Influence of incorrect application of a water-based adhesive system on themarginal adaptation of Class V restorations

Purpose: To determine the influence of incorrectly performed steps during t he application of the waterbased adhesive system OptiBond FL on the margina l adaptation of Class V composite restorations. Materials and Methods: In 9 6 extracted human teeth Class V cavities were prepared. Half of the margin length was situated in dentin. The teeth were randomly divided into 12 grou ps. The cavities were filled with Prodigy resin-based composite in combinat ion with OptiBond FL according to the manufacturer's instructions (Group O) and including several incorrect application steps: Group A: prolonged etch ing (60 s); Group B: no etching of dentin; Group C: excessive drying after etching; Group D: short rewetting after excessive drying; Group E: air dryi ng and rewetting; Group F: blot drying; Group G: saliva contamination; Grou p H: application of primer and immediate drying; group I: application of on ly primer; group J: application of only adhesive; Group K: no light curing of the adhesive before the application of composite. After thermocycling, r eplicas were taken and the margins were quantitatively analyzed in the SEM. Statistical analysis of the results was performed using non-parametric pro cedures. Results: With exception of the "rewetting groups'' (D and E) and t he group with saliva contamination (G), all other application procedures sh owed a significantly higher amount of marginal openings in dentin compared to the control group(O). Margin quality in enamel was only affected when th e primer was not applied.