The Effects Of Bioactive Glass On The Remineralization Of Early Enamel Caries In Vitro

Objectives Early enamel caries model of bovine teeth was established,drugs were used for therapy,demineralization of bovine teeth enamel stocks were detected, including micro hardness, surface morphology,calcium and phosphorus ratio and demineralization depth. Evaluated the efficacy of bioactive glass on remineralization of early enamel caries under different concentrations.Observed the effect of three drugs on the remineralization of demineralization enamel,which included bioactive glass,casein phosphopeptide amorphous calcium phosphate and sodium fluoride,providing a theoretical basis for the clinical application.Methods Experiment one,55 pieces of bovine enamel specimens were prepared,and divided into five groups that included normal group,demineralization group,3%BAG group, 6%BAG group and 9%BAG group.Normal group without any treatment,which was consisted of five pieces of specimens.The remaining of specimens were placed in containers with demineralization liquid at 37℃ for 72 hours,which were prepared as early enamel caries model.Then specimens of concentration groups were soaked in bioactive glass solution respectively, whose mass fraction were 3%,6% and 9%.Twice a day for five minutes each.They were dipped circularly into artificial demineralization solution and artificial saliva solution for 15 days.Experiment two,70 pieces of bovine enamel specimens were prepared,and divided into seven groups,which included normal group, demineralization group,6% BAG group,2% Na F group,10% CPP-ACP group and deionized water group.Enamel specimens of drug groups were treated with 6% bioactive glass,10% casein phosphopeptide amorphous calcium phosphate,2% sodium fluoride and deionized water respectively.The histomorphologic changes of enamel surface was compared by scanning electron microscope and the elements of enamel was analyzed by X-ray energy spectrometer.The surface microhardness of enamel was measured by microhardness detector.Thickness of fluorescence beneath the surface of early enamel caries, which was observed by fluorescence microscopy.Results Experiment one,1 Enamel surface of normal group was smooth and flat,no apparent porosity.There was large pores in demineralization group,enamel surface of them was uneven.Minerals of 3% group was spherical.There was a large number of minerals deposited in the enamel surface of 6% group.Sediment of 9% group was larger,gap still existing.2 The molar ratio of Ca and P in 9% group was the highest, that in 6% group was second, the differences being significant.3 The value of microhardness in 6% group was the highest, that in 3% group was the lowest, the differences being significant.4 The depth of remineralization was significant differences among these groups.The thickness of fluorescence band was the narrowest,which was observed in 6% group.Experiment two 1 Bioactive glass group was roughness,covering massive deposition that were larger particles or flakes.Gaps still visible among them. Sodium fluoride group was smooth, covered with large granular deposits,uniform distribution and compact structure.Phosphoric casein peptide amorphous calcium phosphate group was uneven.There was less minerals deposited in deionized water.2 The molar ratio of Ca and P of the bioactive glass group was lower than that of sodium fluoride group,while there was no significant difference between bioactive glass group and phosphoric casein peptide amorphous calcium phosphate group.3 The difference value of micro hardness in bioactive glass group was the highest. There was significant differences among these groups.4 There was not statistically significant among them, which included the difference value of remineralization depth.Conclusions Bioactive glass could efficiently promote the remineralization of initial enamel carious lesions.The better effect was 6% group.