One of the longstanding federal warnings on smokeless tobacco is: “This product can cause gum disease and tooth loss.” This warning has no scientific basis.
I previously discussed a study from Sweden concluding that snus use was not associated with gum disease (here). A 2012 study by the same research group concluded that “snus use does not increase the risk of dental caries [cavities].”
The latter study was based on 1,500 residents of Jönköping, Sweden, who underwent detailed dental health exams in 1983, 1993 and 2003. Lead author Anders Hugoson and colleagues employed teams of dentists who observed the number of teeth, saliva factors, oral hygiene and cavities. A key indicator of cavities is the number of tooth surfaces that are decayed or already filled with silver or other material (abbreviated DFS). A lower DFS means healthier teeth.
The study’s snus users in 1983 had an average 20 DFS, a statistically significant half of the 41 DFS in smokers and nonusers of tobacco. In 1993, snus users had 22 DFS, compared with 37 in smokers and 36 in nonusers, also significant. By 2003, the margin was narrower and not significant, but the 19 DFS among snus users was still lower than among nonusers (28) and smokers (29).
The results of this research were similar to an American study published in 1999 (abstract here). It showed that while American chewing tobacco, which is coated with a sugar solution, is associated with cavities, users of moist snuff, with no added sugar, had lower cavity scores than nonusers of tobacco.
Both of the above studies, however, were less than forthright in their portrayal of smokeless tobacco. It is the norm in epidemiologic research for risks among exposed groups to be compared with risks among a referent, nonexposed group. In the Swedish studies, the protective effect of snus was masked by making snus users the “referent group” for some of the statistical analyses. The American study was similarly flawed, as chewing tobacco users were the referent group, thus masking the protective effect of moist snuff.
The authors of the American research, Drs. Scott Tomar and Deborah Winn, are outspoken tobacco opponents. I have previously discussed Dr. Winn’s oral cancer misinformation campaign here, here and here.
Why might snus and moist snuff be protective for cavities? Neither product has any added sugar, and both probably stimulate saliva production, which is generally protective against cavities. In addition, smokeless products tend to have an alkaline pH, which Dr. Hugoson writes “may favour the remineralization of the tooth surfaces and the inhibition of the [cavity-forming] acid [bacteria].”
Unbiased scientific research and reporting is the best prescription for healthy teeth and healthy lives.