抄録
We investigated how the thickness of an adhesive layer between two Co-Cr alloy plates affected the mode I fracture toughness of dental adhesive resin by varying the type of resin using a double cantilever beam (DCB) test. Two typical adhesive resins (PV and SB) were used. The adhesive layers of the DCB test specimens were 20, 100 and 200μm thick. The fracture modes of PV differed with the thickness of the adhesive layer, such as interface fracture at 20μm thickness, and similar cohesive fracture at 100 and 200μm thickness. In the case of SB, crackpropagating areas were observed as cohesive fractures in all test specimens with different adhesive layer thickness, and the surfaces of these areas became remarkably rougher as the thickness of the adhesive layer increased. The fracture toughness of PV was not affected by the difference in thickness between the 100 and 200μm adhesive layers, but there was a notable decrease in fracture toughness when the adhesive layer decreased to a thickness of 20μm. That of SB showed a tendency to increase as the adhesive layer became thicker.
