Tooth decay risk doubles in children exposed to secondhand smoke

Smoking is bad for your oral health on its own merit, but did you know that smoking can also cause dental problems for the children subjected to your smoke secondhand? Researchers have solidified the link between early exposure to secondhand smoke and a greater number of cavities in early childhood.

Across the globe, cavities in deciduous (baby) teeth are common. In the United States, one in every five children has a cavity in their baby teeth while it’s one in every four children in Japan. Oftentimes, parents focus on restricting sugar intake as the method for preventing cavities, but dentists often will also recommend fluoride treatments or varnishes as well as sealants. But new studies indicate that secondhand smoke may also play a role in the development of cavities even long after the secondhand smoke exposure. Cavities come from a number of factors including heredity, biological issues like disease, bacteria flora, and the like, as well as environmental factors (presence or absence of fluoridated water), and lifestyle. It turns out that exposure to secondhand smoke may be both an environmental and lifestyle factor for children.

Some common causes of cavities in children include cariogenic bacteria, inadequate salivary flow, insufficient exposure to fluoride, and poor oral hygiene. A crucial event in oral health is the acquisition of Streptococcus mutans (S. mutans). S. mutans, among other bacteria, produce acids from sugar that is consumed, and these dissolve the hard enamel coating on teeth. The bacteria are usually transmitted from mothers at the highest-risk ages of 19-31 months old.

So how does secondhand smoke contribute to a child’s cavities? Secondhand smoke may cause inflammation of the oral membrane, damage to the salivary gland function, and a decrease in serum vitamin C levels, as well as immune dysfunction. These all contribute to the development of cavities in small children.

Children exposed to passive smoking also have lower salivary IgA levels and higher levels of sialic acid with higher activity. Sialic acid enhances the agglutination of S. mutans, leading to the formation of dental plaque and caries. This would suggest that reducing secondhand smoke among children could help prevent caries.

For the purpose of the study, researchers in Japan investigated smoking during pregnancy and exposure to household smoke in infants at 4 months of age as risk factors for caries in deciduous teeth. They wanted to know whether maternal smoking during pregnancy and exposure of infants to tobacco smoke at the age of 4 months would increase the risk of caries in deciduous teeth.

The team analyzed data for 76,920 children born between 2004 and 2010, who attended routine health checkups at 0, 4, 9 and 18 months, and at 3 years of age at health care centers in Kobe City, Japan.

Mothers completed questionnaires to provide information about secondhand smoke exposure from pregnancy to 3 years of age and other lifestyle factors, such as dietary habits and oral care. Incidence of caries in deciduous teeth was defined as at least one decayed, missing or filled tooth assessed by qualified dentists.

For study participants, there was a 55% prevalence of household smoking and 6.8% showed evidence of tobacco exposure. A total of 12,729 cases of dental caries were identified, mostly decayed teeth.

Compared with having no smokers in the family, exposure to tobacco smoke at 4 months of age was associated with an approximately twofold increase in the risk of caries. The effect of maternal smoking during pregnancy was not statistically significant.

The finding that smoking during pregnancy did not affect outcomes in young children to age 3 but secondhand smoke did increase the prevalence of cavities to age 3 speaks of the near-certain link between secondhand smoke and cavities. Smoking around young children doubles their risk of developing cavities by age 3. A smoking cessation program is your family’s best bet for overall wellness, and at least minimizing secondhand smoke exposure is also advised.

In addition to mitigating smoke exposure, it is important for parents to introduce good oral care habits during infancy and toddlerhood so that children develop good oral habits that will last their lifetimes. If you have questions about how to make your household a tooth-friendly zone, contact our office today for tips!


Brazier, Y. (2015, October 22). “Tooth decay risk doubles in children exposed to secondhand smoke.” Medical News Today. Retrieved from


Contact us

Smiles by Shields
3940 San Jose Park Dr.
Jacksonville, FL 32217