Fabrication of hydroxyapatite block from gypsum block based on (NH4)2HPO4 treatment.
The aim of this study was to evaluate the feasibility of fabricating low-crystalline, porous apatite block using set gypsum as a precursor based on the fact that apatite is thermodynamically more stable than gypsum. When the set gypsum was immersed in 1 mol/L diammonium hydrogen phosphate aqueous solution at 100 degrees C, it transformed to low-crystalline porous apatite retaining its original shape. The transformation reaction caused a release of sulfate ions due to an ion exchange with phosphate ions, thus leading to a decrease in the pH of the solution. Then, due to decreased pH, dicalcium phosphate anhydrous--which has similar thermodynamic stability at lower pH--was also produced as a by-product. Apatite formed in the present method was low-crystalline, porous B-type carbonate apatite that contained approximately 0.5 wt% CO3, even though no carbonate sources--except carbon dioxide from air--were added to the reaction system. We concluded therefore that this is a useful bone filler fabrication method since B-type carbonate apatite is the biological apatite contained in bone.
Suzuki
Yumiko
Y
Department of Biomaterials, Faculty of Dental Science, Kyushu University, Higashi-ku, Fukuoka, Japan. yumi-szk@dent.kyushu-u.ac.jp
Matsuya
Shigeki
S
Udoh
Koh-ichi
K
Nakagawa
Masaharu
M
Tsukiyama
Yoshihiro
Y
Koyano
Kiyoshi
K
Ishikawa
Kunio
K
D018786:Bone Substitutes / Q000138:chemical synthesis*; D002133:Calcium Sulfate / Q000737:chemistry; D017886:Durapatite / Q000138:chemical synthesis*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
D018786:Bone Substitutes; D010710:Phosphates; D000644:Quaternary Ammonium Compounds; C024788:ammonium phosphate; D017886:Durapatite; D002133:Calcium Sulfate