Effect of Galla chinensis extract and chemical fractions on demineralization of bovine enamel in vitro

Abstract 

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 2× 5min application with one of the seven treatments: 1000ppmFaq. (as NaF, positive control); deionized water (negative control); or 4000ppm 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 (ΔSMH) 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 (ΔSMH) 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.

Abbreviations: AAS, atomic absorption spectrophotometry, CDR, calcium demineralization rate, GCEs, Galla chinensis extracts, KHN, Knoop hardness number, SMH, surface microhardness

Keywords: Galla chinensis, Chemical fractions, Denimeralization