Role of sweeteners in the etiology and prevention of dental caries
Dental caries is a multifactorial disease that is caused by an interplay of three major factors, i.e., teeth, cariogenic bacteria, and fermentable sugars. Streptococcus mutans and S. sobrinus, collectively termed mutans streptococci (MS), are principal causative agents of dental caries. Initial MS-tooth surface attachment is followed by firm and irreversible adhesion of MS to the tooth surface, accompanied by the synthesis of water-insoluble glucan from sucrose via enzymatic action of glucosyltransferases (GTases). MS induce severe dental caries in rats fed on a high-sucrose diet. Epidemiological surveys indicate that frequent sucrose intakes are associated with high prevalence of dental caries in humans. In contrast, dietary sucrose restrictions and/or use of nonfermentable sucrose substitutes clearly influence the GTase activities of MS, resulting in decreased caries development. Structural isomers of sucrose (i.e., disaccharides composed of glucose and fructose with different linkages) will not function as substrates for GTases of MS, nor be utilized as energy sources by MS. Palatinose and trehalulose are included in this category, and are produced in commercial scales in Japan. Glucose oligomers containing α-1, 6 and/or α-1, 4 linkages are found to inhibit glucan synthesis by MS from sucrose, although these oligomers are hydrolyzed by MS to release acids. Lastly, sugar alcohols, including maltitol and palatinit, are useful as noncaries-inducing sweeteners.