Selection of Composite Resin Affects Shear Bond Strength to Dentin

Objectives: The purpose of this study was to evaluate the effects of changing the composite resin material on the 24-hour shear bond strength (SBS) of composite resin to dentin using two Universal adhesive systems.
Methods: Flat bonding surfaces were prepared on extracted human molars (400 grit surface) exposing dentin. Groups (n=8) were prepared in the self-etch (SE) mode for Prime & Bond active (PB) and AdHese Universal (AU) dental adhesives (DA). The adhesives were applied per IFU. Following application and light curing of the adhesive bonded assemblies were formed using an Ultradent bonding fixture. Spectrum TPH3 (T), Quixx (Q), and Clearfil AP-X (X) composite resin restoratives were bonded to the prepared surfaces. After water storage for 24 hours at 37°C the specimens were debonded and shear bond strength (SBS) was calculated (MPa). 2-way ANOVA and LSD post-hoc test was used for determining group differences at p<0.05. 1-way ANOVA was used to identify differences per adhesive (capital letter) or composite (letter) at p<0.05.
Results: Mean SBS for the three composite resins and 2 adhesives are shown in table 1. Composite resin was a significant factor (p≤0.0005). There was not a significant difference in SBS for any composite between the adhesives (p>0.05). However X generated significantly higher SBS compared to T and Q (p<0.05) for both adhesives.
Conclusions: The selection of the composite material was a significant factor in the mean SBS of universal adhesives to dentin.