Effect of compounds of Galla chinensis and their combined effects with fluoride on remineralization of initial enamel lesion in vitro

Objective To investigate the effect of chemical compounds of Galla chinensis and their combined effects with fluoride on remineralization of artificial early enamel caries. Method Bovine enamel blocks with in vitro produced initial lesion were used. The lesions were subjected to a pH-cycling regime for 12 days. Each daily cycle included 4× 1 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 G. 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 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. Groups E and F showed the shallowest lesion. In the groups with gallic acid (groups D and F), mineral deposition predominated in the surface layer. In groups with GCE (groups C and E), more mineral deposition occurred in the lesion body. Conclusion The chemical compounds of G. chinensis were able to enhance remineralization of dental enamel. They also had combined effects with fluoride on enhancing remineralization.