Effects of resin-compatible cavity varnishes on the polymerization of visible light-cured composites

The effects of three proprietary resin-compatible cavity varnishes on the polymerization of two visible light-cured composites were investigated. A conventional varnish (Copalite) was included for the sake of comparison. The four cavity varnishes showed no significant difference in average hardness values of the light-cured composites when cured against completely set varnish. It was also found there was no statistical difference in the thickness of the uncured resin layer when the light-cured composites were cured against all four partially set cavity varnishes. The average thickness of the uncured resin layer in Silux was found to be significantly higher than that of Command Ultrafine. Based upon the hardness and thickness evaluations, the data of this study suggest that none of the four cavity varnishes (including Copalite) affected the hardness of the composites when allowed to set completely before the composite was applied. In contrast, all four tested cavity varnishes showed a softening of resin at the interface when the composites were cured against a partially set varnish. It is important therefore to permit the cavity varnish to dry completely before applying composite.