Effect of the calcium to phosphorus ratio on the setting properties of calcium phosphate bone cements.
α-Tricalcium phosphate (α-TCP) has become the main reactant of most experimental and commercial ceramic bone cements. It has calcium-to-phosphorus (Ca/P) ratio of 1.50. The present study expands and reports on the microstructures and mechanical properties of calcium phosphate (CP) cements containing sintered monolithic reactants obtained in the interval 1.29 < Ca/P < 1.77. The study focuses on their cement setting and hardening properties as well as on their microstructure and crystal phase evolution. The results showed that: (a) CP-cements made with reactants with Ca/P ratio other than 1.50 have longer setting and lower hardening properties; (b) CP-cements reactivity was clearly affected by the Ca/P ratio of the starting reactant; (c) reactants with Ca/P < 1.50 were composed of several phases, calcium pyrophosphate and α- and β-TCP. Similarly, reactants with Ca/P > 1.50 were composed of α-TCP, tetracalcium phosphate and hydroxyapatite; (d) only the reactant with Ca/P = 1.50 was monophasic and was made of α-TCP, which transformed during the setting into calcium deficient hydroxyapatite; (e) CP-cements developed different crystal microstructures with specific features depending on the Ca/P ratio of the starting reactant.
Interdepartment Research Group for the Applied Scientific Collaboration (IRGASC), Division of Biomaterials & Bioengineering, Technical University of Catalonia (UPC), Avda. Diagonal 647, 08028, Barcelona, Spain.
M D
MD
Vlad
S
S
Gómez
M
M
Barracó
J
J
López
E
E
Fernández
D001843:Bone Cements / Q000138:chemical synthesis / Q000737:chemistry*; D002118:Calcium / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000138:chemical synthesis / Q000737:chemistry*; D002484:Cementation / Q000379:methods; D011232:Chemical Precipitation; D019245:Compressive Strength; D003460:Crystallization; D006244:Hardness / Q000187:drug effects / Q000502:physiology; D006245:Hardness Tests; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D014961:X-Ray Diffraction
D001843:Bone Cements; D002130:Calcium Phosphates; D010758:Phosphorus; D002118:Calcium