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A series of TiO2 modified hydroxyapatite composites (HA/TiO2) with different compositions were prepared. Phase formations and morphologies of the obtained HA/TiO2 composite were characterised using X-ray diffraction and SEM, and their photocatalytic activities were also determined by decomposition of methylene blue solution. Filter cloths were prepared by depositing the composite on polyester non-wovens via pad dry cure, and their filtering effectiveness was examined by photocatalytic activity measurement and bactericidal test. Hydroxyapatite/TiO2 composites were successfully prepared and exhibited photocatalytic properties. With increasing ratio of anatase titania in the HA/TiO2 composite from 20 to 30 and 50%, photocatalytic activity of composite material increased such that HATi5050 composite exhibited the highest photocatalytic activity. Non-woven filters coated with HA/TiO2 composites also exhibited good photocatalytic activities. Less difference in photocatalytic activity between HATi7030 an...

To improve biphasic calcium phosphate (BCP) ceramic strength, well known biocompatible and strong ceramics such as SiO2, ZrO2 and TiO2 were added to BCP with hydroxyapatite/tricalcium phosphate ratios of 70:30 (BCP7030). SiO2, ZrO2 and TiO2 powders with 2, 5 and 10 wt-% each were mixed with the BCP7030 powder. X-ray diffractometry and scanning electron microscopy (SEM) were used to determine the crystal structures and morphology of the sintered samples respectively. The physical properties and flexural strength of the samples were measured. Cell proliferation and differentiation of osteoblast-like Saos-2 cells cultured on BCP ceramics were determined by Alamar Blue assay and alkaline phosphatase expression respectively. Finally, SEM was performed to investigate the cell morphology on the surfaces of the specimens. The BCP7030 sample with 10 wt-%TiO2 displayed an optimum bending strength of ∼61 MPa and showed the strongest enhancement of cell proliferation and differentiation among all tested reinf...

The aim of this study is to investigate glass compositions containing BaO and MgO with a view to improve the mechanical properties of conventional glass ionomer cements. Two glass systems based on the compositions of SiO2–Al2O3–CaF2–TiO2 and SiO2–Al2O3–CaF2–ZrO2 were prepared and reacted with an in-house produced co-poly(alkenoic acid) to produce glass ionomer cements. X-ray diffraction and X-ray fluorescence were used to determine the phases and chemical compositions of the glass after melting. The morphologies of the glass powder and cement surfaces were analysed by SEM. The compressive strength and the working and setting times of the cements were also measured. Cements prepared from glass systems of SiO2–Al2O3–CaF2–TiO2 and SiO2–Al2O3–CaF2–ZrO2 containing barium and magnesium ions showed significantly increased strength compared to their original glasses. ZrBa1Mg1 cement that contained equal amounts of barium/magnesium oxide possessed high cement strength at ∼110 MPa but long setting time at ∼16 min. ...

Two Lithium Disilicate (LD) glass ceramics based on SiO2-Li2O-K2O-Al2O3 system were prepared through a glass melting method. The glass rods were then fabricated into dental crowns via a hot pressing at 900˚C and 850˚C in order to study the effect of the pressing temperatures on the phase formation and microstructure of the glasses. Different samples of as cast glass and heat treated samples (600˚C and 700˚C) were used to press for investigating the effect of an initial microstructure on the hot pressing technique. Xray diffraction (XRD) and scanning electron microscopy (SEM) were performed to determine the phase formation and microstructure of the samples, respectively. XRD results show that the main crystalline structure was Li2Si2O5 by having Li3PO4, Li0.6Al0.6Si2O6, Li2SiO3, Ca5 (PO4)3F and SiO2 as minor phases. Glass compositions with different heat treatment temperatures exhibited a difference phase formations but have less effect during pressing. SEM micrographs showed the microstructure of Li2Si2O5 as lath-like shape in all glasses. With increasing the initial heat treatment temperature, the longer the lath-like crystals of lithium disilicate were increased especially when using glass heat treatment at 700˚C followed by pressing at 900˚C. This could be suggested that LD1 heat treatment at 700˚C which pressing at 900˚C presented the best formation by the hot pressing and compiled microstructure.

Calcium phosphate cement (CPC) is one of the most attractive bioceramics due to its moldable and shape ability to fill complicated bony cavities or small dental defect positions. In this study, CPC was produced by using mixture of tetracalcium phosphate (TTCP, Ca4O(PO4)2) and dicalcium phosphate anhydrous (DCPA, CaHPO4) in equimolar ratio (1/1) with aqueous solutions of acetic acid (C2H4O2) and disodium hydrogen phosphate dehydrate (Na2HPO4.2H2O) in combination with sodium alginate in order to improve theirs moldable characteristic. The concentration of the aqueous solutions and sodium alginate were varied to investigate the effect of different aqueous solutions and alginate on properties of the cements. The cement paste was prepared by mixing cement powder (P) with aqueous solution (L) in a P/L ratio of 1.0g/0.35ml. X-ray diffraction (XRD) was used to analyses phase formation of the cements. Setting time and compressive strength of the set CPCs were measured using the Gilmore apparatus and Universal testing machine, respectively. The results showed that CPCs could be produced by using both basic (Na2HPO4.2H2O) and acidic (C2H4O2) solutions. XRD results show the precipitation of hydroxyapatite in all cement samples. No change in phase formation among cements using difference concentrations of Na2HPO4.2H2O solutions. With increasing concentration of acidic solutions, samples obtained less hydroxyapatite with a high dicalcium phosphate dehydrate leaded to a shorter setting time. Samples with sodium alginate exhibited higher crystallization of hydroxyapatite than that of without alginate as a result of shorten setting time in a basic solution but a longer setting time in an acidic solution. The stronger cement was attained from samples using the acidic solution with sodium alginate; however the strength was lower than that of using the basic solution., {"references":["C.D. 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