants OR outcomes) AND interventions. We contacted experts in the area to locate unpublished studies in an effort to minimise publication bias.
Two authors screened the records retrieved by the searches for potential relevance against stated inclusion criteria: randomized/pseudo-randomized clinical trial, dental setting, tobacco cessation interventions, and cessation measures of six-month minimum follow-up. Two authors checked studies of possible relevance for inclusion or exclusion, and independently extracted and compared data. We resolved disagreements by discussion and consensus (referring to a colleague or Cochrane Review Group staff when necessary).
We extracted the following information about each study:
For each study we selected the outcome with the most rigorous definition available with regards to maintenance of abstinence (i.e., continuous versus point prevalence) and type of tobacco abstinence (i.e., all tobacco versus smokeless tobacco only) (Hughes 2003). Rates were based on an intention-to-treat analysis with drop-outs and losses to follow-up assumed to be continuing tobacco users. We noted any difference in numbers lost to follow-up between intervention and control groups.
The risk of randomization and allocation concealment were judged to be low if the method was described in sufficient detail to ensure that allocation was blinded until after trial enrolment, unclear if there was insufficient detail with which to judge, and high if allocation was not concealed (as in use of patient record numbers, day of attendance, etc.). We also assessed the risk of attrition bias in included studies. Where there appears to have been a large loss to follow-up we assessed whether the findings were sensitive to the use of different denominators. In addition to the judgements above, we assessed bias impact on strength of the evidence by identifying trials with multiple sources of bias, and we comment on the potential impact of the bias on the overall treatment effect.
The outcome from each trial was expressed as an odds ratio (OR). Where cessation is the outcome this was defined as (number of quitters in treatment group/number of smokers in treatment group)/(number of quitters in control group/number of smokers in control group). The OR was greater than 1 if people were more likely to quit in the treatment group. For cluster randomized trials we adjusted for clustering using the reported intraclass correlation coefficient (ICC) and the average cluster size. We calculated the logarithm of the adjusted or natural OR and its standard error and pooled studies using the generic inverse variance method (Higgins 2011, Section 16.3.4). We have displayed the raw data in Analysis 1.4.
We hypothesized that the following would explain heterogeneity which was explored through subgroup analyses: 1) Patients - smokers (cigarette, cigar, pipe) versus smokeless tobacco users, patients enrolled based on their interest in tobacco cessation versus patients enrolled regardless of interest in quitting (e.g., subjects enrolled in a study requiring informed consent to participate versus subjects enrolled in a study implemented in a dental practice enrolling all patients who are treated clinically), highly dependent versus less dependent tobacco users using the Fagerström Tolerance Questionnaire or modifications of the this dependence measure (to the extent that dependence is similarly categorized across trials), specialty practice versus general practice dental settings; 2) Interventions - interventions delivered by dentists versus dental hygienists or other dental staff, behavioral interventions versus pharmacologic interventions; 3) Outcomes - all tobacco abstinence versus tobacco-specific (cigarette smoking, smokeless tobacco) outcomes; 4) Method of randomization - cluster versus individual. We assessed heterogeneity using the I2 statistic (Higgins 2003).
Sensitivity analyses included assessment of changes in the estimate of the treatment effect using the random effects model compared with the fixed effect model.
We include in this updated review the Cochrane Tobacco Addiction Group’s Glossary of smoking-related terms (Appendix 1).
The review included 14 studies involving over 10,500 participants (Andrews 1999; Binnie 2007; Ebbert 2007; Gordon 2010a; Gordon 2010b; Gansky 2005; Hanioka 2010; Lando 2007; Nohlert 2009; Severson 1998; Severson 2009; Stevens 1995; Walsh 1999; Walsh 2003). Although Andrews 1999 and Severson 1998 reported the same trial they are treated here as separate studies since Andrews 1999 focused on outcomes in smokeless tobacco users and Severson 1998 on smokers. One eligible study had to be excluded due to unavailable subgroup denominator values (Cohen 1989). Other papers identified as potentially relevant but not meeting all inclusion criteria are listed in Characteristics of excluded studies along with the reason for exclusion.
The dental offices involved in the included studies were a heterogeneous group: six studies were conducted in private practice office settings (Andrews 1999; Ebbert 2007; Gordon 2010a; Hanioka 2010; Nohlert 2009; Severson 1998;); one study involved community public health dental clinics (Gordon 2010b); one was set in a hospital-based periodontal clinic (Binnie 2007); two took place in managed care clinics (Lando 2007; Stevens 1995); and one took place in military clinics (Severson 2009). Three involved oral health professionals (dentists and dental hygienists) providing interventions to athletes within high school or college community settings (Gansky 2005; Walsh 1999; Walsh 2003). The school community studies included a dental professional intervention component as a major part of the intervention.
Eight studies targeted smokers (Binnie 2007; Ebbert 2007; Gordon 2010a; Gordon 2010b; Hanioka 2010; Lando 2007; Nohlert 2009; Severson 1998). Five studies involved dental practice settings where adult smokers were provided at least brief behavioral counselling as part of the intervention (Binnie 2007; Ebbert 2007; Hanioka 2010; Gordon 2010b; Gordon 2010a). One study targeted both smokers and smokeless tobacco users; the data for the two types of participant were reported separately and are treated as two studies, Severson 1998 covering smokers and Andrews 1999 covering smokeless tobacco users. Six studies targeted smokeless tobacco users (Andrews 1999; Walsh 2003; Gansky 2005; Severson 2009; Stevens 1995; Walsh 1999). In the dental office studies, studies included tobacco users not actively seeking treatment (Andrews 1999; Gordon 2010a; Severson 1998; Stevens 1995) and those willing to participate (Binnie 2007; Ebbert 2007; Gordon 2010b; Hanioka 2010; Lando 2007; Nohlert 2009; Severson 2009).
Interventions in the dental office setting occurred during hygiene visits in general dental practices (Andrews 1999; Binnie 2007; Ebbert 2007; Gordon 2010a; Gordon 2010b; Hanioka 2010; Lando 2007; Nohlert 2009; Severson 1998; Stevens 1995), and involved either: 1) brief advice plus quitline referral (Ebbert 2007), brief advice plus motivational interviewing (Lando 2007), brief advice plus video-based cessation program with phone follow-up (Andrews 1999; Severson 1998; Severson 2009), or 2) counselling using the 5 A’s plus nicotine replacement therapy (NRT) (Binnie 2007), 5 A’s plus NRT and population-specific printed material (Gordon 2010b), 3 A’s plus pharmacotherapy and referral as needed (Gordon 2010a). One study used target population-specific videos as an adjunct to counselling (Severson 2009). Two studies used a high intensity intervention where intensity was gauged as frequency of personal contact, and occurred five times or more (Hanioka 2010; Nohlert 2009).
In the school community studies, tobacco users had to agree to participate and informed consent was obtained (Gansky 2005; Walsh 1999; Walsh 2003). Some dental office studies restricted enrolment to 15 years of age or older (Andrews 1999; Severson 1998; Stevens 1995), one of which placed gender restrictions on inclusion, while the remaining targeted adults. All of the school community studies based their intervention on the Cognitive Social Learning Theory (Bandura 1986), two of which reported that the Diffusion of Innovation Theory (Rogers 1983) was instrumental for incorporating the use of peer leaders. No such theoretical foundation was mentioned for the interventions applied to the dental office studies.
Nicotine replacement therapy in the form of gum (2 mg) was used in one of the school community studies (Walsh 1999). The gum was reinforced with counselling by a dental professional. In the majority of the studies, dental professionals (dentists and dental hygienists) provided counselling interventions which most often included combinations of an oral examination, feedback from the examination as to oral effects of tobacco use, a message to quit, motivational counselling using printed material or media presentations, and self-help aids. In five dental office studies, the usual care group included was either not described (Hanioka 2010) or involved no structured intervention (Andrews 1999; Gordon 2010a; Gordon 2010b; Stevens 1995), and in all the school community studies the control schools received no formal training.
In five of the dental office studies, the dental office was the unit of randomization (Andrews 1999; Ebbert 2007, Gordon 2010a, Gordon 2010b, Severson 1998), and in six studies, the patient was the unit of randomization (Binnie 2007, Hanioka 2010, Lando 2007, Nohlert 2009, Severson 2009, Stevens 1995). In the school community studies, the school was the unit of randomization following stratification based on baseline prevalence of tobacco use.
In the included trials, participants were followed for a maximum of six months (Ebbert 2007; Severson 2009), seven and a half months (Gordon 2010b), 12 months (Andrews 1999; Binnie 2007; Gansky 2005; Gordon 2010a; Hanioka 2007; Lando 2007; Nohlert 2009; Severson 1998; Stevens 1995; Walsh 1999), and 24 months (Walsh 2003, two year outcomes reported in Gansky 2002).
Of the studies targeting smokeless tobacco users, three reported all tobacco abstinence outcomes (Andrews 1999; Severson 1998; Stevens 1995). Point prevalence was reported as the primary outcome in three studies (Gansky 2005; Stevens 1995; Walsh 1999). Two studies reported abstinence as one week (seven day) point prevalence (Ebbert 2007; Stevens 1995), while four reported 30-day point prevalence abstinence (Gansky 2005; Lando 2007, Walsh 1999; Walsh 2003). Seven studies used continuous (sustained or prolonged) abstinence requiring either no tobacco use at both 3 and 12 months (Andrews 1999; Severson 1998), 12 months continuous abstinence (Hanioka 2007), six months continuous abstinence (Nohlert 2009), prolonged abstinence (Gordon 2010a, Gordon 2010b), or no current tobacco use at both 12 and 24 months after quitting before the one-month follow-up (Walsh 2003, reported in Gansky 2002).
Details of included studies can be found in Characteristics of included studies.
The risk of selection bias, judged on the basis of random sequence generation, was considered low in 12 studies (Binnie 2007; Ebbert 2007; Gansky 2005; Gordon 2010a; Gordon 2010b; Hanioka 2010; Lando 2007; Nohlert 2009; Severson 1998; Severson 2009; Walsh 1999; Walsh 2003), unclear in Andrews 1999, and high in Stevens 1995. Methods of allocation concealment were judged to be at low risk of bias in 11 studies (Andrews 1999; Binnie 2007; Gansky 2005; Gordon 2010a; Gordon 2010b; Hanioka 2010; Nohlert 2009; Severson 1998; Severson 2009; Walsh 1999; Walsh 2003), at unclear risk of bias in Ebbert 2007 and Lando 2007, and at high risk of bias in Stevens 1995. The risk of attrition bias was judged to be low in nine studies (Andrews 1999; Gansky 2005; Gordon 2010a; Gordon 2010b; Hanioka 2010; Severson 1998; Severson 2009; Walsh 1999; Walsh 2003), unclear in three studies (Binnie 2007; Ebbert 2007; Nohlert 2009), and high in two studies (Lando 2007; Stevens 1995).
Biochemical confirmation was used to validate self report in two studies (Binnie 2007; Hanioka 2010). In three other studies, biochemical confirmation was initially utilized and abandoned due to poor compliance (Stevens 1995), or used as a strategy to enhance self report (Walsh 1999; Walsh 2003) (i.e., the ‘bogus pipeline’ method). The remaining studies did not use biochemical confirmation.
The control of detection bias through the blinding participants or oral health care personnel was limited due to the nature of the behavioral interventions evaluated.
In one school-based study (Gansky 2005), the authors describe a ‘spill-over’ effect between the intervention and control group that was felt to bias the results of the trial. In one study which took place in a managed care setting, the authors describe a host of process constraints limiting the effectiveness of achieving study goals, therefore impacting the outcomes (Lando 2007).
Rationale for risk of bias judgements can be found in Characteristics of included studies.
When the 14 clinical trials of dental interventions compared to usual care, no contact, or less treatment intensive controls are pooled (including all tobacco users), a statistically significant increase in the odds of tobacco abstinence at 6 to 24 months is observed (odds ratio [OR] 1.71, 95% confidence interval [CI] 1.44 to 2.03, Figure 1, Analysis 1.1,) but with evidence of heterogeneity between the studies (I2 = 61%).
Heterogeneity was explored by assessing the prespecified potential explanations.
Heterogeneity is not fully explained by separating studies targeting cigarette smokers (I2 = 51%) and smokeless tobacco (ST) users (I2 = 74%). The estimated effect size was similar in both subgroups. In both groups the study contributing the greatest weight had a point estimate close to no effect, with confidence intervals ruling out large benefits or harms. In the subgroup of interventions for smokers, the largest trial, Severson 1998, failed to detect any effect of an extended intervention compared to a brief intervention by dental hygienists. The same intervention showed a benefit in ST users recruited as part of the same study (Andrews 1999). The next three largest studies amongst smokers did detect significant or near significant benefits and the pooled estimate indicated a clinically and statistically significant effect (OR 1.74, 95% CI 1.33 to 2.27, 8 studies, I2 = 51%). In a sensitivity analysis using a random effects model the pooled estimate was similar and the confidence intervals still excluded one.
Heterogeneity may be due in part to type of practice. The included studies took place in dental settings characterized as either a specialty dental practice, general dental practices, federally funded dental practices, or managed care dental practices. Some targeted adolescents and adults while others focused only on adults. Recognizing these different features, we conducted a post hoc subgroup analysis of studies conducted in the settings most representative of typical dental environments (general dental practitioners seeing adult smokers). Dental practices providing, at a minimum, brief counselling to adult smokers showed a significant benefit of intervention when compared to usual care or less treatment intensive controls (OR 2.38, 95% CI 1.70 to 3.35, Analysis 1.2) with no evidence of heterogeneity (I2 = 3%).
In the ST use subgroup, Gansky 2005 had narrow CIs ruling out large benefits or harms, but all other studies suggested benefit and three showed significant effects. As noted above, Gansky 2005 is likely have been affected by spill-over of intervention to control groups. The estimate including Gansky 2005 indicated a clinically and statistically significant effect (OR 1.70, 95% CI 1.36 to 2.11, 6 studies, I2 = 74%). In a sensitivity analysis using a random effects model the pooled estimate was larger and the confidence intervals still excluded 1. A sensitivity analysis omitting Gansky 2005 removed all evidence of heterogeneity and increased the effect estimate (OR 2.40, 95% CI 1.82 to 3.18).
Odds ratios were similar in a subgroup analysis comparing three studies in which participants were actively seeking treatment with three studies in which participants were not actively seeking treatment (actively seeking treatment: OR 1.41, 95% CI 1.07 to 1.86; not actively seeking treatment: OR 1.48, 95% CI 1.05 to 2.09, analysis not shown).
Interventions in all studies were a team effort involving brief dental encounters plus additional behavioral interventions and/or pharmacotherapy. Interventions differed in intensity as measured by number of planned contacts but there was no clear indication of a dose-response relationship. Gordon 2010a had three arms: a ‘3 As’ intervention using a ‘fax-to-quit’ referral form; a ‘5As’ arm with Quitline referral at the provider’s discretion; and a usual care control arm. Our analysis uses the ‘3As’ intervention, but opting to use the ‘5As’ intervention arm would not alter the findings.
There was no evidence that the length of follow-up or definition of abstinence explained heterogeneity between studies.
The group of six trials that were individually randomized had lower heterogeneity (I2 = 27%), although this may be due to chance, because the two studies contributing most to heterogeneity were both cluster randomized (Severson 1998 and Gansky 2005). The effect estimate in the individually randomized study subgroup, although indicating significant benefit, was not clinically large (OR 1.46, 95% CI 1.06 to 2.01, Analysis 1.3).
The findings of our review are consistent with the hypothesis that dental interventions conducted in the dental office and school community setting are more effective than usual care for promoting tobacco use cessation. When dental interventions were compared to usual care, no contact, or less treatment intensive controls, the pooled odds ratio for abstinence at a follow-up of between 6 and 24 months was 1.71 (95% CI 1.44 to 2.03), although this estimate must be viewed cautiously because of unexplained heterogeneity (I2 = 61%).
Current results are based on a much greater body of research on cigarette smokers when compared to the previous version of this review (Carr 2006), with eight studies of interventions for cigarette smoking now included compared to just one (Severson 1998). Findings now suggest a significant benefit of intervention for increasing tobacco abstinence rates. Findings may be of particular interest to dental care providers whose practices focus on adult patients, as adult smokers may be particularly responsive to the effect of an intervention in this setting (OR 2.38, 95% CI 1.70 to 3.35, Analysis 1.2).
Results should also be viewed cautiously due to the inability to blind, unclear methods of treatment allocation, a lack of biochemical validation of self reported tobacco cessation in most studies and inconsistent content and delivery of dental-specific interventions within the pooled studies. Although all of the included studies contained a dental intervention component, they involved varying dental settings, personnel, and interventions, and statistical heterogeneity was evident. The source of heterogeneity was unclear, and seemed largely attributable to null effects in two large trials. In one of these, the control communities may have been exposed to intervention (Gansky 2005). For the other (Severson 1998), there was no clear reason for the lack of effect of the intervention.
All of the studies included in this review included brief advice to quit by an oral health professional. Brief advice from physicians has been shown to be an effective means to promote cessation (Lancaster 2008), and this review suggests the same can be expected from dental professionals interacting with smokeless tobacco users. Clinical practice guidelines advise brief interventions in the clinical setting where patients are asked about their tobacco use and then advised to quit. If the user is ready to quit, the clinician can offer specific assistance and provide follow-up care. An insufficient number of studies are available to determine what specific assistance measures delivered by a dental professional provide additional effectiveness beyond brief advice.
The public health benefits of tobacco cessation interventions within the dental setting are potentially significant. The findings for both the smokeless tobacco users and smokers in this review suggest that there is an advantage of cessation interventions using dental professionals. However, the limited number of studies reviewed does not allow identification of intervention components most critical for cessation.
Interventions for tobacco users delivered by oral health professionals, either in the dental office or in the school community, increase the odds of quitting tobacco. Insufficient evidence exists to make conclusions about the effectiveness of specific intervention components, but behavioral counselling (typically brief) is a consistent component.
Additional study of interventions for tobacco cessation within the dental office setting is important to identify critical intervention components which are effective for this group of providers in this clinical setting.
We would like to acknowledge Sylvia Bickley of the Cochrane Oral Health Group for her assistance in obtaining references for this review, and Rafael Perera of the Tobacco Addiction Group for his statistical assistance with adjustment for clustering effects. We would also like to thank Patricia Erwin, MLS, for her assistance with search strategy development and execution. We would like to thank Dr. Kristen Vickers-Douglas for her review of the study protocol, and Drs Ian Needleman and Helen Worthington for comments and suggestions on the full review draft.
We would like to acknowledge the assistance of the Tobacco Addiction Group staff in this update. We especially want to acknowledge Lindsay Stead for her assistance with obtaining references, review input, statistical analysis, and general facilitation with this update.
Sources of support
|Abstinence||A period of being quit, ie stopping the use of cigarettes or other tobacco products, May be defined in various ways; see also:|
point prevalence abstinence; prolonged abstinence; continuous/sustained abstinence
|Biochemical verification||Also called ‘biochemical validation’ or ‘biochemical confirmation’:|
A procedure for checking a tobacco user’s report that he or she has not smoked or used tobacco. It can be measured by testing levels of nicotine or cotinine or other chemicals in blood, urine, or saliva, or by measuring levels of carbon monoxide in exhaled breath or in blood.
|Bupropion||A pharmaceutical drug originally developed as an antidepressant, but now also licensed for smoking cessation; trade names Zyban, Wellbutrin (when prescribed as an antidepressant)|
|Carbon monoxide (CO)||A colourless, odourless highly poisonous gas found in tobacco smoke and in the lungs of people who have recently smoked, or (in smaller amounts) in people who have been exposed to tobacco smoke. May be used for biochemical verification of abstinence.|
|Cessation||Also called ‘quitting’|
The goal of treatment to help people achieve abstinence from smoking or other tobacco use, also used to describe the process of changing the behaviour
|Continuous abstinence||Also called ‘sustained abstinence’|
A measure of cessation often used in clinical trials involving avoidance of all tobacco use since the quit day until the time the assessment is made. The definition occasionally allows for lapses. This is the most rigorous measure of abstinence
|‘Cold Turkey’||Quitting abruptly, and/or quitting without behavioural or pharmaceutical support.|
|Craving||A very intense urge or desire [to smoke].|
See: Shiffman et al ‘Recommendations for the assessment of tobacco craving and withdrawal in smoking cessation trials’
Nicotine & Tobacco Research 2004: 6(4): 599–614
|Dopamine||A neurotransmitter in the brain which regulates mood, attention, pleasure, reward, motivation and movement|
|Efficacy||Also called ‘treatment effect’ or ‘effect size’:|
The difference in outcome between the experimental and control groups
|Harm reduction||Strategies to reduce harm caused by continued tobacco/nicotine use, such as reducing the number of cigarettes smoked, or switching to different brands or products, e.g. potentially reduced exposure products (PREPs), smokeless tobacco.|
|Lapse/slip||Terms sometimes used for a return to tobacco use after a period of abstinence. A lapse or slip might be defined as a puff or two on a cigarette. This may proceed to relapse, or abstinence may be regained. Some definitions of continuous, sustained or prolonged abstinence require complete abstinence, but some allow for a limited number or duration of slips. People who lapse are very likely to relapse, but some treatments may have their effect by helping people recover from a lapse.|
|nAChR||[neural nicotinic acetylcholine receptors]: Areas in the brain which are thought to respond to nicotine, forming the basis of nicotine addiction by stimulating the overflow of dopamine|
|Nicotine||An alkaloid derived from tobacco, responsible for the psychoactive and addictive effects of smoking.|
|Nicotine Replacement Therapy (NRT)||A smoking cessation treatment in which nicotine from tobacco is replaced for a limited period by pharmaceutical nicotine. This reduces the craving and withdrawal experienced during the initial period of abstinence while users are learning to be tobacco-free The nicotine dose can be taken through the skin, using patches, by inhaling a spray, or by mouth using gum or lozenges.|
|Outcome||Often used to describe the result being measured in trials that is of relevance to the review. For example smoking cessation is the outcome used in reviews of ways to help smokers quit. The exact outcome in terms of the definition of abstinence and the length of time that has elapsed since the quit attempt was made may vary from trial to trial.|
|Pharmacotherapy||A treatment using pharmaceutical drugs, e.g. NRT, bupropion|
|Point prevalence abstinence (PPA)||A measure of cessation based on behaviour at a particular point in time, or during a relatively brief specified period, e.g. 24 hours, 7 days. It may include a mixture of recent and long-term quitters. cf. prolonged abstinence, continuous abstinence|
|Prolonged abstinence||A measure of cessation which typically allows a ‘grace period’ following the quit date (usually of about two weeks), to allow for slips/lapses during the first few days when the effect of treatment may still be emerging.|
See: Hughes et al ‘Measures of abstinence in clinical trials: issues and recommendations’; Nicotine & Tobacco Research, 2003: 5 (1); 13–25
|Relapse||A return to regular smoking after a period of abstinence|
|Secondhand smoke||Also called passive smoking or environmental tobacco smoke [ETS]|
A mixture of smoke exhaled by smokers and smoke released from smouldering cigarettes, cigars, pipes, bidis, etc. The smoke mixture contains gases and particulates, including nicotine, carcinogens and toxins.
|Self-efficacy||The belief that one will be able to change one’s behaviour, e.g. to quit smoking|
|SPC [Summary of Product Characteristics]||Advice from the manufacturers of a drug, agreed with the relevant licensing authority, to enable health professionals to prescribe and use the treatment safely and effectively.|
|Tapering||A gradual decrease in dose at the end of treatment, as an alternative to abruptly stopping treatment|
|Tar||The toxic chemicals found in cigarettes. In solid form, it is the brown, tacky residue visible in a cigarette filter and deposited in the lungs of smokers.|
|Titration||A technique of dosing at low levels at the beginning of treatment, and gradually increasing to full dose over a few days, to allow the body to get used to the drug. It is designed to limit side effects.|
|Withdrawal||A variety of behavioural, affective, cognitive and physiological symptoms, usually transient, which occur after use of an addictive drug is reduced or stopped.|
See: Shiffman et al ‘Recommendations for the assessment of tobacco craving and withdrawal in smoking cessation trials’
Nicotine & Tobacco Research 2004: 6(4): 599–614
Last assessed as up-to-date: 1 November 2011.
|10 April 2012||New citation required and conclusions have changed||Conclusions updated to include interventions among cigarette smokers as well as among smokeless tobacco users. New included studies increase strength of effect.|
|10 April 2012||New search has been performed||8 new included studies added, evaluating interventions among cigarette smokers.|
Protocol first published: Issue 1, 2005
Review first published: Issue 1, 2006
|22 February 2012||New search has been performed||Updated search to November 2011|
|29 July 2008||Amended||Converted to new review format.|
|5 September 2006||New search has been performed||Updated for issue 1 2007. No new studies identified. Two studies reviewed and added to excluded studies list.|
|Outcome or subgroup title||No. of studies||No. of participants||Statistical method||Effect size|
|1 Abstinence at longest follow-up||14||10535||Adjusted Odds Ratio (Fixed, 95% CI)||1.71 [1.44, 2.03]|
|1.1 Cigarette Smokers||8||7294||Adjusted Odds Ratio (Fixed, 95% CI)||1.74 [1.33, 2.27]|
|1.2 Smokeless Tobacco Users||6||3241||Adjusted Odds Ratio (Fixed, 95% CI)||1.70 [1.36, 2.11]|
|2 Abstinence at longest follow-up. Subgroup of trials in adult smokers seen by general dental practitioners||5||Adjusted odds ratio (Fixed, 95% CI)||2.38 [1.70, 3.35]|
|3 Abstinence at longest follow-up. Subgroups by method of randomization||14||Adjusted odds ratio (Fixed, 95% CI)||1.56 [1.32, 1.85]|
|3.1 Cluster Randomization||8||Adjusted odds ratio (Fixed, 95% CI)||1.61 [1.32, 1.96]|
|3.2 Individual Randomization||6||Adjusted odds ratio (Fixed, 95% CI)||1.46 [1.06, 2.01]|
|4 Tobacco abstinence at longest follow-up. Raw data for all studies||Other data||No numeric data|
|4.1 Cigarette Smokers||Other data||No numeric data|
|4.2 Smokeless Tobacco Users||Other data||No numeric data|
Contributions of authorsJOE and ABC both conceived and planned the review, sought trials and extracted data; both were equally involved in writing the review.
Declarations of interest
Medical Subject Headings (MeSH)
*Dental Offices; Counseling; Oral Health; Randomized Controlled Trials as Topic; Schools; Smoking Cessation [methods; psychology]; Tobacco Use Cessation [*methods; psychology]; Tobacco, Smokeless [adverse effects]; Universities
MeSH check words
* Indicates the major publication for the study