



@article {2624,
	title = {Reinforcement of hydroxyapatite by adding P                    2O
                    5-CaO glasses with Na
                    2O, K
                    2O and MgO
},
	journal = {Journal of Materials Science: Materials in MedicineJ. MATER. SCI. MATER. MED.},
	volume = {7},
	year = {1996},
	note = {Cited By (since 1996): 49Export Date: 21 November 2012Source: ScopusCODEN: JSMMELanguage of Original Document: EnglishCorrespondence Address: Santos, J.D.; Dept. of Metallurgical Engineering, FEUP, University of Porto, Rua dos Bragas, 4099 Porto Codex, PortugalChemicals/CAS: hydroxyapatite, 1306-06-5, 51198-94-8; magnesium oxide, 1309-48-4, 1317-74-4References: Barney, V.C., Levin, M.P., Adams, D.F., (1986) J. Perio Dont., 57, p. 764;Legeros, R.Z., (1988) Adv. Dent. Res., 2, p. 164; 
Aoki, H., (1991) Science and Medical Applications of Hydroxyapatite, p. 165. , Takayama Press System Center, JAAS, Tokyo; 
Ducheyne, P., (1987) J. Biomed. Mater. Res. Appl. Biomater., 21, p. 219; 
Heughbaert, J.C., Bonel, G., (1986) Biological and Biomechanical Performance of Biomaterials, p. 9. , edited by P. Christel, A. Meunier and A. J. C. Lee Elsevier Science Publishers B.V., Amsterdam; 
Ellis, L.G., Nelson, D.G.A., Featherstone, J.D.B., (1988) J. Biomed. Mater. Res., 22, p. 541; 
Raemdonck, W.V., Ducheyne, P., Meester, P.D., (1984) Metal and Ceramic Biomaterials, p. 143. , edited by P. Ducheyne and G. W. Hashi CRC Press, Boca Raton, FL; 
Shors, E.C., Holmes, R.E., (1993) An Introduction to Bioceramics, p. 181. , edited by L. L. Hench and J. Wilson World Scientific, Hong Kong; 
Rey, C., (1990) Biomaterials, 11, p. 14; 
Evans, G., Behiri, J., Currey, J., Bonfield, W., (1990) J. Mater. Sci. Mater. Med., 1, p. 38; 
Rey, C., Fr{\`e}che, M., Heughebaert, M., Heughebaert, J.C., Lacout, J.L., Vignoles, M., Bioceramics 4, London, 1991, p. 57. , edited by W. Bonfield, G. W. Hastings and K. E. Tanner (Butterworth-Heinemann, London); 
With, G., Van Dijk, H., Hattu, N., Prijs, K., (1981) J. Mater. Sci., 16, p. 1592; 
Akao, M., Aoki, H., Kato, K., (1981) J. Mater. Sci., 16, p. 809; 
Santos, J., Knowles, J., Reis, R., Monteiro, F., Hastings, G., (1994) Biomaterials, 15, p. 5; 
Soltesz, U., Richter, H., Kienzler, R., (1987) High Technology Ceramics, p. 110. , Elsevier Science Publishers, B.V., Amsterdam; 
(1971) Determination Micrographique de la Grosseur du Grain Ferritique ou Aust{\'e}nitique des Aciers; 
Daculsi, G., LeGeros, R.G., Nery, E., Lynch, K., Kerebel, B., (1989) J. Biomed. Mater. Res., 23, p. 883
},
	month = {1996///},
	pages = {187 - 189},
	publisher = {Chapman \& Hall Ltd},
	abstract = {Commercial hydroxyapatite was reinforced by adding small amounts (2 and 4 wt\%) of P                        2O
                        5-based glasses during its sintering process. The composites prepared had a chemical composition closely related to the mineral part of bone tissues in terms of trace elements usually detected, such as Na, K and Mg. X-ray diffraction analysis (XRD) showed that the glass reinforced-HA composites were composed of a HA matrix and variable amounts of tricalcium phosphate phase, depending on sintering temperature and glass composition. These composites were shown to have much higher biaxial bending strength than sintered HA, 107 MPa for Ha/2\% of 35P
                        2O
                        5-35CAO-10Na
                        2O-10K
                        2O-10MgO glass composite and 28 MPa for sintered HA. The presence of β-tricalcium phosphate in the microstructure of the composites is an important factor in the reinforcement process.
Commercial hydroxyapatite was reinforced by adding small amounts (2 and 4 wt\%) of P
                        2O
                        5-based glasses during its sintering process. The composites prepared had a chemical composition closely related to the mineral part of bone tissues in terms of trace elements usually detected, such as Na, K and Mg. X-ray diffraction analysis (XRD) showed that the glass reinforced-HA composites were composed of a HA matrix and variable amounts of tricalcium phosphate phase, depending on sintering temperature and glass composition. These composites were shown to have much higher biaxial bending strength than sintered HA, 107 MPa for Ha/2\% of 35P
                        2O
                        5-35CaO-10Na
                        2O-10K
                        2O-10MgO glass composite and 28 MPa for sintered HA. The presence of β-tricalcium phosphate in the microstructure of the composites is an important factor in the reinforcement process.
},
	keywords = {article, Bending strength, Bone, chemical composition, Composite materials, Composition, Composition effects, glass, Glass composition, Glass reinforced hydroxapatite composite, hydroxyapatite, implant, Magnesium Oxide, metal oxide, Microstructure, molecular dynamics, Phosphates, potassium derivative, priority journal, Sintering, Sintering temperature, sodium derivative, Thermal effects, Trace Elements, Tricalcium phosphate phase, X ray diffraction},
	isbn = {09574530 (ISSN)},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0030108677\&partnerID=40\&md5=e9c978c3e018a1dd2db9b534ef00ea1b},
	author = {Santos, J.D. and Silva, P.L. and Knowles, J.C. and Talal, S. and Monteiro, F.J.}
}
@article {2620,
	title = {Sintering effects in a glass reinforced hydroxyapatite},
	journal = {BiomaterialsBIOMATERIALS},
	volume = {17},
	year = {1996},
	note = {Cited By (since 1996): 39Export Date: 21 November 2012Source: ScopusCODEN: BIMADdoi: 10.1016/0142-9612(96)87287-5PubMed ID: 8830972Language of Original Document: EnglishCorrespondence Address: Knowles, J.C.; Eastman Dental Institute, Queen Mary and Westfield College, Mile End Road, London E1 4NS, United KingdomChemicals/CAS: Durapatite, 1306-06-5References: Currey, J.D., (1984) The Mechanical Adaptations of Bones, , Princeton University Press;Brown, W.E., Chow, L., Chemical composition of bone mineral (1976) Ann Res Mater Sci, 6, pp. 213-226; 
Glimcher, M.J., Recent studies of the mineral phase in bone and its possible linkage to the organic matrix by protein bound phosphate conds (1984) Phil Trans R Soc Land, B304, pp. 479-508; 
Cook, S.D., Thomas, K.A., Kay, J.F., Jarcho, M., Hydroxyapatite-coated porous titanium for use as an orthopaedic biologic attachment system (1980) Clin Orthop, 230, pp. 303-312; 
Patka, P., Den Otter, G., De Groot, K., Driessen, A.A., Reconstruction of large bone defects with calcium phosphate ceramics. An experimental study (1985) Neth J Surg, 37, p. 38; 
Wolford, L.M., Wardrop, R.W., Hartog, J.M., Coralline porous hydroxyapatite as a bone graft substitute in orthognathic surgery (1987) J Oral Maxillofac Surg, 45, pp. 1034-1042; 
Santos, J.D., Morrey, S., Hastings, G.W., Monteiro, F.J., The production and characterisation of a hydroxyapatite ceramic material (1991) Bioceramics, Vol 4. Proceedings of the 4th International Symposium on Ceramics in Medicine, 4, pp. 71-78. , Bonfield W, Hastings GW, Tanner KE, eds. London: Butterworth Heinemann; 
D{\"o}rre, E., Dawihl, W., Ceramic hip endoprostheses (1980) Mechanical Properties of Biomaterials, pp. 113-127. , Hastings GW, Williams DF, eds. New York: Wiley; 
Murray, M.G.S., Ponton, C.B., Marquis, P.M., Emulsion processing of hydroxyapatite (1992) Bioceramics, Vol 4. Proceedings of the 4th International Symposium on Ceramics in Medicine, 4, pp. 15-22. , Kyoto: Kobunshi Kankokai; 
Puajindanetr, S., Best, S.M., Bonfield, W., Characterisation and sintering of precipitated hydroxyapatite (1994) Br Ceram Trans, 93 (3), pp. 96-99; 
Knowles, J.C., Bonfield, W., Development of a glass reinforced hydroxyapatite with enhanced mechanical properties. The effect of glass composition on mechanical properties and its relationship to phase changes (1993) J Biomed Mater Res, 27, pp. 159-1598; 
Santos, J.D., Knowles, J.C., Reis, R.L., Monteiro, F.J., Hastings, G.W., Microstructural characterisation of glass reinforced hydroxyapatite composites (1994) Biomaterials, 15 (1), pp. 5-10; 
Knowles, J.C., Development of hydroxyapatite with enhanced mechanical properties: Effect of high glass additions on mechanical properties and phase stability of sintered hydroxyapatite (1994) Br Ceram Trans, 93 (3), pp. 100-103; 
Ruys, A.J., Wei, M., Sorrell, C.C., Dickson, M.R., Brandwood, A., Milthorpe, B.K., Sintering effects on the strength of hydroxyapatite (1995) Biomaterials, 16, pp. 409-415; 
Santos, J.D., Reis, R.L., Monteiro, F.J., Knowles, J.C., Hastings, G.W., Liquid phase sintering of hydroxyapatite by phosphate and silicate glass additions. Structure and properties of the composites (1995) J Mater Sci Mater Med, , to be published; 
Soltesz, U., Ritcher, H., Keinzler, R., (1987) High Tech Ceramics, p. 110. , Vincenzini P, ed. Amsterdam: Elsevier; 
Laugier, M.T., New formula for indentation toughness in ceramics (1987) J Mater Sci Lett, 6, pp. 355-356; 
Knowles, J.C., Abrahams, I., Bonfield, W., Effect of reinforcing glass composition on phase transformation and crystallographic parameters in hydroxyapatite (1993) Bioceramics, 6, pp. 191-196. , Ducheyne P, Christiansen D, eds. Butterworth-Heinemann
},
	month = {1996///},
	pages = {1437 - 1442},
	publisher = {Elsevier Science Ltd},
	abstract = {Glass was incorporated into hydroxyapatite (HA) to act as a sintering aid in order to improve the mechanical properties. The glass was added at 2 and 4 wt\% and the powders compacted uniaxially. The compacts were sintered at a variety of temperatures (1200, 1250, 1300 and 1350{\textdegree}C) and the effects of the glass addition and the firing temperature were studied to determine their effects on the sintering process. It was found that the glass promoted some phase changes, related to the amount of glass added to the composite. At 1200 and 1250{\textdegree}C, some β-tricaicium phosphate (TCP) was found with the residual being HA. However, at 1300 and 1350{\textdegree}C, both β- and α-TCP were formed. The 4 wt\% addition, as expected, promoted higher levels of secondary phases in the composite. The flexural bend strength (FBS) showed high values and also significant differences dependent on the amount of glass added. A 2 wt\% addition gave a gradual increase in FBS with temperature. With a 4 wt\% addition there was an increase in FBS, but above 1300{\textdegree}C there was a rapid decrease. These effects were mirrored in the linear shrinkage. Both the linear shrinkage and the FBS results were attributed to both the phase changes occurring and also change in grain size with increasing firing temperature.Glass was incorporated into hydroxyapatite (HA) to act as a sintering aid in order to improve the mechanical properties. The glass was added at 2 and 4 wt\% and the powders compacted uniaxially. The compacts were sintered at a variety of temperatures (1200, 1250, 1300 and 1350{\textdegree}C) and the effects of the glass addition and the firing temperature were studied to determine their effects on the sintering process. It was found that the glass promoted some phase changes, related to the amount of glass added to the composite. At 1200 and 1250{\textdegree}C, some β- tricalcium phosphate (TCP) was found with the residual being HA. However, at 1300 and 1350{\textdegree}C, both β- and α-TCP were formed. The 4 wt\% addition, as expected, promoted higher levels of secondary phases in the composite. The flexural bend strength (FBS) showed high values and also significant differences dependent on the amount of glass added. A 2 wt\% addition gave a gradual increase in FBS with temperature. With a 4 wt\% addition there was an increase in FBS, but above 1300{\textdegree}C there was a rapid decrease. These effects were mirrored in the linear shrinkage. Both the linear shrinkage and the FBS results were attributed to both the phase changes occurring and also change in grain size with increasing firing temperature.
},
	keywords = {article, Bending strength, Biomaterials, calcium phosphate, Chemistry, Physical, Durapatite, glass, Glass reinforced hydroxyapatite, Grain growth, hydroxyapatite, priority journal, Sintering, Sintering aid, temperature, tensile strength, Tricalcium phosphate, X-Ray Diffraction},
	isbn = {01429612 (ISSN)},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0030199532\&partnerID=40\&md5=e2e97bf466dcee25ee1b5c2c14022ecd},
	author = {Knowles, J.C. and Talal, S. and Santos, J.D.}
}
