Is a low viscosity bonding resin necessary?

Summary Low viscosity bonding resins have been introduced for use on etched enamel surfaces prior to the application of the viscous composite resins. In this in vitro study the effects of a low viscosity bonding resin on the bond strength, adaptation and microleakage of a composite resin to etched enamel were evaluated. The low viscosity bonding resin did not improve the tensile bond strength of a composite resin to etched enamel, did not increase resin penetration into etched enamel and did not decrease marginal leakage at the composite resin/etched enamel interface. The continued use of low viscosity bonding resins in clinical dentistry is questioned.