Objectives: The purpose was to evaluate the influence of the root canal dentin substrate on pull-out bond strength of conventionally and adhesively luted glass-fiber-reinforced posts [FRCP].
Methods: 250 extracted bovine [BT] and 250 human teeth [HT] were randomly assigned to each of the 5 luting systems (n=50), root canal treated, filled and post space (8mm) prepared. The custom-made FRCPs [PXRO] (RTD, France) (group 1-4) and the titanium-post [TIP] (NTI, Germany) (control) were cleaned with alcohol; the posts of groups 3 and 4 additionally pretreated, using the corresponding adhesive system and than cemented into to the root canals. After water storage (24h, 37°C), the pull-out-test was performed; bond strength (MPa) calculated and analyzed using Kolmogorov-Smirnov-test (p>0.05) followed by ANOVA and post-hoc-tests (t-test, Dunnett T3) (α=0.05). The assessment of failure mode was made under a stereomicroscope.
Results: The influence of the substrate and the luting system was statistically significant (p<0.05). When comparing the two substrates, significant differences were found for all luting systems, except for group 2.The bond strength evaluated on BT were higher in groups 1, 3 and 4 then for HT. The bond strengths, achieved with all luting systems, were statistically significant compared to the control. The comparison of bond strength, within the luting systems, showed predominantly significant differences.
Group | Luting System | Post | Bond Strength (MPa) | t-test p-value | |
BT | HT | ||||
control | Ketac Cem | TIP | 5.4±1.9 | 6.3±1.4 | 0.007 |
1 | Fuji Plus | PXRO | 8.6±1.5 | 7.9±1.3 | 0.016 |
2 | RelyX Unicem | 10.4±3.4 | 11.0±3.0a | 0.341 | |
3 | Multilink Primer_Multilink | 12.7±3.0 | 9.4±2.4b | 0.000 | |
4 | LuxaBond_LuxaCore Z | 15.7±2.5 | 10.4±1.3a,b | 0.000 | |
ANOVA p-value | 0.000 | 0.000 |
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Conclusion: The substrate and the luting systems influenced the bond strength of conventionally and adhesively luted FRCPs. The luting systems involving bonding agents revealed considerably higher bond strength in bovine teeth.