An Evaluation of CaF2 Doping Tricalcium Silicate as Dental Restorative Materials

The aim of this study was to evaluate the suitability of CaF2 doping tricalcium silicate (Ca3SiO5, C3S) as dental restorative materials. The solid state reaction method was used to prepare CaF2 doping C3S (F-C3S) using CaCO3, SiO2 and CaF2 as the starting materials. The in vitro bioactivity, the rate of heat evolution and the compressive strength were investigated. The in vitro bioactivity was examined by soaking the pastes in simulated body fluid (SBF). The FTIR and SEM results indicated the hydroxycarbonate apatite (HCA) layers of F-C3S pastes and pure C3S pastes occurred after soaking for 1 day and 3 days, respectively. The difference in bioactivity was attributed to the formation of F-substituted apatite, which has a Ksp lower than HCA. As compared with the pure C3S, the rate of heat evolution during the hydration of F-C3S was slower. This was avail to the dimensional stability of dental restorative materials. The pastes of F-C3S had a lower early compressive strength in the early stage, but a higher compressive strength in the later stage. Our results indicated that F-C3S would be bonded better to the teeth because of the earlier formation of HCA and the higher later compressive strength. F-C3S may be a progressive candidate for dental restorative materials.