The use of NaOCl in combination with CHX produces cytotoxic product

Objectives

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.

Methods

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?Results 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?p?Conclusion PPT is more cytotoxic than NaOCl and CHX alone, particularly in the short term.

Clinical significance

Protocols which suggest the use of CHX and NaOCl must be revised because this mixture produces cytotoxic product.