Degree Of Conversion And Color Stability To Resin/Ceramic Composite Materials

Dental resin/ceramic composite has become a hot research area due to its extraordinary overall performance.The color stability and the degree of conversion(DC)have become two important criteria with the gradual improvement of the people's aesthetic level and their concern of the security.This study was conducted to investigate the influence of different monomer and proportion on DC and color stability of resin/ceramic composite,as well as the effect of different curing methods.We also measured water absorption and solubility of the composite prepared by different monomers to have a better comprehension.The results are listed as follows.The DC of monomer group were found to decrease in the order of UDMA,Bis-EMA,Bis-GMA,as 79.98%,69.29%,51.87% respectively.The color change had the opposite trend compared to the DC,as 0.534,1.244,1.780 respectively.There was no difference in the degree of conversion when used the same monomer,even the proportion was different.The color stability enhanced with the decrease of the diluent TEGDMA.There was little difference between heat-cured ones and light-cured ones on the DC.But dual curing would observably improve the DC.Heat-light-cured sample reached a DC of 87.52%.The sample prepared with Bis-EMA had the lowest water absorption,Bis-GMA and UDMA showed slightly difference.The sample prepared with UDMA showed higher solubility compared to Bis-EMA or Bis-GMA.We can see that,composite prepared with UDMA has the best DC and color stability.The existence of Bis-EMA will reduce the water absorption and solubility.If preparation condition allows,the addition of TEGDMA in the UDMA or Bis-EMA system will enhance the color stability meanwhile maintain the DC.Dual curing process,especially the heat-light-curing process can increase the DC,which has clinical significance.In clinical application,we should choose the monomers,their proportion and curing method according to practical requirements.