Bond strength of dentin submitted to bleaching and restored with different materials

Resumo

The use of adhesive composite resin with fluoride
and with greater fluidity can be favorable to the restoration of the
palatal/lingual face of teeth submitted to internal bleaching. Objective:
This study evaluated the bond strength of adhesive systems and
composite resins to bleached dentin. Material and methods: Forty
maxillary canines were sectioned to obtain 40 blocks (5 x 5 mm) of
intracoronary dentin. The fragments were included and bleached with
37% carbamide peroxide. After 7 days, the specimens were divided
into two groups according to the adhesive system: with (Optibond
Solo Plus) and without (Single Bond) fluoride and subdivided into 2
subgroups (n = 10) according to the composite resin: microhybrid
(Z250) and flowable (Z350). The restoration was carried out through
a bipartite matrix. After 24 hours, the specimens were subjected to
shear bond strength test. The data (MPa) were analyzed by ANOVA
and Tukey test (α = 0.05). Results: The best results (p < 0.05)
were obtained for fluoridated adhesive (7.44 ± 2.35) compared with
that without fluoride (5.36 ± 2.01); flowable resin (7.76 ± 2.23)
performed better than microhybrid resin (5.03 ± 1.72). When the
two variables were associated, the highest results were obtained for
the specimens restored with fluoridated adhesive and flowable resin
(9.04 ± 1.92). Lower results were observed for non-fluoridated adhesive
+ microhybrid resin – control (4.24 ± 1.59), without statistically significant differences when compared with the fluoridated adhesive
+ microhybrid resin (5.83 ± 1.52). Conclusion: The combination
with fluoridated adhesive and flowable resin increases the shear
bond strength of bleached dentin.