Effect of ceramic type and thickness on the masking ability of chairside machinable all-ceramic crowns
Objective This study aimed to evaluate the influence of ceramic type and thickness on the masking abili-ty and final aesthetic effects of chairside machinable all-ceramic crowns.Methods Six kinds from three types chairside machinable ceramic materials(IPS e.max CAD HT/MT/LT,IPS Empress LT,and VITA Suprinity HT/T)in shade A2 were fabricated to slice specimens into 1.0,1.5,and 2.0 mm-thick sections(n=10).The color parameters of the speci-mens against black and white tiles and four resin substrates(A2,A4,B3,and C4 shade)were measured with a spectro-photometer.The translucency parameter(TP)was calculated using color parameters measured over standard white and black backgrounds.The color differences(ΔE)were cal-culated between there substrate shades(A4,B3,C4)and A2 shade(control group).Two-way analysis of variance(ANOVA)was performed on the TP values.The two va-riables were ceramic type and ceramic thickness.Three-way ANOVA was used to determine the effects of ceramic materials,ceramic thickness,and substrate shades on the ΔE values,followed by Tukey test for multiple comparisons(α=0.05).Results Ceramic type,ceramic thickness,and sub-strate shade significantly affected the ΔE values(P<0.001).The L* and b* values of the specimens increased with in-creasing ceramic thickness,except in substrate A2,whereas the ΔE values decreased.The color difference of all 1.0 mm-thick specimens or all specimens over the substrates C4 shade exceeded the clinically acceptable threshold(ΔE>3.3).Conclusion The masking ability of chairside machinable all-ceramic crowns is influenced by ceramic type and thick-ness,and ceramic material.The thickness of ceramic less than 2.0 mm cannot mask the gray shade abutment.
国家科技期刊平台
NSTL
万方数据
