Influence of the bleaching agent and adhesive system on the bond strength of the restorative material to intracoronary dentin

Resumo

The bond strength of dentin bleached with high
concentrated agents can be reestablished if the appropriate restorative
material is selected. Objective: The aim of this study was to evaluate
the influence of bleaching agents and adhesive system on bond
strength of restorative material to intracoronary dentin. Material
and methods: 60 fragments of intracoronary dentin (25 mm2) were
embedded in acrylic resin and divided into 3 groups (n = 10): GI
– not bleached (control), GII – 35% hydrogen peroxide (35HP), GIII
– 38% hydrogen peroxide (38HP). The gel was applied for 10 min
onto the dentin surface. This protocol was repeated three times
at a single session. After 14 days, the groups were divided into
subgroups according to the adhesive system used in the restoration:
A – Self-etching (Clearfil SE Bond) and B – Total etching (Single
Bond 2). The fragments were restored with Z100 Filtek resin using
a bipartite matrix. After 24 h, the specimens were subjected to
shear bond strength test. Data were analyzed by two-way ANOVA
and Tukey test (p < 0.05). Results: The group bleached with 38HP
(6.02 ± 3.95) had the highest bond strength to dentin, followed
by 35HP (5.36 ± 3.54), and control group (3.11 ± 2.71) (p < 0.05),
although without statistically significant differences. It was also verified
a higher bond strength in the group restored with the self-etching adhesive system (6.60 ± 4.18) when compared to the total etching
system (3.06 ± 1.57). Conclusion: When performing the restoration
of teeth bleached with hydrogen peroxide at high concentrations (35%
and 38%), self-etching adhesive system should be the first choice.