SALIVARY FLUORIDE CONCENTRATION AND PLAQUE PH AFTER USING A FLUORIDE-CONTAINING CHEWING GUM

The aim was to study the salivary fluoride (F) concentration and plaqu e pH recovery on the chewing and the non-chewing side of the dentition during and after chewing 1 piece of chewing gum containing 0.25 mg F as NaF. Ten subjects refrained from toothbrushing for 3 days. On the f ourth day, they rinsed for 1 min with 10 mi of a 10% sucrose solution. When plaque pH had reached a low value, they started to chew for eith er 5, 10, 15, 20, 30 or 45 min. Measurements of F concentration in sal iva and of pH of approximal plaque were carried out at 2 contralateral sites for up to 60 min. In each individual, the chewing and non-chewi ng side were registered. Two to 3 times higher salivary F concentratio ns (expressed as area under the curve, AUG) were found on the chewing than on the non-chewing side (p < 0.05 or p < 0.01). The most pronounc ed recovery of plaque pH after the sucrose rinse was also registered f or the chewing side, but the difference between the chewing and the no n-chewing side was not so obvious as for the salivary F concentration. Significantly higher values of plaque pH (expressed as AUG) were foun d during prolonged chewing (p<0.05 or p<0.01), while only small numeri cal differences in salivary F concentration were noted between short a nd long chewing times. Thus, this study showed: (I) that the F concent rations in saliva after chewing a F-containing chewing gum were highes t on the chewing side, and (2) that a prolonged chewing time increased the plaque pH recovery after a sucrose rinse, but had only a minor ef fect on the salivary F concentration.