Physico-mechanical characteristics of tri-calcium silicate pastes as dentin substitute and interface analysis in class II cavities: effect of CaCl(2) and SBF solutions

The influence of using simulated body fluid (SBF) as a curing medium on some characteristics of pure single tri-calcium silicate (C(3)S) bio-cement was investigated. CaCl(2) salt solution was used as an accelerating liquid for setting and hardening of C(3)S pastes in comparison with distilled water (DW). Solid state reaction was applied to synthesis C(3)S phase at elevated temperature followed by rapid cooling. The results showed that 10 wt.% CaCl(2) solution was the optimum concentration that showed the lowest setting time (106 min). C(3)S pastes prepared with CaCl(2) solution have better physical and mechanical properties than those mixed with DW even after curing under SBF solution for the different curing ages. However, SBF solution has an adverse effect on the hydrated compound C-S-H that results in a little decrease in strength and hardness values. The elemental analysis emphasized the presence of apatite layer on the surface of the hardened C(3)S paste. Scanning electron microscopy (SEM) photomicrographs and elemental analysis revealed reliable adaptation of the experimentally prepared C(3)S paste to the tooth structure, in addition to its bioactivity makes it a consistent material to be used as dentin substitute.