Shear bond strength of brackets bonded with nanofilled flowable resins

Resumo

To evaluate the shear bond strength
of brackets fixed with different materials (two light-cured nanofilled
low-viscosity resins – Transbond Supreme LV and Flow Tain LV and
two light-cured traditional resins – Transbond XT and Transbond
Plus Color Change) after 10 min and 24 h, and to evaluate the
type of failure. Material and methods: Eighty bovine incisors were
selected and randomly divided into groups (n = 10) according to the
material and fixation period. The brackets were bonded following the
manufacturer's instructions and stored in deionized water at 37oC for
10 min or 24 h. After, the specimens were submitted to shear bond
strength test at 0.5 mm/min and evaluated for adhesive remnant
index (ARI). The data were submitted to Kruskal Wallis and Wilcoxon
tests (p < 0.05) and the ARI scores to Chi-Square test. Results:
There was a significant difference among the materials (p < 0.05)
(after 10 min – Transbond XT > Transbond Plus Color Change >
Transbond Supreme LV = Flow Tain LV and after 24 h – Transbond
XT > Transbond Plus Color Change = Transbond Supreme LV =
Flow Tain LV). There was no significant difference
in resistance values between 10 min and 24 h,
except for Transbond Plus Color Change. Most
groups showed adhesive remaining adhered to the
enamel (scores 2 and 3) without statistical significant
difference (p > 0.05). Conclusion: The light-cured
traditional resins showed higher resistance than the
nanofilled materials. The period of fixation had no
influence on the resistance for different materials,
except for Transbond Plus Color Change.