2种方法制作金属基底冠边缘适合性和金瓷结合力比较

Comparison of edge fitness and metal-ceramic bonding force of base metal crowns performed using two methods

目的:比较激光打印金属基底冠与铸造钴铬合金基底冠边缘适合性及金瓷结合力的差异。方法:分别采用激光打印制作钴铬合金基底冠(A组)和传统铸造法制作钴铬合金基底冠(B组)各10个,均以下颌第一磨牙全冠牙体为金属代型,将制作好的基底冠放置于标准代型。体式显微镜下观察基底冠边缘与代型肩台间间隙,以评估边缘适合性;利用万能测试机对基底冠进行加载实验,以评估金瓷结合力。比较2种方法制作的基底冠边缘适合性和金瓷结合力的差异,采用SPSS 25.0软件包对数据进行统计学分析。结果:A组金属基底冠与代型肩台间隙为(48.52±5.26)μm,显著小于B组的(76.25±8.37)μm(P<0.05);A组金属基底冠金瓷结合强度为(11.35±3.29)N,显著高于B组的(7.24±2.07)N(P<0.05)。电镜下观察,A组金属层与瓷层结合更为紧密。结论:激光打印和传统铸造法制作的金属基底冠边缘适合性和金瓷结合力均在可接受范围,而激光打印的金属基底冠边缘适合性更好、金瓷结合力更强,是理想的金属基底冠制作技术。

PURPOSE:To compare the marginal fitness and metal-ceramic bonding strength between laser printing metal crown and cast cobalt-chromium alloy crown.METHODS:Cobalt-chromium alloy crowns(n=10)(group A)were made by laser printing and another 10 by traditional casting(group B),respectively.All the first molar crowns were metal substitutes,and the basal crowns were placed in the standard substitutes.The marginal fitness of the basal crown was assessed by observing the margin of the basal crown and the shoulder gap of the substitution under stereomicroscope.Shear test of the basal crown was carried out by universal tester to evaluate the bonding strength between the metal and the porcelain.The differences of the marginal fitness and the bonding strength between the two methods of making basal crown were compared.SPSS 25.0 sofware package was used to analyze the data.RESULTS:The gap between the metal base crown and the generation shoulder of group A was significantly smaller than that of group B[(48.52±5.26)μm vs(76.25±8.37)μm,P<0.05].The intensity was significantly higher than that of group B[(11.35±3.29)N vs(7.24±2.07)N,P<0.05].Under electron microscope,the metal layer of group A was more closely combined with the porcelain layer.CONCLUSIONS:The marginal fitness and bonding strength of metal base crowns made by laser printing and traditional casting methods are acceptable.Laser printing metal base crowns have better marginal fitness and stronger bonding strength between metal and porcelain,which is an ideal technology for metal base crowns.