Objective: To evaluate the demineralization inhibition property of extracts and chemical fractions of Galla chinensis in vitro.
Methods: Seventy sound bovine enamels blocks were prepared and randomly divided into seven groups. These samples were pH-cycled for 12 times in 6 days. Each daily cycle included 2x 5 min application with one of the seven treatments: 1000 ppmFaq. (as NaF, positive control); deionized water (negative control); or 4000 ppm aqueous solutions of five G. chinensis extracts (GCEs): GCE, GCE-A, GCE-B, GCE-C or GCE-D. Surface enamel microhardness was measured on the enamel blocks before and after pH-cycling, and the reduction of surface microhardness (DeltaSMH) was calculated. The acidic buffers were retained for calcium analysis.
Results: There were significant differences between the GCE groups and the two controls (p<0.01). Among all the GCE groups, the reduction of surface microhardness (DeltaSMH) in GCE group was the least (p<0.01). No significant differences were found between the GCE group and GCE-C group in CDR, as well as the other three GCE groups (GCE-A, GCE-B and GCE-D) (p>0.05).
Conclusions: The present study has demonstrated the potential of the GCE to effect the demineralization under dynamic pH-cycling conditions. None of the chemical fractions was as effective as GCE. Combined with its anti-bacterial properties, the demineralization inhibition of GCE suggests that this material could be a useful source for the development of promising anti-cariogenic agents.