DOES THE PRESENCE OF XYLITOL IN A SORBITOL-CONTAINING CHEWING GUM AFFECT THE ADAPTATION TO SORBITOL BY DENTAL PLAQUE

It is known that xylitol inhibits sorbitol metabolism in some bacteria in vitro. The effect of xylitol/sorbitol-containing chewing gum on so rbitol adaptation of dental plaque was therefore examined. Ten subject s used this chewing gum for 12 wk, and plaque was collected before (co ntrol plaque) and after (test plaque) the exposure to sorbitol/xylitol . The metabolism of sorbitol by the plaque was examined with C-14-labe led sorbitol, and the radioactive metabolites were detected by high-pe rformance liquid chromatography (HPLC). A considerable individual vari ation in acid formation was found. The mean values of total acids in t he test plaque increased, as compared with the control plaque. An adap tation of dental plaque to sorbitol thus occurred in spite of the pres ence of xylitol in the chewing gum. The concentration of acetic acid p redominated over other acids in both the control and test plaques. The proportions of acids expressed in percentage of total acids differed only slightly. Thus, long-term use of xylitol/sorbitol-containing chew ing gum did not eliminate the adaptation of dental plaque to sorbitol.