To examine the influence of acidic monomers in self-etching primer on the degree of polymerization of dual-curing resin cement, the bond strength of the resin cement to bovine tooth dentin or acrylic resin was determined while varying the primer treatment time and polymerization mode. Four adhesive resin systems, Bistite II (BII), Linkmax (LM), Panavia F2.0 (PF), and ResiCem (RC), were evaluated. In all systems except LM, the bond strength to dentin was not significantly influenced by the primer treatment time (10 or 30 sec) and polymerization mode (light- or self-curing) of resin cement (p>0.05). On the other hand, the bond strength to acrylic resin on which acidic monomers could remain was significantly influenced by the polymerization mode in all systems (p<0.01). This suggested that the effect of acidic monomers appeared more easily in self-curing mode, and all systems had some means to reduce this effect.

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The purpose of this study was to evaluate the influence of dynamic loading on glass fiber reinforced hybrid resin in a moist oral environment on the bending strength. Up to 5×10⁵ cycles (100N, 200N, and 300N) of cyclic impact load were applied to glass fiber reinforced hybrid resin immersed in water at temperatures of 37℃ and 55℃, and the residual bending strength as well as the number of unfractured specimens after impact loading were determined. From the results, the mean residual bending strength for the impact load of 100N at temperatures of 37℃ and 55℃ were 634.0MPa and 636.0MPa, respectively. All specimens fractured at less than 5×10⁵ cycles for loads of 200N and 300N. As the maximum load increased and the immersion temperature elevated, a decreased cycle number to fracture and fatigue due to cyclic impact loading were observed.

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The aim of this study was to measure the machining accuracy of CAD/CAM crowns applying a 3D measuring system and μCT, and compare the accuracy of these two different measuring systems. From the results of t-tests for the machining accuracy of 3D and μCT, it was shown that there were significant differences between 1.2 and 2.0mm. However, their accuracy was almost the same, so μCT was shown to be a useful technique to assess the machining accuracy of CAD/CAM crowns nondestructively.

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Composite resins have been in clinical use for over 50 years. Papers on composites have been classified into components and properties and reviewed. Studies have been conducted in most fields of composites; however, in some fields, more data are necessary to clarify the properties of composite resins such as matrix monomer selection, the water absorption of each monomer component, and biological properties such as reactions between components and oral enzymes, and those in the human body.

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