The degrees of marginal leakage was tested for different restorative techniques with use of both ultraviolet-polymerized and cold-curing resins. All the materials tested showed severe marginal leakage when applied as conventional butt joint restorations. When the restorations were extended onto peripheral etched enamel, either with or without a sealant-primed etched surface, marginal leakage was prevented in most instances with both the cold-curing and ultraviolet-polymerized materials. However, the ultraviolet-polymerized sealant was more effective in preventing marginal leakage than the cold-curing sealants when applied as a covering over the restorations and extended onto the peripheral etched enamel.