Effect of low-viscosity resins on the performance of dental adhesives

Purpose: To determine whether the use of low-viscosity intermediate resins (LVR) reduces microleakage of dental adhesive systems. Materials and Methods: Wedge-shaped Class V cavities were prepared in sound extracted molars. Occlusal margins were in enamel and gingival margins were in dentin/cementum. Five adhesive systems (All-Bond 2, Clearfil Liner Bond 2, OptiBond, Prime & Bond and Scotchbond Multi-Purpose) were applied to the preparations strictly according to manufacturers' directions on one side of the tooth and with the addition of LVR (OptiBond FL Adhesive or Protect Liner F) on the other. All cavities were restored with Z100 resin composite. Specimens were then stored in water at 37°C for 24 hours, thermocycled 800x, stained with silver nitrate, sectioned, and evaluated for leakage. Marginal penetration of silver nitrate was scored on 0-3 scale. Results: Statistical analysis (Kruskal-Wallis non-parametric ANOVA) revealed a significant difference (P<0.0001) in leakage at dentin margins. Multiple pairwise comparisons of control groups revealed considerable overlapping between groups, but with a trend toward less leakage by OptiBond and Clearfil Liner Bond 2. Leakage of Scotchbond Multi-Purpose was significantly reduced when Protect Liner F was used.