渗透陶瓷双层结构的双轴抗弯强度及断裂模式研究

Bi-axial flexure strength and fracture mode of alumina glass-infiltrated core/veneer ceramic composites

目的:考察渗透陶瓷与饰面瓷双层结构的双轴抗弯强度及其可靠性和断裂方式,以帮助了解修复体失败的原因。方法:制作1.6mm×16mm盘状试件40个,MC和MV分别为渗透陶瓷和饰面瓷的单层试件,BV和BC为两者的双层试件,采用球-环法测定以上4组的双轴抗弯强度,其中BV组在加载时饰面瓷承受张应力,BC组加载时渗透陶瓷承受张应力。结果用SPSS13.0软件包行单因素方差分析及Weibull分析,体视显微镜及扫描电镜观察确定试件断裂源及断裂模式。结果:MC组强度最高(P<0.001),BC组强度高于BV组(P<0.001),MV组与BV组双轴抗弯强度无统计学差异(P=0.381)。Weibull模量主要受承受张应力一侧的材料影响,BC组与BV组都未发生明显的界面剥离。结论:加载时,承受张应力的材料决定双层试件的双轴抗弯强度和断裂模式。强度较差的饰面瓷会影响全瓷修复体的强度。

PURPOSE：To determine the bi-axial flexural strength and fracture mode of bilayered alumina glass-infiltrated core and the veneering porcelain. METHODS：Forty disk specimens were made from alumina glass-infiltrated core （HSDC-A） and veneer porcelain （Vintage AL）,and equally divided into four groups as follows：monolithic specimens of veneer （MV）,monolithic specimens of core material （MC）,bilayered specimens with the veneer on top （BC） and bilayered specimens with core material on top（BV）. Mean flexure strength,standard deviation and associated Weibull modulus were determined using bi-axial flexure （ball-on-ring） for each group. The results were analyzed with one-way ANOVA and the Weibull distribution with SPSS 13.0 software package. Both optical and scanning electron microscopy were employed for identification of the fracture mode and origin. RESULTS：The strength in the group MC and BC were significantly stronger than that in the group MV and BV. The frequency of specimen delamination,Hertzian cone formation and subcritical radial cracking in the bilayered discs were dependent on the surface loaded in tension. CONCLUSION：Material which lies on the bottom surface dictates the strength and fracture mode of the specimens.