一种新型超支化聚丙烯酸，用于改善树脂改性玻璃离子体修复材料。
A novel hyperbranched poly(acrylic acid) for improved resin-modified glass-ionomer restoratives.
机构信息
Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
出版信息
Dent Mater. 2011 May;27(5):478-86. doi: 10.1016/j.dental.2011.02.005. Epub 2011 Mar 5.
OBJECTIVE
The objective of this study was to synthesize and characterize novel hyperbranched poly(acrylic acid)s via atom-transfer radical polymerization (ATRP) technique and tether the photo-curable methacrylate onto the poly(acrylic acid), use these polymers to formulate the resin-modified glass-ionomer cements, and evaluate the mechanical strengths of the formed cements.
MATERIALS AND METHODS
The hyperbranched poly(acrylic acid)s were synthesized using a self-condensing vinyl polymerization initiator via ATRP. The effects of the concentrations of both catalyst and initiator on molecular weight (MW) and degree of branching (DB) were studied. Compressive, diametral tensile as well as flexural strengths, fracture toughness, hardness and wear-resistance of the experimental cement were evaluated and compared to those of Fuji II LC cement. The specimens were conditioned in distilled water at 37°C for 24h prior to testing.
RESULTS
The concentrations of both catalyst and initiator had significant effects on MW and DB of the synthesized polymers. The concentration of the initiator also significantly affected both CS and DTS values of the cement. The experimental cement showed significantly higher mechanical properties, i.e., 53% in CS, 50% in compressive modulus, 125% in DTS, 95% in FS, 21% in FT and 96% in KHN, higher than Fuji II LC. The experimental cement was only 5.4% of abrasive and 6.4% attritional wear depths of Fuji II LC.
CONCLUSIONS
This study developed a novel resin-modified glass-ionomer cement system composed of newly synthesized hyperbranched poly(acrylic acid)s. It appears that this novel experimental cement is a clinically attractive dental restorative and may potentially be used for high-wear and high-stress-bearing site restorations.
目的
本研究的目的是通过原子转移自由基聚合（ATRP）技术合成和表征新型超支化聚（丙烯酸），并将光固化甲基丙烯酸盐键合到聚（丙烯酸）上，用这些聚合物来配制树脂改性玻璃离子水门汀，并评估形成的水门汀的机械强度。
材料与方法
使用自缩合乙烯基聚合引发剂通过 ATRP 合成超支化聚（丙烯酸）。研究了催化剂和引发剂的浓度对分子量（MW）和支化度（DB）的影响。评估和比较了实验性水门汀的抗压、直径拉伸和弯曲强度、断裂韧性、硬度和耐磨性，并与 Fuji II LC 水门汀进行了比较。测试前，将试件在 37°C 的蒸馏水中养护 24h。
结果
催化剂和引发剂的浓度对合成聚合物的 MW 和 DB 有显著影响。引发剂的浓度也显著影响水门汀的 CS 和 DTS 值。实验性水门汀表现出显著更高的机械性能，即 CS 提高 53%，抗压模量提高 50%，DTS 提高 125%，FS 提高 95%，FT 提高 21%，KHN 提高 96%，均高于 Fuji II LC。实验性水门汀的磨耗率仅为 Fuji II LC 的 5.4%，损耗率仅为 Fuji II LC 的 6.4%。
结论
本研究开发了一种由新合成的超支化聚（丙烯酸）组成的新型树脂改性玻璃离子水门汀系统。该新型实验性水门汀似乎是一种有吸引力的临床牙科修复体，可能有潜力用于高磨损和高应力部位的修复。
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