Determination of residual parachloroaniline produced by endodontic treatment after the use of 5% sodium hypochlorite and 2% chlorhexidine combined: an ex-vivo study

Abstract

Aim: The objective of this work was to determine the concentrations of irrigating solutions and the residual content of parachloroaniline (PCA) formed after endodontic irrigation, using 5% NaOCl, 0.9% NaCl, 10% EDTA and 2% CHX 2%. Methodology Twenty premolars were used and 13 samples were collected per tooth from each of the treatment phases. Samples of: NaOCl, EDTA, CHX and PCA were quantified by UV and visible spectrophotometry. Results: Sodium hypochlorite decreased its concentration from 3.8% to 3.4% in phases 1 to 4. In phases 5, 6 and 7, residual NaOCl was measured with concentrations of 0.007%, 0.003% and 0.001% %. The concentration of EDTA decreased to 8.85% in phase 8. In phases 9, 10 and 11, irrigated with serum, EDTA was quantified with concentrations of 0.013% to 0.002% and NaOCl values of 0.0011% to 0, 0006%. In phases 12 and 13, CHX concentrations were 1.850% and 1.812% and PCA values were 0.0005% and 0.0007%. PCA formation occurred in presence of 2% CHX and residual NaClO and was detected colorimetrically in phases 12 and 13. Conclusions. During endodontic irrigation the concentration of 5% NaOCl decreases significantly in the first four phases and the concentrations of EDTA and CHX also decrease. There is PCA training in the last stages of the procedure.

Soluções irrigadoras utilizadas no preparo químico-mecânico do sistema de canais radiculares: uma revisão da literatura

“…Mohammadi et al, (2015), ainda relata que ao associar a CHX com EDTA ocorre a formação de um sal. Em concordância, no estudo feito por Alegre et al, (2017), comprovaram que a combinação do NaOCl 5% com a CHX 2% ocorreu a formação de um precipitado denominado Paracloroanilina (PCA), apresentando citotoxicidade e um alto potencial carcinogênico em humanos. Dessa forma, relataram a necessidade de um protocolo de irrigação para reduzir possíveis contaminações.…”