Ratanasathien S, Wataha J C, Hanks C T, Dennison J B
Oral Health Sciences Program, University of Michigan, School of Dentistry, Ann Arbor 48109-1078, USA.
J Dent Res. 1995 Sep;74(9):1602-6. doi: 10.1177/00220345950740091601.
Previous studies have shown a wide range of pulpal reactions to dentin bonding systems and a poor correlation between in vitro and in vivo toxicity of dentin bonding agents. Because dentin bonding agents are composed of multiple components which may diffuse through dentin, we hypothesized that these components may cause cytotoxicity through interactive (synergistic) effects. We investigated the cytotoxicities of four dentin bonding components--HEMA, Bis-GMA, TEGDMA, and UDMA--and interactive effects for three binary combinations of the dentin bonding components--HEMA and Bis-GMA, Bis-GMA and TEGDMA, and TEGDMA and UDMA. Cytotoxicities to Balb/c 3T3 mouse fibroblasts were measured by the MTT assay. Concentrations which caused 50% toxicity compared with controls (TC50 values) were compared, and the interactive effects were determined by evaluation of the differences between observed and expected MTT activities of the cells. The ranks of toxicity of the dentin bonding components in terms of TC50 values were as follows: Bis-GMA > UDMA > TEGDMA >>> HEMA (least toxic) after 24- and 72-hour exposures. As binary combinations, the three combinations of dentin bonding components interacted in three ways--synergism, additivism, and antagonism--which were influenced by the concentrations of both components. The longer period of exposure resulted in a significant increase in the cytotoxicity of the dentin bonding components and combinations. The findings indicate that both exposure time and the interactions between the dentin bonding components may be important parameters in determining the cytotoxicity of dentin bonding agents in vivo.
以往的研究表明，牙髓对牙本质粘结系统会产生广泛的反应，并且牙本质粘结剂的体外毒性与体内毒性之间的相关性较差。由于牙本质粘结剂由多种成分组成，这些成分可能会透过牙本质扩散，因此我们推测这些成分可能通过相互作用（协同）效应导致细胞毒性。我们研究了四种牙本质粘结成分——甲基丙烯酸羟乙酯（HEMA）、双酚A缩水甘油醚（Bis-GMA）、三乙二醇二甲基丙烯酸酯（TEGDMA）和1,6-己二醇二甲基丙烯酸酯（UDMA）——以及三种牙本质粘结成分二元组合——HEMA与Bis-GMA、Bis-GMA与TEGDMA、TEGDMA与UDMA——的相互作用效应。通过MTT法测定对Balb/c 3T3小鼠成纤维细胞的细胞毒性。比较与对照组相比引起50%毒性的浓度（TC50值），并通过评估细胞观察到的和预期的MTT活性之间的差异来确定相互作用效应。在24小时和72小时暴露后，根据TC50值，牙本质粘结成分的毒性排名如下：Bis-GMA > UDMA > TEGDMA >>> HEMA（毒性最小）。作为二元组合，三种牙本质粘结成分组合以三种方式相互作用——协同、相加和拮抗——这受到两种成分浓度的影响。暴露时间越长，牙本质粘结成分及其组合的细胞毒性显著增加。这些发现表明，暴露时间和牙本质粘结成分之间的相互作用可能是决定牙本质粘结剂体内细胞毒性的重要参数。
