Loss of Hydroxyl Ions from Gutta-Percha Points with Calcium Hydroxide in Their Composition: An In Vivo Study

The aim of this study was to quantify variations in the pH of calcium-hydroxide, gutta-percha cones that had remained for 1 week inside the root canals of molars or premolars whose endodontic treatment could not be concluded in a single visit. All teeth were instrumented and dried before the placement of the points. The cones were removed, and placed in vials with distilled water. Additional, new gutta-percha cones were also studied as a control. The pH was measured by a pH meter, model CRISON MicropH 2001. The average pH mensurations obtained for new, calcium-hydroxide, gutta-percha points was 10.11; for cones that were used 1 week, it was 7.08. There was a statistically significant difference observed between the two groups by the Student's t test (p > 0.001). After 7 days, a significant decrease takes place in the alkalinity of these points.