Purpose: To evaluate the effect of chlorhexidine or glutaraldehyde pretreatment on the bonding stability of selfetching
and etch-and-rinse adhesives to bleached dentin.
Materials and Methods: The occlusal surface of 80 third molars was abraded to expose a flat mid-dentin surface,
which was then subjected to a bleaching procedure using 20% hydrogen peroxide and sodium perborate for
14 days. Afterwards, the specimens were kept in distilled water, followed by application of either a three-step etchand-
rinse (Adper Scotchbond Multi-Purpose Plus, SBMP) or a two-step self-etching (Clearfil SE Bond, CSE) adhesive
system. For each approach, the bleached dentin was treated with chlorhexidine or glutaraldehyde, or left untreated,
prior to the adhesive procedure. Unbleached dentin was used as a control. Composite cylinders were built up over
the adhesive-covered dentin followed by parallel sectioning of specimens to obtain 1-mm slices. The slices were
trimmed to obtain hourglass-shaped specimens with approximately 1.0 mm2 of bonding interface. Half of the specimens were subjected to microtensile bond strength (μTBS) testing after 24 h, while the other half were stored in distilled water for 3 months prior to the μTBS test. The mode of failure was analyzed using optical microscopy.
Results: For the SBMP protocol, the highest μTBS was achieved with glutaraldehyde-treated dentin, and the same
μTBS values were maintained after 3 months of storage. For the CSE protocol, the highest μTBS was obtained with
Conclusion: Glutaraldehyde and chlorhexidine pretreatment should be considered to improve the μTBS of adhesives
to bleached dentin, while the pretreatment effect was adhesive dependent.