Objectives:
The aim of this study was to compare the shear bond strength (sbs) of three different
adhesives on bleached
enamel imm ediately after bleaching, bleached/delayed for 1 week, and bleached/applied antioxidizingagent. Study
Design:
The
enamel surfaces of 144 freshly extracted
incisors without any caries and restorations were flattened and divided into 12 groups. The following
adhesives were investigated Optibond FL (OFL) (three-stepetch&rinse), Optibond Solo Plus (OSP) (two-step etch&rinse), Optibond All-in-One (OA) (one-step
self-etch),(Kerr,
Orange, USA ). Unbleached
enamel groups were prepared as negative controls. The remainder surfaces were bleached with 20% Opalescent PF (Ultradent, USA ) 6 h/d for 5 consecutive days. Specimens were bondedimm ediately after bleaching, after 1 week or after using 10%
sodium ascorbate gel for 6 hours. After 500 rounds of thermocycling, sbs was measured and data was analyzed with Kruskall-Wallis and Mann-Whitney U-tests (á= 0.05).
Results:
The sbs decreased for the
adhesives after bleaching except for OFL. The effect of applying
sodium ascorbatesubsequent to bleaching was not equal for the studied
adhesives. While for OFL, sbs of the
sodium ascorbategroup was significantly higher than the unbleached
control group, for OSP, the
sodium ascorbate group had nostatistically significant difference with the unbleached
control group and for OA, sbs was significantly lower thanthe unbleached
control group.
Conclusions:
Different
adhesives demonstrate different degrees of reversed bond strength subsequent to applyingantioxidant. It seems the
method of application and the chemical composition of the
adhesives could
affect the
antioxidant as a
reducing agent (AU)