Puska Mervi A, Kokkari Anne K, Närhi Timo O, Vallittu Pekka K
Department of Prosthetic Dentistry & Biomaterials Research, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, FIN-20520 Turku, Finland.
Biomaterials. 2003 Feb;24(3):417-25. doi: 10.1016/s0142-9612(02)00354-x.
The aim of this study was to determine the mechanical properties of acrylic bone cement modified with an experimental oligomer filler, based on an amino acid of trans-4-hydroxy-L-proline synthesized in the laboratory. The test specimens were tested either dry, or after being stored in distilled water or in simulated body fluid (SBF) for 1 week and then tested in distilled water. The three-point bending test was used to measure the flexural strength and flexural modulus of the cement, and the compression tests were used to measure the compression strength and modulus. One test specimen from each group was examined under a scanning electron microscope (SEM) to determine the nature of the oligomer filler in the polymethylmethacrylate-polymethylacrylate copolymer-based (PMMA-PMA/PMMA) polymer blend. In dry conditions, the flexural strength of the test specimens tested in air was 66 MPa, and the compression strength was 93 GPa (p<0.001) for the plain bone cement. For the test specimens including 20 wt% of oligomer filler, the flexural strength was 37 MPa, and the compression strength was 102 MPa(p<0.001) in dry conditions. The storage in wet conditions (in distilled water and the SBF) decreased the flexural strength of the test specimens with 20 wt% of oligomer filler (p<0.001) by 60% and the flexural modulus by 44% compared to the plain bone cement specimens stored in the same conditions. The reduction in compression strength in wet conditions was 32%, and that of the compression modulus was 30% (p<0.001). No significant differences were found between test specimens stored in distilled water or SBF (ANOVA, p<0.001). In the SEM examinations, random voids were observed in the oligomer-PMMA-PMA/PMMA polymer blend after water or SBF storage. The results suggest that both water and SBF storage decrease the mechanical properties of the PMMA-PMA/PMMA bone cement modified with oligomer, while at the same time, there was porous formation in the bone cement structure.
本研究的目的是确定用一种实验性低聚物填料改性的丙烯酸骨水泥的力学性能，该填料基于实验室合成的反式-4-羟基-L-脯氨酸氨基酸。测试样本要么在干燥状态下进行测试，要么在蒸馏水中或模拟体液（SBF）中储存1周后再在蒸馏水中进行测试。采用三点弯曲试验来测量骨水泥的弯曲强度和弯曲模量，采用压缩试验来测量抗压强度和模量。每组取一个测试样本在扫描电子显微镜（SEM）下进行检查，以确定基于聚甲基丙烯酸甲酯-聚甲基丙烯酸酯共聚物（PMMA-PMA/PMMA）的聚合物共混物中低聚物填料的性质。在干燥条件下，在空气中测试的样本的弯曲强度为66MPa，普通骨水泥的抗压强度为93GPa（p<0.001）。对于含有20wt%低聚物填料的测试样本，在干燥条件下弯曲强度为37MPa，抗压强度为102MPa（p<0.001）。与在相同条件下储存的普通骨水泥样本相比，在潮湿条件下（在蒸馏水和SBF中）储存使含有20wt%低聚物填料的测试样本的弯曲强度降低了60%（p<0.001），弯曲模量降低了44%。潮湿条件下抗压强度的降低为32%，压缩模量的降低为30%（p<0.001）。储存在蒸馏水或SBF中的测试样本之间未发现显著差异（方差分析，p<0.001）。在SEM检查中，在水或SBF储存后的低聚物-PMMA-PMA/PMMA聚合物共混物中观察到随机孔隙。结果表明，水和SBF储存都会降低用低聚物改性的PMMA-PMA/PMMA骨水泥的力学性能，同时，骨水泥结构中会形成孔隙。
