Mechanical properties and microstructure analysis of mineral trioxide aggregate mixed with hydrophilic synthetic polymer.

Abstract

In dentistry, mineral trioxide aggregate (MTA) has been widely used for root perforation, retrograde filling, pulp capping and regenerative endodontics. Despite its superior sealing ability and biocompatibility, MTA has critical drawbacks regarding handling property such as sandy property, lacking cohesive properties and wash-out tendency. So, it is necessary to improve the fluidity of MTA in order to improve its handling properties. In this study, we applied modified liquid to improve handling properties of MTA. Polyvinyl alcohol (PVA; 3 and 5 wt %) aqueous solutions were prepared and the samples were divided into three groups: DW group (MTA mixed with distilled water), P3 group (MTA mixed with 3% PVA), and P5 group (MTA mixed with 5% PVA). Handling property, initial setting time, and compressive strength were evaluated. The microstructures were observed by Field emission scanning electron microscope (FE-SEM) and X-ray diffractometer (XRD) phase analyses were performed. PVA modified group showed similar behavior of IRM compared to DW group. The initial setting time of P3 or P5 group was significantly longer than that of DW group (p < 0.05). The compressive strength of DW group was higher than that of P3 or P5 groups (p < 0.05). Experimental groups (P3 and P5) showed no microstructural differences compared with DW group when the fractured surfaces were observed by FE-SEM with XRD patterns after 3 and 14 days. Polyvinyl alcohol, a modified liquid for MTA, improved the handling properties of the material without violating its microstructure.