Microleakage in three designs of glass ionomer under composite resin restorations.

Three Class V cavity configurations with walls above and below the cemento-enamel junction were compared when 'sandwich' technique restorations with glass ionomer and composite resin were used. No dye penetration occurred at the occlusal cavosurface margin when the latter was bevelled and light-cured Scotchbond was applied to the etched enamel before restoration with Durafil composite resin. The least dye penetration at the gingival margin was observed when Ketac bond glass ionomer covered the entire non-bevelled wall. No configuration entirely eliminated dye penetration at the gingival margin.