| Objective:To compare the bonding strength of fiber posts cemented to root canals with three different resin adhesive and to guide the rational choose of the luting systems during clinical workMethod:A total of 15 extracted healthy lower bicuspid teeth of similar size extracted in one month were selected. The crowns was removed with a diamond bur at 1.0-mm coronal to the cemento-enamel junction, and endodontic treatment was performed,The roots were prepared after 3 days, and the teeth were randomly divided into 3 equal groups of 5 each. three resin adhensive system (Bisco One-step; Clearfil DC; 3M ESPE RelyX Unicem) were used respectively to bond glass fiber-posts (MATCHPOST, RTD,St Egreve,France) with 1.4mm in diameter,and embedded into the PVC tube with self-curing resin.then the roots were cut into 2.0-mm-thick sections perpendicular to the long-axis of the roots with a slow speed diamond saw. Push-out tests were performed with an fatigue testing machine at a crosshead speed of 0.5 mm/min, the fracture modes were observed using stereomicroscope. The mean bond strengths values (MPa) were compared using one-way ANOVA and Post Hoc tests (with the probability level set at a=0.05 for statistical significance),and the fracture modes were recorded and analyzed with a multiplication microscope.The interface between fiber post and resin core was observed by a scanning electron microscope (SEM) at×50 and×1000.Result:The bonding strength of fiber posts cemented to root canals is significant difference with different adhesive system. Mean bond strengths were:3M ESPE RelyX Unicem group (7.0490±0.92126)Mpa, Clearfil DC group(6.1000±0.36350)Mpa, One-step group (4.6860±1.84645)Mpa.3M ESPE RelyX Unicem group obtained the highest mean value than the other two.The one-way analysis of variance (ANOVA)and Post Hoc tests revealed that,3M ESPE RelyX Unicem group had a significantly higher bond strength than One-step group(P<0.05),and a significant difference between Clearfil DC group and One-step group was showed (P<0.05), no significant difference could be found between 3M ESPE RelyX Unicem group and Clearfil DC group.The fracture modes observed by using multiplication microscope indicated that the adhesive failure was the most mode of fracture.SEM evaluation revealed that resin tags were not observed from a self-adhesive and self-etching adhesive system, which were obtained from the total-etching adhesive system.Conclusion:The bonding strengths are different for the three resin adhesive system to root canal dentine. The self-adhesive resin cement and self-etching adhesive system may gain higher bonding strength than total-etching adhesive system. |
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