| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1999: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1998: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
Thin calcium-phosphate coatings prduced by the ion beam mixing method instead of the plasma spraying method were amorphous, resulting in films that easily dissolved in simulated body fluid. These costings crystallized with conventional heat treatment in an electric furnace but tended to crack easily. Therefore, this study aimed to find a suitable heat treatment that controls the solubility of Ca-P coations without weakening adhesion to titanium substrate. Thin coatings (approximately 1 μm) were coated onto the titanium substrates, followed by heat-treatment with conventional furnace heating and rapid heating of infrared radiation and laser radiation. These data indicate that rapid, homogeneous, and comparatively low temperature heating such as defocused infrared radiation around 600℃ controls Ca-P solubility and ensures the adherence of the coatings.
Bisphosphonates are a new class of drugs that have developed for use in treating several diseases related to bones, teeth, and calcium met
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abolism. These compounds are potent inhibitors of bone resorption, and inhibit soft tissue calcification in vivo. The efficiency of surface modifications on the immobilization of bisphoshonates on titanium was investigated with Ca-ion implantation, thin hydroxyapatite coatings and β-tricalcium phosphate coatings. The ALP activity of osteoblastic cells and the inhibitory effects on the initial adherence of P. gingivalis were also evaluated using bisphosphonate-immobilized titanium. X-ray photoeletron spectroscopy analysis suggested that titianium surfaces modified with Ca-ion implantation and thin hydroxyapatite coatings caused the immobilization of bisphosphonate on titanium plates.The ALP activity of osteoblastic cells cultured on plates immobilized with bisphosphonate was almost same as that of cells cultured on titanium plates, indicating that the bisphosphonate-immobilization showed no toxic effect on osteoblastic cels, and that it provides a favorable micro-enviroment with osteogenetic ability. Data of the adherence of oral bacteria showed that a bisphosphonate-immobilized titanium surface inhibited the initial adherence of P. gingivalis. These results indicate that the immobilization of bisphosphonates on titanium modified with Ca-ion implantation and thin hydroxyapatite coatings are useful for dental implants.
Activity of osteoblastic cells, which were isolated from calvariae of rats, decreased on the Ca-P surface with high dissolution rate in vitro. The surfaces of Cp-titanium of 3.0mm in diameter were modified with (1) titanium-blast + acid etching, Ca-implantation, thin HA coating of 0.5μm in thickness using an ion beam dynamic mixing (IBDM) method, and hisphosphonate-treating at a bone tissue/implant interface, (2) making a hole with pore size of 100 μm at a soft tissue/implant surface with 0.5mm and 1.5mm wide,and (3) F-implantation and alumina coating of 1μm in thickness at surfaces exposed to oral cavity. These implants were implanted into Beagle dogs, and then carried out with histopathological examination at 4 an 8 weeks after implantation. Even though a detailed analysis was not yet done, ossointegration was observed on comparative early stage after implantation. Less
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