The Effect of Liner Thickness on the Color of Y-TZP Based All-Ceramic Restorations

摘要

To evaluate the effect of various liner thickness on the color of Y-TZP based all-ceramic restorations.Forty disc specimens (10 mm diameter,0.5 mm thick) were fabricated from IPS e.max ZirCAD core material.The specimens were randomly divided into four groups (n=10) according to layering with different ZL1 IPS e.max ZirLiner thicknesses as:0.1 mm,0.2 mm,0.3 mm and one group had received no treatment as the control group.And 0.6 mm veneering porcelain was fired on the IPS e.max ZirCAD core material by traditional layering technique.Using a spectrophotometer to measure Color parameters L,a and b of the specimens after veneered.ΔE were calculated to compare color difference among the four groups.Intergroup differences of ΔE in different thicknesses were statistically significant at P＜0.05.The ΔE between groups with different thickness were 2.03±0.07,2.88±0.07,3.54±0.07,0.86±0.06,1.47±0.06 and 0.67±0.06 respectively.Usually researchers apply ΔE=1.5 as the threshold for distinguishing two different colors by the human eye.Color difference ΔE between different groups with and without liner application was more than 1.5,which was in the perceptible range,but ΔE of liner application with the thickness of 0.1 mm,0.2 mm and 0.3 mm were undistinguishable by human eye (ΔE＜1.5).Thus liner application of the all ceramic system could significantly affected the final color of the all ceramic restorations and it ameliorated esthetics of Y-TZP all-ceramic restorations to good purpose.However,Changes in the thickness (0.1 ～ 0.3 mm)of liner application have no significant effect on the final shade of Y-TZP based all-ceramic restorations.