title: [Influence of tannic acid on physical and chemical properties of alpha-tricalcium phosphate-citric acid-tannic acid complex].
abstract: A mixture of alpha-tricalcium phosphate [alpha-Ca3(PO4)2; alpha-TCP] with a citric acid solution produces a hardened alpha-TCP-citric acid complex. The influence of tannic acid as an additive in the solution on the physical and chemical properties of the obtained complex was examined as a basic study for new calcium phosphate materials incorporating alpha-TCP. alpha-TCP was mixed with mixing liquids containing citric and tannic acids at various ratios [total acid = 45% (w/w)] at a powder/liquid = 2.2/1.0 (g/g). Compressive strength, setting time, and solubility & disintegration of the resulting complexes were measured by the methods specified by ADAS No. 61. After immersing the plates of the complexes in distilled water for 1 and 7 days, the surface structure of the plates was examined by using X-ray diffraction, scanning electron microscopy and IR spectroscopy. The substances solubilized and disintegrated in the water for 1 day were also examined by measuring quantitative Ca and P concentration. When the ratio of tannic acid to total acids (T/A) was higher than 30% (w/w), both setting time and solubility & disintegration increased remarkably. In the case of the complex at T/A = 30%, both setting time and solubility & disintegration showed the minimum value (6.25 min and 1.70%). For compressive strength, the maximum value (139 MPa) was obtained at T/A = 10%. Although the strength decreased markedly with increasing T/A beyond 10%, that of the complex at T/A = 30% was still a high level (103 MPa). The products on the surfaces before and after immersing the plates in distilled water were also discussed.
authors.forename: F
authors.initials: F
authors.lastname: Sugihara
authors.forename: T
authors.initials: T
authors.lastname: Ishii
authors.forename: T
authors.initials: T
authors.lastname: Takano
authors.forename: S
authors.initials: S
authors.lastname: Hata
authors.forename: H
authors.initials: H
authors.lastname: Oonishi
mesh_terms: D002130:Calcium Phosphates; D002951:Citrates; D019343:Citric Acid; D003799:Dental Stress Analysis; D047348:Hydrolyzable Tannins; D012995:Solubility; D013634:Tannins; D013997:Time Factors
chemical_list: D002130:Calcium Phosphates; D002951:Citrates; D047348:Hydrolyzable Tannins; D013634:Tannins; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D019343:Citric Acid; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous