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Abstract Background Surface tension and contact angle properties, which play a crucial role in determining the effectiveness of irrigation solutions in penetrating dentin surfaces and dentin tubules, are highly important for the development of new irrigation solutions and their preferences. The aim of the current study was to compare the surface tension and contact angle properties of different irrigation solutions used in endodontics, both on the dentin surface and within dentin tubules. Methods In this study, the contact angles and surface tensions of 5.25% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine (CHX), 5% boric acid (BA), 0.02% hypochlorous acid (HOCl), 0.2% chlorine dioxide (ClO2), Biopure MTAD, QMix solutions, and distilled water (control group) were measured. Measurements were conducted using a goniometer device (Attension Theta Lite Tensiometer, Biolin Scientific, USA), employing the sessile drop method for contact angle measurements on pre-prepared dentin surfaces, and the pendant drop method for surface tension. Results Contact angle measurements revealed no statistically significant differences between the contact angle values of MTAD, ClO2, and CHX or between NaOCl, QMix, BA, and HOCl (p > 0.05). However, EDTA exhibited a significantly greater contact angle than did MTAD, ClO2, CHX, NaOCl, QMix, BA, and HOCl (p 0.05). CHX exhibited lower surface tension than distilled water and HOCl (p

The aims of this study were to systematically review the literature and compare the relative effects of various luting agents on bonding between glass-fiber posts and root canal dentin in short- and long-term aging conditions. The literature was electronically searched in PubMed, Embase, and Scopus. A manual search was performed by scanning the reference lists of the included studies. Two reviewers independently conducted the selection of studies, data extraction, and risk of bias assessment. Pairwise meta-analyses were based on random effect models. Network meta-analyses were conducted within a frequentist framework with a multivariable random effects approach. The standardized mean difference and 95% confidence interval was calculated. One hundred and eighteen studies were included and assessed the effects of five luting agents. For pairwise meta-analyses, in short-term aging conditions, a significantly higher bond strength of self-adhesive resin cement (SARC) compared to etch-and-rinse adhesive composite resin core material (ERCM) in the total, coronal, and middle regions. In long-term aging conditions, a significantly higher bond strength of ERCM compared to etch-and-rinse adhesive resin cement (ERRC) in all regions. Furthermore, SARC showed a significantly higher bond strength compared to self-etch adhesive composite resin core material (SECM) in the total, middle, and apical regions. For network meta-analyses, in the apical region, a significantly higher bond strength of SARC compared to ERRC in both aging conditions. The SARC tended to be the most effective luting agent in bonding between glass-fiber posts and root canal dentin in short- and long-term aging conditions. [Display omitted] • Self-adhesive resin cement is effective in bonding glass-fiber posts to root canal. • Etch-and-rinse adhesive resin cement is ineffective in bonding glass-fiber posts. • Self-etch adhesives exhibit superior short-term bond strength than etch-and-rinse systems. • Composite core materials exhibit superior long-term bond strength than resin cements. [ABSTRACT FROM AUTHOR]

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]

Introduction: Endodontic root canal sealers serve the purpose of providing a fluid-tight seal, sealing off accessory canals and multiple foramina, while comprehensively confining the bacteria. Of late, rather than seeking a hermetic seal of the root canal, a more biological perspective is being tackled in which, sealers resolve to interact with root dentin, resulting in bioactivity. Tricalcium silicate sealers set the bioactivity in motion on the material surface after contacting the tissue fluids. The Aim: The purpose of this paper is to review the properties of calcium silicate sealers in addition to the recent advances of the same and their clinical applications. Results: Although calcium silicate sealers possess subpar physical properties in comparison to resin-based sealers, they manifest promising properties like biocompatibility, antimicrobial potential along with their propensity for bioactivity. Conclusion: Beneficial properties of calcium silicate sealers render these sealers beneficial in the long-term success of root canal treatment. With newer competent sealers being put forth in the market on a regular basis, it is imperative to study their properties to simplify the clinician's selection of sealer, where indicated.

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Purpose: The aim of the present study was to measure the bond strength of adhesively luted glass-fiber bundles inside the root canal with respect to the application procedure in comparison to conventional solid glass-fiber posts. Materials and Methods: 104 human anterior teeth were endodontically treated, root filled and divided into 8 groups (n = 13). After post space preparation, fiber bundles consisting of 6 and 12 glass fibers, respectively, were luted adhesively with a multi-mode adhesive (Futurabond U; Voco, Cuxhaven, Germany) and a dual-curing composite (Rebilda DC, Voco) with the following application modes into the root canal: (1) direct application with tweezers, (2) distribution of the fibers using a spreader, (3) application of ultrasound after insertion of fibers. Two different solid posts (Rebilda DC, Voco; and DentinPost, Komet, Lemgo, Germany) were used as controls. Roots were sectioned into 6 slices per root (thickness 1 mm). Bond strengths were measured using thin--slice push-out tests for 3 slices 24 h after post insertion and for 3 slices per sample following thermocycling (TC) for 6000 cycles and storage in 0.9% NaCl for 6 months. Homogeneity of the slices was analyzed using a stereomicroscope and, for representative samples, micro-computed tomography (μCT). Results: Mean push-out bond strengths (MPa) were significantly affected by post system (p < 0.0005) and location inside the root canal (p = 0.004) but not by application mode (p = 0.544) or TC (p = 0.098; repeated measurement ANOVA). Fiber bundles consisting of 6 (13.2 ± 4.7) and 12 fibers (14.5 ± 4.3) revealed bond strength comparable to that of Rebilda Post (13.67 ± 3.2) but significantly higher than that of Dentin Posts (8.7 ± 3.02). Inhomogeneities were detected among 35.5% to 43.1% of the fiber-bundle samples, irrespective of number of fibers and application mode, and among 24.4% to 27.3% of the solid posts (p = 0.010; chi-squared test). μCT revealed voids inside the composite bulk between the fibers as well as between composite and dentin of adhesively luted fiber bundles. Conclusion: Adhesively luted fiber bundles achieved bond strengths comparable to those of solid fiber posts for one investigated post type, and even higher values compared to another post type. Inhomogeneities were frequently detected irrespective of application mode. [ABSTRACT FROM AUTHOR]

Introduction: The removal of smear layer using chelating agents often involves decalcification of the dentin that affects its physical properties. Hence, the objective of this study was to assess the outcome of SmearOFF and 17% ethylenediaminetetraacetic (EDTA) solutions on the surface roughness and microhardness of human root canal dentin. Materials and Methods: Twenty-three extracted human mandibular single-rooted premolars were split into 46 sections and placed into an autopolymerizing acrylic resin and were grated flat using silicon carbide abrasive papers. Forty-five samples were arbitrarily categorized into three groups as per experimental solutions used: control group (n = 15), 5 ml of 0.9% saline for 1 min + 5 ml of distilled water for 1 min, EDTA group (n = 15), 5 ml of 17% EDTA for 1 min + 5 ml of distilled water for 1 min, and the SmearOFF group (n = 15), 5 ml of SmearOFF for 1 min + 5 ml of distilled water for 1 min. The samples were then assessed for surface roughness using an atomic force microscope. The same samples were then assessed for microhardness using Vickers microhardness tester. The data were statistically analyzed using one-way analysis of variance, and the mean values were juxtaposed using Tukey's honest significant difference test. Results: The lowest surface roughness value was seen in the control group, followed by 17% EDTA and SmearOFF in an increasing order. The highest decrease in microhardness was seen in the SmearOFF group samples, followed by 17% EDTA group samples and least in the control group (P < 0.001). Conclusion: SmearOFF produced more surface roughness and caused a greater reduction in microhardness of root canal dentin in contrast to 17% EDTA.

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]

Purpose: To analyze the effects of ethanol for final post space irrigation and etching mode on the bond strength of fiber posts luted with a mild multimode adhesive (pH 2.3) as compared with a reference group using a self-adhesive resin cement (SAR). Materials and Methods: Human anterior teeth were endodontically treated. After post space preparation, the root canals were irrigated using 1% sodium hypochlorite (NaOCl) applied with passive ultrasonic irrigation, followed by either distilled water (control) or distilled water and ethanol 99% as final post space irrigation. Fiber posts were luted using Futurabond U in self-etch mode (FU-SE), Futurabond U in etch-and-rinse mode (FU-ER), or Futurabond DC (SE) in combination with a dual-curing core buildup material (Grandio Core, all VOCO); alternatively, posts were inserted using a self-adhesive composite cement (RelyX Unicem 2, 3M ESPE). Bond strengths were evaluated using push-out tests following thermocycling (TC) and storage in 0.9% NaCl for 3 months. Results: Mean push-out bond strengths (MPa) were significantly affected by the luting system (p < 0.0005) but not by the irrigation protocol (p = 0.068; ANOVA), although a significant interaction between the factors "luting agent" and "pre-treatment" was observed. FU E&R (21.28 [4.34]) and RX (20.12 [7.32]) revealed significantly higher bond strengths compared to FU SE (15.9 [6.02]), whereas F DC (18.8 [6.9]) did not differ significantly from all other groups. Ethanol pre-treatment increased bond strength in the apical part of the root canal for all materials, with the exception of FU E&R. Conclusion: Mild multimode adhesives exhibit comparable mean bond strengths to a SAR cement within the root canal for luting fiber posts if applied in an etch-and-rinse mode. Using this approach, ethanol application has no positive effects on bond strength. [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]

The effect of different air-blowing strategies using a prototype of a newly developed clinically applicable warm air-blowing device on the microtensile bond strength (μTBS) of one-step self-etch adhesives (1-SEAs) to human root-canal dentin was evaluated. Post cavities (8 mm depth, 1.5 mm diameter) were prepared and bonded with four 1-SEAs. Air-blowing was performed using normal air (23±1°C) for 10 or 20 s; warm air (60±1°C) for 10 or 20 s; or their combination for 10 s (5 s normal, 5 s warm) or 20 s (10 s normal, 10 s warm). After filling with corresponding core materials and 24-h water storage, μTBS test was performed. For three of the 1-SEAs, combined air-blowing for 20 s significantly increased μTBS compared to other air-blowing strategies (p<0.05). This suggests that the combination of normal and warm air-blowing for 20 s can enhance solvent evaporation from 1-SEAs, thus resulting in their improved bonding performance to root-canal dentin. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the depth of nanoleakage of four luting agents for bonding fiber posts after thermomechanical fatigue. Materials and Methods: Twenty-four extracted human anterior teeth were endodontically treated, sectioned at the cementoenamel junction, and restored with fiber posts using four commercially available resin cements with the corresponding core buildup materials (n = 6): Panavia F 2.0/Clearfil DC Core Automix (Kuraray), Variolink II/Multicore Flow (Ivoclar Vivadent), RelyX Unicem/Filtek Z250 (3M ESPE), and Multilink Sprint/Multicore Flow (Ivoclar Vivadent). The specimens received all-ceramic crowns and were subjected to thermomechanical fatigue (1.2 million cycles). After cutting off the crowns, the roots were isolated with nail polish except for a 1-mm rim around the root canal, and immersed in 50 wt% ammoniacal silver nitrate solution for 24 h. The specimens were sectioned perpendicular to the long axis of the tooth into four slices, fixed, dehydrated, and processed for FE-SEM. Leakage was analyzed using backscattered FE-SEM and EDS. Results: The depth of nanoleakage was significantly affected by the factor resin cement (p < 0.015; Kruskall-Wallis). Multilink Sprint resulted in significantly deeper penetration of silver particles than the other materials (p < 0.05; Mann Whitney U-Test). Conclusion: Hybridization of the root canal dentin created by self-etching or etch-and-rinse adhesive systems demonstrated distinctive nanoleakage up to 0.8 mm, whereas the self-adhesive resin cement RelyX Unicem was able to prevent distinctive leakage at this penetration depth. However, none of the investigated luting systems would be able to hermetically seal the root canal if leakage occurred around the margins of the coronal restoration. [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]

Purpose: To evaluate the influence of the brush type as a carrier of priming adhesive solutions and the use of paper points as a remover of the excess of these solutions on the push-out bond strength of resin cement to bovine root dentin. The null hypotheses were that brush type and the use of paper points do not affect the bond strength. Materials and Methods: The canals of 80 single-root bovine roots (16 mm in length) were prepared at 12 mm using the preparation drill (FRC Postec Plus, Ivoclar). Half of each root was embedded in acrylic resin and the specimens were divided into 8 groups, considering the factors "brush type" (4 levels) and "paper point" (2 levels) (n = 10): Gr 1: small microbrush (Cavi-Tip, SDI); Gr 2: Microbrush (Dentsply); Gr 3: Endobrush (Bisco); Gr 4: conventional brush (Bisco); Gr 5: Cavi-Tip (SDI) + paper points; Gr 6: Microbrush (Dentsply) + paper points; Gr 7: Endobrush (Bisco) + paper points; Gr 8: conventional brush (Bisco) + paper points. The root dentin was treated with a multistep total-etch adhesive system (All Bond 2). The adhesive system was applied using each microbrush, with and without using paper points. One fiber post was molded with addition silicon and 80 posts were made of resin cement (Duolink). The resin posts were luted (Duolink resin cement), and the specimens were stored for 24 h in water at 37°C. Each specimen was cut into 4 disk-shaped samples (1.8 mm in thickness), which were submitted to the push-out test. Results: The brush type (p > 0.0001) (small microbrush > microbrush = endobrush = conventional brush) and the use of paper points (p = 0.0001) (with > without) influenced the bond strength significantly (two-way ANOVA). The null hypotheses were rejected. Conclusion: The smallest brush (Cavi-Tip) and the use of paper points significantly improved the resin bond to bovine root dentin. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of canal irrigation protocols with 5.25% calcium hypochlorite [Ca(OCl)2], 5.25% sodium hypochlorite (NaOCl) and 17% EDTA solution on the inorganic component of root canal dentin. Sixty roots were randomly divided into six groups (n = 10): Saline solution (SS) (control); Saline solution (SSE) +17% EDTA; CH − 5.25% Ca(OCl)2; CHE − 5.25% Ca(OCl)2 + 17% EDTA; SH − 5.25% NaOCl; SHE − 5.25% NaOCl +17% EDTA. After canal irrigation, the specimens were longitudinally split and analyzed by scanning electron microscopy (SEM). Dentinal tubules were observed in transverse (middle and apical thirds) direction. The images were classified in scores, according to smear layer removal and peritubular dentin alteration, and data were analyzed by Kruskal–Wallis's test, followed by Dunn's test (α = 0.05). In the middle third, all groups with EDTA presented better removal of the smear layer with higher peritubular dentin alteration (p < .05). In the apical third, this happened only in SHE (p < .05). Ca(OCl)2 and NaOCl exhibit similar performance to remove smear layer and alteration of the inorganic component in the middle third. In the apical third, NaOCl associated with EDTA showed better performance in smear layer removal. Ca(OCl)2 and NaOCl were similar in the smear layer removal and the alteration of the inorganic component at the root canal middle third. NaOCl + EDTA showed better performance than groups without EDTA in the smear layer removal at the apical third. [ABSTRACT FROM AUTHOR]

Background: Chelating agents are believed to aid root canal irrigation and to be able to remove the inorganic smear layer. Aims: The purpose of the present study was to evaluate and to compare the decalcifying capability of different irrigating solutions (Tubuliclean, Largal Ultra, ethylenediaminetetraacetic acid 17%, Tetraclean, Tetraclean NA). Materials and Methods: Sixty maxillary central incisors were used. Root canals were instrumented and irrigated. From each root, four comparable slices of cervical dentin were obtained. At three successive 5-min interval immersion times, the concentration of calcium extracted from root canal dentin was assessed with an inductively coupled plasma-atomic emission spectrometer. Statistical Analysis Used: Data were analyzed by means of Kruskal Wallis and Mann-Whitney tests. Significance was predetermined at P < 0.05. Results and Conclusions: For all irrigating solutions, the maximum amount of Ca 2+ extracted from root canal dentin samples was reached after 10 min contact time except for citric acid-based agents (Tetraclean and Tetraclean NA) which induced a higher and still increasing calcium release even after 10 min contact time. In order to obtain an efficient decalcifying action on dentin and to facilitate the biomechanical procedures, citric acid-based irrigants can be applied.

Background and Objectives: Outcomes of root canal therapy depends on chemical cleaning of root canal by irrigating solutions, which may affect root canal dentin microharness. Only a few studies have specifically studied this effect. To fill this gap, we aimed to assess several irrigating solutions on the microhardness of root canal dentin. Subjects and Methods: A total of 50 premolar teeth were selected. The roots were split in the horizontal direction from middle, and were embedded in self-curing acrylic resin and polished. The samples were divided into 5 groups (n=10) and immersed for 15 min according to the irrigating solution: 5.25% NaOCl, 2% CHX, Tetraclean, Hypoclean, and Chlor-Xtra. Then, the specimens were subjected to microhardness testing utilizing Vickers method before and after immersion. Data were analyzed using SPSS ver 20, Paired T-test, and One-Way ANOVA. Results: The microhardness of root canal dentin in all irrigating solutions groups, except for 2% CHX, were significantly decreased (P<0.05). The highest microhardness reduction of root canal dentin was related to 5.25% NaOCl, Tetraclean, Hypoclean, and Chlor-Xtra, respectively and the difference was not statistically significant (p > 0.05). Conclusion: Based on the results of this study, the endodontic irrigating solutions, as well as 5.25% NAOCL, cause the same degree of reduction in the microhardness of root canal dentin. While 2% CHX has no effect on the microhardness of root canal dentin. [ABSTRACT FROM AUTHOR]

Purpose The use of warm air-blowing to evaporate solvents of one-step self-etch adhesive systems (1-SEAs) has been reported to be a useful method. The purpose of this study was to evaluate the effect of warm air-blowing on root canal dentin. Methods Four 1-SEAs (Clearfil Bond SE ONE, Unifil Core EM self-etch bond, Estelink, BeautiDualbond EX) were used. Each 1-SEA was applied to root canal dentin according to the manufacturers’ instructions. After the adhesives were applied, solvent was evaporated using either normal air (23 ± 1 °C) or warm air (80 ± 1 °C) for 20 s, and resin composite was placed in the post spaces. The air from the dryer, which could be used in normal- or hot-air-mode, was applied at a distance of 5 cm above the root canal cavity in the direction of tooth axis. The temperature of the stream of air from the dryer in the hot-air-mode was 80 ± 1 °C, and in the normal mode, 23 ± 1 °C. After water storage of the specimens for 24 h, the μTBS were evaluated at the coronal and apical regions. The μTBSs were statistically analyzed using three-way ANOVA and Student’s t-test with Bonferroni correction ( α = 0.05). Results The warm air-blowing significantly increased the μTBS of all 1-SEAs at the apical regions, and also significantly increased the μTBS of two adhesives (Estelink and BeautiDualBond EX) at coronal regions. Conclusions The μTBS of 1-SEAs to root canal dentin was improved by using warm air-blowing. [ABSTRACT FROM AUTHOR]

Background: Calcium hydroxide pastes used in the endodontic therapy may produce changes in the physical properties of the dentin. Objective: The purpose of this study was to evaluate the effect of calcium hydroxide pastes and their vehicles on microhardness of root canal dentin. Materials and Methods: Sixty maxillary anterior teeth were used. The crowns of the teeth were removed at the cemento-enamel junction. Canals were instrumented, horizontally sectioned into 2 segments, embedded in acrylic resin, and polished. A total of 120 specimens were randomly divided into 12 groups. Specimens stayed in contact with the vehicles or the pastes prepared with the calcium hydroxide powder and the same vehicles. The vehicles are: Distilled water, chlorhexidine, carticaine in the anesthetic solution, propylene glycol, monochlorophenol and monochlorophenol - propylene glycol. The references Vickers microhardness were obtained prior the application of the medicaments. Samples were then exposed to the medicaments for 3, 7, and 14 days, and microhardness measured again. The results were statistically analyzed by one-way ANOVA, Tukey test, and regression. Results: All vehicles and pastes, except distilled water, significantly decreased the microhardness of the root dentin; however, calcium hydroxide + camphorated monochlorophenol - propylene glycol and camphorated monochlorophenol - propylene glycol showed the highest decrease. Conclusion: Vehicles contribute to calcium hydroxide reduction of root canal dentin microhardness as constituent of endodontic pastes.

Objectives: To compare the mean thickness of hybrid layer by using selfetch adhesive at coronal dentin and root canal dentin with scanning electronic microscope. Study Design: Experimental study. Setting: Liaquat University of Medical & Health Sciences, Jamshoro. Period: July 2009 to 31st December 2009. Material & Methods: Fifty permanent single rooted extracted teeth were used in this study. The sample size was divided into two equal groups of 25 teeth each. Group 1(n=25) self etch adhesive was applied on coronal dentin then light cured for 10seconds. Group 2(n=25)self etch adhesive to root canal dentin and then light cured was applied for 10seconds then 2mm thick layer was placed to adhesive bonded surfaces of coronal and root canal dentin. Data were analyzed using t-test of significance. p-Value was significant at ≤0.05. Results: The mean ±standard deviation of thickness of hybrid layer was 2.3088 ±1.027 um in coronal dentin; and it was 2.1104 ±1.0316 um in root canal dentin. Conclusion: There is no statistically significant differences in mean thickness of hybrid layer between root canal dentin and coronal dentin with self etch adhesive. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the bond strength of fiber post previously laser treated root canals. Forty single-rooted bovine teeth were endodontically treated, randomly and equally divided into two main groups according to the type of pretreatment: G1: 2.5% NaOCl (control group); and G2: Er,Cr:YSGG laser. Each group was further subdivided into 2 groups based on the category of adhesive systems/ luting materials used: a: an etch-and-rinse resin cement (Single Bond/RelyX ARC; 3M ESPE), and b: a self-adhesive resin cement (Rely X Unicem; 3M ESPE). Three 1.5 mm thick slabs were obtained per root and the push-out test was performed at a crosshead speed of 0.5 mm/min until post dislodgement occurred. Data were analyzed by ANOVA and post-hoc Tukey's test at a pre-set alpha of 0.05. Analysis of variance showed no statistically significant difference (p > 0.05) among the groups G1a (25.44 ± 2.35) and G1b (23.62 ± 3.48), G2a (11.77 ± 2.67) and G2b (9.93 ± 3.37). Fractures were observed at the interface between the dentin and the resin in all groups. The Er,Cr:YSGG laser irradiation did not influence on the bond strength of the resin cements and the etch-and-rinse resin cement had better results on bond strength than self-adhesive resin cement.

Statement of the problem: Shear bond strength test is a common test to evaluate the bond between restorative materials and tooth structure but it cannot measure the marginal adaptation of the restorative filling materials. Therefore, in this research an evaluation method of punch out test was employed to evaluate resin bonding to root canal wall dentin by measuring both marginal adaptation and shear bond strength simultaneously. Objectives: The aim of this study is to investigate the reliability and efficiency of punch out shear test to evaluate the effect of sodium hypochlorite (NaOCl) as a root canal irrigant on composite resin bonding to canal dentin and also to evaluate the contraction gap formation from the same specimen. The null hypothesis tested was that treatment of root canal with NaOCl would not compromise bonding to root canal dentin, whether a total etching adhesive or self-etching adhesive was used. Materials and Methods: A total etching adhesive system (Optibond Solo Plus) and a self etching adhesive system (XenoIII) were employed in this study. A standardized truncated cone cavity (4 mm in base diameter, 3 mm in depth and a convergence angle of 5° ), was prepared at the top portion of the root canal. The cavities were subjected to sodium hypochlorite treatment for different periods of time and then rinsed with distilled water. Then, one of the aforementioned dentin bonding systems was applied to the cavity walls according to the manufacturer's instructions. The cavities were then filled with a micro-hybrid composite resin. Results and conclusion: The increase in the NaOCl application time resulted in a progressive decrease in the punch out shear bond strength for the specimens treated with a self etching adhesive system. A marginal gap was detected when XenoIII was applied after NaOCl application.

Aim: The aim of this study was to evaluate the microhardness of human dentin by using four irrigating solutions. Materials and Methodos: A total of 40 extracted mandibular premolars were selected and sectioned horizontally in the middle third of the root. Forty specimens of 4 mm thickness were embedded in acrylic resin and polished. Four test groups, each group containing ten specimens were immersed in respective irrigating solution and subjected to vicker’s microhardness test at T0, T2 and T5min. Statistical Analysis: The data obtained were analyzed using the one way ANOVA followed by Tukey HSD method with ap=0.05 as the level for statistical significance. Results: Suggested that there was no statistically significant difference in mean values between four experimental irrigating solutions. Conclusion: Mixture of Tetracycline isomer i.e. Doxycycline, Citric acid and a Detergent (Tween 80) MTAD not altered the microhardness of root canal dentin significantly and seems to be an appropriate irrigating solution, because of its harmless effect on the microhardness of the root canal dentin.

Background: Chelating agents are believed to aid root canal irrigation and to be able to remove the inorganic smear layer. Aims: The purpose of the present study was to evaluate and to compare the decalcifying capability of different irrigating solutions (Tubuliclean, Largal Ultra, ethylenediaminetetraacetic acid 17%, Tetraclean, Tetraclean NA). Materials and Methods: Sixty maxillary central incisors were used. Root canals were instrumented and irrigated. From each root, four comparable slices of cervical dentin were obtained. At three successive 5-min interval immersion times, the concentration of calcium extracted from root canal dentin was assessed with an inductively coupled plasma-atomic emission spectrometer. Statistical Analysis Used: Data were analyzed by means of Kruskal Wallis and Mann-Whitney tests. Significance was predetermined at P < 0.05. Results and Conclusions: For all irrigating solutions, the maximum amount of Ca2+ extracted from root canal dentin samples was reached after 10 min contact time except for citric acid-based agents (Tetraclean and Tetraclean NA) which induced a higher and still increasing calcium release even after 10 min contact time. In order to obtain an efficient decalcifying action on dentin and to facilitate the biomechanical procedures, citric acid-based irrigants can be applied. [ABSTRACT FROM AUTHOR]

Objectives: The aim was to investigate the effects of chlorhexidine and ethanol pretreatment of the root canal on push-out bond strengths and durability of adhesion of fiber posts luted with two different adhesive strategies. Materials and methods: One hundred twenty human anterior teeth were endodontically treated. After post space preparation, the root canals were irrigated using 1 % sodium hypochlorite (NaOCl) applied with passive ultrasonic irrigation followed by distilled water (control). In pretreatment (PT) group, chlorhexidine (CHX) root canals were irrigated using 2 % chlorhexidine; and in the PT group, 99 % ethanol was used prior application of the luting agent. Two different post-and-luting systems with an etch-and-rinse (CX) adhesive approach ( n = 60) and a self-adhesive resin cement (RX; n = 60) were inserted into the root canals. Bond strengths were evaluated initially and after thermocycling and storage for 6 months using push-out tests. Results: Bond strength was significantly affected by the adhesive strategy ( p < 0.0005), the pretreatment ( p < 0.0005) and the location inside the root canal ( p < 0.0005; repeated measurement ANOVA). Ethanol significantly increased bond strengths irrespective of the luting agent used compared to the control and CHX group ( p < 0.05; Tukey's B). Conclusion: Ethanol significantly increased bond strength of the CX and the RX system inside the root canal and could be recommended as a final rinse for luting fiber posts using an ethanol-based etch-and-rinse adhesive system or self-adhesive resin cement. Clinical relevance: PT of the root canal using ethanol seems to facilitate adhesive luting of fiber posts with the tested adhesive system and luting cements. [ABSTRACT FROM AUTHOR]

Irrigation after post space preparation and its effects on the bond strength of different adhesive strategies are still an issue of interest. The aim of the present study was to investigate the effects of various irrigation protocols ( IPs) on the push-out bond strengths of fiber posts. One-hundred and fifty extracted human anterior teeth were divided into three groups ( n = 50 each) and endodontically treated. The post space was irrigated before post placement using the following five IPs in each group: IP1 (control): 5 ml of distilled water; IP2: 5.25% sodium hypochlorite (Na OCl) applied with passive ultrasonic irrigation ( PUI); IP3: 1% Na OCl applied with PUI; IP4: 18% ethylenediaminetetracetic acid ( EDTA) followed by 5.25% Na OCl; and IP5: 2% chlorhexidine ( CHX). Fiber posts placement in each group was performed using three different adhesive strategies. A self-etch adhesive system revealed higher bond strength (16.2 ± 6.9 MPa) compared with an etch-and-rinse adhesive (8.5 ± 4.2 MPa) and a self-adhesive resin cement (9.2 ± 4.7 MPa). The use of 18% EDTA/5.25% Na OCl increased the bond strength of the self-adhesive resin cement. Conversely, this IP decreased the bond strength for the etch-and-rinse adhesive system, whilst 1% Na OCl enhanced the bond strength for the same system. Consequently, each adhesive strategy may need to be adapted to a specific IP. [ABSTRACT FROM AUTHOR]

The weak link in the adhesive luting of fiber posts to root canal dentin is at the cement-dentin interface. The aim of the present study was to evaluate the effect of Er,Cr:YSGG laser irradiation on push-out bond strength of fiber posts cemented to root canal dentin using a self-adhesive cement. A total of 30 sound human maxillary central incisors were equally divided into two groups after root canal treatment, decoronation and preparation of the post space. Teeth of group 1 were treated with the Er,Cr:YSGG laser, and teeth of group 2 (control) received no laser treatment. After cementation of fiber posts with Maxcem self-adhesive cement, 3-mm cervical, middle and apical sections were prepared from the roots. Then a push-out test was performed using a universal testing machine at a strain rate of 0.5 mm/min. Data were analyzed using two-way ANOVA and the Bonferroni test. Statistical significance was defined as P < 0.05. There was a significant difference in the mean bond strength values between groups 1 and 2 ( P = 0.001), but there were no significant differences between the various root parts ( P = 0.14). In addition, the cumulative effects of dentin treatment type and various root parts were not statistically significant ( P = 0.41). The mean bond strength in the laser group was significantly higher than in the control group ( P = 0.001, post hoc Bonferroni test).The failure mode was evaluated under a stereomicroscope at ×20 magnification. [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]

The aim of this study was to compare the effects of Nd:YAG, Er:YAG, and diode lasers on the morphology and permeability of root canal walls. The three laser wavelengths mentioned interact differently with dentin and therefore it is possible that the permeability changes caused will determine different indications during endodontic treatment. Twenty-eight human single-rooted teeth were instrumented up to ISO 40 and divided into four groups: group C, control (GC), non-laser irradiated; group N (GN), irradiated with Nd:YAG laser; group E (GE), with Er:YAG laser and group D (GD) with diode laser. After that, the roots were filled with a 2% methylene blue dye, divided into two halves and then photographed. The images were analyzed using Image J software and the percentage of dye penetration in the cervical, middle, and apical root thirds were calculated. Additional scanning electron microscopy (SEM) analyses were also performed. The analysis of variance (ANOVA) showed significant permeability differences between all groups in the middle and cervical thirds (p < 0.05). The Tukey test showed that in the cervical third, GN presented means of dye penetration statistically significantly lower than all of the other groups. In the middle third, GE and GD showed statistically higher dye penetration means than GC and GN. SEM analysis showed melted surfaces for GN, clean wall surfaces with open dentinal tubules for GE, and mostly obliterated dentinal tubules for GD. Er:YAG (2,094 nm) laser and diode laser (808 nm) root canal irradiation increase dentinal permeability and Nd:YAG (1,064 nm) laser decreases dentin permeability, within the studied parameters. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: This study investigated the effects of light penetration and removal of smear layer on the adhesive properties of self-etching adhesives to root canal dentin when using fiber posts. Methods: Altogether 54 human incisors and premolars were decoronated, and the roots after preparing the post space were randomly assigned into six groups. Three groups were treated with a light-cured self-etching adhesive and the other three with a dual-cured self-etching adhesive. In a further sub-division, the first group was light-cured with an irradiation unit; the second was light-cured with the irradiation unit and a light-guiding attachment; and the third was light-cured with the irradiation unit and the attachment after removing smear layer by EDTA and NaOCl. Then, a glass-fiber post was luted into the post space by a dual-cured composite. After 24h, an hourglass-shaped specimen was trimmed and subjected to MTBS testing. Results: Using the light-guiding attachment and removing the smear layer reduced the incidence of pre-testing failure significantly from 57.1% to 19.0% (p <0.05) in the light-cured adhesive groups and from 68.3% to 3.2% (p <0.01) in the dual-cured adhesive groups. The MTBS in different locations within a post space were in the range from 8.9 to 17.5MPa in the light-cured group and from 11.2 to 17.2MPa in the dual-cured group. Significance: Better light penetration in post spaces and removal of the smear layer are effective in improving the adhesive properties of self-etching adhesives to root canal dentin when using fiber posts. [Copyright &y& Elsevier]

This study correlated the morphological characteristics with the bond strengths of various resin cements used for bonding fiber posts to root canal dentin. Fifty glass-fiber posts (FRC Postec Plus) were luted into the root canals of extracted human anterior teeth using five resin cements ( n = 10): Panavia F 2.0, PermaFlo DC, Variolink II, RelyX Unicem, and Clearfil Core. Before insertion of the post, the adhesive systems were labeled with fluorescein and the resin cement was labeled with rhodamine isothiocyanate. The roots were sectioned into three slices (of 2 mm thickness), and each slice was analyzed using confocal laser scanning microscopy in dual fluorescence mode to determine hybrid layer thickness, the number of resin tags, and the number of broken tags. Bond strengths were measured using a micro push-out test. Bond strengths to root canal dentin, as well as the morphological characteristics, were significantly affected by the materials. However, these factors did not correlate. The self-adhesive resin cement, which showed the formation of a hybrid layer and resin tags only sporadically, had the highest bond strengths. These results indicate that chemical interactions between the adhesive cement and hydroxyapatite may be more crucial for root dentin bonding than the ability of the same material to hybridize dentin. [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: Discovering a durable restorative method to reconstruct and reinforce pulpless teeth is a vital key to help prevent root fractures. Complete and firm adhesion of resin cement in root canal dentin using a post is critical to achieve it. The null hypothesis in the present study was that the bond strength of dual-cured and chemical-cured adhesive resin cements to root canal dentin is not affected by their vertical locations in the root canal. In the experiments, extracted human incisors restored with fiber-reinforced posts and adhesive resin cements were subjected to microtensile bond strength testing. Then, the failure modes and the dentin-bonding interfaces were observed. Self-etch and self-adhesive dual-cured resin cements showed frequent pretesting failure despite using a silane coupling agent. Chemical-cured total-etch adhesive material showed stable bonding performances throughout the entire post space and thus has an advantage in post-core restorations. [Copyright &y& Elsevier]

Abstract: The aim of the present study was to investigate the effects of antibacterial agents (erbium:yttrium-aluminum-garnet [Er:YAG] laser or gaseous ozone) intended to disinfect root canals on bond strengths of fiber posts compared with canals that were finally irrigated using chlorhexidine (CHX). One hundred forty-four human anterior teeth were divided into three groups (n = 48); root canal instrumentation was performed, and antimicrobial pretreatment was conducted as follows: control group: CHX, group 2: Er:YAG laser, and group 3: gaseous ozone. In all groups, fiber posts were inserted using Panavia F 2.0 (Kuraray, Osaka, Japan), Variolink II (Ivoclar Vivadent, Schaan, Liechtenstein), RelyX Unicem (3M Espe; Seefeld, Germany), or Ketac Cem (3M Espe) (n = 12 each). Push-out bond strengths to root canal dentin were affected by the type of luting agent but not by the antimicrobial pretreatment regimen. However, significant interactions between the luting agent and pretreatment could be observed, and adhesion of the self-adhesive resin cement RelyX Unicem was significantly reduced after using gaseous ozone. [Copyright &y& Elsevier]

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]