Comparison of the enhanced remineralization of initial enamel carious lesions treated with original and neutral Galla chinensis in vitro

Abstract

To compare the effect of original and neutral Galla chinensis in promoting the remineralization of initial enamel carious lesions in vitro and to investigate the influence of Galla chinensis with different pH on the promoting effect. Bovine sound enamel slabs were demineralized to produce initial carious lesion in vitro. Then the lesions were exposed to a pH-cycling regime for 12 days. Each daily cycle included 4 × 1 min application of one of four treatments: distilled and deionized water (DDW), aqueous solutions of NaF, acidic or neutral aqueous solutions of Galla chinensis extract (GCE). Before and after pH-cycling, the surface topography of the enamel slabs was observed by atomic force microscopy (AFM), and the integrated mineral loss and lesion depth of all the specimens were analysed by transverse microradiography. AFM images revealed the surface topographical changes of GCE-treated enamel. The percentage change of integrated mineral loss (ΔIML%) of the samples of NaF group, DDW group, pH 3.8 GCE group and pH 7.0 GCE group was (-38 ± 14)%, (+43 ± 7)%, (-10 ± 4)% and (-11 ± 4)% respectively. The percentage of lesion depth (ΔLD%) of the samples of NaF group, DDW group, pH 3.8 GCE group and pH 7.0 GCE group was (-27.79 ± 3.51)%, (+21.13 ± 2.83)%, (-8.43 ± 3.32)% and (-9.20 ± 3.89)% respectively. There was no significant difference in ΔIML% and ΔLD% between pH 3.8 and pH 7.0 GCE-treated enamel. There is no significant difference in enhancement of remineralization of initial enamel carious lesions between the original and neutral Galla chinensis. Different pH Galla chinensis does not have obvious influence on remineralization. It is unnecessary to regulate the pH value of queous solution of Galla chinensis extract which acts as a anti-caries agent.