PHYSICAL AND CHEMICAL-PROPERTIES OF A NEW ROOT-END FILLING MATERIAL

This study determined the chemical composition, pH, and radiopacity of mineral trioxide aggregate (MTA), and also compared the setting time, compressive strength, and solubility of this material with those of a malgam, Super-EBA, and Intermediate Restorative Material (IRM). X-ray energy dispersive spectrometer in conjunction with the scanning electr on microscope were used to determine the composition of MTA, and the p H value of MTA was assessed with a pH meter using a temperature-compen sated electrode. The radiopacity of MTA was determined according to th e method described by the International Organization for Standardizati on. The setting time and compressive strength of these materials were determined according to methods recommended by the British Standards I nstitution. The degree of solubility of the materials was assessed acc ording to modified American Dental Association specifications. The; re sults showed that the main molecules present in MTA are calcium and ph osphorous ions. In addition, MTA has a pH of 10.2 initially, which ris es to 12.5 three hours after mixing. MTA is move radiopaque than Super -EBA and IRM. Amalgam had I the shortest setting time (4 min) and MTA the longest (2 h 45 min). At 24 h MTA had the lowest compressive stren gth (40 MPa) among the materials, but it increased after 21 days to 67 MPa. Finally, except for lRM, none of the materials tested showed any solubility under the conditions of this study.