Center for Mechanical and Materials Technologies, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
J Mech Behav Biomed Mater. 2012 Sep;13:206-14. doi: 10.1016/j.jmbbm.2012.04.019. Epub 2012 May 4.
The purpose of this study was to evaluate the shear bond strength between CoCrMo dental alloy and porcelain restorations by application of different metal-ceramic transitional interfaces aiming at improvement of the bond strength and fracture tolerances.
Several metal-ceramic specimens with different composite interlayers were produced. The interlayers consisted of metal/ceramic composites with different metal volume fractions (20 M; 40 M; 60 M; 80 M). The metal-ceramic bond strength as well as the fracture strength of the composites and monolithic base materials were assessed by the means of a shear test performed in a universal test machine. The interfaces of fractured and untested specimens were examined by the means of optical microscopy. The microstructures of monolithic base materials were analyzed using SEM/EDS. The elastic and inelastic properties of the homogeneous compositions were additionally evaluated using dynamic mechanical analysis.
The bond strength results obtained for metal-ceramic gradated specimens were the highest (261±38 MPa) for 40 vol% metal in the interlayer [40 M] vs. 109±27 MPa for a direct metal-ceramic joint. The Young's moduli and the fracture resistance of the composites revealed an increasing trend for increasing metal contents.
This study shows that a graded transition between metal and ceramic, provided by a metal/ceramic composite interlayer, is regarded for an increase by 2.5 times in the bond strength between the two materials relative to conventional sharp transitions. The elastic modulus of the composites used as interlayers might be very reasonably approximated by a micromechanical model.
本研究旨在通过应用不同的金属-陶瓷过渡界面来评估 CoCrMo 牙科合金与瓷修复体之间的剪切结合强度，以提高结合强度和断裂容限。
制作了具有不同复合中间层的几种金属陶瓷标本。这些中间层由具有不同金属体积分数的金属/陶瓷复合材料组成（20M；40M；60M；80M）。通过万能试验机进行剪切试验评估金属陶瓷结合强度以及复合材料和整体基材料的断裂强度。通过光学显微镜检查断裂和未经测试的标本的界面。使用 SEM/EDS 分析整体基材料的微观结构。使用动态力学分析进一步评估均匀成分的弹性和非弹性性质。
梯度金属陶瓷标本的结合强度结果最高（261±38 MPa），中间层为 40vol%金属[40M]，而直接金属-陶瓷接头为 109±27 MPa。复合材料的杨氏模量和断裂阻力随着金属含量的增加呈上升趋势。
本研究表明，金属和陶瓷之间的梯度过渡，由金属/陶瓷复合材料中间层提供，与传统的锐度过渡相比，两种材料之间的结合强度增加了 2.5 倍。用作中间层的复合材料的弹性模量可以通过微观力学模型非常合理地逼近。
