γ-Radiation-induced changes in structure and properties of tetracalcium phosphate and its derived calcium phosphate cement

The purpose of the present study was to investigate the γ‐radiation effect on the structure and properties of the single‐phase tetracalcium phosphate (TTCP) powder and its derived calcium phosphate cement (CPC). Experimental results show that low‐dosed (0–30 kGy) CPC has a setting time of 10–12 min, while high‐dosed (40–120 kGy) CPC has a setting time of 8–10 min. The low dose γ‐radiation does not significantly change porosity volume fraction or compressive strength of the CPC. The pH values of all CPC samples fell in a relatively narrow band, with a band width of 8.5–9.1 (in terms of pH value). With a dose of 10 or 20 kGy γ‐radiation, the TTCP–apatite conversion ratio does not change much. With 30 kGy the conversion ratio significantly increases and reaches a maximum value. With further increases in dose, the conversion ratio quickly declines. With increasing γ‐ray dose, the CPC morphology becomes more porous/loose and apatite particles become larger in size. When exposed to a high dose (120 kGy) of γ‐radiation, TTCP structure is radiation‐damaged, and γ‐ray‐induced formation of apatite is confirmed by transmission electron microscopic/selected‐area diffraction/lattice imaging analyses. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007