To evaluate the water-absorbing properties of polymers including HEMA and adhesive monomers, an HEMA homopolymer(PHEMA), copolymers consisting of MMA and HEMA or adhesive monomers [(P(HEMA/MMA), P(MDP/MMA), P(Phenyl-P/MMA), and P(4-META/MMA)], and an MMA homopolymer(PMMA) were prepared and their water absorption, solubility, and compressive strength were measured. Water absorption increased with an rose in the underwater storage period up to 3 months in all the tested polymers, being largest in PHEMA and second largest in P(HEMA/MMA). Copolymers of adhesive monomers and MMA showed greater water absorption compared to PMMA. The solubility of the tested polymers showed a tendency similar to that of water absorption. The compressive strength of all polymers after underwater storage significantly decreased with an increase in the storage period. Since characteristic differences in water absorption, solubility, and compressive strength were found among polymers of MMA and HEMA or adhesive monomers, it was inferred that the adhesive durability would depend on the kinds of adhesive monomers used.

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In adhesive restoration, water intervention during or after the formation of the adhesive layer is an important factor having a decisive influence on adhesion. To improve the durability of the adhesive layer, two kinds of fluorine compounds: (sodium1-[(4-heptadecafluorooctyl)phenyl]-1-butyl-phenyl phosphate : FH3, and 2,2,2-trifluoroethyl methacrylate : 3FMA), were added to experimental selfetching primers on the HEMA-ethanol base containing 4-META(ME) or MDP, and measured bond strength was measured after one-year water storage or a thermal cycling test to evaluate the efficiency of the fluorine compounds. For adhesion to enamel, the addition of fluorine compounds to either adhesive monomer showed no effect. In contrast, for adhesion to dentine, the ME-containing primer added to 3FMA (0.5〜5% by weight) retained stable adhesive bonding over time, while the addition of FH3 had no effect. No distinct resin hybrid-layer was observed in any specimen on SEM observation. The results suggested that 3FMA would be a promising monomer to improve the durability of dentin adhesion of self-etching primers containing ME.

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To produce porcelain using a convenient method in which expensive equipment is not required, one and two percent aqueous solutions of poly (acrylic acid)s with a molecular weight of 7,000, 3〜4×10⁴, 30〜40×10⁴, and 100×10⁴, sodium silicate, poly (vinyl alcohol), polyethylene glycol 6,000, methyl cellulose 15cp, and CM-cellulose were respectively prepared as binding agents for the aggregation of the porcelain mud. The porcelain powder was UNIBOND VINTAGE (OPAL SUPER LUCENT, SHOFU). The porcelain was aggregated by the binding agents and then sintered. For the results, when one percent poly (acrylic acid) with a molecular weight of 7,000, sodium silicate, and poly (vinyl alcohol) were used as a binding agent, the operability for binding was good, and porcelain with luster was obtained. The compressive strength showed a value of over 400 MPa. In case of the poly (acrylic acid), the strength of the sintered porcelain increased, as the molecular weight decreased, and luster was achieved.

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