Fast-setting and anti-washout tricalcium silicate/disodium hydrogen phosphate composite cement for dental application

Although Mineral trioxide aggregate (MTA) has been widely used in endodontic treatments and gained great clinical success, development of fast-setting tricalcium silicate (TCS)-based cements with good anti-washout performance remains a huge challenge. Hence, this study was aimed at engineering a novel TCS-based endodontic material to meet abovementioned requirements via introduction of disodium hydrogen phosphate (Na 2 HPO 4 ) as the hydration accelerator. The setting time, flowability , mechanical strength and anti-washout property of the composite cements were evaluated. Furthermore, bioinert ZrO 2 was used as radiopacifier and the effects of ZrO 2 content on the radiopacity, physicochemical properties, apatite-formation ability, pH, antibacterial activity, cement-dentin interface and cell cytocompatibility of radiopaque composite cements with an optimal component were also investigated. The results showed that the setting time of cement pastes notably shortened from 169 to 33 min with adjusting the amount of Na 2 HPO 4 from 0 to 30 wt%, whereas flowability and compressive strength of cements exhibited a decreasing trend. Meanwhile, cement pastes displayed good anti-washout performance because of acceleratory effect of Na 2 HPO 4 on hydration process of TCS and formation of additional binding phase. Furthermore, the radiopacity of hybrid cements obviously enhanced with the addition of ZrO 2 while a little increase in setting time was observed, and washout resistance of composite pastes was slightly reduced with the increase in ZrO 2 amount. The radiopaque composite pastes could induce apatite deposition on their surfaces and showed good marginal adaptation at cement-dentin interface. Additionally, the addition of ZrO 2 content had no significant influences on alkaline formation ability, antibacterial activity, and cell cytocompatibility of cement pastes. Our results indicated that TCS/Na 2 HPO 4 /ZrO 2 cement exhibited a great potential to be used as a novel dental material and might be a promising candidate for endodontic treatments.