Preparation of tetracalcium phosphate from catile bone

Abstract

Tetracalcium phosphate (TTCP) was synthesized from cattle bone by sintering the eqiomolar mixture of dicalcium phosphate dehydrate with calcium carbonate and by sintering the stoichiometric mixture of gamma calcium pyrophosphate with calcium carbonate at 1350-1400℃ and following with quenching in air. Both methods could produce single phase TTCP but the second method gave a better reproducibility due to the lesser moisture in the furnace atmosphere. Self-setting calcium phosphate cements were prepared from an equimolar mixture of DCPD and TTCP, and the effects of the following factors on the compressive strength and setting time of cements were investigated : specific surface area of TTCP, seeding with hydroxyapatite (HA), powder /liquid ratio (P/L) and curing time. It was found that the compressive strength increased with the specific surface area of TTCP but decreased with the increase of the crystallinity of the HA seed. The highest 1 day compressive strength achieved with the pressed specimens (TTCP,1350℃, specific surface area of TTCP = 1.06±0.01 m²/g) with 35 wt% HA (70℃, specific surface area 140.15±4.20 m²/g), P/L ratio = 2.4 g/ml, was 16.2±3.0 MPa. The setting time of the cement decreased with the increase of specific surface area and content of HA seed.