Marginal gap repair with flowable resin-based composites

This study was designed to test the hypothesis that the flowable/dentin interface has the weakest bond and highest frequency of failure when a resin-based composite is repaired using a flowable composite. Comparing three specific groups--dentin, flowable composite, and hybrid composite-under the Kruskal-Wallis test showed that the mean bond strength values at the flowable/dentin interface and within the dentin were significantly lower than those at the hybrid/flowable interface and within the flowable resin. Dentin near the pulp chamber yielded consistently lower bond strength values than dentin located at the dentino-enamel junction. Bonding at the flowable resin/dentin interface showed the weakest bond and highest frequency of failure.