Hydroxyapatite ceramic bodies with tailored mechanical properties for different applications L. M. Rodrı ´guez-Lorenzo, 1 M. Vallet-Regı ´, 1 J. M. F. Ferreira, 2 M. P. Ginebra, 3 C. Aparicio, 3 J. A. Planell 3 1 Departamento de Quı ´mica Inorga ´nica y Bioinorga ´nica, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain 2 Departamento de Engenharia Cera ˆmica e do Vidro, UIMC, Universidade de Aveiro, 3810-193 Aveiro, Portugal 3 Departament de Cie `ncia dels Materials i Enginyeria Metallu ´ rgica, Universitat Polite `cnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain Received 27 March 2001; accepted 6 July 2001 Abstract: A perfect control on the final ceramic features will enable the research/clinical community to spread the use of calcium phosphate ceramic bodies to a large number of applications and/or requirements. The mechanical prop- erties of hydroxyapatite ceramic bodies manufactured by different techniques and with different porosities is pre- sented. The flexural strength, hardness, fracture toughness, surface roughness, and their evolution after immersion in SBF are studied. An increase of the mechanical properties with density is observed. The factors governing these results are analyzed. The increase of the porosity percentage of the bodies results in an increase on the surface roughness. The degradation studies show that the HA ceramics keep their integrity and mechanical properties under physiological conditions during the soaking time studied. The OHAp ceramic bodies with controlled porosity could be appropri- ated for hard tissue substitution or as a carriers for con- trolled delivery of drugs or as scaffolds for tissue engineer- ing. © 2002 John Wiley & Sons, Inc. J Biomed Mater Res 60: 159–166, 2002 Key words: hydroxyapatite ceramic bodies; applications; mechanical properties INTRODUCTION There is an escalating interest in calcium phos- phates, particularly apatites, which seems to be driven mainly by the requirements for the development, un- derstanding, and manufacture of biomaterials. 1 Thus, in recent years, an increasing number of articles have been published focusing on new routes or modifica- tions of old methods to synthesize calcium phos- phates. This literature has been conveniently reviewed by several authors. 1–11 The development of applications for porous ceramic bodies such as scaffolds for tissue engineering 12–16 and systems for controlled delivery of drugs 17–21 have largely contributed to this growing interest. The main drawback of porous and nonporous cal- cium phosphate ceramics is their weakness and the difficulty to manufacture bodies with the required shape. Thus, efforts to develop methods for processing porous bioceramics that enable the clinical and re- search community to spread their study and applica- tions are even more necessary now than before. Recently, a systematic study on the preparation of apatites with different stoichiometry and morphology has been carried out. 22 Then, the processing ability of these powders has been checked, and ceramic bod- ies with different porosity grades have been fabri- cated. 23–25 The knowledge gained enabled us to have a good control on the final ceramic characteristics, which is promising to design calcium phosphate ce- ramic bodies for different specific applications and/or requirements. Because the behavior of this kind of materials after implantation depends on the maintenance of the physical integrity in physiological conditions, a step forward now is to study the final mechanical proper- ties such as flexural strength, hardness or fracture Correspondence to: M. Vallet-Regı ´; e-mail: vallet@eucmax. sim.ucm.es Contract grant sponsor: JNICT (Portugal); contract grant number: PBIC/CTM/1968/95s Contract grant sponsor: CICYT (Spain); contract grant number: MAT99-0466 Contract grant sponsor: Spanish network “Fosfatos de cal- cio para la sustitución y regeneración o ´ sea;” contract grant number: C.I.C.Y.T MAT96-2106-E © 2002 John Wiley & Sons, Inc. DOI 10.1002/jbm.1286