Microstructure and color stability of calcium silicate-based dental materials exposed to blood or platelet-rich fibrin

Abstract

Objectives: To investigate the effects of blood and platelet-rich fibrin (PRF), commonly used scaffolds in regenerative endodontic treatment (RET), on the hydration, microstructure, and color stability of three hydraulic calcium silicate cements (HCSCs), OrthoMTA, RetroMTA, and TotalFill-BC-RRM.

Materials and methods: The HCSCs were prepared and placed into polyethylene molds and transferred to Eppendorf tubes containing PRF, blood, or PBS and then incubated for 1 week or 1 month. The microstructure and hydration of the cements were studied by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The chromatic alteration of materials was also measured using a spectrophotometer. The data for color stability were analyzed using 2-way analysis of variance and Tukey post hoc tests.

Results: There was no significant difference between the color stability of cements exposed to PBS (p > 0.05). The chromatic alteration of cements exposed to blood was significantly greater than those exposed to PRF and PBS (p < 0.001). In the presence of blood and PRF, the color change of OrthoMTA was significantly greater than that of RetroMTA and TotalFill (p < 0.05), with no significant difference between RetroMTA and TotalFill (p > 0.05). XRD analysis of all cements revealed a calcium hydroxide peak after 1-week and 1-month exposure to the media; however, OrthoMTA and TotalFill exposed to blood and PRF for 1 month showed weaker calcium hydroxide peaks. SEM images revealed cements exposed to PBS had a different surface microstructure compared to those exposed to blood and PRF. Furthermore, the surface microstructure of HCSCs was influenced by the type of cement radiopacifier (bismuth oxide or zirconium oxide). EDS analysis of the elemental composition in all groups displayed peaks of Ca, O, C, Si, P, and Al.

Conclusions: Color stability, hydration behavior, and microstructure of HCSCs were affected by exposure to PRF and blood and the type of cement radiopacifier.

Clinical relevance: As some important physicochemical properties of HCSCs could be influenced by the environmental conditions and the type of radiopacifier, alternatives to blood clot and HCSCs containing substitutes for bismuth oxide might be more suitable in RETs.

Keywords: Calcium silicate cements; Color stability; Hydration; Microstructure; Mineral trioxide aggregate; Regenerative endodontic treatment.