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Keywords:

  • apatite;
  • bioactive materials;
  • calcium hydroxide;
  • calcium release;
  • calcium-silicate cements;
  • endodontic cements;
  • fluorapatite;
  • fluoride release;
  • fluoride-doped MTA;
  • mineral trioxide aggregate

Gandolfi MG, Taddei P, Siboni F, Modena E, Ginebra MP, Prati C. Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: early fluorapatite formation in a phosphate-containing solution. International Endodontic Journal, 44, 938–949, 2011.

Abstract

Aim  To test the chemical–physical properties and apatite-forming ability of experimental fluoride-doped calcium silicate cements designed to create novel bioactive materials for use in endodontics and oral surgery.

Methodology  A thermally treated calcium silicate cement (wTC) containing CaCl2 5%wt was modified by adding NaF 1%wt (FTC) or 10%wt (F10TC). Cements were analysed by environmental scanning electron microscopy with energy-dispersive X-ray analysis, IR and micro-Raman spectroscopy in wet conditions immediately after preparation or after ageing in a phosphate-containing solution (Dulbecco’s phosphate-buffered saline). Calcium and fluoride release and pH of the storage solution were measured. The results obtained were analysed statistically (Tukey’s HSD test and two-way anova).

Results  The formation of calcium phosphate precipitates (spherulites) was observed on the surface of 24 h-aged cements and the formation of a thick bone-like B-type carbonated apatite layer (biocoating) on 28 day-aged cements. The rate of apatite formation was FTC > F10TC > wTC. Fluorapatite was detected on FTC and F10TC after 1 day of ageing, with a higher fluoride content on F10TC. All the cements released calcium ions. At 5 and 24 h, the wTC had the significantly highest calcium release (P < 0.001) that decreased significantly over the storage time. At 3–28 days, FTC and F10TC had significantly higher calcium release than wTC (P < 0.05). The F10TC had the significantly highest fluoride release at all times (P < 0.01) that decreased significantly over storage time. No significant differences were observed between FTC and wTC. All the cements had a strong alkalinizing activity (OH release) that remained after 28 days of storage.

Conclusions  The addition of sodium fluoride accelerated apatite formation on calcium silicate cements. Fluoride-doped calcium silicate cements had higher bioactivity and earlier formation of fluorapatite. Sodium fluoride may be introduced in the formulation of mineral trioxide aggregate cements to enhance their biological behaviour. F-doped calcium silicate cements are promising bone cements for clinical endodontic use.