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Objectives: 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., Data/sources: The literature was electronically searched in PubMed, Embase, and Scopus. A manual search was performed by scanning the reference lists of the included studies., Study Selection: 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., Results: 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., Conclusions: 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., (Copyright © 2023 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)

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., (© 2021. The Author(s).)

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 37°C 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.

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.

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.

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 20s, 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 5cm 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 24h, 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., (Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.)

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 (NaOCl) applied with passive ultrasonic irrigation (PUI); IP3: 1% NaOCl applied with PUI; IP4: 18% ethylenediaminetetracetic acid (EDTA) followed by 5.25% NaOCl; 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% NaOCl 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% NaOCl enhanced the bond strength for the same system. Consequently, each adhesive strategy may need to be adapted to a specific IP., (© 2013 Eur J Oral Sci.)

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: 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]

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]

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 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: 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]

The purpose of this study was to evaluate the regional bond strength of a dual-cure resin core material to root canal dentin using four self-etching primer/adhesive systems. Post spaces were prepared in extracted premolars, and their root canal dentin was treated with one of the following self-etching primer/adhesive systems: ED Primer II and Clearfil Photobond, photo-cure/dual-cure systems of Clearfil Liner Bond 2V, or Clearfil SE Bond. Post spaces were filled with the dual-cure resin core material, and microtensile bond strength (µTBS) at the coronal and apical regions was measured after 24-hour storage. There were no regional differences in µTBS of the photo-cure and dual-cure systems of Clearfil Liner Bond 2V, while µTBS at the coronal region of Photobond and SE Bond groups were higher than those at the apical region. At the apical region, photo-cured Clearfil Liner Bond 2V exhibited significantly higher bond strength than those of the other systems. [ABSTRACT FROM AUTHOR]