| Objective: To evaluate the influence of different surface treatments on the surface morphology and push-out bond strength between a fiber post and root dentin.Methods: Twenty sound human central incisors and canines of similar size extracted in recent period were selected. After endodontic treatment was performed, the crowns were removed with a diamond bur at 1.0-mm coronal to the cemento-enamel junction, and the roots were randomly divided into four equal groups of 5 each. The root canals were prepared after a week, the glass fiber posts (MATCHPOST, RTD, St Egrève, France) were luted in four groups separately with SE bond and Panavia F resin agents after receiving one of the following pretreatment procedures: silane coupling agent (S), methylene chloride (CH), 2% hydrofluoric acid (HF), 24% hydrogen peroxide (HO), and embedded into the PVC tube with self-curing resin. Then the roots were cut into 3.0-mm-thick slices with low speed diamond saw, perpendicular to the long-axis. Push–out tests were performed in an universal testing machine and evaluated the bond strengths between root dentin and posts. The date were statistically analyzed (one–way ANOVA and Post Hoc tests; with the probability level set atα= 0.05 for statistical significance). For all specimens, the type of failure was recorded and classified after a careful examination of each fractured sample with a microscope at×20 magnification. The fiber post surface in pre-and post-treatment were observed using a scanning electron microscope (SEM) at×200 and×1000. Results: The surface treatment influenced the bond strength between a fiber post and root dentin significantly. The one–way analysis of variance (ANOVA) and Post Hoc tests revealed that HO group obtained the highest mean value(10.00±3.17MPa) had a significantly higher bond strength than CH group(7.98±2.46 MPa), HF group(6.15±1.87 MPa) and S group(5.82±1.76 MPa) (P<0.05); and a significant difference between the CH group and the other two groups was showed (P<0.05), although no significant difference could be found between HF and S group (P>0.05). SEM evaluation revealed that the post surface morphology was modified after different pretreatment on fiber post.Conclusion: 24% Hydrogen peroxide and methylene chloride enhanced the bond strength between a glass fiber post and root dentin. |
