Effects of four lubricants used during incremental insertion of two types of visible light-activated composites.

The effect of alcohols, bonding resins, or dentin adhesives on the adhesive bond between the layers of visible light-activated composites when used as lubricant for composite instruments was investigated. The results of this study indicated that alcohols are not compatible with certain BIS-GMA-based and UEDMA-based composite systems (Herculite and Heliomolar composites were used for this investigation). Use of ethanol as a lubricant caused pure adhesive failure and low bond strength in UEDMA-based composite (Heliomolar), indicating that the bond strength was less than the cohesive strength of the composite. A bonding resin of a similar brand (or the same system) used to lubricate the composite instrument did not affect the bond strength of the bonded composite specimens. In light of this study, a bonding resin of the same resin system as the composite may be the most suitable and reliable material to be used for lubricating the composite instrument.