Cintra Luciano Tavares Angelo, Watanabe Simone, Samuel Renata Oliveira, da Silva Facundo Aguinaldo Cândido, de Azevedo Queiroz India Olinta, Dezan-Júnior Eloi, Gomes-Filho João Eduardo
Department of Endodontics, Araçatuba Dental School, UNESP-Universidade Estadual Paulista, R. José Bonifácio, 1193, Araçatuba, São Paulo, Brazil,
Clin Oral Investig. 2014 Apr;18(3):935-40. doi: 10.1007/s00784-013-1049-5. Epub 2013 Jul 28.
The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) yields a "precipitate potentially toxic" (PPT). The aim of this study was to evaluate the tissue response to implanted polyethylene tubes filled with PPT-soaked fibrin sponge.
Forty rats received four polyethylene tubes each; each tube was filled with fibrin sponge soaked by 2.5 % NaOCl, 2.0 % CHX, PPT (2.5 % NaOCl plus 2.0 % CHX), or not soaked (control). The observation time points were 7, 15, 30, 60, and 90 days. At each time point, eight animals were killed, and the tubes and surrounding tissues were removed, fixed, and prepared for light microscopic analysis by performing glycol methacrylate embedding, serial cutting into 3-μm sections, and hematoxylin-eosin staining. Qualitative and quantitative evaluations of the reactions were performed. Results were statistically analyzed by Kruskal-Wallis test (p < 0.05).
All chemical solutions caused moderate reactions at 7 days. On day 30, PPT group was more cytotoxic than the control group and the CHX group (p < 0.05). On days 15 and 60, PPT group was more cytotoxic than the control group (p < 0.05). On day 90, there was no statistically significant difference between the different groups.
PPT is more cytotoxic than NaOCl and CHX alone, particularly in the short term.
Protocols which suggest the use of CHX and NaOCl must be revised because this mixture produces cytotoxic product.
次氯酸钠（NaOCl）与洗必泰（CHX）混合会产生“潜在有毒沉淀物”（PPT）。本研究的目的是评估植入填充有浸有PPT的纤维蛋白海绵的聚乙烯管后组织的反应。
40只大鼠，每只大鼠植入4根聚乙烯管；每根管子填充浸有2.5% NaOCl、2.0% CHX、PPT（2.5% NaOCl加2.0% CHX）的纤维蛋白海绵，或不浸泡（对照组）。观察时间点为7、15、30、60和90天。在每个时间点，处死8只动物，取出管子及其周围组织，固定后通过甲基丙烯酸乙二醇酯包埋、连续切成3μm切片并进行苏木精-伊红染色，制备用于光学显微镜分析的样本。对反应进行定性和定量评估。结果采用Kruskal-Wallis检验进行统计学分析（p < 0.05）。
所有化学溶液在7天时均引起中度反应。在第30天，PPT组的细胞毒性高于对照组和CHX组（p < 0.05）。在第15天和60天，PPT组的细胞毒性高于对照组（p < 0.05）。在第90天，不同组之间无统计学显著差异。
PPT的细胞毒性比单独的NaOCl和CHX更大，尤其是在短期内。
建议使用CHX和NaOCl的方案必须修订，因为这种混合物会产生细胞毒性产物。
