Greater Risk for Root Canal Treatment
Recent research by Krall and colleagues found that smoking cigarettes may contribute to the disease processes that create a need for root canal treatment. In a prospective cohort study that tracked 811 men for nearly 30 years, the researchers found that the men who smoked cigarettes had a 70% higher risk of root canal treatment than those who never smoked, after controlling for differences between smokers and nonsmokers. They found that the longer patients smoked, the higher their risk, but the longer patients abstained from cigarettes, the lower their risk. Cigar and/or pipe use was not significantly associated with root canal treatment. Krall noted that of the more than 400 million root canal treatments performed in the United States, approximately 25 million could have been prevented by not smoking cigarettes.

(Source: Krall EA, Abreu Sosa C, Garcia C, et al. Cigarette smoking increases the risk of root canal treatment. J Dent Res. 2006;85:313-317.)

Subgingival Calculus Deposition and Apical Periodontitis
Recent studies by Bergstrom and colleagues have found that while there is a strong and independent impact of tobacco smoking on subgingival calculus deposition, there is not, as it has been assumed, significant evidence to support the association between tobacco smoking and apical periodontitis. Bergstrom performed a radiographic assessment of subgingival calculus on mesial and distal root surfaces for the presence or absence of radiopaque deposits apical to the cementoenamel junction. The subgingival calculus load increased with increasing smoking exposure, suggesting a dose-response relationship. The prevalence of patients exhibiting at least 1 subgingival calculus positive site was 71% among current smokers, 53% among former smokers, and 28% among nonsmokers.

Bergstrom and colleagues also investigated the relationship between periapical periodontitis and tobacco smoking. As opposed to the more recent study above, they found that there was no significant influence of smoking on the prevalence of either apical periodontitis or endo­dontic treatment. The percentage of lesions per patient was 6% in smokers, 4% in former smokers, and 3% in nonsmokers. When controlling for age, the mean periapical severity index including all teeth, or teeth affected by perioapical lesions alone, did not significantly differ between groups.

(Source: Bergstrom J. Tobacco smoking and subgingival dental calculus. J Clin Peri­dontol. 2005;32:81-88. Bergstrom J, Babcan J, Eliasson S. Tobacco smoking and dental periapical condition. Eur J Oral Sci. 2004;112:115-120.)

Smoking Cessation Success
The American Dental Hygienists' Association (ADHA) reports that more than 80% of registered dental hygienists are incorporating the "Ask.Advise.Refer." intervention program into their clinical practice. The objective for the ADHA's Smoking Cessation Initiative's third year is to further establish dental hygienists as advocates of smoking cessation and to place dental hygiene on the frontline of smoking cessation intervention. Dental hygienists have the unique opportunity to promote better oral health through smoking cessation, and research demonstrates that the advice of a health professional can be a major motivation for a quit attempt by a patient who smokes.

Nationally, ADHA members have distributed 750,000 "Quit Now" cards, which were designed for distribution to tobacco users by health professionals to promote smoking cessation and the first national toll-free quitline, (800) QUIT NOW.

(Source: The American Dental Hygienists' Association, www.adha.org/media/releases/12012005_rwy.htm.)

Link to Periodontal Disease
In 2004, the US Surgeon General released the report The Health Consequences of Smoking. Although oral cancer was addressed by the Surgeon General in 1982, this report noted the causal relationship between smoking and cancers of the oral cavity and pharynx as well as between smoking and periodontitis. The report concluded that, currently, the evidence is inadequate to infer the presence or absence of a causal relationship between smoking and coronal dental caries; however, the evidence is suggestive, but not sufficient, to infer a causal relationship between smoking and root surface caries.

(Source: The Health Consequences of Smoking. A Report of the Surgeon General. www.cdc.gov/tobacco/sgr/sgr_2004/index.htm.)

Perceived Dental Treatment Needs and Overall Perception of Dental Health
Two recent investigations examined data from the Third National Health and Nutrition Examination Survey (NHANES III) in regard to smoking and oral health perception. Both sets of researchers studied the data of dentate participants aged 20 to 79 years, including perceived dental health, sociodemographic attributes, smoking status, frequency of dental visits, dental insurance, and general health perception.

Morin and colleagues investigated the relationship between lifestyle factors and perceived oral health. They found that 46.6% of smokers had an unfavorable dental health perception, compared with 28.3% of nonsmokers. However, smoking was not a significant predictor for an unfavorable dental health perception among Mexican-Americans, but was a significant predictor among non-Hispanic black or non-Hispanic white Americans, indicating an interaction between smoking and race/ethnicity.

Dye and colleagues investigated the effect of smoking status on perceptions of dental needs. They found that smokers were more likely than nonsmokers to perceive a need for dental care in all categories, including periodontal treatment and extractions, but excluding dental cleaning. An interaction between smoking and race/ethnicity also was discovered in this analysis in models describing the need for teeth to be filled/replaced and for ortho­dontic/­ cosmetic work.

(Source: Morin NM, Dye BA, Hooper TI. Influence of cigarette smoking on the overall perception of dental health among adults aged 20-79 years, United States, 1988-1994. Public Health Rep. 2005;120:124-132. Dye BA, Morin NM, Robinson V. The relationship between cigarette smoking and perceived dental treatment needs in the United States, 1988-1994. J Am Dent Assoc. 2006;137:224-234.)

Secondhand Smoke and Children's Dental Health
The Third National Health and Nutrition Examination Survey (NHANES III) data was also examined by Aligne and colleagues to investigate whether passive smoking is a modifiable risk factor for dental caries. The researchers studied the data on children aged 4 to 11 years who had had both dental examinations and a serum continine level measurement. They defined passive smoking as serum continine levels of 0.2 ng/mL to 10 ng/mL and caries as decayed (unfilled) or filled tooth surfaces.

An association between environmental tobacco smoke and risk of caries was found. An elevated continine level was significantly associated with both decayed and filled tooth surfaces in deciduous, but not permanent, teeth. After adjusting for age, sex, race, family income, geographic region, frequency of dental visits, and blood lead level, the researchers estimated that the attributable risk of caries among children from passive smoking is 27% for decayed and 14% for filled tooth surfaces.

(Source: Aligne CA, Moss ME, Auinger P, et al. Association of pediatric dental caries with passive smoking. JAMA. 2003;289:1258-1264.)