Hydration characteristics of Biodentine and Theracal used as pulp capping materials

Objectives. Investigation of the hydration and characterization of Theracal and Biodentine used for pulp capping. Methods. The setting mechanism and characterization of set Biodentine and Theracal after immersion in Hank's balanced salt solution (HBSS) for 28 days was investigated by scanning electron microscopy (SEM) of polished specimens and X-ray diffraction (XRD) analysis. The bioactivity and surface microstructure of cements immersed in HBSS or water was also assessed by similar techniques together with leaching in solution investigated by ion chromatography (IC). Results. Biodentine hydration resulted in the formation of calcium hydroxide which was present in the material matrix and also on the material surface. Theracal was composed of large cement particles which showed some evidence of reaction rims on hydration. The material matrix included a barium zirconate phase as radiopacifier and also a glass phase composed of strontium, silicon and aluminum. This phase could not be detected in XRD analysis. Formation of a calcium phosphate phase was demonstrated on Theracal immersed in HBSS. Both materials leached calcium ions in solution. Conclusions. The presence of a resin matrix modifies the setting mechanism and calcium ion leaching of Theracal. The clinical implications of these findings need to be investigated. (C) 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.