title: Formulation and characterization of glass-ceramics based on Na2Ca2Si3O9-Ca5(PO4)3F-Mg2SiO4-system in relation to their biological activity.
abstract: Glasses having a chemical composition based on combeite [Na(2)Ca(2)Si(3)O(9)]-fluoroapatite [Ca(5)(PO(4))(3)F] and forsterite [Mg(2)SiO(4)] system were crystallized through controlled heat-treatment. Two forms of sodium calcium silicate e.g. combeite Na(2)Ca(2)Si(3)O(9) and pectolite Na(2)CaSi(3)O(8), were formed together with diopside (CaMgSi(2)O(6)) and monticellite (CaMgSiO(4)) in addition to fluoroapatite (Ca(5)(PO(4))(3)F) phases by thermal treatment of the glasses. Selected glass-ceramics were exposed to a simulated body fluid solution (SBF) which is close to human plasma for 3 weeks. Energy dispersive X-ray analysis (EDX) and inductive coupled plasma (ICP) analysis confirmed the formation of an apatite layer which indicate bioactivity in the all crystallized sample. A decreasing of surface bioactivity with increasing Mg(2)SiO(4)/Na(2)Ca(2)Si(3)O(9) replacement was observed as indicated by the decrease in the amount of apatite layer on the surface of the crystallized specimens. The Vicker's microhardness of the studied glass-ceramic materials are between 5,047 and 6,781 MPa.
authors: Glass Research Department, National Research Centre, El-Behoos St. Dokki, Cairo, Egypt. abomosallam@yahoo.com.au
authors: H A
authors: HA
authors: Abo-Mosallam
authors: S N
authors: SN
authors: Salama
authors: S M
authors: SM
authors: Salman
mesh_terms: D001031:Apatites / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002516:Ceramics; D005898:Glass; D008855:Microscopy, Electron, Scanning; D017640:Silicates / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D017640:Silicates; D017655:Silicon Compounds; C503823:forsterite; C025105:fluorapatite