Are Sugar Substitutes Bad for Teeth? Q. Are there certain sugar substitutes that are as corrosive to dental enamel as sugar? A. Sugar substitutes do not present the same risk to teeth that sugar does. Sugar itself is not corrosive to the enamel, according to the science division of the American Dental Association. Rather, the bacteria in dental plaque metabolize sugar and release acid that can break the enamel down. Sugar substitutes, like low-calorie sweeteners, do not have the same effect. In fact, some sweeteners, called polyols, have antibacterial properties. Polyols, also known as sugar alcohols because they can be derived from sugars through a chemical process, include malitol, sorbitol, xylitol and isomalt. They are not broken down by oral bacteria and thus do not contribute to the formation of cavities. A 1998 review article in The British Dental Journal concluded that chewing sugarless gums containing some kinds of sugar substitutes helps prevent dental decay by promoting the saliva flow. "In addition," the article said, "xylitol's antibacterial properties seem likely to lead to caries reductions superior to the more modest reductions with sorbitol gum." A later review, in The Journal of the American Dental Association in 2006, found less evidence for xylitol itself as a preventer of decay, but concluded that the evidence was still strong enough to support the regular use of xylitol-sweetened gum. "Chewing xylitol-sweetened gum, especially for patients who like chewing gum, can be fitted readily into a regimen that includes frequent fluoride exposure, good oral hygiene and regular dental appointments," the article said. Readers may submit questions by mail to Question, Science Times, The New York Times, 620 Eighth Avenue, New York, N.Y. 10018, or by e-mail to question@nytimes.com.