In this study, the amount of water sorption, flexural strength, flexural elastic modulus, fluidity, contact angle and inorganic filler content of five commercial low-viscosity resin composites were evaluated, and the surface of each cured composite was observed by scanning electron microscopy (SEM). The amount of water sorption varied from 4.9 to 23.0μg/mm³ with the product. Flexural strength also varied in the range of 160〜200 MPa with the product. Composites with a higher filler content showed a greater flexural elastic modulus. The fluidity of composite paste increased with a decrease in the apparent contact angle of the paste. Although 10〜15μm irregular-shaped fillers and spherical fillers under 1μm in diameter were found on SEM observation, the particle size of fillers differed with the product. It was suggested that the fluidity was influenced by the matrix resin monomer.

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To improve the bonding strength of adhesive resin cements to phosphate glass ceramics (PGC), the PGC surface was treated with various mordants containing Sn²⁺, Al³⁺, Fe³⁺, Mg²⁺, Co²⁺, Cu²⁺, Ni²⁺, La³⁺, and Zn²⁺ ion. In case of using Super bond C&B as the resin cement, the adhesive strength to the PGC surface treated with Sn²⁺, Al³⁺ and Fe³⁺ showed higher than that without mordant. With Panavia 21 EX, Sn²⁺ mordant only was effective. And adhesive functional monomer, such as 4-methacryloxy-ethyl trimellitic acid anhydride (4-META) or 10-methacryloxydecamethylene phosphoric acid (MDP), was required in order to improve the adhesive strength. The treatment of 3-methacryloxypropyl triisocyanatosilane (3-MPSN) and the hydrochloric, nitric, and citric acid as a pretreatment of mordant were not effective.

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The recent development of magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy has enabled us to investigate the structure of solids irrespective of their crystalline or amorphous state. MAS NMR analysis has been performed on the main constituents, such as Si, Al, Na, and O, of silicate and aluminosilicate glasses to elucidate the glass structure. ¹³C CP/MAS NMR has also been applied to polymeric materials to investigate their molecular structure. In this review, we give some examples regarding the application of simple ²⁷Al, ²⁹Si, ²³Na, ³¹P MAS NMR, and ¹³C CP/MAS NMR to elucidate the structure of glass related to the glass ionomer cements and their setting reaction.

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