Physicochemical properties, cytotoxicity and penetration into dentinal tubules of sodium hypochlorite with and without surfactants

OBJECTIVES: The aim of this study was to assess the physicochemical properties, cytotoxicity and penetration into dentinal tubules of ChlorCid™ Surf (3% sodium hypochlorite [NaOCl] with surfactant) in comparison to ChlorCid™ (3% NaOCl without surfactant). MATERIALS AND METHODS: The physicochemical properties evaluated were pH, surface tension, free available chlorine (FAC) and contact angle. Cytotoxicity was evaluated in L929 fibroblasts exposed to the solutions by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and neutral red assays. Assessment of penetration into dentinal tubules was performed by staining single-rooted permanent human teeth with crystal violet (n = 9), which were irrigated with the solutions and analyzed in cervical, middle and apical segments. Data were analyzed by one-way analysis of variance (ANOVA) and Tukey's post-test, 2-way ANOVA and Bonferroni's post-test or t-test (α = 0.05). RESULTS: ChlorCid™ Surf and ChlorCid™ FAC values were close to those indicated by the manufacturer. ChlorCid™ Surf showed lower surface tension and contact angle on dentin, and higher pH than ChlorCid™ (p < 0.05). The penetration of ChlorCid™ Surf was higher in cervical and middle segments, compared with ChlorCid™ (p < 0.05). There was no difference in irrigant cytotoxicity (p > 0.05). CONCLUSIONS: ChlorCid™ Surf showed lower surface tension, lower contact angle on root canal dentin, higher penetration into dentinal tubules and more alkaline pH, compared with ChlorCid™. However, both solutions showed similar cytotoxicity and FAC content.