Fracture resistance of dentin-composite interfaces using different adhesive resin layers

Objectives: The objective of this study was to study the effect of different adhesive layers on the interfacial fracture toughness ( K ICi) of dentin-resin composite interfaces. Methods: Miniature short-rod fracture toughness specimens containing a chevron-shaped dentin-bonded interface along their midplane were used for testing. Each interface zone contained a thinned (one coat of unfilled adhesive resin, air-thinned), one-layer (one coat of unfilled adhesive resin, brush-thinned), two-layer (two coats of unfilled adhesive resin, brush-thinned), 10% filled or 45% filled adhesive resin layer. After storage in distilled water at 37°C for 24 h, the fracture toughness test specimens were loaded in tension at an extension rate of 0.5 mm/min until fracture and the K ICi were determined. The results were analysed by ANOVA and Fisher's LSD test ( p