Comparison of bond strength in different levels of post space of fiber-reinforced post luted with different resin cements

Background: with the advent of new adhesive materials in dentistry, it has become important to measure regional bond strength along the length of the canal of human teeth to assess the bond strength of resin cements to endodontically treated teeth. This study aimed to investigate the effect of post space region (coronal, middle and apical) and the mode of polymerization of the resin cement on the retention of the translucent fiber post to root canal dentin, by using pull-out and push-out test methods. Material and methods: extracted single rooted mandibular first premolars (n=32) were instrumented with ProTaper universal system files (for hand use)and obturated with gutta-percha and AH26® root canal sealer. After 24hrs in the incubator, post space was prepared to a depth of 8mm using FRCPostec drills no.3. . The prepared samples were randomly divided into two main groups (16 samples each) according to the resin cement mode of polymerization (Group A Dual-cure, RelyxU100), (Group B Self-cure, SpeedCem). Then each group was subdivided into two groups (each with 8 samples) according to the test performed (A1: RelyxU100 and Push-out test, A2: RelyxU100 and pull-out test, B1: SpeedCem and push-out test, B2: SpeedCem and pull-out test). Pull-out and push-out bond strength test were measured using a universal testing machine to measure the bond strength. Results: regarding the root region, the bond strength values decreased significantly from the coronal to the apical region in both cements tested. For the mode of polymerization, no statistical significant difference was detected between the dualand selfpolymerized resin cements. Conclusions: the retention of fiber post was affected by the root region while the mode of polymerization didn’t affect the bond strength. When measuring the bond strength of luted fiber post, the push-out test appears to be more dependable than the conventional pull-out