Xylitol in relation to the incidence of dental caries.

Two clinical trials were carried out in order to evaluate differences in caries increment as influenced by various sugars. The first study involved almost complete substitution of sucrose (S) by fructose (F) or xylitol (X) during a period of 2 years. The second study comprised partial substitution, the effects of a S- or X-containing chewing gum being compared during 1 year. In the first trial there were no significant differences initially between the sugar groups; 35 subjects in the S-group, 38 in the F-group, and 52 in the X-group. During the entire study 10 subjects discontinued, in one case due to osmotic diarrhoea in the X-group, the other cases being due to difficulties in adhering to the strict diet, other personal reasons and in 3 cases due to excessive caries incidence. After 2 years the mean increment of decayed, missed and filled tooth surfaces was 7.2 in the S-group, 3.8 in the F-group and 0.0 in the X-group. The caries incidence was additionally expressed in combined quantitative and qualitative terms by considering also the changes in lesion size. Irrespective of the way of using these indices, a massive reduction of the caries increment was noted in the X-group as compared to the S-group. The second trial comprised initially 102 subjects divided randomly into S- and X-groups. The subjects consumed 4.5 chewing gums per day in the X-group and 4.0 in the S-group. The frequency of the sucrose intake was 4.94 per day in the X-group, and 4.24 in the S-group. The caries incidence equalled the one-year observations in the first study. The results show a massive reduction of the caries increment not only in relation to total, but also in connection with partial substitution of sucrose and low xylitol consumption. The findings indicate a therapeutic, caries-inhibitory effect of xylitol.