Microleakage of composite resin inserted over an experimental liner: a laboratory study

The purpose of this study was to evaluate, in the laboratory, marginal leakage of an experimental liner that expands upon setting. The expansion could be effective in minimizing leakage of the composite materials due to polymerization shrinkage. The expansion appeared to affect leakage only some of the restorations. Large restorations apparently have too great a bulk of composite resin to be affected by the expansion of the experimental liner. It is recommended that an acid-etch/unfilled resin system be used in conjunction with the experimental liner to minimize leakage.