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 为探究替代共引发剂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。本研究采用三种浓度（0.2%、0.5%与1.2%）的BZN作为共引发剂，并以相同浓度的二甲氨基乙基甲基丙烯酸酯（DMAEMA）作为对照。樟脑醌（camphorquinone, CQ）与共引发剂的摩尔浓度保持固定比例（1:1）。对实验树脂制备试样后，开展维氏显微硬度（VHN）测试、抗弯强度与抗压强度测试（单位：MPa）、弹性模量测试（单位：GPa）、转化率检测（采用傅里叶变换红外光谱FT-IR）以及针对3T3成纤维细胞的体外细胞毒性试验。所有数据采用双因素方差分析（two-way ANOVA）结合Tukey事后检验进行统计学分析，显著性水平设定为α=0.05。试验结果表明，添加BZN的实验复合树脂的DC值显著高于DMAEMA对照组。力学性能方面，BZN组的显微硬度值更高；各组的抗弯强度与弹性模量无显著统计学差异。BZN0.5组与DMAEMA0.5组的抗压强度无显著差异，而BZN0.2组的抗压强度为各组最低。含BZN与DMAEMA的实验树脂对3T3成纤维细胞均无细胞毒性。综上，在实验复合树脂中引入共引发剂BZN不会损害其转化率与力学性能，且对3T3成纤维细胞无细胞毒性。