Risk assessment of root canal disinfectants in terms of endocrine-disruption and development of their substitutes

本研究对福尔马林/甲酚(FC)、福尔马林/愈创木酚(FG)、对氯酚/愈创木酚(R！0)、愈创木酚(Creodon^[R！0])四种根管消毒剂及其成分之一的雌激素活性进行了体内外研究。体外报告基因分析显示，甲氧基酚在10μg/m L以上具有雌激素活性，对氯酚和对甲酚在50μM以上具有雌激素样活性。对于FC和FG，由于样品的毒性，即使在最低浓度下也无法测定其活性，因为细胞被杀死。甲氧基酚的雌激素活性依赖于对氯苯酚，而FC可能因含有对氯苯酚而具有雌激素活性。消毒剂剂量L 15μ/kg/d，成分50 mg/kg/d。这些结果表明，在体内条件下，所测试的根管消毒剂的雌激素活性几乎可以忽略不计，尽管它们的一些成分在体外试验中显示出雌激素活性。

In this study, estrogenic activities of four root canal disinfectants; Formalin/Cresol (FC), Formalin/Guaiacol (FG), p-Chlorophenol/Guaiacol (Methocol^【R!○】), and Guaiacol (Creodon^【R!○】), and their components were investigated in vitro and in vivo.By in vitro reporter gene assay, Methocol was found to demonstrate estrogenic activity at 10μg/mL or greater, and p-Chlorophenol and p-Cresol were estrogenic at 50 μM and over. For FC and FG, the activity could not be determined as the cells were killed due to the toxicity of the specimens even at the least concentration tested. The estrogenicity shown by Methocol is considered to be dependent upon p-Chlorophenol, and it is possible that FC exhibits estrogenic activity as it contains p-Cresol.In vivo estrogenicities of the four disinfectants and the components were studied by uterotrophic assay using ovariectomized rats. Disinfectants were administered at 15 μL/kg/day and, the componentsat 50 mg/kg/day. For any of the specimens, no change in the weight or morphology of ovary was observed, indicating that these chemicals were not estrogenic in vivo.These results indicate that estrogenicities of root canal disinfectants tested were negligible under in vivo condition, although some of their components showed estrogenic-activity by in vitro assays.