Xu H H, Quinn J B
Paffenbarger Research Center, American Dental Association Health Foundation, National Institute of Standards and Technology, 100 Bureau Drive Stop 8546, Gaithersburg, Maryland 20899-8546, USA.
J Biomed Mater Res. 2001 Nov;57(2):165-74. doi: 10.1002/1097-4636(200111)57:2<165::aid-jbm1155>3.0.co;2-w.
Calcium phosphate cement (CPC) sets to form microporous solid hydroxyapatite with excellent osteoconductivity, but its brittleness and low strength prohibit use in stress-bearing locations. The aim of this study was to incorporate prehardened CPC particles and ceramic whiskers in a resin matrix to improve the strength and fracture resistance, and to investigate the effects of key microstructural variables on composite mechanical properties. Two types of whiskers were used: silicon nitride, and silicon carbide. The whiskers were surface-treated by fusing with silica and by silanization. The CPC particle fillers were either silanized or not silanized. Seven mass ratios of whisker-silica/CPC were mixed: 0:1 (no whisker-silica), 1:5, 1:2, 1:1, 2:1, 5:1, and 1:0 (no CPC). Each powder was blended with a bisphenol-a-glycidyl methacrylate-based resin to harden in 2 x 2 x 25 mm molds by two-part chemical curing. The specimens were tested in three-point flexure to measure strength, work-of-fracture (toughness), and elastic modulus. Two-way analysis of variance was used to analyze the data, and scanning electron microscopy was used to examine specimen fracture surfaces. The whisker-silica/CPC ratio had significant effects on composite properties (p < 0.001). When this ratio was increased from 0:1 to 1:0, the strength was increased by about three times, work-of-fracture by five times, and modulus by two times. Whisker surface treatments and CPC filler silanization also had significant effects (p < 0.001) on composite properties. Scanning electron microscopy revealed rough fracture surfaces for the whisker composites with steps and whisker pullout. Resin remnants were observed on the surfaces of the pulled-out whiskers, indicating strong whisker-matrix bonding. In conclusion, incorporating highly osteoconductive CPC fillers and ceramic whiskers yielded composites with substantially improved mechanical properties compared with composites filled with CPC particles without whiskers. The composite properties were determined by whisker-to-CPC ratio and filler surface treatments.
磷酸钙骨水泥（CPC）凝固后形成具有优异骨传导性的微孔固体羟基磷灰石，但其脆性和低强度使其无法用于承受应力的部位。本研究的目的是将预硬化的CPC颗粒和陶瓷晶须加入树脂基体中，以提高强度和抗断裂性，并研究关键微观结构变量对复合材料力学性能的影响。使用了两种类型的晶须：氮化硅和碳化硅。通过与二氧化硅熔合和硅烷化对晶须进行表面处理。CPC颗粒填料进行了硅烷化或未进行硅烷化处理。将晶须 - 二氧化硅/CPC的七种质量比进行混合：0:1（无晶须 - 二氧化硅）、1:5、1:2、1:1、2:1、5:1和1:0（无CPC）。每种粉末与双酚 - a - 甲基丙烯酸缩水甘油酯基树脂混合，通过双组分化学固化在2×2×25毫米的模具中硬化。对试样进行三点弯曲测试，以测量强度、断裂功（韧性）和弹性模量。使用双向方差分析来分析数据，并使用扫描电子显微镜检查试样的断裂表面。晶须 - 二氧化硅/CPC的比例对复合材料性能有显著影响（p < 0.001）。当该比例从0:1增加到1:0时，强度提高了约三倍，断裂功提高了五倍，模量提高了两倍。晶须表面处理和CPC填料硅烷化对复合材料性能也有显著影响（p < 0.001）。扫描电子显微镜显示晶须复合材料的断裂表面粗糙，有台阶和晶须拔出。在拔出的晶须表面观察到树脂残余物，表明晶须与基体之间有很强的结合力。总之，与不含晶须的CPC颗粒填充的复合材料相比，加入高骨传导性的CPC填料和陶瓷晶须可使复合材料的力学性能得到显著改善。复合材料的性能由晶须与CPC的比例和填料表面处理决定。
