Evaluation of the dimensional changes of mineral trioxide aggregate sealer

Abstract

To evaluate the setting time, early age restrained dimensional stability, fluid uptake, microstructure and porosity of a root canal sealer based on mineral trioxide aggregate (MTAS). The MTAS, mineral trioxide aggregate (MTA) and a commercially available sealer pulp canal sealer (PCS) were investigated. The setting time of the materials was determined according to ISO 6876; 2002. The dimensional change in the vertical direction was measured over a period of 7 days from setting time using a linear variable differential transducer. The test samples were restrained in lateral directions by the metal mould. The fluid uptake of the cements was evaluated in Hank's balanced salt solution (HBSS), and their porosity was investigated using light optical microscopy. The addition of a water-soluble polymer to MTA reduced its setting time but PCS displayed the shortest setting time (P < 0.05). The dimensional stability of the materials was not affected by the test environmental conditions (P > 0.05). PCS exhibited a much higher degree of shrinkage than MTA (P = 0.997, 0.640, 0.449, 0.191) and MTAS (P = 0.952, 0.523, 0.380, 0.149) at 3 h and 1, 3, 7 days, respectively, when allowed to set at 100% humidity. An increase in weight and expansion was recorded for MTA when immersed in HBSS. Microscope investigation of test specimens revealed the highest degree of porosity in MTA followed by MTAS and PCS. The novel sealer based on MTA demonstrated adequate setting time and was dimensionally stable. It has the potential to be used as root canal sealer cement in clinical practice.