Fabrication and mechanical properties of calcium phosphate cements (CPC) for bone substitution

• Published in: Materials Science and Engineering C: Biomimetic and Supramolecular Systems Vol. 31; no. 4; pp. 740 - 747
• Main Authors: Zhang, J T, Tancret, F, Bouler, J M
• Format: Journal Article
• Language: English
• Published: Elsevier 10.05.2011
• Subjects: Apatite; Bioengineering; Biomaterials; Calcium phosphate; Cements; Compressive strength; Life Sciences; Mechanical properties; Microstructure; Modulus of elasticity; Strength
• ISSN: 0928-4931
• DOI: 10.1016/j.msec.2010.10.014

Calcium phosphate cements have been used in medical and dental applications for many years but low strength and high brittleness prohibit their use in many stress-bearing locations. Apatite cements were fabricated through alpha-TCP (alpha-tricalcium phosphate) hydrolysis, and their mechanical properties (Young's modulus, fracture toughness and compressive strength) were measured as a function of various parameters such as particle size, liquid-to-powder ratio, amount and morphology of porosity, including macropores created by mannitol particles used as porogen. Five days after the mixing of phases, identification and microstructural observation indicated the presence of unreacted alpha-TCP particles, exhibiting very weak links with the apatite matrix and often surrounded by microcracks, causing a decrease in Young's modulus. The coarser the microstructure, the larger the critical flaw size causing fracture. In the case of macroporous materials, the critical flaw size increased with macroporosity. The knowledge gained should help to improve the mechanical properties by controlling the microstructure, and should help to find a better compromise between strength and biological behaviour.