The Effect of a Physiologic Solution pH on Properties of White Mineral Trioxide Aggregate

The purpose of this study was to investigate the effect of two solutions differing by pH (6.4 and 4.0) and the use of a setting accelerator (15% Na2HPO4 solution) on the properties of white-colored mineral trioxide aggregate (WMTA). These studies indicated that pH 4.0 had a deleterious effect on the morphology of WMTA mixed with water, however, not for WMTA mixed with Na2HPO4. When immersed in a pH 4.0 solution for 7 days, WMTA mixed with water or Na2HPO4 achieved a diametral tensile strength of 7.9 and 9.0 MPa, respectively, which was significantly lower (p < 0.05) than those obtained at pH 6.4 (11.2 and 12.0 MPa) but significantly higher (p < 0.05) than day 0 samples (4.4 and 4.8 MPa). Mixing WMTA with the accelerator did not significantly affect the microstructure, solubility, or strength in an acidic environment. (J Endod 2009;35: 98-101)