Dissolution kinetic and structural behaviour of natural hydroxyapatite vs. thermal treatment. Comparison to synthetic hydroxyapatite.

Abstract

International audienceThe dissoln. kinetic and structural behavior of natural hydroxyapatite (N-HA) and synthetic hydroxyapatite (S-HA) was studied vs. sintering temp. and using 'in vitro' expts. Obtained results highlight the chem. stability of N-HA. Any structural modification was obsd. until 1200°C. In the fact S-HA undergoes some modifications. XRD diagrams show the tricalcium phosphate (TCP) phase formation between 800 and 1100°C and tetracalcium phosphate (TetCP) phase formation at 1200°C. The 'in vitro' assay shows that the dissoln. was occurred more in N-HA than in S-HA. The formed TCP activated the dissoln. kinetic and then the pptn. phenomena when a continuous dissoln. of TetCP leaded to slow down the kinetic pptn