ANALYTICAL MODEL OF MICRO-TENSILE BOND STRENGTH AND FACTORS IN DENTAL ADHESIVE SYSTEMS

摘要

This study was to determine the strength and the factors in a microtensile test using a calculation model. The strength was considered as an interfacial strength along the interfaces between hybrid layer and mineralized dentine (interface Ⅰ), between adhesive resin layer and hybrid layer (interface Ⅱ) and between resin composite and adhesive resin layer (interface Ⅲ), associated with crack formation and propagation of a main crack. At first, the relation between interfacial properties and factors affecting the interfacial stress was introduced. Secondly, the model was done to clarify crack dimensions along the interfaces, considering a main crack formation and adhesive strength. The effective elasticity as Ec/ER (Ec, elasticity of each interface ; ER, elasticity of adhesive resin) changed from 0.3 to 1.0 at the interfacial stress = 10 to 100 MPa when the thicknesses of hybrid layer were 1, 5, and 50 μ m. The effective elasticity values of interfaces Ⅰ and Ⅱ were smaller than that of interface Ⅲ at the constant values of interfacial stress. The interfacial stress was determined when the thicknesses of adhesive resin layer and hybrid layer were given, and also the critical stress for a main crack formation was estimated.