Effect of Galla chinensis on remineralization of initial enamel lesion

Objective: This study examined the effect of chemical compounds of Galla chinensis (GCE and gallic acid)and their combined effects with fluoride on enhancing remineralization of artificial early enamel caries.Method: Bovine enamel blocks with in vitro produced initial lesion were used. Then baseline microhardness was measured and sixty blocks with baseline KHN values between 165.50 and 175.50 were subjected to a pH-cycling regime for 12 days. Each daily cycle included 4 ¨w1 min applications with one of six treatments: Group A: 1000 ppm F aq. (as NaF, positive control); Group B: deionized water (DDW, negative control); Group C: 4000 ppm crude aqueous extract of Galla chinensis (GCE); Group D: 4000 ppm gallic acid; Group E: 4000 ppm GCE with 1000 ppm F; Group F: 4000 ppm gallic acid with 1000 ppm F. The enamel specimens were then analyzed by Transverse Microradiography. Integrated mineral loss (IML) and lesion depth (LD) were measured and mineral content in the surface layer and lesion body were calculated.Results: The LD and IML were significantly different among the different treatment groups. GCE and gallic acid could reduce LD and IML significantly compared with DDW. Group E and Group F showed the shallowest lesion. In the groups with gallic acid (Group D and F), mineral deposition predominated in the surface layer. In groups with GCE (Group C and E), more mineral deposition occurred in the lesion body.Conclusion: The chemical compounds of Galla chinensis were able to enhance remineralization of artificial early enamel caries. They also had combined effects with fluoride on enhancing remineralization.Supported by the National Natural Science Foundation of China (Grant No. 30430800).