Bond Strengths to Dentin and Enamel using Self-etch Adhesives

The values generated from shear bond strength testing can be affected by the direct restorative material selected.  Objective:  To determine the shear bond strength (SBS) to dentin and enamel of two self-etch adhesive systems with two resin-based restorative materials.  Methods:  Flat enamel and dentin bonding sites were prepared on the buccal surface of 80 extracted human teeth (40 each group).  Filtek Supreme and Beautifil II (Giomer) were bonded to enamel and dentin sites using Clearfil S³ Bond or OptiBond All-In-One (n = 10 each) using an Ultradent bonding assembly.  After 24 hours, specimens were loaded to failure at a speed of 1 mm/min.  Statistical analysis included ANOVA (factors: 1) adhesive, 2) substrate and 3) restorative) and Fisher's LSD post hoc test.  Results: (in Megapascals MPa).

The type of resin-based restorative material used was not a significant factor (p=0.419); however the factors of substrate and the adhesive were significant (p=0.000).  The interaction between the substrate and the adhesive was also significant (p=0.005).  All other interactions were not significant.  The SBS of Clearfil S³ Bond was similar in both enamel and dentin (p>0.05) but statistically less than OptiBond All-In-One for both enamel and dentin (p<0.05).  Values for Optibond All-In-One were significantly higher on dentin than enamel (p<0.05).  Conclusions:  Significant differences were observed for in-vitro dentin and enamel shear bond strengths between the self-etching adhesive materials tested.  The restorative materials used in this study were not significant factors affecting bond strengths.  Supported by the Health Future Foundation.