Changes in pH of irrigating solutions after contact with human root dentin

The aim of this study was to analyze the in vitro behavior of the pH of different irrigating solutions, used alone or consecutively, after contact with extracted human teeth. Mandibular human premolars were selected. The middle thirds were divided into 6 parts. The specimens obtained were divided into 6 groups and treated with irrigating solutions: 1) distilled water; 2) 1% NaOCl; 3) 1% Citric Acid (CA); 4) 17% EDTA; 5) 1% CA + 1% NaOCl; 6) 17% EDTA + 1% NaOCl. Specimens were immersed in 1 mL of each solution at 37oC, those of groups 1, 2, 3 and 4, for 5 minutes, and the rest, consecutively for 2.5 minutes in each solution. Initial and final pH of the solutions were determined. Data were analyzed by the T Test, one-way analysis of variance (ANOVA) and Tukey multiple comparison Test. At 2.5 and 5 minutes there were significant differences between the initial and final pH for all solutions. The pH values decreased for distilled water and NaOCl, while they increased for CA and EDTA. In vitro, the pH of all solutions was modified after contact with root dentin at both test times (2.5 and 5 min).