Dental materials are known as efficient tools to revive the functionality and integrity of decayed/missing tooth structure. Being frequently subjected to different mixtures of tensile and shear loads accompanied by temperature changes and suffering from pre-existing voids and imperfect interfaces at the same time, dental restorations and prostheses are found to be susceptible to crack initiation and growth. In this paper, fracture properties of three dental biomaterials namely polymethylmethacrylate (PMMA), 75Sr and 75Sr10 undergoing mixed tensile-shear loads are investigated. The PMMA used in this study has application as a cold-cured acrylic resin for repairing dental prostheses, while 75Sr and 75Sr10 are dental restorative materials. Fracture growth angle and onset of crack propagation are evaluated experimentally using shortened semi-circular bend specimens made from PMMA. In addition, the generalized maximum tangential strain (GMTSN) criterion is applied to theoretically predict the fracture behavior of the tested PMMA, as well as two other dental bio-composites reported in the literature viz 75Sr and 75Sr10. Good agreement is met between theory and practice when comparing fracture curves extracted from the GMTSN criterion and the experimental data points. Further, it is found that conventional stress- and strain-based fracture models fail to provide suitable estimates of crack growth behavior.

牙科材料被公认为是恢复蛀牙/缺失牙齿结构的功能和完整性的有效工具。牙齿修复体和假体经常受到拉伸和剪切载荷的不同混合，伴随着温度变化，并同时存在既有的空隙和不完善的界面，因此很容易产生裂纹和生长。本文研究了三种牙科生物材料，即混合甲基丙烯酸甲酯（PMMA），75Sr和75Sr10在混合拉伸剪切力作用下的断裂性能。本研究中使用的PMMA作为冷修复丙烯酸树脂可用于修复义齿，而75Sr和75Sr10是牙科修复材料。使用由PMMA制成的缩短的半圆形弯曲试样，通过实验评估了裂缝的生长角度和裂纹扩展的开始。此外，广义最大切向应变（GMTSN）准则可用于理论上预测被测PMMA以及文献75Sr和75Sr10中报道的两种其他牙科生物复合材料的断裂行为。比较从GMTSN准则中提取的断裂曲线和实验数据点，理论与实践之间达成了良好的共识。此外，发现传统的基于应力和应变的断裂模型无法提供适当的裂纹扩展行为估计。以及文献中报道的另外两种牙科生物复合材料，即75Sr和75Sr10。比较从GMTSN准则中提取的断裂曲线和实验数据点，理论与实践之间达成了良好的共识。此外，发现传统的基于应力和应变的断裂模型无法提供适当的裂纹扩展行为估计。以及文献中报道的另外两种牙科生物复合材料，即75Sr和75Sr10。比较从GMTSN准则中提取的断裂曲线和实验数据点，理论与实践之间达成了良好的共识。此外，发现传统的基于应力和应变的断裂模型无法提供适当的裂纹扩展行为估计。