The stress reducing capacity of unfilled resin in a Class V cavity

This study examined the stress reducing capacity of varying thicknesses of unfilled resin in a Class V cavity. A two dimensional plane strain mesh of a Class V cavity, 3 mm in diameter and 2 mm deep, was produced and the thickness of the unfilled resin layer was varied from 0 to 80 microm. A polymerization shrinkage of 1.5% was applied to the composite resin and the interfacial forces examined. The maximum shear stresses were found to occur along the pulpal floor of the restoration at the unfilled resin-dentine interface. The maximum shear stress values varied from 11.1 to 22.4 MPa and the shear stresses decreased by up to 38% as the thickness of the unfilled resin increased to 80 microm.