The fracture toughness K_Ic of 11 clinically used acrylic bone cements was studied in air at room temperature with single edge V‐notched beam specimens. By driving the crack step‐wise through the specimens, crack resistance curves (“R‐curves”) were recorded. One group of bone cements showed an increase of the fracture toughness with increasing crack length (including CMW1+G and several Palacos bone cements) whereas another group (including Simplex, SmartSet, Copal and some Palacos bone cements) did not exhibit an R‐curve behavior. The plateau values for K_Ic ranged from 0.93 MPa√m (Simplex P) to 1.98 MPa√m (Palacos R+G). The observation of the crack growth with an optical microscope revealed some mechanisms influencing the crack growth like the formation of microcracks in the extended damage zone of the crack tip, the attraction of the crack by inclusions or the shielding of the crack tip by bridges in the wake of the crack. Furthermore, bone cements could be distinguished by the pattern of the path the crack followed during propagation. The crack pattern of CMW1+G provides a possible explanation of the distinct R‐curve behavior of this cement.

中文翻译：

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丙烯酸骨水泥的断裂韧性和抗裂性曲线。

用单边 V 形缺口梁试样在室温下在空气中研究了 11 种临床使用的丙烯酸骨水泥的断裂韧性K _Ic。通过在试样中逐步驱动裂纹，记录抗裂性曲线（“R 曲线”）。一组骨水泥随着裂缝长度的增加（包括 CMW1+G 和几种 Palacos 骨水泥）显示出断裂韧性增加，而另一组（包括 Simplex、SmartSet、Copal 和一些 Palacos 骨水泥）没有表现出 R 曲线行为。K _Ic的平台值范围从 0.93 MPa√m (Simplex P) 到 1.98 MPa√m (Palacos R+G)。用光学显微镜观察裂纹扩展揭示了一些影响裂纹扩展的机制，如裂纹尖端扩展损伤区微裂纹的形成、夹杂物对裂纹的吸引或裂纹尖端对裂纹尖端的屏蔽。裂缝的苏醒。此外，可以通过裂纹在传播过程中所遵循的路径模式来区分骨水泥。CMW1+G 的裂纹模式为这种水泥的独特 R 曲线行为提供了可能的解释。