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The objective of this research was to evaluate the efficacy of diclofenac sodium solutions, with or without cetrimide (CTR) added, against polymicrobial root canal biofilms grown in dentin specimens. The study groups were: (1) 5% diclofenac sodium (DCS); (2) 2.5% DCS; (3) 2.5% DCS + 0. 2% CTR; (4) 2.5% DCS + 0.4% CTR and (5) 0.9% saline solution (SS) as the control. After 5 min of solution contact with the biofilms, the antimicrobial activity was evaluated by means of the adenosine triphosphate (ATP) assay as well as confocal laser scanning microscopy (CLSM). Microbial quantification was indicated as the percentage reduction of relative light units (RLUs) for the ATP assay, the Log10 total biovolume and the viability percentage (green cells) for CLSM. Solutions of 2.5% DCS + 0.4% CTR and 5% DCS showed the highest antimicrobial efficacy. Cetrimide increased the antibiofilm activity of diclofenac sodium against endodontic biofilms. [ABSTRACT FROM AUTHOR]

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The adhesion of composite resin to caries-affected dentin differs from the adhesion of resin to sound dentin. We evaluated the bond strengths of dual-cure resin composites applied to caries-affected root canal dentin under various clinical conditions and using several caries removal indicators. In the dye stain 1 group, caries were removed to a pale pink stain level using a caries detector. In the dye stain 2 group, caries were removed to a stain-free level using a caries detector. In the probing group, caries were removed to the level of hardness based on probing with a sharp explorer. Additionally, a sound dentin group was used as a control. We compared the resin composite microtensile bond strengths and failure mode distribution among the groups. The bond strengths (MPa) of the probing (64.6 ± 11.9) and the sound dentin (68.7 ± 11.1) groups were significantly higher than those of the dye stain 1 (46.9 ± 7.9) and 2 (47.5 ± 8.4) groups (p < 0.05). The removal of caries-affected dentin using a dentin-hardness-based technique showed higher tensile strength than that using a dye stain technique involving removal to any color level. Thus, the caries removal technique used on root canal dentin affects the bond strength of the resin composite. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the effect of different pre-treatments on the long-term bond strength of fiberglass posts luted either with dual-curing self-etch adhesives and core build-up composites or with a self-adhesive resin (SAR) cement. Materials and methods: In total, 180 human root-filled teeth received post-space preparations and three different dentin pre-treatments (PTs): PT1, ethanol (99%); PT2, ethanol-tertiary-butanol-water-solution (AH Plus Cleaner, Dentsply Sirona; York, USA); and PT3, distilled water (control). Five luting systems were used: FU, Futurabond U (Voco; Cuxhaven, Germany); CL, Clearfil DC Bond (Kuraray Noritake; Okayama, Japan); GR, Gradia Core SE Bond (GC Europe NV; Leuven, Belgium); LU, LuxaBond Universal (DMG; Hamburg, Germany); and RX, RelyX Unicem 2 (3M; Minnesota, USA). Roots were cut into six slices (1 mm thick). From each root canal region, three slices were submitted to immediate and three to post-storage push-out testing. The latter were subjected to thermocycling (5–55°C, 6.000 cycles) and stored for six months in saline solution (0.9%, 37°C). Data were analysed using repeated measures ANOVA and chi-square tests (MV±SD). Results: Bond strength was significantly affected by material (p<0.0005), pre-treatment (p=0.016), and storage (p<0.0005; repeated-measures ANOVA). LU (18.8±8.1MPa) revealed significantly higher bond strength than RX (16.08±6.4MPa), GR (15.1±4.6MPa), CL (13.95±5.2MPa), and FU (13.7±6.3MPa). PT1 (16.5±6.9MPa) revealed significantly higher bond strength than PT3 (14.5±5.7MPa). Conclusions: A universal adhesive in self-etch mode combined with a core build-up material revealed higher bond strength than a SAR cement, both interacted positively with Ethanol pre-treatment. Clinical relevance statement: Ethanol (99%) rinsing can be recommended as part of post and core pre-treatment for the investigated luting systems. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to clarify the effects of different bonding systems (BSs) with various polymerization modes and root canal regions on the bond strength of core build-up resin composite to dentin.Methods: Post cavities were prepared in the roots of 54 bovine teeth. Three types of BS with various polymerization modes (light, chemical, and dual-cure) were applied to the walls of the cavities, which were subsequently filled with core build-up resin composite, and stored in 37ºC water for 7 days. Each tooth was then sectioned perpendicular to the long axis of the tooth into 9-disk from the coronal to the apical side. Bond strengths were measured on two-thirds of the disks, while dye penetration was examined in the remaining third.Results: Statistical analysis revealed significant differences between the bond strengths of BSs with different polymerization modes, indicating chemical-cured BS had higher bond strength than light-cured BS. The chemical-cured BS group showed cohesive failure in both resin composite and dentin regardless of the root canal region, while adhesive failure was observed in the coronal region for dual-cured BS and in the apical region for light-cured BS. Dye penetration was significantly more at the bonding interface at the apical region of the light-cured BS. Conclusions: Chemical-cured BS displayed a greater bond strength than light-cured BS. Cohesive failure was observed in both core build-up resin and dentin, indicating that the integration of tooth structure with resin composite was effective for retaining the resin core and sealing the root canal. [ABSTRACT FROM AUTHOR]

Purpose: To compare scanning electron microscopic (SEM) and confocal laser scanning microscopic analyses (CLSM) of hybrid layer thickness and the number of dentinal tubules penetrated with composite resin inside the root canal on identical samples. Materials and Methods: Central maxillary incisors were restored using fiber posts (FRC Postec) inserted with a chemically curing composite resin (Clearfil Core/New Bond). Two different fluorescent dyes were used to respectively label adhesive and composite resin. Each root was sectioned into two slices starting 2 mm below the cementoenamel junction. SEM (low vacuum mode) and CLSM (dual fluorescence mode) analyses of 18 samples were performed. Hybrid layer thickness was measured at five characteristic points of each sample and the number of dentinal tubules penetrated with composite resin was counted on both corresponding images by two independent observers. Correlation coefficients as well as pairwise comparisons were calculated for both parameters. Results: SEM and CLSM measurements of hybrid layer thickness were positively correlated (r2 = 0.772; Pearson), and thickness was significantly higher after evaluation with CLSM (p < 0.0005; Wilcoxon). The observed number of dentinal tubules penetrated with composite resin revealed a nonsignificant correlation (r2 = 0.111; p = 0.193). Significantly lower tag numbers were counted when using SEM (p = 0.010; Wilcoxon). Conclusion: With respect to the variability of the hybrid layer measurements, the two methods yielded comparable results. CLSM provided more detailed information regarding the penetration and distribution of resin cement and adhesive than did SEM imaging. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the bond strength of two etch-and-rinse adhesive systems (two- and three-step) and a self-etching system to coronal and root canal dentin. Materials and Methods: The root canals of 30 human incisors and canines were instrumented and prepared with burs. The posts used for luting were duplicated with dual resin cement (Duo-link) inside Aestheti Plus #2 molds. Thus, three groups were formed (n = 10) according to the adhesive system employed: All-Bond 2 (TE3) + resin cement post (rcp) + Duo-link (Dl); One-Step Plus (TE2) + rcp + Dl; Tyrian/One-Step Plus (SE) + rcp + Dl. Afterwards, 8 transverse sections (1.5 mm) were cut from 4 mm above the CEJ up to 4 mm short of the root canal apex, comprising coronal and root canal dentin. The sections were submitted to push-out testing in a universal testing machine EMIC (1 mm/min). Bond strength data were analyzed with two-way repeated measures ANOVA and Tukey's test (p < 0.05). Results: The relationship between the adhesives was not the same in the different regions (p < 0.05). Comparison of the means achieved with the adhesives in each region (Tukey; p < 0.05) revealed that TE3 (mean ± standard deviation: 5.22 ± 1.70) was higher than TE2 (2.60 ± 1.74) and SE (1.68 ± 1.85). Conclusion: Under the experimental conditions, better bonding to dentin was achieved using the three-step etch-andrinse system, especially in the coronal region. Therefore, the traditional etch-and-rinse three-step adhesive system seems to be the best choice for teeth needing adhesive endodontic restorations. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The purpose of this study was to evaluate the effect of waiting interval on the chemical activation of dual-cure one-step self-etching adhesives before placing resin core materials on the regional bond strength to root canal dentin. Materials and methods: Forty-eight post spaces prepared in human lower premolars were applied with four dual-cure one-step self-etching adhesives Estelite Core Quick: ECB/ECQ, Clearfil DC Core Automix: CDB/CDC, Unifil Core EM: UNB/UNC, BeautiCore: BTB/BTC as the manufacturers’ instructions. These adhesives were cured with light activation for 10s, or chemical activation with 0, 10, and 30s waiting intervals prior to placing resin core material. Resin core materials were then placed into the post space and light-cured for 60s. After 24h water storage, each specimen was serially sliced into 8, 0.6mm×0.6mm thick beams for the μTBS test. The regional μTBS data were analyzed using three-way ANOVA and Dunnett''s T3 test (p <0.05). Results: For the chemical activation with 10 and 30s waiting intervals, ECB and CDB exhibited significantly improved μTBS, whereas for UNB and BTB, the μTBS were not significantly different but increased with waiting interval. On the other hand, light-activation of all the adhesives produced significantly higher μTBS to root canal dentin than chemical activation (p <0.05), except for the UNB group. Conclusions: For the chemical activation of dual-cure one-step self-etching adhesives, a waiting interval prior to placing resin core material improved μTBS to root canal dentin. Polymerising the adhesives before polymerisation reaction of resin core material would be effective for bonding to root canal dentin. Clinical relevance: For chemical activation mode as well as light activation mode, pre-curing of adhesive layer before proceeding polymerisation of resin filling material would produce higher bonding performance to dentin in the cavity. [Copyright &y& Elsevier]

Abstract: Introduction: The objective of this study was to evaluate and compare in vitro the decalcifying capability on root canal dentin of 4 different irrigating solutions. Methods: Twenty-five freshly extracted maxillary central incisors were selected. The canals were prepared to obtain a total of 4 samples from each root. The samples were randomly divided into 5 equal experimental groups (n = 20) according to the irrigating solutions tested (Tetraclean, Largal Ultra, 17% ethylenediaminetetraacetic acid, Tubuliclean). For each irrigating solution, the specimens were immersed for 5, 10, and 15 minutes. After exposures, the concentration of Ca2+ extracted was measured by inductively coupled plasma-atomic emission spectrometry. Data were analyzed by means of nonparametric tests, and statistical analysis was performed. Results: The higher release of Ca2+ was observed in samples treated with Tetraclean; this citric acid–based agent showed significantly higher decalcifying capability. For all irrigating solutions tested, 10 minutes of application are sufficient to obtain the maximum Ca2+ release. Conclusions: The results indicated that Tetraclean could be applied to obtain more efficient removal of the smear layer and to facilitate the biomechanical instrumentation procedures. [Copyright &y& Elsevier]

Objective: This study aimed to evaluate a prototype surface reaction-type pre-reacted glass-ionomer (S-PRG) filler-containing endodontic sealer (S-PRG sealer) in terms of its ion-releasing ability and the incorporation of the released ions by root canal dentin. Materials and Methods: The concentration of ions in the set S-PRG sealer was measured by ICPS and with a fluoride ion electrode. Element mapping and chemical component bulk analysis of the outermost dentin of the S-PRG sealer-dentin interface were performed by SEM-EPMA. The incorporation depth of the elements in dentin was measured by element line scanning. Results and Discussion: Ions released from the S-PRG sealer (Al, B, F, Na, Si, Sr, and Zn) were detected over time. The incorporation of fluoride (F), strontium (Sr), silicon (Si), and boron (B) was observed along the outermost dentin of the S-PRG sealer-dentin interface by EPMA analysis, and the incorporation depth increased with prolonged immersion. Conclusion: The continuous release of ions from the S-PRG sealer and their subsequent incorporation by root canal dentin were confirmed. [ABSTRACT FROM AUTHOR]

The purpose of this in vitro study was to compare the bond strength between fiber post and laser-treated root canals. Forty single-rooted bovine teeth were endodontically treated and randomly divided into four groups of equal size according to the root canal treatment: group 1 conventional treatment (without laser irradiation); group 2 Nd:YAG laser (1.5 W, 10 Hz, 100 mJ); group 3 Er,Cr:YSGG laser (0.75 W, 20 Hz); and group 4 Nd:YAG + Er,Cr:YSGG lasers. The fiber posts were cemented with an adhesive system + resin cement, in accordance with the manufacturer's instructions. A mini acrylic pipe was fixed on the coronal section of the post using a light-polymerized resin. Specimens were mounted on an acrylic pipe with a self-polymerized resin. Retention forces were determined using a universal testing machine (0.5 mm/min). Data were analyzed using one-way ANOVA and Tukey tests (p <0.05). The post retention force in group 2 was found to be lower than that in the other experimental groups. Fractures were observed at the interface between the dentin and the resin in all groups. High-intensity lasers can be used in conventional endodontic treatment; however, root canal surface irradiation using the Nd:YAG laser was shown to negatively affect the post retention force. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of composite post placement and/or light-irradiation of dual-cure resin composite on adhesion to root canal dentin using the chemical activation mode of a 1-step self-etch dual-cure adhesive. Post spaces were prepared in extracted premolars. Root canal spaces were applied with Unifil Core EM Self-Etching Bond, which was chemically-polymerized, and then filled with Unifil Core EM with or without the placement of composite post. Half the specimens of each group were light-cured for 10 seconds and the other half were chemically-cured in darkness for 30 minutes. After 24 h storage, microtensile bond strengths (μTBS) at the coronal and apical regions were measured. When light-curing, placement of the composite post significantly reduced the μTBS to root canal dentin. On the other hand, when chemical-curing, there was no significant difference in μTBS between with and without placement of the composite post. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of light power density and light exposure time on regional bond strength of Clearfil DC Bond to root canal dentin. Post spaces were prepared in extracted premolars. Root canal dentin was treated with a dual-cure bonding system, Clearfil DC Bond, and light-cured for 10, 20, or 30 seconds using two halogen light curing units: Optilux 501 (830 mW/cm²) and Hyperlightel (1350 mW/cm²). Following which, all post spaces were filled with a dual-cure resin composite. After 24-hour storage, microtensile bond strengths (μTBS) at the coronal and apical regions were measured. At the coronal region, μTBS values were similar among all the experimental groups. At the apical region, bond strength improved when the curing time was extended to 30 seconds with Optilux 501, and likewise with Hyperlightel when curing time was extended to 20 or 30 seconds. In addition, significant differences in μTBS between the coronal and apical regions disappeared with prolonged curing times. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: To evaluate the regional mechanical properties of dual-cure resin composites and their regional bond strengths to root canal dentin. Methods: One of the following dual-cure resin composites was placed in artificial post spaces: Unifil Core (UC), Clearfil DC Core (DC), Build-It FR (BI), Clearfil DC Core-automix (DCA), and photo-cured for 60s. After 24h storage, each specimen was serially sliced to harvest eight hour-glass shaped specimens for measurement of regional ultimate tensile strength (UTS), and the remaining eight semi-circular slabs were polished for the measurement of Knoop Hardness Number (KHN). For the microtensile bond strength (μTBS) test, post cavities were prepared in human premolar roots, and the cavity surfaces treated with Clearfil SE Bond and photo-cured for 10s. The post spaces were then filled with one of the above resin composites and photo-cured for 60s. After 24h storage, each specimen was serially sliced into 8, 0.6×0.6 mm-thick beams for the μTBS test. The data were divided into coronal and apical regions and analyzed using ANOVA and post hoc test (α =0.05). Results: UTS and KHN were affected by the type of dual-cure resin composite and region (p <0.0001). There was no relationship between UTS and KHN for each material. The auto-mix type of resin composite possessed superior UTS to that of the hand-mix type. μTBS among the four composite materials were not significantly different at both apical and coronal regions (p >0.05). Regional differences in bond strengths were found for all materials (p <0.05). Significance: The UTS and KHN of the dual-cure resin composites varied among each material, however, differences in the mechanical properties of the resin core materials did not affect their adhesion to root canal dentin. [Copyright &y& Elsevier]