锂基玻璃陶瓷核瓷瓷块种类和厚度对深色基牙遮色能力的研究

Masking ability of core lithium disilicate glass ceramics with different types and thicknesses on dark abutments

目的:研究不同锂基玻璃陶瓷核瓷种类和厚度对深色基牙的遮色能力,为临床医生和技师选择修复材料提出指导意见。方法:将IPS E.max Press低透LT A1色铸瓷块(LT)、中度不透MO1色铸瓷块(MO)和高度不透HO1色铸瓷块(HO)制作成厚度为0.4 mm、0.5 mm、0.6 mm和0.8 mm的瓷片试件,分别粘接在金合金、镍铬合金、ND6色和ND8色树脂底物上,用以模拟金属桩核及深色基牙,以A2色作为基线,使用数字比色仪测量各组Lab值,并与基线相比较计算色差值ΔE。结果:无论是LT、MO还是HO瓷块,随着瓷片厚度的增加,其在不同颜色底物上的色差值均显著减小(除金合金外);当瓷层厚度大于等于0.5 mm时,对于各种底物,HO组的色差值均显著小于MO组和LT组;当瓷层厚度小于等于0.6 mm时,底色偏黄的基牙使用遮色核瓷后效果优于底色偏灰黑的基牙;当瓷层厚度达到0.8 mm时,各类核瓷对各种颜色底物的遮色效果均较好且差异无统计学意义。结论:瓷层厚度、核瓷种类以及基牙底色均会影响最终修复体的颜色,对于深色基牙,使用高度不透的核瓷瓷块和/或增加瓷层厚度均可提高遮色效果。

Objective:The aim of this study was to investigate the masking ability of three kinds of lithium disilicate glass ceramics with different thicknesses on different backgrounds,hoping to put forward guidance for clinicians and technicians.Methods:Three kinds of lithium disilicate glass ceramics,IPS E.max Press LT,IPS E.max Press MO and IPS E.max Press HO,were made into disk specimens with four different thicknesses(0.4 mm,0.5 mm,06 mm,0.8 mm),which were cemented separately on four different backgrounds(precious gold alloy,nichel-chromium alloy,ND6 and ND8 composite resin).The baseline was using LT,MO and HO specimens with 0.8 mm thickness cemented on A2 composite resin.Measuring Lab value of each specimen by an optoelectronic colorimeter and calculating theΔE value compared with the baseline.Results:No mater LT,MO or HO specimens,theΔE values were decreased in all groups with thickness increasing(except for gold alloy group).When the thickness of ceramic was equal or greater than 0.5 mm,theΔE values of HO groups were significantly less than MO and LT groups.When the thickness of ceramic was equal or less than 0.6 mm,the masking ability of the yellowish abutments was better than that of the greyish ones.When the thickness of ceramic was 0.8 mm,all the specimens had a preferable masking effect of all substrates,which were no significant difference.Conclusion:Both the type and thickness of ceramic and the color of background could affect the masking ability of lithium disilicate glass ceramics.For the dark abutments,using HO ceramic and/or increasing the thickness of ceramic may improve the masking effect.