Introduction: Calcium-silicate cements (CS) are novel materials for endodontic and oral surgery able to set in wet/humid environment through the formation of a calcium-silicate hydrate gel. The addition of sodium fluoride delay their setting time and improve their expansion and sealing. The hypothesis was that fluoride addition improve the bioactivity of CS cements. Experimental F-doped cements were examined in real-time by environmental scanning electron microscopy (ESEM) with energy dispersive X-ray analysis (EDX) and by micro-Raman spectroscopy. Methods:A thermally treated calcium-silicate cement (wTC)was modified adding NaF 1%wt (FTC) or 10%wt (F10TC). Cement discs were analyzed by ESEM/EDX and micro-Raman in fresh wet conditions immediately after their preparation or after aging in DPBS at 37 ◦C for 24 hrs. and Calcium and fluoride releasing and pH of soaking water were tested using ion-selective electrodes. Results: ESEM/EDX of fresh/wet samples showed a nanoporous gel matrix mainly composed by calcium-silicate hydrates C-S-H (Ca and Si EDX peaks and Raman band 940-920 cm-1) and a network of nanopores filled with water nanodroplets. F10TC showed higher number of nanopores. EDX of 24-hrs aged samples showed higher P peaks on Fdoped cements. FTC and wTC surfaces were partially covered by spherulites together with irregular Ca/P precipitates; the surface of F10TC was covered by a homogeneous layer of apatite spherulites (0.2-0.8 microns) filling the nanopores. Micro-Raman demonstrated the earliest formation of apatite on F10TC; the rate of apatite formation was F10TC > FTC >wTC. Fluorapatitewas detected on F10TC. Fresh and aged cements proved high calcium release and alkalinizing ability (pH of soaking water basified to 10.5-12). Noticeable fluoride releasing was registered only from F10TC. Conclusions: Fluoride-doped calcium-silicate cements proved greater reactivity, earlier/higher bioactivity probably in relationship with higher number of nanopores than conventional CS. F-doped cements are promising bone-cements for endodontic and oral surgery.
Fluoride-doping of nanoporous calcium-silicate cement to enhance early fluorapatite formation / M. G. Gandolfi; F. Siboni; P. Taddei; C. Prati. - In: JOURNAL OF BIOTECHNOLOGY. - ISSN 0168-1656. - STAMPA. - 150S:(2010), pp. S203-S204. (Intervento presentato al convegno 14th International Biotechnology Symposium and Exhibition. Biotechnology for the Sustainability of Human Society tenutosi a Rimini nel 14-18 September 2010).
Fluoride-doping of nanoporous calcium-silicate cement to enhance early fluorapatite formation
GANDOLFI, MARIA GIOVANNA;SIBONI, FRANCESCO;TADDEI, PAOLA;PRATI, CARLO
2010
Abstract
Introduction: Calcium-silicate cements (CS) are novel materials for endodontic and oral surgery able to set in wet/humid environment through the formation of a calcium-silicate hydrate gel. The addition of sodium fluoride delay their setting time and improve their expansion and sealing. The hypothesis was that fluoride addition improve the bioactivity of CS cements. Experimental F-doped cements were examined in real-time by environmental scanning electron microscopy (ESEM) with energy dispersive X-ray analysis (EDX) and by micro-Raman spectroscopy. Methods:A thermally treated calcium-silicate cement (wTC)was modified adding NaF 1%wt (FTC) or 10%wt (F10TC). Cement discs were analyzed by ESEM/EDX and micro-Raman in fresh wet conditions immediately after their preparation or after aging in DPBS at 37 ◦C for 24 hrs. and Calcium and fluoride releasing and pH of soaking water were tested using ion-selective electrodes. Results: ESEM/EDX of fresh/wet samples showed a nanoporous gel matrix mainly composed by calcium-silicate hydrates C-S-H (Ca and Si EDX peaks and Raman band 940-920 cm-1) and a network of nanopores filled with water nanodroplets. F10TC showed higher number of nanopores. EDX of 24-hrs aged samples showed higher P peaks on Fdoped cements. FTC and wTC surfaces were partially covered by spherulites together with irregular Ca/P precipitates; the surface of F10TC was covered by a homogeneous layer of apatite spherulites (0.2-0.8 microns) filling the nanopores. Micro-Raman demonstrated the earliest formation of apatite on F10TC; the rate of apatite formation was F10TC > FTC >wTC. Fluorapatitewas detected on F10TC. Fresh and aged cements proved high calcium release and alkalinizing ability (pH of soaking water basified to 10.5-12). Noticeable fluoride releasing was registered only from F10TC. Conclusions: Fluoride-doped calcium-silicate cements proved greater reactivity, earlier/higher bioactivity probably in relationship with higher number of nanopores than conventional CS. F-doped cements are promising bone-cements for endodontic and oral surgery.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
