EFFECT OF XYLITOL AND SORBITOL IN CHEWING-GUMS ON MUTANS STREPTOCOCCI, PLAQUE PH AND MINERAL LOSS OF ENAMEL

Seventeen subjects with more than 3 x 10(5) mutans streptococci per mi llilitre of saliva completed this randomised, cross-over study. Four d ifferent chewing-gums, containing: (1) 70% xylitol, (2) 35% xylitol 35% sorbitol, (3) 17.5% xylitol + 52.5% sorbitol, and (4) 70% sorbitol , were tested. The participants used 12 pieces of each gum per day for 25 days. During the four experimental periods, they wore a removable palatinal plate containing two demineralised enamel samples, and brush ed their teeth with a non-fluoridated toothpaste. The results showed t hat an increased concentration of xylitol in the gum resulted in a low er number of mutans streptococci in both saliva and dental plaque, alt hough the decreases were only significant in the saliva samples (p < 0 .01). The pH drop in plaque, measured in vivo after a 1-min mouthrinse with a 10% sorbitol solution, was least pronounced after the 70% xyli tol gum and most pronounced after the 70% sorbitol gum period (p < 0.0 1). No significant differences were found after a mouthrinse with a 10 % sucrose solution. All demineralised enamel samples lost mineral duri ng the experimental periods. However, the lesion depth as well as the mineral loss values, assessed microradiographically, did not differ si gnificantly between the four chewing-gums.