title: Fabrication of B-type carbonate apatite blocks by the phosphorization of free-molding gypsum-calcite composite.
abstract: B-type carbonate apatite (CO3Ap) block may be an ideal artificial bone substitute because it is closer in chemical composition to bone mineral. In the present study, the feasibility to fabricate CO3Ap blocks was investigated using compositional transformation, which was based on the dissolution-precipitation reaction of a gypsum-calcite composite with free-molding behavior. For the compositional change, or phosphorization, gypsum-calcite composites of varying CaCO3 contents were immersed in 1 mol/L (NH4)3PO4 aqueous solution at 100 degrees C for 24 hours. No macroscopic changes were found after the treatment, whereas microscopic change was observed at SEM level. X-ray diffraction, Fourier transform infrared spectroscopy and CHN analysis indicated that the composites were B-type CO3Ap containing approximately 6-7 wt% of CO3, a value similar to that of biological bone apatite. Diametral tensile strength of the CO3Ap block was approximately 1-3 MPa. Based on the results obtained, it was therefore concluded that gypsum-calcite was a good candidate for the fabrication of CO3Ap blocks, coupled with the advantage that the composite can be molded to any shape by virtue of the setting property of gypsum.
authors.affiliation: Department of Biomaterials, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Chowdury Tanira
authors.initials: CT
authors.lastname: Zaman
authors.forename: Akari
authors.initials: A
authors.lastname: Takeuchi
authors.forename: Shigeki
authors.initials: S
authors.lastname: Matsuya
authors.forename: Q H M Shawket
authors.initials: QH
authors.lastname: Zaman
authors.forename: Kunio
authors.initials: K
authors.lastname: Ishikawa
mesh_terms: D001031:Apatites / Q000138:chemical synthesis* / Q000737:chemistry; D018786:Bone Substitutes / Q000138:chemical synthesis* / Q000737:chemistry; D002119:Calcium Carbonate / Q000737:chemistry*; D002133:Calcium Sulfate / Q000737:chemistry*; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D005240:Feasibility Studies; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000737:chemistry; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D018786:Bone Substitutes; D010710:Phosphates; C024788:ammonium phosphate; C030782:carboapatite; D002119:Calcium Carbonate; D002133:Calcium Sulfate