Democritus University of Thrace, Department of Orthopaedic Surgery, University General Hospital of Alexandroupolis, Dragana, Alexandroupolis, Greece.
Injury. 2012 Mar;43(3):266-71. doi: 10.1016/j.injury.2011.02.004. Epub 2011 Mar 2.
The aim of this laboratory work was to study the compressive and flexural characteristics of various commercially available bone graft substitute (BGS) ceramic cements, in their initial as-mixed condition, and compare them to polymethylmethacrylate (PMMA). The tested biomaterials were two different calcium phosphate cements, two different calcium sulphate cements, one nanocrystalline hydroxyapatite and one PMMA cement. All biomaterials were prepared according to manufacturers instructions and the methodology described in ISO 5833 (2002) for acrylic bone cement was followed, as the one closest approaching in vivo requirements. All BGS cements had a brittle behaviour and when subjected to mechanical stress they all failed under sudden crack propagations in their bulk. Both in compression and bending, all BGS cements failed under loads lower than those of PMMA. In compression, the calcium sulphate extra strength cement showed a strength value of approximately 60% of PMMA, the other cements following at a distance. In bending, all BGS cements showed strengths below 22% of PMMA. However, due to limited number and fragility of specimens, calculated bending strengths can only be considered as indicative figures with limited comparative value. The results of this in vitro study showed a varying mechanical performance between tested BGS ceramic cements, whilst all of them exhibited lower compression and bending strength than the selected PMMA. These findings, of course, cannot be directly extrapolated to surgical or clinical implications, since the adopted in vitro context does not necessarily reflect the actual in vivo conditions met by such biomaterials.
本实验室工作的目的是研究各种市售骨移植替代物（BGS）陶瓷水泥的抗压和抗弯特性，研究对象为初始混合状态下的各种材料，并将其与聚甲基丙烯酸甲酯（PMMA）进行比较。测试的生物材料有两种不同的磷酸钙水泥、两种不同的硫酸钙水泥、一种纳米晶羟基磷灰石和一种 PMMA 水泥。所有生物材料均按照制造商的说明和 ISO 5833（2002）中规定的方法制备，遵循最接近体内要求的方法。所有 BGS 水泥均表现出脆性，在受到机械应力时，它们都会在整体突然出现裂纹扩展的情况下失效。在压缩和弯曲两种情况下，所有 BGS 水泥在低于 PMMA 的负载下失效。在压缩试验中，硫酸钙超强水泥的强度值约为 PMMA 的 60%，其他水泥则紧随其后。在弯曲试验中，所有 BGS 水泥的强度均低于 PMMA 的 22%。然而，由于样本数量有限且易碎，计算出的弯曲强度只能作为具有有限比较价值的指示性数据。本体外研究的结果表明，测试的 BGS 陶瓷水泥之间具有不同的机械性能，而所有这些水泥的抗压和抗弯强度均低于所选的 PMMA。当然，这些发现不能直接外推到手术或临床意义，因为所采用的体外环境不一定反映此类生物材料在实际体内条件下的情况。
