Effects of Epigallocatechin-3-gallate (EGCG) on the bond strength of fiber posts to Sodium hypochlorite (NaOCl) treated intraradicular dentin

In Vitro Bond Strength of Dentin Treated with Sodium Hypochlorite: Effects of Antioxidant Solutions

This systematic review aims to evaluate whether the application of antioxidant solutions can enhance the bond strength of resin-based materials to sodium hypochlorite (NaOCl)-treated dentin. This study follows the PICOT strategy: population (sodium hypochlorite-treated dentin), intervention (application of antioxidants), control (distilled water), outcome (bond strength), and type of studies (in vitro studies). The systematic review and meta-analysis were conducted following PRISMA guidelines. Electronic databases were searched for in vitro studies evaluating the effects of antioxidants on bond strength to sodium hypochlorite-treated dentin. Two independent reviewers screened articles, extracted data, and assessed risk of bias. Meta-analyses were performed using a random-effects model to compare standardized mean differences in bond strength between antioxidant pretreatment and control groups. Inclusion criteria consisted of in vitro studies that examined the bond strength of resin-based materials to NaOCl-treated dentin with antioxidant application, while exclusion criteria included studies with incomplete data, those not using a control group, or those that did not directly measure bond strength. From 3041 initial records, 29 studies were included in the qualitative analysis and 25 in the meta-analysis. Ascorbic acid, sodium ascorbate, grape seed extract, green tea, and rosmarinic acid significantly improved bond strength to sodium hypochlorite-treated dentin (p < 0.05). The effectiveness of grape seed extract varied with adhesive system type. Hesperidin, p-toluene sulfonic acid, and sodium thiosulfate did not significantly improve bond strength. Most studies had a high risk of bias. This suggests that the conclusions drawn from these studies should be interpreted with caution, and further research with more robust methodologies may be needed to confirm the findings. In conclusion, this systematic review implies that certain antioxidants can improve bond strength to sodium hypochlorite-treated dentin, with efficacy depending on the specific agent and adhesive system used. Further standardized studies are needed to optimize protocols and confirm these findings.

Post-Space Treatment Influences the Bond Strength In Endodontically Treated Teeth: A Systematic Review and Meta-Analysis of In Vitro Studies

OBJECTIVES

This systematic review of in vitro studies investigated the influence of the post-space treatment used to remove the smear layer on the bond strength of the post to root canal dentin.

METHODS AND MATERIALS

In vitro studies included in this study were identified from PubMed/MEDLINE, Lilacs, and Scopus databases up until March 2019, without limits on publication year or language. Two reviewers independently selected the studies based on the inclusion and exclusion criteria, extracted the data, and evaluated the risk of bias of all studies. A random effects model was used for pairwise meta-analyses (control vs. post-space preparation groups) at a significance level of p<0.05.

RESULTS

Of the 2,832 potentially eligible studies, 453 studies were selected for full-text analysis, and 75 were included in this systematic review. Only one study was considered to have a low risk of bias. Overall, post-space treatment significantly improves the bond strength to root canal dentin (p<0.00001).

CONCLUSION

Post-space treatment has a positive influence on the bond strength of the post to root canal dentin. In this review, the post-space treatments that improve the adhesive resistance of the post were ethanol, sodium hypochlorite, and ethylene diamine tetra-acetic acid (NaOCl + EDTA), NaOCl + EDTA + ultrasound, erbium-doped yttrium aluminium garnet laser (Er:YAG laser), neodymium-doped yttrium aluminium garnet laser (Nd:YAG laser), and diode laser.

Effect of epigallocatechin-3-gallate and thermal cycling on the bond strength of resin cements to the root dentin

This study evaluated the effect of epigallocatechin-3-gallate (EGCG) solution and thermal cycling on the bond strength (BS) of fiber posts to the root dentin using two different resin cements (conventional or self-adhesive). One hundred and forty-four bovine roots were endodontically treated. After post space preparation, specimens were randomly divided into six groups (n = 24) according to dentin pretreatment [distilled water, 0.05% EGCG solution or 2% chlorhexidine (CHX) solution] and resin luting agent used for fiber post cementation (RelyX ARC or RelyX U200-3 M ESPE). Then, the samples were separated into two subgroups (n = 12): storage in distilled water at 37 °C for 24 h and thermal cycling (5 °C/55 °C, dwell time 30 s-12,000 cycles) during 6 months. After that, the specimens were subjected to the pull-out BS test (Universal Testing Machine-0.5 mm/min) and the failures pattern was analyzed in a stereomicroscope. According to the BS results (three-way ANOVA, Tukey's test, α = 0.05), the highest values were reported in the group EGCG + RelyX U200, showing significant statistical differences compared to all the other experimental groups. For Control and CHX groups BS values, there was no significant difference (p > .05) between the resin cements. For conventional resin cement, there was no significant difference among treatment solutions (p > .05). The thermal cycling did not influence the BS results (p > .05). As reported by the failure mode analysis, adhesive failure was predominant in all groups. EGCG solution improved the bond strength of self-adhesive resin cement to root dentin.

Polyphenols in Dental Applications

(1) Background: polyphenols are a broad class of molecules extracted from plants and have a large repertoire of biological activities. Biomimetic inspiration from the effects of tea or red wine on the surface of cups or glass lead to the emergence of versatile surface chemistry with polyphenols. Owing to their hydrogen bonding abilities, coordination chemistry with metallic cations and redox properties, polyphenols are able to interact, covalently or not, with a large repertoire of chemical moieties, and can hence be used to modify the surface chemistry of almost all classes of materials. (2) Methods: the use of polyphenols to modify the surface properties of dental materials, mostly enamel and dentin, to afford them with better adhesion to resins and improved biological properties, such as antimicrobial activity, started more than 20 years ago, but no general overview has been written to our knowledge. (3) Results: the present review is aimed to show that molecules from all the major classes of polyphenolics allow for low coast improvements of dental materials and engineering of dental tissues.

The effects of different irrigation solutions on the bond strength of cemented fiber posts

Objective

To study effect of root canal irrigant solutions on the bond strength of cemented fiber posts, and resin cement-tags in root canal dentin.

Materials and methods

Fifty-two human single-rooted anterior teeth were selected and stored in 1% sodium azide. Crowns were sectioned 2 mm incisal to the cemento enamel junction with diamond bur at high speed under water-cooling. After standard root canal treatment to tested teeth, they were randomly assigned into four groups (n=13) corresponding to the endodontic irrigant solution that was used during post space preparation. The treatment groups were: Group 1: 6.15% sodium hypochlorite; Group 2: 17% EDTA; Group 3: 6.15% NaOCl +17% EDTA; Group 4: 6.15% NaOCl +0.12% chlorhexidine solution. Parallel-sided fiber posts were used for all specimens. Samples were embedded in a cylindrical PVC mounting jig to facilitate perpendicular sectioning. With low speed diamond saw, cervical and apical specimens from each tooth were obtained and subjected to push-out test using universal testing machine. SEM was used to examine the root-canal dentin surface.

Results

Statistical analysis revealed significant difference among the groups at P<0.05. Group 2 treated with EDTA, had the highest bond strength; 18.63±2.85 MPa in cervical specimens and 13.49±3.67 MPa in apical specimens. The cervical specimens of Groups 2 and 3 were significantly different than the apical specimens in the same group. Adhesive failure between cement and dentin was the main failure mode observed in all groups. Groups irrigated with EDTA showed cleaner dentin surface and better resin tag formation, while groups treated with NaOCl showed less resin tag formation and insufficient smear layer removal.

Conclusion

NaOCl had adverse effect on bond strength of self-adhesive resin cement to radicular dentin. EDTA irrigant solution produced higher bond strength and was more effective in removing smear layer than NaOCl.

Adhesion performance of a universal adhesive in the root canal: Effect of etch-and-rinse vs. self-etch mode

PURPOSE

Universal adhesives are new systems that can be used in etch-and-rinse (ER) and self-etch (SE) modes. This in vitro study evaluated the bonding performance of a universal adhesive in ER mode and SE mode with two irrigants for luting fiber posts in the root canal.

MATERIALS AND METHODS

After separation of the roots from the crowns of 56 maxillary central incisors and endodontic treatment, 10-mm post space was prepared. The roots were divided into seven groups according to irrigant/adhesive protocol used for cementation of posts: 1) sodium hypochlorite (NaOCl) irrigant + acid etching + One-Step Plus, 2) NaOCl + Clearfil SE Bond (CSE) and 3) EDTA + CSE as controls; 4) NaOCl + All-Bond Universal (AB) in ER mode, 5) NaOCl + AB in SE mode, 6) EDTA + AB in SE mode, 7) distilled water + AB in SE mode. Posts were luted using Duo-link. The bonded roots were sectioned into microslices. After push-out bond strength (PBS) testing, data in MPa were analyzed with two-way ANOVA and Tukey test (α = 0.05).

RESULTS

PBS was significantly affected by irrigation/adhesive protocol and root region (P<0.05), with no significant interaction of these factors. PBS of ABU in ER mode with NaOCl and in SE mode with NaOCl or EDTA was comparable to that in the respective controls. The highest and lowest PBSs were recorded for ABU in the SE mode with EDTA (15.38 ± 4) and NaOCl (10.17 ± 3.5), respectively. PBS of AB in ER and SE modes was similar when distilled water was used in the SE mode.

CONCLUSION

Adhesive performance of AB in the ER mode was comparable to or different from the SE mode, depending on the irrigant used to prepare post space in SE approach. AB could behave as a reliable bonding for post cementation.