Bio-coating formation on bio-active endodontic materials derived from Portland cement.

Objectives: The aim of this study was to assess the in vitro ability of experimental materials, derived from Portland cement and designed as endodontic sealers and root-end filling materials, to produce apatite on their surface in presence of phosphate ions. Materials and methods: Calcium chloride, calcium sulphate and a phyllosilicate were added to a thermally treated white Portland cement to prepare the experimental cements wTC1% and wTC1%-TCP. The cements were mixed with deionized water. Cement disks were prepared and immersed in DPBS at 37°C. ATR-FTIR, micro-Raman and SEM-EDX analyses were carried out at different storage times on both superficial/outer and internal/fractured surfaces of the discs. Results: SEM-EDX of cements surface showed high peaks of Ca, the disappearance of Si and the absence of P the early stages (1-7 days) of storage. Detectable amount of P and the formation of a coating layer P-containing on surface were revealed after 14 days. After 21 and 28 days a thick coating layer high in P was present on cements surface. Higher peaks of P were always displayed by wTC1%-TCP. The ATR-FTIR and micro-Raman spectra of the samples stored for 1 day revealed the presence of a poorly crystalline calcium phosphate deposit on the surface of both cements. The deposit seems to be thicker and more homogeneous on wTC1%-TCP than on wTC1%. The samples stored in DPBS for longer times (7, 14 days) displayed the same bands with a better-defined profile. The samples stored for 21 and 28 days showed the bands typical of a more crystalline carbonate-apatite layer. The deposit resulted to be more crystalline on the wTC1%-TCP. Conclusions: The experimental cements may be considered Bio-active materials for the ability to form apatite on their surface in presence of environmental phosphate ions. These materials represent innovative materials for endodontics and bone application.