Papers by Keyword: Tricalcium Phosphate (TCP)

Abstract: A Co-Cr-Mo (ASTM CoF-75) alloy is normally used because of their good in physical, mechanical, wear and as well as biocompatibility. In order to obtain similarity chemical structure of bone, addition of HAP or TCP into CoF-75 alloy is required. The samples were fabricated using powder metallurgy (P/M) technique under pressure of 350 MPa and sintered at 1200 °C under argon atmosphere. The results on the effect of different additives were studied in terms of shrinkage, bulk density, apparent porosity and microstructural analysis.

Abstract: Apatite formation behavior of tricalcium phosphate (TCP) ceramics with different phases and porosity was investigated in a simulated body fluid (SBF, Kokubo solution). The pure α-TCP with 80% porosity did not form hydroxyapatite (HAp) on its surface after soaking in SBF for 7 days. On the other hand, the pure α-TCP with 20% porosity formed HAp on its surface after soaking in SBF within 7 days, and the biphasic TCP, which consisted of mixture of α-TCP and β-TCP and had 20% porosity, formed HAp within 1 day. The low porosity and coexistence of α-TCP and β-TCP phases in TCP ceramics were effective for apatite formation in SBF.

Abstract: Surface morphology and degradation behavior of mechanically mixed and chemically precipitated biphasic calcium phosphate (M-BCP and P-BCP) were compared. For the M-BCP powder, commercial HA and TCP powders were used. In order to prepare P-BCP powder, precipitation method was used. The particle size of P-BCP was smaller than that of M-BCP. The disk-type specimens of each powder were prepared for the morphology comparison and degradation test. The surface morphology of sintered samples was porous in M-BCP and dense in P-BCP. The degradation test was conducted in the revised simulated body fluid (R-SBF) for 1, 7, and 21 days. Surface morphology and degradation rate of two samples were different. The weight gain in both samples increased linearly with immersion period due to apatite-like layer formation. However, the weight gain in M-BCP was much higher than that in P-BCP. The weight gain was related to the surface morphology and degradation with immersion period.

Abstract: Biphasic ceramic consisting of tricalcium phosphate with α- and β -phases (αβ-TCP) is a candidate as biodegradable bone substitutes since its biodegradability may be controlled by the ratio of the phases. In the present study, preparation of porous αβ-TCP body with continuous pores of 10-50 µm in diameter was attempted using additives of Mg, and its in vivo behavior was examined. Powder of β-TCP was mixed with Mg and potato starch to form slurry, followed by loading in polyurethane foam. The sample was fired at 1400°C for 12 hours for sintering process. α-TCP content of the sample decreased with increasing the Mg content, while β-TCP increased. Ceramic body consisting of β-TCP phase was obtained when 1.0 mass% of Mg was added. Porosity of the body decreased with increasing the content of Mg. The αβ-TCP body with 80% porosity was obtained when the content of Mg was 0.1 mass%. The in vivo experiments showed that the rate of degradation of the obtained αβ-TCP was almost same as α-TCP, and much higher than β-TCP.