Twenty recently extracted human molars had standardized Class II slot cavities prepared on the mesial and distal surfaces with the gingival floor located on dentin. The teeth were embeeded in a stone template, warmed to 37 degrees C, and restored immediately using one of two incremental placement techniques with visible light-cured composite (VLC), or one of two directed shrinkage placement techniques using an autocrure/VLC composite combination. Teeth were stored at 37 degrees C for 2 weeks, thermocycled, stained, sectioned in the middle of the preparation, and evaluated for dye penetration. Reevaluation of the microleakage following removal of the resin composite from the preparation revealed greater microleakage at the gingival margin than did the initial sectioning technique. There were no differences among any of the groups. Enamel margins exhibited minimal leakage and no differences among the groups.