Effects of xylitol and carbohydrate diets on dental caries, dentine formation and mineralization in young rats.

Female Wistar rats were weaned at the age of 3 weeks and fed for 7 weeks either a high-sucrose diet, a non-cariogenic raw potato-starch diet, a high-sucrose diet with 5% xylitol supplement, a raw potato-starch diet with 5% xylitol supplement or a non-cariogenic, commercial, powdered rat food (Ewos R3) for reference. A low xylitol concentration reduced the progression and severity of carious lesions but did not affect dentine apposition or the width of predentine in rats fed high-carbohydrate diets. Widening of the predentine zone in rats fed a high-sucrose diet might reflect disturbed mineralization, which could not be explained by serum ionized calcium or phosphate ion levels and which could not be corrected by low xylitol concentrations. It is concluded that the reduced area of dentinal carious lesions after low xylitol supplementation is not dependent on dentine formation or mineralization, but rather on direct effects in the mouth.