| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1992: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1991: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
The effect of tooth surface treatment and its mechanism was examined to obtain improved adhesion of restoraive resin. From the fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and adhesive strength studies with respect to collagen and acid-etched dentin, treated with aqueous solution of 2-hydroxyethyl methacrylate (HEMA), the following results were obtained. Water was an essential component in respect to the adsorption of HEMA to collagen fiber. Substantial amounts of HEMA were adsorbed by collagen fiber when the concentration range of HEMA in aqueous solution was 6-60wt%. Scanning electron photomicrographs of the dentin plates treated by various methods are illustrated. As stated in the Experimental section, the hydroxyapatite is removed and only collagen fibers are exposed. The phospholic acid and succinic acid-treated dentin plates show only dentinal-tuble structure of the dentin, but do not show individual collagen fibers. All collagen fibers collapsed and show a smooth appearance due to aggregate formation. Contrary to these two samples treated only by acid, the sample that is pre-treated by phospholic acid followed by HEMA solution treatment clearly shows individual collagen fibers. This morphological difference is likely caused by a stiffening effect by anti-plastization of the absorbed HEMA. In regard to tensile bond strength of a composite resin to dentin, 12.07, 10.9, and 7.04 MPa was obtained with phosphoric acid, 30%HEMA, citric acid, 30%HEMA and EDTA, 30%HEMA aqueous solution, respectively.
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