Daguano, Juliana K. M. F.
Rogero, Sizue O.
Crovace, Murilo C.
dos Santos, Claudinei
Número total de Autores: 6
Afiliação do(s) autor(es):
 Univ Sao Paulo, Dept Engn Mat, Escola Engn Lorena, Lorena, SP - Brazil
 Inst Pesquisas Energet & Nucl, Sao Paulo - Brazil
 Univ Fed Sao Carlos, Lab Mat Vitreos, Dept Mat Engn, BR-13560 Sao Carlos, SP - Brazil
 Univ Fed Sao Joao del Rei, Sao Joao Del Rei, MG - Brazil
 UNIFOA, Ctr Univ Volta Redonda, Volta Redonda, RJ - Brazil
Número total de Afiliações: 5
Tipo de documento:
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE;
Citações Web of Science:
The mechanical strength of bioactive glasses can be improved by controlled crystallization, turning its use as bulk bone implants viable. However, crystallization may affect the bioactivity of the material. The aim of this study was to develop glass-ceramics of the nominal composition (wt%) 52.75(3CaO center dot P2O5)-30SiO(2)-17.25MgO, with different crystallized fractions and to evaluate their in vitro cytotoxicity and bioactivity. Specimens were heat-treated at 700, 775 and 975 A degrees C, for 4 h. The major crystalline phase identified was whitlockite, an Mg-substituted tricalcium phosphate. The evaluation of the cytotoxicity was carried out by the neutral red uptake methodology. Ionic exchanges with the simulated body fluid SBF-K9 acellular solution during the in vitro bioactivity tests highlight the differences in terms of chemical reactivity between the glass and the glass-ceramics. The effect of crystallinity on the rates of hydroxycarbonate apatite (HCA) formation was followed by Fourier transformed infrared spectroscopy. Although all glass-ceramics can be considered bioactive, the glass-ceramic heat-treated at 775 A degrees C (V775-4) presented the most interesting result, because the onset for HCA formation is at about 24 h and after 7 days the HCA layer dominates completely the spectrum. This occurs probably due to the presence of the whitlockite phase (3(Ca,Mg)O center dot P2O5). All samples were considered not cytotoxic. (AU)