Shear bond strength of one etch-and-rinse and five self-etching dental adhesives when used by six operators

Objective. To test the hypothesis that some single-bottle self-etching adhesives bond as well to enamel and dentin as a typical two-bottle etch-and-rinse adhesive. Material and methods. Six operators used one two-bottle etch-and-rinse dentin adhesive (Scotchbond MP) and five all-in-one self-etching adhesives (iBond Gluma Inside, Clearfil S³ Bond, iBond Experimental, Xeno IV, and G-BOND). Each operator carried out six bondings to enamel and six bondings to dentin with each adhesive. After 24 h of storage in water at 37°C, bond strength was determined in shear. Results. The pooled results of all the adhesives revealed no significant difference (p>0.05) in bond strength between dentin and enamel. However, there were significant differences (p<0.0001) between the different adhesives. The etch-and-rinse adhesive did better than the self-etching adhesives when substrate was not an issue (pooled enamel and dentin results). On comparing the performance of the different adhesives, it became clear that there were significant interactions (p<0.0001) between substrates and products. There were also significant differences (p<0.0001) between operators, and the interaction between operators and products was significant (p<0.0002). Conclusions. The tested etch-and-rinse adhesive did better than the tested self-etching adhesives. The shear bond strength results were also strongly affected by the operator as well as by the interaction between operator and used product. The pooled bond strength values of the different adhesives revealed no difference in bond strength to dentin versus enamel.