Chemical Modification of MTA and CEM-cement to Decrease Setting Time and improve bioactivity properties by addition of alkalin salts."

Background: Mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM) cement are used for pulp capping since they induce the formation of dentinal bridge. Long setting time is a shortcoming of these cements. This study aimed to assess the effect of addition of some alkaline salts to MTA and CEM cement on their setting time, ion release profile, pH and surface morphology. Materials and Methods: In this in vitro experimental study, 5% calcium chloride (CaCl2 calcium oxide (CaO), sodium fluoride (NaF) and calcium nitrate [Ca(NO3)2] were separately added to MTA and CEM cement. The primary and final setting time of cements were measured using a Gillmore needle apparatus. Samples were immersed in simulated body fluid (SBF) for one, seven and 14 days and subjected to X-ray diffraction (XRD) and scanning electron microscopy (SEM)for phase identification and surface morphology assessment. The change in pH of solutions was studied and the calcium ion release profile was determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES).Data were analyzed using ANOVA followed by post hoc testResults: CaCl2 and CaO decreased the setting time of MTA, and Ca(NO3)2 decreased the setting time of CEM cement. Addition of salts increased the pH and calcium ion release from both cements, and hydroxyapatite deposits were noted covering the surface of samples (observed by SEM and confirmed by EDXA).Conclusion: Addition of CaCl2 and CaO to MTA and Ca(NO3)2 to CEM cement decreases their setting time and increase their pH and calcium ion release.