Effect of mouthrinse with low pH on the surface microhardness of artificial carious enamel

Choi, Hye Jin; Lee, Hye Jin; Jeong, Seong Soog; Choi, Choong Ho; Hong, Suk Jin

Abstract

OBJECTIVES
The aim of the present study was to evaluate the effect of fluoride mouthrinse with low pH on the surface microhardness of artificial incipient carious enamel.
METHODS
Firstly, the concentration of sodium fluoride and pH values were measured in commercially available mouthrinse. Secondly, DOCTOR Clean & Fresh(R) (Jang In Pharm, co., LTD. KOREA) with 0.02% sodium fluoride and pH value below pH 4.0 was selected as the experimental group, 0.02% sodium as the positive control group and distilled water as the negative control group. Enamel samples of n vine teeth (n=36) were divided into the three groups respectively and treated with the mouthrinse solutions for 3 and 20 minutes. The surface microhardness (Vickers hardness number, VHN) was measured with microhardness tester before and after the treatments.
RESULTS
The average pH of DOCTOR Clean & Fresh(R) was 3.45+/-0.00, and it was acidic enough to cause tooth erosion. The difference of surface microhardness (DeltaVHN) before and after the 20 minute treatment was statistically significant among the groups: DOCTOR Clean & Fresh(R) (12.77+/-2.25 DeltaVHN), distilled water (0.24+/-0.75 DeltaVHN), 0.02% sodium fluoride solution (-0.62+/-1.62 DeltaVHN) (P<0.05). The DOCTOR Clean & Fresh(R) group with low pH showed greater changes on the surface microhardness of the carious enamel than those of other groups (P<0.05).
CONCLUSIONS
It is suggested that the mouthrinse with low pH can reduce the surface microhardness of incipient carious enamel.