Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31097
Microstructural and In-Vitro Characterization of Glass-Reinforced Hydroxyapatite Composites

Authors: Uma Batra, Seema Kapoor


Commercial hydroxyapatite (HA) was reinforced by adding 2, 5, and 10 wt % of 28.5%CaO-28.5%P2O5-38%Na2 O- 5%CaF2 based glass and then sintered. Although HA shows good biocompatibility with the human body, its applications are limited to non load-bearing areas and coatings due to its poor mechanical properties. These mechanical properties can be improved substantially with addition of glass ceramics by sintering. In this study, the effects of sintering hydroxyapatite with above specified phosphate glass additions are quantified. Each composition was sintered over a range of temperatures. Scanning electron microscopy and x-ray diffraction were used to characterize the microstructure and phases of the composites. The density, microhardness, and compressive strength were measured using Archimedes Principle, Vickers Microhardness Tester (at 0.98 N), and Instron Universal Testing Machine (cross speed of 0.5 mm/min) respectively. These results were used to indicate which composition provided suitable material for use in hard tissue replacement. Composites containing 10 wt % glass additions formed dense HA/TCP (tricalcium phosphate) composite materials possessing good compressive strength and hardness than HA. In-vitro bioactivity was assessed by evaluating changes in pH and Ca2+ ion concentration of SBF-simulated body fluid on immersion of these composites in it for two weeks.

Keywords: sintering, Composite, Bioglass, hydroxyapatite

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1531


[1] J. C. Knowles, "Development of a glass-reinforced hydroxyapatite with enhanced mechanical properties - the effect of glass composition on mechanical properties and its relationship to phase changes," J Biomed Mater Res, 1993, vol. 27, pp. 1591-1598.
[2] G. Evans, J. Behiri, J. Currey, and W. Bonfield, "Microhardness and Young's modulus in cortical bone exhibiting a wide-range of mineral volume fractions and in a bone analog," J Mater Sci - Mater Med, 1990, vol. 1, pp. 38-43.
[3] H. Aoki, Science and Medical Applications of Hydroxyapatite, Tokyo: Takayama Press System Centre, 1991.
[4] J. C. Knowles, "Development of hydroxyapatite with enhanced mechanical properties - effect of high glass additions on mechanical properties and phase stability of sintered hydroxyapatite," Br Ceram Trans, 1994, vol. 93(3), pp. 100-103.
[5] J. C. Knowles, S. Talal, and J. D. Santos, "Sintering effects in a glass reinforced hydroxyapatite," Biomaterials, 1996, vol. 17(14), pp. 1437-1442.
[6] M. A. Lopes, J. D. Santos, F. J. Monteiro, and J. C. Knowles, "Glassreinforced hydroxyapatite: a comprehensive study of the effect of glass composition on the crystallography of the composite, Biomed Mater Res, 1998, vol. 39(2), pp. 244-251.
[7] C. Rey, M. Freche, M. Heughebaert, J. C. Heughebaert, J. L. Lacout, and M. Vignoles, Apatite chemistry in biomaterial preparation, shaping and biological behaviour, In: W. Bonfield, G. W. Hastings, and K. E. Tanner, editors. Bioceramics, vol. 4. London: Butterworth Heinemann, 1991.
[8] R. Z. LeGeros, J. P. LeGeros, An introduction to bioceramics, In: L. L. Hench, and J. Wilson editors, World Scientific: Singapore, 1993.
[9] J. D. Santos, F. J. Monteiro, and J. C. Knowles, "Liquid-phase sintering of hydroxyapatite by phosphate and silicate glass additions - structure and properties of the composites," J Mater Sci-Mater Med, 1995, vol. 6(6), pp. 348-52.
[10] C. Rey, "Calcium phosphate biomaterials and bone mineral. Difference in composition, structure and properties," Biomaterials, 2000, vol. 11, pp. 13-15.
[11] J. D. Santos, P. L. Silva, J. C. Knowles, S. Talal, and F. J. Monteiro, "Reinforcement of hydroxyapatite by adding P2O5-CaO glasses with Na2O, K2O and MgO," J Mater Sci-Mater Med, 1996, vol. 7(3), pp. 187-189.
[12] S. R. Radin, and P. Ducheyne, "Effect of bioactive ceramic composition and structure on in vitro behavior. III. Porous versus dense ceramics," Biomed Mater Res, 1994, vol. 28, pp. 1303-1309.
[13] F. Ye1, X. Lu1, B. Lu1, J. Wang, Y. Shi, L. Zhang, J. Chen, Y. Li, and H. Bu, "A long-term evaluation of osteoinductive HA/β-TCP ceramics in vivo: 4.5 years study in pigs," J Mater Sci-Mater Med, 2007, vol. 18, pp. 2173-2178.
[14] N. Matsushita, H. Terai, T. Okada, K. Nozaki, H. Inoue, S. Miyamoto, and K. Takaoka, "A new bone-inducing biodegradable porous BETA.- tricalcium phosphate, Journal of Biomedical Materials Research - Part A, 2004, vol. 70, pp. 450-458.
[15] D. C. Moore, M. W. Chapman, and D. Manske, "The evaluation of a biphasic calcium phosphate ceramic for use in grafting long bone diaphyseal defects," J Orthop Res, 1987, vol. 5, pp. 356-365.
[16] W. Cao, and L. L. Hench, "Bioactive materials," Ceramics International, 1996, vol. 22, pp. 493 - 507.
[17] J. D. Santosa, Lakhan J. Jhab, and F. J. Monteiro, "Surface modifications of glass-reinforced hydroxyapatite composites," Biomaterials, 1995, vol. 16, pp. 521-526.
[18] E. J. Lee, H. E. Kim, and H. W. Kim, "Production of Hydroxyapatite/Bioactive Glass Biomedical Composites by the Hot- Pressing Technique," Journal of the American Ceramic Society, 2006, vol. 89, pp. 3593 - 3596.
[19] D. C. Tancred, A. J. Carr, and B. A. O. McCormack, "The sintering and mechanical behavior of hydroxyapatite with bioglass additions," J Mater Sci-Mater Med, 2001, vol. 12, pp. 81-93.
[20] M. Jarcho, "Calcium Phosphate ceramics as a hard tissue prosthetics," Biomaterials, 1981, vol. 12, pp. 157-168.
[21] Jae-Man Cho, "Formation and characterization of Hydroxyapatite coating layer by electron beam deposition," Journal of Material Research, 1999, vol. 14, pp. 145-158.
[22] C. J. Kirkpatrick, "A critical view of current and proposed methodologies for biocompatibility testing: cytoxicity in vitro," Regulatory Affairs, 1992, vol. 4, pp. 13-32.