Papers by Author: Koh-ichi Udoh

Abstract: We have previously reported that the carbonate apatite (CAP) foam that has similarities in both inorganic chemical composition and morphology to cancellous bone could be prepared from α-tricalcium phosphate (α-TCP) foam by the hydrothermal treatment with Na2CO3 at 200°C for 24 hrs. However, the crystallinity of the CAP foam was much higher than that of bone. In order to prepare CAP foam similar to cancellous bone in crystallinity as well as its inorganic composition and morphology, this study attempted to prepare CAP foam at lower temperature. Hydrothermal treatment at 100°C allowed low-crystalline CAP foam whereas longer period was imposed for complete conversion of α-TCP foam into CAP foam.

Abstract: Present study evaluated the feasibility of apatite monolith preparation from calcium sulfate monolith using ammonium phosphate solution. We found that calcium phosphate monolith transforms to apatitic monolith without changing its original morphology when a proper temperature and a proper phosphate solution was selected. Prepared apatite was B-type carbonate apatite with low crystallinity. Although mechanical strength of the apatite monolith was lower than original calcium sulphate monolith, we concluded present method may be useful for the fabrication of apatite monolith since we can prepare different shape of apatite monoliths based on the setting reaction of calcium sulphate and compositional transformation to apatitic mineral.

Abstract: Carbonate apatite form that has three-dimensional fully interconnected pore was prepared based on so-called ceramics form preparation method. First, a-tricalcium phosphate (a-TCP) form was prepared by immersing polyurethane form into a-TCP powder suspension. The form was heated in an electronic furnace for sintering a-TCP as well as for burning out of the polyurethane form. Then hydrothermal treatment was preformed at 200 degrees in the presence of saturated sodium bicarbonate for 24 hours. Although the mechanical strength of the carbonate apatite form was poorer when compared with a-TCP form, we found that the hydrothermal treatment of a -TCP form result in the formation of B-type carbonate apatite form without changing the ideal morphology of a -TCP form.