Comparative Study of the Effect of Flavonoids and the Whey Extract on Enamel Microhardness: An In Vitro Study

Background: Preventing caries or stopping primary caries lesions is one of the most important goals of oral health care. The aim of this study was to compare the effect of flavonoids and the whey extract on tooth enamel by measuring the microhardness of enamel following its demineralization. Methods: In general, 42 samples of healthy enamel were prepared in this experimental-laboratory study. After measuring the initial microhardness using Vickers hardness tester )Buehler, Lake Bluff, IL, USA(, the samples were immersed in the demineralization solution for 4 days and re-tested for microhardness. Then, the samples were randomly divided into three groups of 14 and treated, including the grape seed extract w/v8%, the whey extract, and the artificial saliva. The samples were in contact with the treatment material for 8 days in an incubator at 37°C and then their microhardness was evaluated again. Results: The analysis of covariance showed that there was a significant difference in the amount of microhardness changes between the study groups (P < 0.001) so that microhardness changes were the highest in the grape seed extract group while they decreased in the control group. However, the post hoc test showed no statistically significant difference between the whey extract and grape seed extract groups (P = 1.000). Finally, the control group had a statistically significant difference from the whey extract and grape seed extract groups. Conclusions: Both grape seed extract and whey extract increased remineralization and the microhardness of tooth enamel compared to the control group. Thus, these two substances can be considered as natural and effective substances in the non-invasive treatment of carious lesions.