Isfahan University of Medical SciencesDental Research Journal1735-33279120120218Post-bleaching application of an antioxidant on dentin bond strength of three dental adhesives895895ENMaryamKhoroushiDepartment of Operative Dentistry and Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran. khoroushi@dnt.mui.ac.irTaherehSaneie20120218Background: Antioxidizing agents have recently been suggested to compensate decreased bondstrength of resin materials to bleached tooth tissues. This study compared the shear bond strength(SBS) of three different adhesives on bleached dentin immediately after bleaching, bleached/delayedfor 1 week, and bleached/applied antioxidizing agent.Materials and Methods: The dentinal surfaces of 132 intact extracted molars were prepared anddivided into 12 groups. The following adhesives were investigated: Optibond FL (OFL) (three-stepetch-and-rinse), Optibond Solo Plus (two-step etch-and-rinse), and Optibond all-in-one (OA) (onestepself-etch) (Kerr, Orange, USA). Unbleached dentin groups (groups 1-3) were prepared as negativecontrols (NC). The remainder surfaces (groups 4-12) were bleached with 20% Opalescent PF (Ultradent,USA). Specimens were bonded immediately after bleaching (groups 4-6), after 1 week (groups 7-9), orafter using 10% sodium ascorbate (SA) gel (groups 10-12). Subsequent to bonding of composite resin,the samples were tested for SBS and analyzed using Kruskal-Wallis and Mann-Whitney tests (α=0.05).Results: Regarding control groups, OA showed the highest SBS among the studied adhesives(P<0.05). The SBS decreased for the adhesives after bleaching except for OFL. No statisticallysignificant difference in SBS were noted when the SA and delayed bonding groups were comparedwith their similar NC groups (P>0.05) except the of delay bonding with OA.Conclusions: The findings suggest that bond strength of resin to bleached dentin may be affectedwith the adhesive system. Reduced SBS to bleached dentin can be amended by the use of SA asan antioxidizing agent. However, the amount of reversed bond strength subsequent to applyingantioxidant might be related to the kind of dental adhesive.Key Words: Antioxidant, bond strength, bleaching, dentin, etch-and-rinse adhesives, self-etchadhesives