Evaluation of the Effect of Sodium Hypochlorite Irrigant on Pull-out Bond Strength of FRC Posts Using Different Resin Cements

Introduction: To evaluate the effects of using sodium hypochlorite irrigant on pull-out bond strength of self-etch and self-adhesive resin cements to dentin. Methods: Sixty intact premolars were decoronated and the root canals were prepared by step-back technique. The teeth were divided into two groups according to the irrigant used during root canal treatment: 5.25% sodium hypochlorite and normal saline. The canals were obturated and after 48 hours storage, 8mm depth post space was prepared with application of normal saline as irrigant. Then, each group was divided into two subgroups depending on the type of the cements used for cementation of fiber reinforced composite (FRC) posts (Panavia F2or Embrace). The pull-out bond strength test was evaluated. Statistical analysis was performed by Two-way AONVA. Results: The type of cement had no statistically significant effect on the bond strength; however, the type of irrigant was statistically effective. There was no interaction between two independent variables. The application of sodium hypochlorite significantly decreased the pull-out bond strength in Embrace cement in comparison with the use of normal saline. Conclusion: The type of irrigants used in endodontic treatment may affect on bond strength of FRC posts cemented by self-adhesive cements.

Effect of Non-Vital Bleaching on the Durability of Resin–Dentin Bond with an Ethanol-Based Etch-And-Rinse Adhesive

To evaluate the bleaching procedure and application of sodium ascorbate on dentin bond durability, the enamel surface of intact human third molars (n = 18) were removed, and the teeth were randomly divided into two groups for immediate and six-month bond strength evaluation. The specimens were further assigned into three subgroups according to treatment procedure, as follows: subgroup A, no bleaching (positive control) was performed prior to the etch-and-rinse bonding with single bond and subsequent build-up with Z250 composite; subgroup B, the samples were bleached with 20% carbamide peroxide 6 h/day for five consecutive days prior to bonding; and subgroup C, bleaching was performed as in subgroup B, after which 10% sodium ascorbate was applied on dentin surface for 10 min before the bonding procedures. A microtensile bond strength test was performed and the failure modes were evaluated under a stereomicroscope. The data were analyzed using two-way analysis of variance (ANOVA) and Tukey’s post-hoc tests with a level of significance of 0.05. Bleaching significantly decreased the immediate and six-month bond strength. The application of sodium ascorbate had no significant effect on the immediate and six-month bond strength of bleached specimens. We conclude that the bleaching procedure may decrease the durability of the resin⁻dentin bond of the tested etch-and-rinse adhesive

An Innovative Rigid Tray Technique for Replacement and Reattachment of the Anterior Composite Tooth Pontic

Replacement and reattachment of a newly detached composite tooth pontic is sometimes justified because of shape, color, function and patient satisfaction. The aim of this case report is to describe a new method using Rigid Tray Technique for exact replacement and reattachment of acceptable detached composite tooth ponti

An Innovative Rigid Tray Technique as a New Alternative Matrix System for Buildup of Severely Damaged Endodontically Treated Teeth (A Case Report)

Direct restoration of severely damaged endodontically treated teeth (ETT) using available and conventional and current matrix systems is sometimes impractical and in some clinical cases is impossible. The aim of this paper is to introduce and describe a new matrix system based on Rigid Tray Technique (RTT) for dealing with such difficult clinical cases