Saliva Contamination and Bond Strength of Two Adhesive Systems

Objectives: To evaluate the effect on bond strength to dentin after saliva contamination when using different adhesion strategies.
Methods: The coronal dentin from extracted human permanent molars (n=48) were randomly allocated to receive either a three-step etch-and-rinse adhesive system (Optibond FL) or a single-step system (Scotchbond Universal). The subgroups were 1) no saliva contamination (control), 2) contamination before primer/adhesive application without water rinsing, 3) contamination before primer/adhesive application with water rinsing, and 4) contamination after primer/adhesive application without water rinsing. A composite restorative material (Tetric EvoCeram) was used in all groups. Unstimulated human saliva was used for contamination. Each dentin-adhesive-composite specimen was sectioned for micro tensile testing (µTBS) after 24 hours storage. The data were analyzed by one-way ANOVA with Scheffe’s test.
Results: Overall, saliva contamination gave lower µTBS compared with controls. For the etch-and-rinse system water rinsing followed by air drying after etching and contamination reduced the µTBS significantly. Contamination after primer application had the most pronounced effect. For the single-step groups, only contamination before adhesive application, followed by air drying, significant reduced µTBS.
Conclusions: Saliva contamination significantly reduced the bond strength to dentin. The etch-and-rinse-adhesive were more sensitive than the single-step system to water rinsing as a decontamination strategy.