Effect of the Bis-Dimethylamino Benzydrol Coinitiator on the Mechanical and Biological Properties of a Composite

Abstract To examine the effect of the alternative coinitiator 4,4’bis dimethylamino benzydrol (BZN) in degree of conversion (DC), mechanical and biological properties of experimental composites. The coinitiator BZN was used in three concentrations (0.2, 0.5 and 1.2%), and the coinitiator DMAEMA was used as control at the same concentrations as above. The molar concentration of camphorquinone (CQ) and coinitiators was kept constant (1:1). The composites were manipulated and submitted to microhardness test (VHN), flexural and compressive strength (in MPa), elastic modulus (GPa), DC (FT-IR) and in vitro cytotoxicity (against 3T3 fibroblastic cells) of the experimental resins. Data were subjected to two-way ANOVA and Tukey post-test (α=0.05). The experimental composite resin with BZN showed higher DC values compared to control DMAEMA groups. For the mechanical properties, microhardness values were higher in BZN groups; flexural strength and elastic modulus were similar between all the groups. Compressive strength for groups BZN0.5 and DMAEMA0.5 were not statistically different, being the lowest values attributed to group BZN0.2. The experimental resins with BZN and DMAEMA were considered nontoxic against 3T3 fibroblasts. The inclusion of the coinitiator BZN in experimental composites was considered nontoxic against 3T3 fibroblast cells, without compromising DC and mechanical properties.

摘要 本研究旨在考察替代共引发剂4,4'-双(二甲氨基)二苯甲醇（4,4’bis dimethylamino benzydrol，BZN）对实验复合树脂的转化率（degree of conversion，DC）、力学性能与生物学性能的影响。本研究设置浓度分别为0.2%、0.5%与1.2%的BZN实验组，并以相同浓度梯度的甲基丙烯酸二甲氨基乙酯（DMAEMA）作为空白对照；樟脑醌（camphorquinone，CQ）与各类共引发剂的摩尔浓度比保持恒定为1:1。对所制备的实验复合树脂开展以下检测：维氏显微硬度测试（Vickers Hardness Number，VHN）、弯曲强度与抗压强度（单位：MPa）、弹性模量（单位：GPa）、转化率（采用傅里叶变换红外光谱（FT-IR）检测）以及体外细胞毒性实验（以3T3成纤维细胞为检测对象）。所有实验数据均采用双因素方差分析（two-way ANOVA）与Tukey事后检验（Tukey post-test）进行统计分析，显著性水平设定为α=0.05。相较于DMAEMA空白对照组，添加BZN的实验复合树脂展现出更高的DC值；在力学性能方面，BZN组的显微硬度值显著更高，各组的弯曲强度与弹性模量均无统计学差异，BZN0.5组与DMAEMA0.5组的抗压强度无显著区别，而BZN0.2组的抗压强度为所有组别中最低。含BZN与DMAEMA的实验树脂对3T3成纤维细胞均无细胞毒性。综上，在实验复合树脂中添加共引发剂BZN不会对3T3成纤维细胞产生毒性，且不会损害其转化率与力学性能。