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Sol–Gel Preparation and Properties of Fluoride‐Substituted Hydroxyapatite Powders
Author(s) -
Kim HaeWon,
Li LongHao,
Koh YoungHag,
Knowles Jonathan C.,
Kim HyounEe
Publication year - 2004
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2004.tb06344.x
Subject(s) - fluoride , ammonium fluoride , crystallinity , apatite , crystallite , materials science , fluorapatite , crystallization , dissolution , nuclear chemistry , sol gel , solubility , chemical engineering , mineralogy , inorganic chemistry , chemistry , organic chemistry , metallurgy , composite material , nanotechnology , engineering
Hydroxyapatite (HA) and fluor‐hydroxyapatite (FHA) powders were synthesized by a sol–gel method for usage as bone filler and drug carrier. Calcium nitrate and triethyl phosphite were used as precursors under an ethanol–water‐based solution. Different amounts of ammonium fluoride (NH 4 F) were incorporated for the preparation of FHA powders. With heat treatment above 400°C, a characteristic apatite phase was observed for all the sol–gel powders. However, the crystallization temperature decreased with increasing fluoride addition. The tricalcium phosphate (TCP) phase formed in the pure HA powder above 800°C was attenuated in the FHA powders, confirming an enhanced phase stability of the FHA powders. Increasing the F − addition improved crystallinity and increased the crystallite size, as was determined from X‐ray diffraction (XRD) analyses. The lattice parameters of the heat‐treated powders varied corresponding to the fluoride addition, i.e., a gradual decrease in the a ‐axis, while little change in the c ‐axis was observed with increasing fluoride addition, indicating a nearly complete substitution of fluoride within the apatite lattice. However, little difference was observed with heat‐treatment temperatures (400°–1000°C). The powders substituted with fluoride exhibited reduced dissolution rates in an in vitro solution as compared with the pure HA powder, suggesting the possibility of tailoring bioactivity with fluoride substitution.