The Water Sorption And Solubility And Microleakage Of Dental Composite Resin With Porous Composite Fillers Toughened By Nano Zirconia

Objectives:The aim of the study was to evaluate the effect of composite fillers with differrent contents and different proportions of nano zirconia/porous "fluorphlogopite-fluorapatite" glass ceramic on the water sorption and solubility and microleakage of dental composite resin.Methods:"Fluorphlogopite-fluorapatite" bioactive glass ceramic powder containing20%fluorapatite was prepared by the method of two-step casting/two-step heat treatment. Then the powder was etched by hydrofluoric acid in order to be porous, and mixed with nano zirconia powder in different proportions. After the surface treatment by KH-570, different groups of composite fillers were added into resin matrix with different mass fractions, preparing6groups of composite resin as experimental groups. FiltekTM P60commercial composite resin was taken as control group. According to ISO4049, the composite resin of the experimental groups and the control group was manufactured into disc specimens. The specimens were soaked in distilled water at a constant temperature of (37±1)℃, then the values of water sorption and solubility were measured and calculated.Meanwhile, the class V cavites of teeth in vitro were filled with the composite resin of the experimental groups and the control group, then the teeth were dyed with "silver-staining method". The depths of the dye infiltration, namely the values of microleakage, were observed under the stereomicroscope.Results:1.The differences of the values of water sorption between the experimental groups with different filler contents (60%,65%,70%) have statistical significance, the value of the water sorption decreased with the filler content increased; except for the comparison between Group A70-1and Group A70-2, the differences of the values of water sorption between the groups with the same filler content (70%) and different packing size ratios have statistical significance, the value of the water sorption decreased with the micro-fillers/nano-fillers ratio increased; the values of water sorption of each experimental groups are greater than the control group (Group P60), the differences are statistically significant; except for Group A60, the values of water sorption of the other groups are in accord with the standard ISO4049.2. Except for the comparison between Group A65and Group A60、 Group A70-1、Group A70-2、Group A70-4, the differences of the values of water solubility between the experimental groups with different filler contents (60%,65%,70%) have statistical significance, the value of the water solubility decreased with the filler content increased; except for the comparison between Group A70-1and Group A70-2、Group A70-2and Group A70-3, the differences of the values of water solubility between the groups with the same filler content (70%) and different packing size ratios have statistical significance, the value of the water solubility decreased with the micro-fillers/nano-fillers ratio increased; except for Group A70-1、Group A70-2、Group A70-3and Group A70-4, the values of water solubility of the other experimental groups are greater than the control group (Group P60), the differences are statistically significant; the values of water solubility of all of the groups are in accord with the standard ISO4049.3.The differences of the microleakage values between the experimental groups with different filler contents (60%,65%,70%) have statistical significance, the microleakage value decreased with the filler content increased; the differences of the microleakage values between the groups with the same filler content (70%) and different packing size ratios have no statistical significance; except for Group A70-1、Group A70-2、Group A70-3and Group A70-4, the microleakage value of the other experimental groups are greater than the control group (Group P60), the differences are statistically significant.Conclusion:1.The water sorption and solubility and microleakage of the composite resin decreased with the content of inorganic fillers increased.2.The water sorption and solubility of the composite resin decreased with the micro-fillers/nano-fillers ratio increased, while the radio has no significant influence on the microleakage.