Effect of Galla Chinese on Enamel Demineralization in Vitro

Objectives: To evaluate the effect of traditional Chinese medicine, Galla Chinensis, on enamel demineralization through the pH-cycling in vitro. Methods: 90 enamel sampes of freshly extracted bovine permanent incisors with Knoop hardness number (KHN) from 400~450 were randomly divided into three groups.There were 30 blocks in each group.All the samples were demineral by pH cycling. During pH cycling ,three groups were respectively treated with different solutions: group 1 with 1g/L NaF , group 2 with deionized water , group 3 with 4g/L Galla Chinensis. After pH-cycling in vitro, KHN of demineral enamel surface were measurded one by one.Enamel mineral loss and lesion depth of the demineral enamel were measured by Transverse Microradiography. The decrease of KHN , the increase of mineral loss and lesion depth were calculated. All the data were analysed using SPSS 11.0 software with t-test. Results: The decrease of KHN of demineral enamel surface in group 1(101.3±5.9)and group 3(205.1±6.8) were obviously less than group 2(310.9±8.8) (P< 0.05). The decrease of KHN of demineral enamel surface in group 1 was significant less than those of group 3 (P<0.05).On the demineral enamel surface of group 1, the increase of mineral loss was (930.3±12.4 )Vol%.µm, and the increase of lesion depth was (50.2±3.6)µm.In group 2, the increase of mineral loss was (4010.4±15.3) Vol%.µm, and the increase of lesion depth was (158.9±9.9)µm.In group 3, the increase of mineral loss was (2450.8±16.1)Vol%.µm, and the increase of lesion depth was (73.5±9.5)µm. The increases of Mineral loss and lesion depth in group 1 and group 3 were obviously less than those of group 2(P<0.05). Both of them in group 1 were significantly less than those of group 3 (P<0.05 ). Conclusion: Galla Chinensis can inhibitate the demineralization of enamel , but it's effect is less than that of NaF.