Influence of ultrasound and irrigant solutions on the bond strength of glass fiber posts to root canal dentine

Resumo

Objective: Assessment of the influence of the
ultrasound and irrigant solutions on the bond
strength (BS) of glass fiber posts. Material and
Methods: Sixty-six roots of bovine teeth standardized
at 16 mm were used. The roots were submitted to a
biomechanical preparation up to size #80 Kerr file,
with irrigation of 5ml of saline solution at every
file change and then filled. The canals underwent
partial desobturation and were divided into 6 groups
according to the irrigant solution and the use of
ultrasound prior to the post cementation: S – saline
solution; C – 2% chlorhexidine solution; H –2.5%
sodium hypochlorite solution; US – saline solution
+ ultrasound; UC – 2% chlorhexidine solution +
ultrasound; UH – 2.5% sodium hypochlorite solution
+ ultrasound. After the cementation of the posts, the
specimens were cut into 3 slices of 2 mm of thickness,
perpendicular to its long axis. The samples were
submitted to push-out test with crosshead speed of
1 mm/min and load of 50kgf. The data obtained
were submitted to ANOVA and Tukey test (level of
significance of 5%). Results: Groups C 7.77(±1.8)a,
UC 7.82(±1.6)a, S 7.33(±2.2)a, US 6.16(±2.3)a, H
5.43(±1.3)b, UH 5.01(±2.3)b values in Mpa. Only
the irrigant solutions showed statistically significant
differences (<0.05). Tukey test revealed smaller
bond strength for the specimens treated with Sodium
Hypochlorite (b). Conclusions: The ultrasound
treatment did not show significant difference
compared with the other groups; therefore, its use
can be indicated prior to the cementation of glass
fiber posts without damage to the bond strength. The
sodium hypochlorite solution showed the smallest BS
values compared with the other groups.