Bioactivity and biomineralization ability of calcium silicate-based pulp-capping materials after subcutaneous implantation

Abstract

Aim

To evaluate the abilities of three calcium silicate-based pulp-capping materials (ProRoot MTA, TheraCal LC, and a prototype tricalcium silicate cement) to produce apatite-like precipitates after being subcutaneously implanted into rats.

Methodology

Polytetrafluoroethylene tubes containing each material were subcutaneously implanted into the backs of Wistar rats. At 7, 14, and 28 days post-implantation, the implants were removed together with the surrounding connective tissue, and fixed in 2.5% glutaraldehyde in cacodylate buffer. The chemical compositions of the surface precipitates formed on the implants were analyzed with scanning electron microscopy-electron probe microanalysis (SEM-EPMA). The distributions of calcium (Ca) and phosphorus (P) at the material-tissue interface were also analyzed with SEM-EPMA. Comparisons of the thicknesses of the Ca- and P-rich areas were performed using Friedman test followed by Scheffe's test at a significant level of 5%.

Results

All three materials produced apatite-like surface precipitates containing Ca and P. For each material, elemental mapping detected a region of connective tissue in which the concentrations of Ca and P were higher than those seen in the surrounding connective tissue. The thickness of this Ca- and P-rich region exhibited the following pattern: ProRoot MTA > prototype tricalcium silicate cement ≥ TheraCal LC. ProRoot MTA had a significantly thicker layer of Ca and P than the other materials at all time points (P < 0.05), and a significant difference was detected between the prototype cement and TheraCal LC at 28 days (P < 0.05).

Conclusions

After being subcutaneously implanted, all of the materials produced Ca- and P-containing surface precipitates and a Ca- and P-rich layer within the surrounding tissue. The thickness of the Ca- and P-rich layer of ProRoot MTA was significantly thicker than that of the other materials.

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