Chewing gum with xylitol, a sugar substitute, may reduce the activity of cavity-causing bacteria.
Certain sugar substitutes appear to have anti-caries benefits beyond that of reducing sugar intake. Children chewing gum containing either xylitol or sorbitol for five minutes five times daily for two years had large reductions in caries risk compared with those not chewing gum. Sorbitol is only slowly used by oral bacteria, and it produces less caries than sucrose.
Xylitol gum was associated with a slightly greater risk reduction than sorbitol gum. Bacteria in the mouth do not ferment xylitol, so they cannot produce the acids that cause tooth decay from xylitol. A double-blind study found 100% xylitol-sweetened gum was superior to gum containing lesser amounts or no xylitol. Another study found xylitol-containing gums gave long-term protection against caries while sorbitol-only gum did not.
Other research has confirmed the anti-caries benefits of xylitol in various forms, including gum, chewable lozenges, toothpastes, mouthwashes, and syrups. Mothers typically transmit one of the decay-causing bacteria to their infant children, but a double-blind trial found that the children of mothers who regularly chewed xylitol-containing gum for 21 months, starting 3 months after delivery, had a greatly reduced risk of acquiring these bacteria, and also had 70% less tooth decay.