In vitro degradation studies of calcium phosphate glass ceramics prepared by controlled crystallization

• Tipo: Artigo em Revista Científica Internacional
• Data: 2003

Autores

A. G. Dias (Autor) Outra; Maria Ascensão Lopes (Autor) FEUP; I. R. Gibson (Autor) Outra; José Domingos Santos (Autor) FEUP

Revista

Título: Journal of Non-Crystalline Solids

Vol. 330 Nº 1

Páginas: 81-89

ISSN: 0022-3093

Editora: Elsevier

Indexação

ISI Web of Knowledge - 40 Citações

ISI Web of Science

Scopus - 48 Citações

COMPENDEX

Classificação Científica

FOS: Ciências da engenharia e tecnologias > Engenharia dos materiais

CORDIS: Ciências Tecnológicas > Engenharia > Engenharia de biomateriais ; Ciências Tecnológicas > Engenharia > Engenharia biomédica

Outras Informações

ID Authenticus: P-000-EFH

DOI: 10.1016/j.jnoncrysol.2003.08.056

Abstract (EN): Calcium phosphate glass ceramics with incorporation of small additions of two nucleating agents, MgO and K2O were prepared in the metaphosphate and pyrophosphate region, using an appropriate two-step heat treatment of controlled crystallization defined by differential thermal analysis results. Identification and quantification of crystalline phases precipitated from the calcium phosphate glass were performed using X-ray diffraction and Rietveld analysis. The beta-Ca2P2O7 (beta-DCP), KCa(PO3)(3), beta-Ca(PO3)(2) and Ca4P6O19 phases were detected in the glass ceramics. In order to evaluate the degradation of the glass ceramics prepared, degradation studies were carried out during 42 days in Tris-HCl solution at 37degreesC, pH 7.4, using granules in the range of 355-415 mum. The materials presented a weight loss ranging up to 12%. The ions leached during the immersion mainly originated from the KCa(PO3)(3) phase, probably due to the presence of K+ ion in the calcium metaphosphate, and the residual glassy phase. The structural changes at the surface of materials during degradation have been analyzed by Fourier transform infrared spectroscopy and X-ray diffraction. Results showed that significant surface changes occurred with immersion time, with the decrease of KCa(PO3)(3), beta-Ca2P2O7 and beta-Ca(PO3)(2) phases occurring at different periods of immersion. This study has demonstrated an easy way to prepared calcium phosphate materials with specific calcium phosphate phases and crystallization, and therefore specific degradation rates.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 9