Effect of bulk insertion, prepolymerized resin composite balls, and beta-quartz inserts on microleakage of Class V resin composite restorations.

Polymerization shrinkage of resin composite at the margin can seriously decrease the longevity of the restoration. Three direct restorative techniques were evaluated for their effects on microleakage. Sixty Class V cavities were prepared in extracted human maxillary molar teeth. The cavities were restored with resin composite placed in one bulk increment, resin composite and a beta-quartz insert, or resin composite and a prepolymerized resin composite ball insert. After they were thermocycled and placed in 0.5% basic fuchsin for 24 hours, the specimens were sectioned and examined for microleakage. The restorations with a prepolymerized ball of resin composite exhibited significantly more microleakage than did restorations with a beta-quartz insert or restorations inserted in bulk.