Can the oral flora adapt to sorbitol?

The number of non-sugar sweeteners that are approved for use in foods and drinks is increasing and manufacturers are using these as alternatives to cariogenic sugar. These non-sugar sweeteners are generally classed as non-cariogenic. The most frequently used non-sugar sweetener is sorbitol, and concern has been expressed that the oral flora may adapt to sorbitol so that it looses its 'safe for teeth' property. The purpose of this review is to describe the mechanisms whereby oral microorganisms, and mutans streptococci in particular, might metabolize sorbitol and to summarize published research into changes in plaque acid production and changes in plaque flora after exposure to sorbitol. Finally, the possibility that some groups of people may be especially 'at-risk' from adaptation of oral microorganisms to sorbitol is considered. It is concluded that frequent or long-term use of sorbitol is unlikely to present any increased risk of dental caries in normal people, but that frequent use of sorbitol may present a small cariogenic risk in people with low salivary flow.