Thermophysical properties and bonding with composite resin of premixed mineral trioxide aggregate for use as base material

Dental bases require low thermal conductivity and good mechanical properties, such as bonding with composite resins. This study aims to elucidate the physicochemical properties of premixed mineral trioxide aggregate (MTA) for its suitability as a dental base and to explore the optimal adhesive strategy with composite resin. The thermal conductivity and compressive strength of this premixed MTA are 0.12 W/(m•K) and 93.76 MPa, respectively, Which are deemed adequate for its application as dental base. When bonded to composite resin, the use of 37% phosphoric acid etching before applying the Clearfil SE bond significantly reduced the bonding strength between composite resin and premixed MTA. This was because the compressive strength and Vickers hardness of premixed MTA decreased, and tricalcium silicate was dissolved from the surface during acid etching. Therefore, it is recommended to avoid using 37% phosphoric acid etching when bonding premixed MTA and composite resin as a dental base.