Post-bleaching application of an antioxidant on dentin bond strength of three dental adhesives

Abstract

Background: Antioxidizing agents have recently been suggested to compensate decreased bond
strength 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/delayed
for 1 week, and bleached/applied antioxidizing agent.
Materials and Methods: The dentinal surfaces of 132 intact extracted molars were prepared and
divided into 12 groups. The following adhesives were investigated: Optibond FL (OFL) (three-step
etch-and-rinse), Optibond Solo Plus (two-step etch-and-rinse), and Optibond all-in-one (OA) (onestep
self-etch) (Kerr, Orange, USA). Unbleached dentin groups (groups 1-3) were prepared as negative
controls (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), or
after 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 statistically
significant difference in SBS were noted when the SA and delayed bonding groups were compared
with 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 affected
with the adhesive system. Reduced SBS to bleached dentin can be amended by the use of SA as
an antioxidizing agent. However, the amount of reversed bond strength subsequent to applying
antioxidant might be related to the kind of dental adhesive.
Key Words: Antioxidant, bond strength, bleaching, dentin, etch-and-rinse adhesives, self-etch
adhesives