In vitro release of hydroxyl ions from six types of calcium hydroxide nonsetting pastes.

The role of intracanal medication in root canal treatment is very important. Calcium hydroxide (Ca(OH)2) is considered to fulfill many of the properties of an ideal root canal dressing mainly due to its alkalizing pH. It is bacteriocidal and neutralizing to the remaining tissue debris in the root canal(s) and through the continuous release of OH- ions it promotes an alkalizing osteogenic environment for the surrounding tissues. The purpose of this study was to examine the pH values of various Ca(OH)2 based on compounds used as intracanal medicaments over a period of 5 days. The following materials were tested: Calasept, Calcicur, Calxyl blue, Calxyl red, Reogan rapid, and Tempcanal. After a fast OH- release period (2 h) each compound reached an asymptotic pH state. The results showed that all materials exhibited alkalizing pH with Reogan rapid, Calxyl Red, and Calcicur being the most potent (p = 0.05). The final pH of each compound correlated positively with the Ca(OH)2 mass fraction contained in it.