In this study, 4-META-containing (MC) and HEMA-containing (HC) adhesives were prepared. The effect of the amount of water added to the MC or HC adhesive on the demineralized amount of tooth apatite and tooth bonding performance were examined. The efficacy of 4-META was compared with that of HEMA. Increases in the amount of water resulted in increases in the demineralized amount of enamel and dentin apatite. However, the bond strengths of both adhesives were independent of the demineralized amount of tooth apatite. The MC adhesive exhibited a higher dentin bond strength than the HC adhesive. These results suggest that the addition of 4-META to one-step adhesive enhances the dentin bond strength more effectively than that of HEMA.

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To evaluate properties to bond to zirconia, four commercial resin cements, four resin-modified glass ionomer cements, conventional glass ionomer cement, and four primers were used. Furthermore, the relation between the compressive strength and tensile bond strength was examined. The tensile bond strength of one resin cement without a primer to the zirconia after 2,000 thermocycles was about 7.5MPa, while the metal tab came off from the zirconia surface during thermocycles when the other resin cements were used. The bond strength to zirconia treated with the four primers was improved, but became almost zero after 5,000 thermocycles. The bond strength of two resin-modified glass ionomer cements markedly decreased, but that of one resin-modified cements did not significantly change after 5,000 thermocycles. A correlation between the compressive strength and tensile bond strength of each cement was not identified.

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