The Optimum Time to Initiate Habitual Xylitol Gum-Chewing for Obtaining Long-Term Caries Prevention.

March 1999

Hujoel PP, Mäkinen KK, Bennett CA, Isotupa KP, Isokangas PJ, Allen P, Mäkinen PL.
Department of Dental Public Health Sciences, School of Dentistry, University of Washington, Seattle 98195, USA.

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Habitual xylitol gum-chewing may have a long-term preventive effect by reducing the caries risk for several years after the habitual xylitol gum-chewing has ended. The goal of this report was (1) to determine if sorbitol and sorbitol/xylitol mixtures provide a long-term benefit, and (2) to determine which teeth benefit most from two-year habitual gum-chewing - those erupting before, during, or after habitual gum-chewing.

Children, on average 6 years old, chewed gums sweetened with xylitol, sorbitol, or xylitol/sorbitol mixtures. There was a "no-gum" control group. Five years after the two-year program of habitual gum-chewing ended, 288 children were re-examined. Compared with the no-gum group, sorbitol gums had no significant long-term effect (relative risk [RR], 0.65; 95% confidence interval [c.i.], 0.39 to 1.07; p < 0.18).

Xylitol gum and, to a lesser extent, xylitol/sorbitol gum had a long-term preventive effect. During the 5 years after habitual xylitol gum-chewing ended, xylitol gums reduced the caries risk 59% (RR, 0.41; 95% c.i., 0.23 to 0.75; p < 0.0034). Xylitol-sorbitol gums reduced the caries risk 44% (RR, 0.56; 95% c.i., 0.36 to 0.89; p < 0.02).

The long-term caries risk reduction associated with xylitol strongly depended on when teeth erupted (p < 0.02). Teeth that erupted after 1 year of gum-chewing or after the two-year habitual gum use ended had long-term caries risk reductions of 93% (p < 0.0054) and 88% (p < 0.0004), respectively. Teeth that erupted before the gum-chewing started had no significant long-term prevention (p < 0.30).

We concluded that for long-term caries-preventive effects to be maximized, habitual xylitol gum-chewing should be started at least one year before permanent teeth erupt.