ABSTRACT
OBJECTIVES: The aim of this study was to compare the remineralization effect of the topical fluoride agents on artificial enamel caries, under the chemical pH cycling model, using surface microhardness. METHODS: Bovine enamel specimens, embedded in acrylic resin with the labial surfaces exposed, were developed artificial enamel caries. Thereafter, this study used 56 samples on VHN 25-45. The experimental groups were divided into 4 groups: control, 2% NaF solution, 1.23% APF gel, 5% NaF varnish. Samples, except in the control group, were applied to each topical fluoride agent for 4 minutes. All groups were exposed to a pH cycling model, which consisted of demineralization (4 hours) and remineralization (20 hours) for 17 days. The Vickers surface microhardness number (VHN) was measured, using the microhardness tester. The results were analyzed, using a repeated measures analysis of variance of a general linear model, and compared the baseline, each day, using a contrast analysis (simple) about within a subject factor at a significance level of 0.05. RESULTS: Result of a repeated measures analysis regarding the surface microhardness of topical fluoride agents, there were significant differences at P-values of within and between the subject factor (P0.05). CONCLUSIONS: In this study, although there were significant differences at P-values of within and between the subject factor, there were no significant differences between the experiment groups on chemical pH cycling model in vitro, and it was limited to utilize this result in a clinical situation of the fluoride application.
Subject(s)
Dental Enamel , Fluorides , Hydrogen-Ion Concentration , Linear Models , PaintABSTRACT
Objective To observe effects of rhubarb extract on Ca dissolved quantity in demineralized enmnel. Methods Demineralization was performed after treating tooth facing with rhubarb extract of different concentrations and deionized water. The concentration of Ca was detected by ASCA biochemical analyzer after demineralization. Results Dissolved quantity of demineralized Ca in the rhubarb extract group (2 mg/ml, 4mg/ml) was significantly lower than that of the deionized water group (P<0.01) and the rhubarb extract group (1 mg/ml) (P<0.05), but higher than that of 2% sodium fluoride group (P>0.05). Dissolved quantity of demineralized Ca in the rhubarb extract (1 mg/ml) group was significantly higher thanthat of 2% sodium fluoride group (P<0.01), but lower than that of the deionized water group(P>0.05).Conclusion The rhubarb exwact (2mg/ml, 4mg/ml) can inhibit Ca dissolution in demineralized enamel.The inidal effective concentration of rhubarb extract is 2 mg/ml.