Effect of xylitol-containing chewing gums on interdental plaque-pH in habitual xylitol consumers.

The aim was to investigate the effect of high and low amounts of xylitol on the interdental plaque-pH, directly and after sucrose challenge in schoolchildren with a habitual consumption. The study group consisted of 11 healthy children (10-15 years) with low caries risk and the experiment had a single-blind crossover (Latin square) design. After a 2-week run-in period with a daily 4.0 g xylitol intake, the children were subjected to single-dose exposures of chewing gums with i) paraffin (CTR; no xylitol), ii) low dose xylitol (LX; 2.0g xylitol), and iii) high dose xylitol (HX; 6.0g xylitol) in a randomised order separated by a wash-out period of one week. Samples of chewing-stimulated whole saliva were collected prior to and after the experimental period for determination of bacterial counts. The outcome measures were in situ plaque-pH (micro-touch method) and area under the curve (AUC) above pH 6.0. The AUC was significantly greater (p<0.05) in the HX group compared to the LX and control groups during the first 5 minutes after chewing. After a 10% sucrose rinse, the interdental plaque-pH dropped in all groups but the HX regimen displayed significantly less reduction 0-5 min after chewing (p<0.05). No significant alterations of the total viable counts or mutans streptococci levels in saliva were disclosed during the 4-week experimental period. The present results suggested that a high single dose of xylitol had a short and limited beneficial effect on interdental plaque-pH in habitual xylitol consumers while a low single dose, resembling a normal chewing gum use, did not differ from the control.