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To compare the push-out bond strength of adhesive resin cement and glass fiber posts (GFP) at different root levels after exposure to Er: YAG laser irradiation compared to other conventional surface treatment procedures. A total of 24 mandibular premolars were decoronated, root canal treatment was done, post spaces were prepared, and roots were mounted in acrylic resin blocks. Fiber posts were divided into four groups (n = 6) according to surface treatment methods: (1) silane only (control group), (2) Er: YAG laser 1.5 W + silane, (3) 30% hydrogen peroxide + silane, (4) sandblasting with 50 μm aluminum oxide particles + silane. GFP were cemented using self-adhesive resin cement. Scanning electron microscope images with 500x magnification were taken for all groups. Push-out test was performed using a universal testing machine at different root levels. The difference between groups was statistically significant with laser group recording the highest mean ± SD value of push-out bond strength (5.668042 ± 1.16 MPa), followed by the H2O2 group, then the control group, meanwhile the lowest value was recorded with Sand-blasting group. There were no statistically significant differences between the Control group and Er: YAG group; Control group and sandblasted group. The difference between the radicular regions was not statistically significant, with the middle region recorded the highest push-out bond strength (4.746851 ± 0.73 MPa). GPF surface treatment using an Er: YAG laser is effective as it increases the retention to resin cement, while sandblasting decreases fiber post retention to resin cement. The hydrogen peroxide and the control groups give similar bond strength. The middle and apical regions of GFP have better retention to resin cement than the coronal one., Competing Interests: Declarations. Ethical approval: This study was an in-vitro study conducted at the Faculty of Dentistry, Cairo University. All procedures carried out followed the ethical standards of Cairo University, and were approved by the institutional review board and research ethical committee of the Faculty of Dentistry, Cairo University, Egypt. The selected teeth were extracted from diabetic patients due to periodontal reasons who signed medico-legal consent for their approval to be used in research. Consent for publication: Not applicable Informed consent: The selected teeth were extracted from diabetic patients due to periodontal reasons who signed medico-legal consent for their approval to be used in research. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Purpose: This study aimed to assess the impact of battery levels in single-peak and multi-peak light-curing units (LCUs) on irradiance, and their effects on glass fiber post push-out bond strength to root dentin and the degree of conversion of dual-cure universal resin cement., Methods and Materials: Sixty bovine roots underwent endodontic treatment and were randomly distributed into 6 groups (n=10), formed by combining two LCUs (single-peak and multipeak) and three battery levels (100%, 50%, and 10%). A spectrophotometer measured irradiance (mW/ cm2) and spectral irradiance (mW/cm2/nm). Push-out bond strength (PBS) tests occurred at three root regions (cervical, middle, and apical), with optical and scanning electron microscopy for failure mode analysis. Degree of conversion (DC) was evaluated across the root regions. Data were analyzed using two-way repeated measures ANOVA and the Tukey HSD test. The Fisher exact test verified failure modes (α=0.05)., Results: As multipeak LCU battery levels decreased, emitted irradiance also diminished, with notable PBS reductions in the apical thirds. Failure modes were influenced by different conditions, primarily exhibiting mixed modes. Battery levels significantly impacted DC in the multipeak LCU, particularly in the cervical region, while the single-peak LCU exhibited DC reduction at the 10% battery level in the cervical region., Conclusions: Emitted irradiance, resin cement DC, and glass fiber post bond strength to root dentin may be influenced by varying cordless LCUs and battery levels., (©Operative Dentistry, 2024.)

Purpose: In clinical prosthetics procedures, including endodontics and post fixation, the presence of a smear layer can reduce the post bond strength. An Er,Cr:YSGG laser, which emits at 2780 nm, can promote a smear-layer-free surface due to the ablation process. Considering these aspects, the purpose of this work was to evaluate the influence of Er,Cr:YSGG laser irradiation using either a radial or an axial fiber tip on the bond strength of three resin cements to the fiber-reinforced composite posts., Materials and Methods: Ninety recently extracted single rooted human teeth had their root canal instrumented and were randomly distributed into nine experimental groups, in which three resin cements (total-etching Variolink II, self-etching Panavia F, and self-adhesive RelyX Unicem Aplicap) and three root canal treatments (no treatment, laser irradiation using the radial fiber tip, laser irradiation using the axial fiber tip) were used. Specimens were then sectioned into three sections (cervical, middle, and apical thirds) with two slices on each section. A push-out test was performed on each slice, and the values were recorded as MPa. The push-out data were analyzed by a Ryan-Joiner normality test followed by a two-way ANOVA test and Tukey pairwise comparison. The statistical analysis was performed on each third section separately, with a 5% significance level., Results: Laser irradiation with axial fiber tip significantly increased the post bond strength of RelyX Unicem Aplicap on middle third of specimens (p < 0.001) when compared to other root canal treatments (unlased or irradiated with radial tip). Considering the Panavia resin cement, laser irradiation with either axial or radial tips promoted a significant increase on the post bond strength of middle third when compared to unlased specimens (p < 0.001); however, laser irradiation did not influence the post bond strength of Variolink resin cement., Conclusions: The use of the Er,Cr:YSGG laser for clinical prosthetics procedures enhances the post bond strength of Panavia and RelyX Unicem Aplicap resin cements, mainly at middle third of roots, and does not interfere with the bond strength of Variolink resin cement. For the RelyX Unicem Aplicap system, the use of axial tip is most advantageous and can be recommended for future clinical application., (© 2017 by the American College of Prosthodontists.)

The purpose of this study was to evaluate the push-out bond strength of two different adhesive cements (total etch and self-adhesive) for glass fiber post (GFP) cementation in simulated, long-term service (thermocycling) when the root canal is treated with chlorhexidine before cementation. One hundred twenty premolar specimens with a single root canal were selected, endodontically treated, and shaped for GFP cementation (n=120). The specimens were randomly placed into one of 12 groups (10 specimens each) according to cement (T = total-etch RelyX ARC or S = self-adhesive RelyX Unicem), treatment with chlorhexidine (N or Y: without or with), and number of thermal cycles (00, 20, or 40: 0, or 20,000 or 40,000 cycles): 1. TN00, 2. TN20, 3. TN40, 4. TY00, 5. TY20, 6. TY40, 7. SN00, 8. SN20, 9. SN40, 10. SY00, 11. SY20, 12. SY40. The root of each specimen was cut perpendicular to the vertical axis, yielding six 1.0 mm-thick sections. A push-out bond strength test was performed followed by statistical analysis using a factorial analysis of variance. Pairwise comparisons of significant factor interactions were adjusted using the Tukey test. Significant differences of push-out bond strengths were found in the four main effects (resin cement [ p<0.0001], treatment with chlorhexidine [ p<0.0001], number of cycles [ p<0.0001], and root third [ p<0.0001]) and all interactions ( p<0.05 for all). Both resin cements produced higher bond strength in the cervical third followed by the middle third, and lower values were detected in the apical third. Additionally, the results suggest that the use of an additional disinfection treatment with chlorhexidine before the cement application produced the highest push-out bond strength regardless of root third. Further, the thermocycling simulation decreased the bond strength for both resin cements long-term when the chlorhexidine was not applied before cementation. However, when the root canal was treated with chlorhexidine and the fiber post was cemented with self-adhesive cement, the bond strength increased after 0, 20,000 and 40,000 cycles.

Introduction: Because there is little information about bond strength of fiber posts cemented with a universal adhesive system (UAS) with different resin cements, the aim of this study was to compare the effect of different bonding strategies in the application of UASs on push-out bond strength of fiber posts to intraradicular dentin., Methods: Seventy-two single-rooted teeth were randomly divided into 6 groups: self-adhesive resin cement (SAC), dual-cure resin cement (DCC), UAS in the etch-and-rinse (E&R) mode and SAC (E&R + SAC), UAS in the self-etch (SE) mode and SAC (SE + SAC), UAS in the E&R mode and DCC (E&R + DCC), and UAS in the SE mode and DCC (SE + DCC). The push-out test was conducted at a crosshead speed of 0.5 mm/min. Data were analyzed with 2-way analysis of variance (P < .05)., Results: Bond strength was significantly influenced by the adhesive strategies (P < .001). However, post space region did not have a significant effect on bond strength (P > .05)., Conclusions: ClearfilSA Luting SAC (Kuraray Noritake Dental Inc, New York, NY) cannot be used alone for fiber post adhesion; it needs an adhesive. Universal adhesive in the SE mode is suggested. When UAS is used for luting fiber posts, the type of cement does not have any effect on bond strength., (Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim: To evaluate the percentage volume of voids within cement layers, to determine the push-out bond strength of circular and oval fibre posts luted with different commercial resin cements in oval cross-sectional root canals, and to correlate push-out bond strength values and volume of voids of circular and oval fibre posts., Methodology: Seventy-two mandibular premolars with oval-shaped root canals were selected. The specimens were divided into two main groups according to the post type (oval and circular). Groups were further divided into three subgroups (n = 24) according to resin cement type: Maxcem Elite, Rely-X Unicem and Duo-Link. The volumes of voids within the cements were analysed by micro-computed tomography (micro-CT). The bond strength was then measured using a push-out test with an Instron universal testing machine. The failure modes were evaluated. Statistical analyses were performed using a three-way anova, Tukey's post hoc, Pearson's correlation and chi-square test (P = 0.05)., Results: The push-out bond strength values were significantly affected by root canal region, post type and cement type (P < 0.001). Root canal region, post type and cement type also significantly affected void volume (P < 0.001). There was a significant interaction between post type and cement type (P < 0.001). The most frequent failure type was adhesive failure in all the groups. There was no significant correlation between the push-out bond strength and void volume (P > 0.05)., Conclusions: Void volume did not affect push-out bond strength of oval and circular posts luted in oval canals., (© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Objectives: The objective was to evaluate whether fiber postsurface conditioning with air abrasion or erbium:yttrium-aluminum-garnet (Er:YAG) laser would influence the bond strength of dual-cure resin cement to the fiber-reinforced (FRC) posts., Materials and Methods: Twenty-one FRC posts were divided into three groups according to surface treatment methods as follows: An untreated control group air abrasion with Al2O3group, and Er:YAG laser treated group with 150 mJ parameter. Fiber posts were then built up to dual-cure resin cement. Eighteen specimens were set and sectioned perpendicularly along the long axis of the post using a saw. Two disks (thickness of 2 mm) were obtained from each specimen (n = 12). Remaining three posts were stored for scanning electron microscopic evaluation. Push out test was performed on the each specimen and the values were recorded as MPa. The data were analyzed using one-way analysis of variance and Tukey post-hoc tests (P < 0.05)., Results: The bond strength values for the groups were as follows: Control (15, 28 MPa), air abrasion group (19, 73 MPa), and Er:YAG group (17, 84 MPa). Air abrasion affected the bond strength significantly (P < 0.05)., Conclusion: Air abrasion attained higher bond strengths when FRC posts were luted to dual-cure resin cement. Additional studies should be designed with different types and parameters of laser devices to understand the effect of these devices on bond strength.

This study evaluated the influence of relining fiber posts on the bond strength (BS) of resin cements in the root canal. Forty bovine teeth were divided in four groups (n = 10): G1 (ARC)-fiber post cemented with resin cement RelyX ARC; G2 (ARC+Z350)-relined fiber post cemented with RelyX ARC; G3 (U200)-fiber post cemented with self-adhesive cement RelyX U200; G4 (U200+Z350)-relined fiber post cemented with RelyX U200. The roots were sectioned in six 1.2-mm slices and the push-out test was performed. Data were analyzed by three-way analysis of variance (ANOVA), and Tukey's test (a = 0.05). For the conventional resin cement, there was no significant difference between groups G1-ARC (15.5 ± 3.8) and G2-ARC+Z350 (16.1 ± 4.5). For the self-adhesive cement, the results revealed higher BS values for relined posts G4-U200 + Z350 (19.9 ± 7.9) as compared to non-relined posts G3-U200 (14.4 ± 4.5). For both cements, in groups of relined posts, the apical and the cervical thirds presented similar BS. Relining enhances the performance of the self-adhesive resin cement, and the interaction between relining and root third influences the BS to the conventional resin cement.

Objective: The aim of this study was to investigate the effects of photon-initiated photoacoustic streaming (PIPS) with various irrigating solutions on the bond strength of a self-adhesive resin cement to root dentin., Materials and Methods: Seventy-two mandibular premolar roots were divided into six groups after post space preparation and treated with a needle irrigation with distilled water and NaOCl, ultrasonic irrigation with NaOCl, PIPS with NaOCl, PIPS with EDTA and PIPS with distilled water at 0.3 W, 15 Hz and 20 mJ per pulse for 60 s. Fiber posts were cemented with a newly marketed, self-adhesive resin cement. The data obtained from the push-out tests were analyzed using analysis of variance (ANOVA) and LSD post-hoc tests (p = 0.05)., Results: PIPS with distilled water resulted in higher push-out values than those of needle (with both distilled water and NaOCl) and ultrasonic irrigation (p < 0.05)., Conclusions: The use of PIPS may provide higher bond strength of self-adhesive resin cement to root dentin than needle and ultrasonic irrigation techniques.

Background: To assist the retention of restorations prepared in endodontically treated teeth, fiber posts are widely used in dental practice. The ideal time to prepare space for the post is still controversial., Aim: The purpose of this study was to evaluate the effects of immediate and delayed postspace preparation on the retention of the self-adhesive resin cement., Materials and Methods: Twelve bovine teeth were used with sectioned roots standardized to 19 mm. The teeth were properly instrumented and filled with gutta-percha and eugenol-free cement AH Plus. Two experimental groups (n = 6) were created based on the different times of post preparation (immediate and delayed). Using cemented cylindrical fiber posts, the teeth were put in acrylic resin and polyvinyl chloride tubes, where the cuts were made. Two slices were obtained from the cervical third, two from the medium third and two from the apical third. Subsequently, the samples were subjected into push-out tests. Statistical analysis were performed using ANOVA and Tukey's test (P = 5%)., Results: The results indicated that, for all of the evaluated thirds, delayed preparation showed greater bond strength than immediate preparation., Conclusion: A delayed post preparation of the root space, following the root canal filling, is recommended.

Purpose: To evaluate the effect of the insertion technique for resin cement and mechanical cycling on the bond strength between fiber posts and root dentin., Materials and Methods: Sixty-four single-rooted bovine teeth were endodontically prepared to receive glass-fiber posts. The insertion of cement into the root canal was performed using one of the following techniques: POS, insertion with the post; LEN, the use of a lentulo-type drill; EXP, insertion with a straight-tip explorer; or CEN, the use of a Centrix syringe. Half of the specimens were mechanically cycled. All specimens were sectioned into slices of 1.8 mm for the push-out test and 0.5 mm for analysis of the cement layer quality., Results: The insertion technique affected the interaction between factors (bond strength and mechanical cycling; p < 0.0001). Insertion of the Centrix syringe after mechanical cycling showed the highest bond values (13.6 ± 3.2 MPa). Group-to-group comparisons for baseline and cycled conditions indicated that mechanical cycling significantly influenced the bond strength (p < 0.0001) of the POS and CEN groups. The quality of the cement layer did not differ between the techniques when evaluated in the middle (p = 0.0612) and cervical (p = 0.1119) regions, but did differ in the apical region (p = 0.0097), where the CEN group had better layer quality for the two conditions tested (baseline and cycled)., Conclusion: The use of the Centrix syringe improved the homogeneity of the cement layer, reducing the defects in the layer and increasing adhesive strength values to dentin, even after mechanical cycling.

Purpose: To evaluate the effect of different radiant exposure values delivered to two simplified etch-and-rinse adhesive systems on push-out bond strength (PBS) of fiber posts to root canal, as well as nanoleakage (NL) and in situ degree of conversion (DC) within the hybrid layer., Materials and Methods: The roots of human premolars were endodontically prepared and divided into 6 groups according to the combination of the main factors adhesive/resin cement (2 commercial brands) and radiant exposure (4, 16, 48, and 288 J/cm2). The posts were cemented and the PBS tested at 0.5 mm/min (n = 7). The NL (n = 3) was evaluated using SEM after immersion of specimens in 50% silver nitrate. Micro-Raman spectroscopy was performed to determine the in situ DC (n = 2). Data were analyzed by three-way repeated measures ANOVA and Tukey's post-hoc test (5%)., Results: PBS (MPa) showed a significant difference only for the middle third when an increase in radiant exposure from 4 to 16 J/cm2 or higher was used (p < 0.05). The NL (%) decreased significantly with increasing radiant exposure from 48 to 288 J/cm2 in the middle and apical thirds when compared to lower radiant exposure (p < 0.05). The radiant exposure of 288 J/cm2 significantly increased the DC (%) in the middle and apical thirds, compared the other radiant exposure values (p < 0.05)., Conclusion: The increase in radiant exposure delivered to the cervical third of root canals during post cementation improved the adhesive performance of simplified etch-and-rinse adhesive systems in the apical and middle thirds.

The aim was to assess the influence of cement translucency on the retentive strength of luted fiber posts. Twenty extracted human premolars were randomly divided into four equal groups, based on the combinations of materials to be tested. Two post types of the same size, shape, and chemical composition, but different light-transmission properties [Translucent post (TP) and Opaque post (OP)] were selected. The two post types were luted using the etch-and-rinse, light-curing adhesive in combination with two shades of the same resin cement of markedly different light-transmitting ability [Transparent shade (TS) and Opaque shade (OS)]. Early post retention was assessed using the thin-slice push-out test. Post type did not significantly influence post retention; however, cement translucency emerged as a relevant factor in intraradicular cementation, with the TS achieving higher push-out strengths. The between-factor interaction was also statistically significant; specifically, OP-OS yielded significantly lower retentive strengths than all the other groups. Post translucency did not influence post retention, provided that a highly translucent cement was utilized for luting., (© 2015 Eur J Oral Sci.)

Aim: To measure the polymerization of light-cured (Variolink Veneer, VLV) and dual-cured (Variolink II, VLII) resin luting cements after light activation through different lengths of fibre post ex vivo., Methodology: Degree of conversion after prolonged direct light activation (PLA) [12 min after LED light activation for 3 min] was determined using ATR-FTIR. Models were then produced to allow samples of VLV and VLII (n = 5 each group) to be light-activated through 3, 6 and 9 mm lengths of fibre post (Fiber Lux). Degree of conversion was assessed by ATR-FTIR and expressed as a percentage of the degree of conversion achieved after PLA. Data were analysed using anova and Tukey's test (P < 0.05)., Results: Mean [SD] degree of conversion for VLV and VLII after PLA was 57.97% [1.51] and 54.71% [3.77], respectively. Light activation of VLV through a 3 mm post produced 81.62% of the PLA value, compared with 71.03% for the 6 mm and 46.04% for the 9 mm post. Conversion after activation through 9 mm posts was significantly less than through 3 mm and 6 mm posts (P < 0.05). For VLII, activation through a 3 mm post produced 66.51% of the PLA value, compared with 54.38% for the 6 mm and 41.56% for the 9 mm post. A significant decrease in degree of conversion was noted for VLII as post length increased (P < 0.05)., Conclusions: The degree of conversion for VLV reduced after light activation through 9 mm posts when compared to 3 mm and 6 mm posts, whilst the degree of conversion for VLII decreased with every increase in post length., (© 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Despite several advantages associated with pre-fabricated glass-fiber posts, the coronal portion of these posts must be cut to allow their use in various clinical situations. However, cutting the cemented post can generate stress on the bonding interface and affect the bond strength. The aim of this study was to investigate the effect the of fiber post cutting on the bond strength of root canals. Sixty bovine incisor roots were included in resin cylinders with simulated periodontal ligaments. Glass-fiber posts were luted using regular resin cement RelyX ARC (3M ESPE) or self-adhesive cement RelyX Unicem (3M ESPE). The posts were cut prior to cementation, immediately after luting or after building up the core (n=10). After storage for 24 h, the samples were cut and subject to push-out testing using a mechanical testing machine (EMIC DL 2000). Data were analyzed using two-way ANOVA (resin cement x moment of post cutting) and Tukey's post hoc test (α=0.05). The moment of fiber post cutting did not affect the bond strength when Unicem was used. However, the bond strength was reduced when ARC was used and when the post was cut immediately. In conclusion, the moment of fiber post cutting may affect the retention of root canal posts when a regular resin cement is used.

Purpose: This study evaluated the influence of punch and base orifice diameters on push-out test results by means of finite element analysis (FEA)., Materials and Methods: FEA was performed using 3D models of the push-out test with 3 base orifice diameters (2.5, 3.0, and 3.5 mm) and 3 punch diameters (0.5, 1.0, and 1.5 mm) using MARC/MENTAT (MSC.Software). The image of a cervical slice from a root restored with a fiberglass post was used to construct the models. The mechanical properties of dentin, post, and resin cement were obtained from the literature. Bases and punches were constructed as rigid bodies. A 10-N force was applied by the punch in the center of the post in a nonlinear contact analysis. Modified von Mises stress, maximum principal stress, as well as shear and normal stress components were calculated., Results: Both punch and base orifice sizes influenced the stress distribution of the push-out test. Bases with larger diameters and punches with smaller diameters caused higher stress in dentin and at the dentin/cement interface., Conclusion: FEA showed that the diameter of the orifice base had a more significant influence on the stress distribution than did the punch diameter. For this reason, both factors should be taken into account during push-out experimental tests.

Purpose: The purpose of this study was to evaluate the effect of self-adhesive and self-etching resin cements on the bond strength of nonmetallic posts in different root regions., Materials and Methods: Sixty single-rooted human teeth were decoronated, endodontically treated, post-space prepared, and divided into six groups. Glass-fiber (GF) posts (Exacto, Angelus) and fiber-reinforced composite (FRC) posts (EverStick, StickTeck) were cemented with self-adhesive resin cement (Breeze) (SA) (Pentral Clinical) and self-etching resin cement (Panavia-F) (SE) (Kuraray). Six 1-mm-thick rods were obtained from the cervical (C), middle (M), and apical (A) regions of the roots. The specimens were then subjected to microtensile testing in a special machine (BISCO; Schaumburg, IL, USA) at a crosshead speed of 0.5 mm/min. Microtensile bond strength data were analyzed with two-way ANOVA and Tukey's tests., Results: Means (and SD) of the MPa were: GF/SA/C: 14.32 (2.84), GF/SA/M: 10.69 (2.72), GF/SA/A: 6.77 (2.17), GF/SE/C: 11.56 (4.13), GF/SE/M: 6.49 (2.54), GF/SE/A: 3.60 (1.29), FRC/SA/C: 16.89 (2.66), FRC/SA/M: 13.18 (2.19), FRC/SA/A: 8.45 (1.77), FRC/SE/C: 13.69 (3.26), FRC/SE/M: 9.58 (2.23), FRC/SE/A: 5.62 (2.12). The difference among the regions was statistically significant for all groups (p < 0.05). The self-adhesive resin cement showed better results than the self-etching resin cement when compared to each post (p < 0.05). No statistically significant differences in bond strengths of the resin cements when comparable to each post (p > 0.05)., Conclusion: The bond strength values were significantly affected by the resin cement and the highest values were found for self-adhesive resin cement.

Aim: To evaluate the effect of fiber post surface treatments on push-out bond strength between fiber post and root dentin., Materials and Methods: Sixty bovine mandibular teeth (N=60) were sectioned (16 mm), prepared (12 mm), embedded with acrylic resin and then allocated into six groups (n=10): Gr1- Silane coupling agent (Sil)+Conventional resin cement AllC em (Al C); Gr2- Sil+Conventional resin cement RelyX ARC (ARC); Gr3- tribochemical silica coating (TBS)+AlC; Gr4- TBS+ARC; Gr5- No treatment (NT)+AlC; Gr6- NT+ ARC. Specimens were sectioned in four slices (2 mm) and submitted to push-out test. Fracture analyses were executed at x200. The values of the push-out bond strength were submitted to two-way ANOVA and Tukey test (α=0.05)., Results: Resincement did not affect the bond strength values (p=0.9674), fiber post surface treatment affected the push-out bond strength (p=0.0353), interaction between factors did not affected the values (p=0.338). Tukey test did not show differences between the groups. Adhesive failure between cement and dentin was predominantly., Conclusion: The fiber post surface treatment appears have no Influence on bond strength between fiber post and root dentin., Clinical Significance: The tested fiber posts surface treatment appears do not Influence the fiber post bond behavior.

Purpose: To evaluate surface roughness and bond strength of glass fiber posts to a resin cement after various surface treatments., Materials and Methods: Sixty individually formed glass fiber posts with a diameter of 1.5 mm and a length of 20 mm were used for this study. They were randomly assigned to six groups of pre-treatment (n = 10/group): Group C, untreated (control); Group SB, sandblasted; Group SC, silica coated; Group HF, hydrofluoric acid-etched; Group N, Nd:YAG laser irradiated; Group E, Er:YAG laser irradiated. Surface roughness of the posts was measured before and after pre-treatment. The posts were then bonded to resin cement and tensile bond strengths were determined in a universal testing machine. For statistical analysis, two-way ANOVA and post-hoc comparison tests (α = 0.05) were performed., Results: The highest bond strength value was observed in group HF, followed by group SC. There was a statistically significant difference in bond strength between group C and groups HF, SC and E (p < 0.001, p = 0.002 and p = 0.041, respectively). Posts of group SB and group N showed the highest surface roughness., Conclusions: The findings of the present study reveal that hydrofluoric acid-etching, silica coating and Er:YAG laser irradiation provided a significant increase in bond strength between glass fiber posts and resin cement.

Aim: This study evaluated the push-out bond strength of cemented fiber posts after deproteinization of root canal dentin walls with NaOCl. The effect of the application of an antioxidant solution (sodium ascorbate) was also evaluated., Materials and Methods: A three-step etch-and-rinse (Scotch-bond - 3M Espe) and a one-step self-etching adhesive (Xeno III - Dentsply Caulk) were evaluated. Thirty bovine incisor roots were divided into 3 groups: a. Irrigation with physiologic solution (control). b. Deproteinization with 10 minutes irrigation of 5% NaOCl. c. Deproteinization with NaOCl followed by 10 minutes irrigation with 10% ascorbic acid. Fiber posts were cemented with a dual-cured cement (Rely X ARC - 3M ESPE). The push-out bond strength was evaluated after 24 hours of storage in distilled water. The data were analyzed with three-way ANOVA, one-way ANOVA and Tukey's test (α = 0.05)., Results: There were significant differences between groups (p < 0.05). The bond strength of Scotchbond was not influenced by the deproteinization. Xeno III showed a decrease in bond strength when deproteinized with 5% NaOCl (p < 0.05). For Xeno III, the subsequent irrigation with ascorbic acid was able to reverse the effect of the deproteinization. Considering the radicular thirds, the bond strength varied in the sequence-apical < middle < coronal., Conclusion: Only the all-in-one adhesive was influenced by the deproteinization. Considering the respective control groups, both systems showed similar bond strength results., Clinical Significance: The decreased bond strength of the self-etching adhesive following deproteinization seams to be related to the oxidant effect of the NaOCl solution and the subsequent irrigation with ascorbic acid was able to reverse the effect of the deproteinization.

Statement of Problem: Information regarding the effect of thermomechanical aging (TMA) on the bond strength of luting cements to root canal dentin and endodontic posts is limited., Purpose: The purpose of this study was to investigate the effect of TMA on the bond strength of fiber and zirconia posts bonded to root canal dentin with 2 different resin cements with microtensile and scanning electron microscopic evaluation., Material and Methods: Eighty extracted single-rooted human premolars were endodontically treated and restored with either a glass fiber post (FP) or a zirconia post (ZP) with 2 commercially available resin luting cements. The teeth were divided into 2 main groups. In the first group, posts (n=40) were bonded with a self-etch adhesive cement (SEAC). In the second group (n=40), posts were bonded using a self-adhesive cement (SAC). During the first aging phase, all specimens in each group were stored in distilled water for 30 days at 37°C. During the second phase, half of the specimens in each group were subjected to the TMA. The test groups were as follows: FP/SEAC, FP/SEAC+TMA, ZP/SEAC, ZP/SEAC+TMA, FP/SAC, FP/SAC+TMA, ZP/SAC, and ZP/SAC+TMA. The bond strength was measured with a microtensile test. Data were analyzed by 3-way analysis of variance and the Tukey honest significant different test (α=.05)., Results: FP/SEAC at 30 days was higher than in the other groups. However, bond strength values were significantly reduced in this group after TMA (P<.001)., Conclusions: Bond strength values and physical properties of SEAC with higher filler content were more affected by the TMA than those of SALC. According to scanning electron microscopic observation, TMA also affected the micromorphologic interface between the posts and the resin cements as well as between the resin cements and the root canal dentin., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Introduction: Luting posts inside the root canal is still a challenge because of the difficulty of bonding adhesive materials in the apical third of roots. This study evaluated the effect of the application mode of 3 simplified etch-and-rinse adhesives on the push-out bond strength (PBS), nanoleakage (NL), and in situ degree of conversion (DC) of fiber posts in the root canal., Methods: The roots of human premolars were endodontically prepared and divided into 6 groups according to the combination of the main factors: adhesive (Ambar, FGM, Joinville, SC, Brazil; Adper Single Bond 2, 3MESPE, St Paul, MN; and XP Bond+self-cure activator, DeTrey Dentsply, Konstanz, Germany) and application mode (manual or sonic). The posts were cemented and the PBS tested at 0.5 mm/min. The NL was evaluated by scanning electron microscopy after the immersion of specimens in 50% silver nitrate. Micro-Raman spectroscopy was used to measure the in situ DC. Root third was also considered in the statistical evaluation. Data were analyzed by 3-way repeated measures analysis of variance and Tukey tests (5%)., Results: Under sonic application, the PBS and the in situ DC increased, whereas NL decreased significantly for all groups in the middle and apical thirds (P < .05)., Conclusions: The application of simplified adhesives by sonic mode in the root canal is a feasible tool to increase the fiber post bond to root canals., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the effect of adjunctive application of ethanol-wet bonding and chlorhexidine (CHX) with a hydrophobic adhesive on bond durability of fibre posts to intraradicular dentine., Methods: Ninety-six extracted human teeth with a single root and root canal were prepared for post placement after endodontic treatment. The teeth were randomly divided into four groups (n=24) after etching and rinsing for rewetting: Group 1: water-wet bonding, Group 2: water-wet bonding with CHX, Group 3: ethanol-wet bonding and Group 4: ethanol-wet bonding with CHX. Teeth in Groups 1 and 2 were treated with either distilled water or distilled water with 2% CHX for 60 s; while teeth in Groups 3 and 4 were treated with either 100% ethanol or 100% ethanol with 2% CHX. Two coats of primer, followed by neat resin were applied and light-cured for 40 s. Fibre posts were luted to bonded root dentine using dual-cure resin cement. Bonded roots were subjected to push-out bond strength testing and interfacial nanoleakage evaluation after 24 h, 6 and 12 months of storage. Data were analyzed using 3-way ANOVA (rewetting solutions, time and post space regions) and SNK tests., Results: Groups 3 and 4 showed significantly (p<0.05) higher bond strengths and lower nanoleakage than Groups 1 and 2 after 12 months of ageing. Addition of 2% chlorhexidine to ethanol-wet bonding with a hydrophobic adhesive did not further improve the bonding of a fibre post to intraradicular dentine, when compared to ethanol-wet bonding alone after 12 months of ageing., Clinical Significance: Ethanol-wet bonding with a hydrophobic adhesive alone could improve the bond durability of fibre post to intraradicular dentine and therefore would increase the success rate of post and core restorations of endodontically treated teeth., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objectives: This study evaluated the influence of 2% chlorhexidine digluconate (CHX) on the bond strength (BS) of a glass-fibre post to the root canal, regarding the cements (dual-cured resin or resin-modified glass-ionomer cement), the root thirds and the time of storage., Method: Eighty bovine roots were selected and endodontically treated, before being randomly assigned to the following groups according to the luting protocol: ARC (RelyX ARC); ARC+CHX; RL (RelyX Luting 2); and RL+CHX. After 24 h of luting, the roots were sliced to obtain 1 mm-thick slices. Half of each group was submitted to either 7-day or 6-month storage in artificial saliva (n=10). The specimens were subjected to push-out tests with a crosshead speed of 0.5 mm/min. The data were analysed with four-way ANOVA and Tukey's test (P≤0.05). The failure modes were analysed with a digital microscope (50× and 200×)., Results: ARC yielded a significantly higher BS compared to RL (P<0.001). Despite CHX exerted a significant effect; it depends on the interaction with the luting cement and time (P<0.001). Thus, CHX decreased the values of BS to those of ARC after 6 months (P<0.001). On the 7th day of storage, the ARC+CHX presented higher BS to the cervical and middle thirds compared to RL+CHX (P=0.012). Time solely was not a significant factor (P=0.081). Adhesive cement-dentine type and mixed failures were predominant modes for the ARC groups. For the RL groups, the main failures were adhesive cement-post and mixed modes., Conclusions: Glass-fibre posts luted with RelyX ARC dual-cure resin cement exhibited higher BS than those luted with RelyX Luting 2 resin-modified glass-ionomer cement. Furthermore, CHX was not effective to improve the BS and negatively affected the BS of RelyX ARC after 6 months of storage., Clinical Significance: The use of chlorhexidine solution seems not to improve the bond strength of fibre posts to root canals, disregarding the composition of the luting cement., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Statement of Problem: The optimal luting material for fiber-reinforced posts to ensure the longevity of foundation restorations remains undetermined., Purpose: The purpose of this study was to evaluate the suitability of 3 dual-polymerizing resin cements and 2 dual-polymerizing foundation composite resins for luting fiber-reinforced posts by assessing their Knoop hardness number., Material and Methods: Five specimens of dual-polymerizing resin cements (SA Cement Automix, G-Cem LincAce, and Panavia F2.0) and 5 specimens of dual-polymerizing foundation composite resins (Clearfil DC Core Plus and Unifil Core EM) were polymerized from the top by irradiation for 40 seconds. Knoop hardness numbers were measured at depths of 0.5, 2.0, 4.0, 6.0, 8.0, and 10.0 mm at 0.5 hours and 7 days after irradiation. Data were statistically analyzed by repeated measures ANOVA, 1-way ANOVA, and the Tukey compromise post hoc test (α=.05)., Results: At both times after irradiation, the 5 resins materials showed the highest Knoop hardness numbers at the 0.5-mm depth. At 7 days after irradiation, the Knoop hardness numbers of the resin materials did not differ significantly between the 8.0-mm and 10.0-mm depths (P>.05). For all materials, the Knoop hardness numbers at 7 days after irradiation were significantly higher than those at 0.5 hours after irradiation at all depths (P<.05). At 7 days after irradiation, the Knoop hardness numbers of the 5 resin materials were found to decrease in the following order: DC Core Plus, Unifil Core EM, Panavia F2.0, SA Cement Automix, and G-Cem LincAce (P<.05)., Conclusions: The Knoop hardness number depends on the depth of the cavity, the length of time after irradiation, and the material brand. Although the Knoop hardness numbers of the 2 dual-polymerizing foundation composite resins were higher than those of the 3 dual-polymerizing resin cements, notable differences were seen among the 5 materials at all depths and at both times after irradiation., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the push-out bond strengths of prefabricated glass-fiber posts (Beijing Oya Biomaterials) with polydopamine functionalized to root dentin using two different resin cements (Paracore and RelyX Unicem) in different root regions (cervical, middle, and apical)., Materials and Methods: Forty extracted human, single-rooted teeth were endodontically treated and a 9-mm post space was prepared in each tooth with post drills provided by the manufacturer. Specimens were then randomly assigned into four groups (n = 10 per group), depending on the adhesive system and post surface treatment used: group IA (Paracore + polydopamine); group IB (Paracore + control); group IIA (RelyX Unicem + polydopamine); group IIB (RelyX Unicem + control). Following post cementation, the specimens were stored in distilled water at 37°C for 7 days. The push-out test was performed using a universal testing machine (0.5 mm/ min), and the failure modes were examined with a stereomicroscope. Data were statistically analyzed using twoway ANOVA (p = 0.05)., Results: Bond strengths (mean ± SD) were: 7.909 ± 3.166 MPa (group IA), 4.675 ± 2.170 MPa (group IB), 8.186 ± 2.766 MPa (group IIA), 4.723 ± 2.084 MPa (group IIB). The bond strength of polydopamine groups was significantly higher than one of the control groups (p < 0.0001). No significant difference was found in the micro push-out bond strengths between the two resin cement groups or the root regions (p > 0.05). Stereomicroscopic analysis showed a higher percentage of adhesive than cohesive failures in all groups., Conclusion: Surface polydopamine functionalization was confirmed to be a reliable method for improving the bond strength of resin luting agents to fiber posts. The bond strength of Paracore to fiber posts was not significantly different from that of RelyX Unicem, and considering its convenient application, Paracore can be recommended.

Aim: To evaluate ex vivo the bond strength and adaptation of fibre posts with oval and circular cross sections luted in oval canals with post spaces prepared using dedicated drills or ultrasonic tips., Methodology: Forty extracted premolars with oval canals were root filled, then randomly divided into four groups according to the post space preparation device and the shape of the luted fibre post: dedicated drill + round post, dedicated drill + oval post, ultrasonic tip + round post and ultrasonic tip + oval post. Posts were cemented with a self-adhesive cement (RelyX Unicem 2; 3M ESPE). Samples were sectioned in 1-mm-thick slices and observed under a microscope, and the area occupied by the post within the post space area was calculated. Bond strength was then measured using a push-out test, and the failure modes were evaluated with a stereomicroscope at 40× magnification. Fibre post adaptation and push-out test results were evaluated by analysis of variance (P < 0.05)., Results: Fibre posts, both round and oval, were better adapted to the apical region of the post space (P = 0.001). In oval canals, the bond strength was significantly higher in coronal regions, when the post space was prepared with a dedicated drill and an oval post was luted (P < 0.0001). Adhesive failures between cement and post were the most frequent type of failure in all groups., Conclusions: Circular and oval posts achieved similar adaptation to oval canals, but the use of ultrasonic tips and round posts resulted in reduced bond strength values., (© 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

This study evaluated the microleakage of resin cements in the pulp chamber dentin. Fifty specimens of sound human molars were divided into five groups. Composite cores cemented using Clearfil SA Luting in the first group to a dried dentin and in the second group to a moistened dentin and then light-cured. In third and fourth groups, cement was placed on dried and moistened dentin and self-cured respectively. In fifth group, composite cores were cemented by Panavia F2.0. After thermocycling, microleakage was evaluated using fluid filtration technique. The highest microleakage mean value was observed in the group with light-cured to a dry dentin. The mode of curing in contrast to moisture value had significant effect on microleakage. The microleakage of self- adhesive resin cement used in this study was lower in case of self cured than in case of light-cured and was not related to the dentin surface moisture.

In this study, we evaluate the influence of post surface pre-treatments on the bond strength of four different cements to glass fiber posts. Eighty extracted human maxillary central incisors and canines were endodontically treated and standardized post spaces were prepared. Four post pre-treatments were tested: (i) no pre-treatment (NS, control), (ii) sandblasting (SA), (iii) silanization (SI) and (iv) sandblasting followed by silanization (SS). Per pre-treatment, four dual-cure resin cements were used for luting posts: DMG LUXACORE Smartmix Dual, Multilink Automix, RelyX Unicem and Panavia F2.0. All the specimens were subjected to micro push-out test. Two-way analysis of variance and Tukey post hoc tests were performed (α=0.05) to analyze the data. Bond strength was significantly affected by the type of resin cement, and bond strengths of RelyX Unicem and Panavia F2.0 to the fiber posts were significantly higher than the other cement groups. Sandblasting significantly increased the bond strength of DMG group to the fiber posts.

Purpose: To evaluate the effect of the resin cement thickness (RCT) on bond strength (BS) and gap formation (GF) of fiber posts bonded to root dentin., Materials and Methods: The roots of 24 extracted human mandibular premolars were treated endodontically and the post spaces were prepared using drills with different diameters according to the following groups (n = 8): well adapted (WA), moderately well adapted (MA) and poorly adapted (PA). The fiber glass posts were cemented (Excite DSC and Variolink II) in accordance with the manufacturer's instructions. After 1 week, the roots were transversely sectioned into six 1-mm-thick disks and photographed using an optical microscope to determine the RCT. After this, epoxy resin replicas of each sample were observed using SEM, and the mean length and width of the gaps formed in the cement/dentin/post interface were measured. Finally, each sample was subjected to the push-out test (0.5 mm/min), and the data were statistically analyzed using one-way ANOVA and Tukey's tests at the 5% level of significance., Results: The lowest RCT (μm) was observed for WA and the highest for PA. The group MA showed an intermediate value. Significantly higher push-out BS values were observed for WA compared to the other groups. The MA and PA groups were statistically similar. The highest mean gap length (%) and width (μm) were observed for PA. The groups MA and WA were statistically similar., Conclusion: Lower resin cement thickness resulted in better fiber post adhesion, that is, in higher bond strength and less gap formation.

Purpose: To evaluate the effect of solvent removal and light-curing methods on the push-out bond strength of fiber posts to root canal dentin using a one-step self-etching adhesive., Materials and Methods: Eighty single-rooted, single-canal human mandibular premolars were used in this study. After removal of the crown, the pulp was extirpated and the post space was prepared. The teeth were divided into two main groups according to the solvent removal method, either using the paper point or the air-drying method. Each of the above main groups was further subdivided into 4 subgroups according to the light-curing method: group 1: both adhesive and resin cement were cured from the top of the post in the same step (cocuring) for 40 s; group 2: the adhesive was light cured for 20 s and the resin cement for 40 s; group 3: the adhesive was light cured for 40 s as was the resin cement; group 4: an intracanal tip was used to cure the adhesive inside the post space for 20 s. In groups 1 to 4, the solvent was evaporated using oil-free compressed air for 5 s from the root surface and excess adhesive was removed from inside the canal using a paper point. In groups 5 to 8, the adhesive and cement were applied and light cured as in groups 1 to 4, except the solvent was evaporated (air dried) from inside the post space using an intra-canal disposable plastic tip attached to the tip of a 3-way syringe. After 24 hours, three 2-mm-thick root slices were obtained from each root. Each slice was subjected to the push-out bond strength test at a crosshead speed of 0.5 mm/min. Factorial analysis (two-way ANOVA) was run to test the effect of solvent evaporation method, light-curing method, and their interactions on bond strength. One-way ANOVA followed by Duncan's Multiple Range Test were used to test the effect of lightcuring method on bond strength within each solvent evaporation method. Student's t-test was performed to compare the effect of solvent evaporation method on bond strength within each light-curing method., Results: Two-way ANOVA revealed that the solvent removal method had a significant effect on the bond strength of fiber post to root canal dentin. Neither the light-curing method nor the interaction between the two independent variables had a significant effect on the push-out bond strength., Conclusions: Only air drying the one-step self-etching adhesive could influence the bond strength of the fiber post to root canal dentin.

Statement of Problem: Translucent fiber posts were developed to conduct light into the root canal more effectively, thereby contributing to the polymerization of dual-polymerized resin luting agents. However, there is no consensus in the literature regarding their effectiveness., Purpose: The purpose of this study was to evaluate the tensile bond strength of fiber posts with different degrees of translucency to bovine dentin with 3 types of resin luting agents., Material and Methods: Ninety bovine roots were endodontically treated and divided into 9 groups (n=10) according to the type of post (translucent, white, and black) and resin luting agent (dual-polymerized self-adhesive; dual-polymerized + etch-and-rinse adhesive system; and autopolymerized + etch-and-rinse adhesive system). Tensile tests were performed on a universal testing machine (0.5 mm/min). To determine tensile stress, the bond area of each specimen was calculated. Data were statistically analyzed with ANOVA, Kruskal-Wallis, and Mann-Whitney tests (α=.05)., Results: Mean (standard deviation) tensile bond strength values (5.53 ± 2.29 MPa) were significantly lower for translucent posts than for white (9.51 ± 1.31 MPa) and black posts (10.12 ± 3.44 MPa) with a dual-polymerized luting agent in combination with an adhesive system (P=.012). For white (6.02 ± 1.88 MPa) and black posts (4.14 ± 0.6 MPa), the self-adhesive luting agent led to lower tensile bond strength than the dual-polymerized luting agent in combination with an adhesive system (P=.003). Irrespective of post type, the autopolymerized luting agent provided the lowest tensile bond strength (P<.001). Microscopic analysis revealed that resin luting agents adhered more to the post surface than to the root dentin., Conclusion: Post translucency did not increase the tensile bond strength of dual-polymerized resin luting agents., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Purpose: To investigate the applicability of flowable composites as post luting agents by assessing the push-out strength of posts., Methods: 36 intact single rooted human premolars were selected. The endodontic treatment was performed and half of the specimens were restored with light transmitting posts (DT Light Post Illusion) and the other half with opaque posts (Tech 21 X-OP). In both groups the following combinations of adhesive/cement were tested: OptiBond Solo Plus/Nexus Third Generation (NX3), XP Bond/SureFil SDR Flow (SDR), and Vertise Flow (VF). Push-out test was used to assess the retentive strength of fiber posts, which was expressed in megapascals (MPa). Specimens were analyzed under a stereomicroscope to determine failure mode (adhesive between luting agent and post, adhesive between luting agent and dentin or mixed failure). Push-out data and failure mode distribution were analyzed by two-way ANOVA and Chi-square test, respectively (P< 0.05)., Results: The statistical analysis revealed that only the type of luting material significantly influenced push-out bond strength of the post (P< 0.001). SDR (9.00 +/- 2.17 MPa) performed similarly to the control group NX3 (7.15 +/- 1.74 MPa), while VF (4.81 +/- 1.51 MPa) should significantly lower bond strength. Failure modes differed significantly among groups.

Objectives: Due to morphological differences along the root canal, serious structural damage, or extensive endodontic preparation, cement thickness of luted fibre-reinforced composite (FRC) post systems can largely vary. This study aimed at evaluating the effects of a self-etch (Multilink Automix, MLA) and various self-adhesive resin cements (G-Cem, GCM; Maxcem Elite, MXE; RelyX Unicem, RLX; SmartCem 2, SMC) on the pull-out bond strengths of FRC posts to root canal dentine, and to compare the effects of different cementation thicknesses., Methods: 100 bovine incisor roots were embedded in acrylic resin and randomly assigned to two groups. Root canals of group 1 were prepared with RelyX Fiber Post drill size one (Ø 1.3mm), whereas in group 2 drill size three (Ø 1.9mm) was used to attain different cement thicknesses (thicknesses 1 and 2). Each group was then subdivided into five subgroups (n=10). RelyX Fiber Posts size one (Ø 0.70mm) were luted with the respective resin cements. All specimens were subjected to pull-out evaluation using a universal testing machine. Post surface areas covered with cement were measured by means of stereomicroscopy., Results: RLX revealed the significantly highest pull-out bond strengths in both groups (p<0.05), while MXE exhibited the significantly lowest pull-out bond strengths in group 2 (p<0.05). Main failure modes were determined as adhesive at the cement-post surface for all examined groups (except for SMC, group 2)., Conclusions: The different resin cements influenced the pull-out bond strengths, whereas the cement thickness itself was not responsible for any differences., Clinical Significance: Self-adhesive resin cements can provide an acceptable retention of FRC posts even in case of use with wider post space conditions., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Introduction: This study examined a clinically feasible protocol for improving hydrolytic stability using a 2-step silanization including a nonorganofunctional silane., Methods: The surfaces of 24 D.T. Light-Posts (Bisco Inc, Schaumburg, IL) were polished and assigned to the following 4 groups: M: 1-step silanization with Monobond-S (MS) (Ivoclar Vivadent, Schaan, Liechtenstein); BM: 2-step silanization with 5% 1,2-bis(triethoxysilyl)ethane and then MS; and HM and HBM: 1-step and 2-step silanization, respectively, after 24% H2O2 etching. Four resin composite cylinders (RelyX Unicem; 3M ESPE, St Paul, MN) were bonded on each surface according to a microshear testing protocol. All bonded samples were stored in water at 37°C for 24 hours, and half of them were then thermocycled 5000 times before microshear testing (n = 12). The failure modes were evaluated under an optical and scanning electron microscope. Water contact angles were measured on the post surfaces before and after silanization to estimate surface hydrophobicity. The results were statistically analyzed using 2-way analysis of variance and the Tukey test., Results: The bond strengths for the BM and HBM groups were significantly higher than the M and HM groups at 5000 thermocycles (P < .05), whereas no significant differences were found between the 4 groups before thermocycling (P > .05). All debonded samples showed some fractured fibers. No significant difference in the hydrophobicity was found between the 1-step and 2-step silanized post surfaces (P > .05)., Conclusions: The 2-step 1,2-bis(triethoxysilyl)ethane/MS treatment has potential as a silanization procedure for enhancing the hydrolytic stability of the fiber post/resin composite interface., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Fiber posts can fail because of loss of retention; and it is unknown which luting agent provides the highest bond strength., Purpose: The purpose of this study was to investigate the tensile bond strength of glass fiber posts luted to premolar teeth with 6 resin composite luting agents., Material and Methods: Ninety-six single-rooted extracted human mandibular premolars were sectioned 2 mm coronal to the most incisal point of the cementoenamel junction. Root canals were instrumented and obturated with laterally condensed gutta percha and root canal sealer (AH26). Gutta percha was removed from the canals to a depth of 8 mm and diameter post spaces with a 1.5 mm were prepared. The specimens were divided into the following 6 groups according to the luting agent used (n=16): Group V, Variolink II; Group A, RelyX ARC; Group N, Multilink N; Group U, RelyX Unicem; Group P, ParaCore; Group F, MultiCore Flow. Each specimen was secured in a universal testing machine and a separating load was applied at a rate of 0.5 mm/min. The forces required to dislodge the posts were recorded. A 1-way analysis of variance (ANOVA) was applied to the mean retentive strengths of various cement materials (α=.05)., Results: Significant differences were recorded among the 6 cement types (P<.001). Three materials provided statistically equivalent mean bond strengths (RelyX Unicem, Paracore, and MultiCore Flow) that were significantly greater than for the other 3 materials., Conclusions: Fiber posts luted with RelyX Unicem, Paracore, and MultiCore Flow demonstrated significantly higher bond strengths., (Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Resin cements are widely used to cement intraradicular posts, but bond strength is significantly influenced by the technique and material used for cementation., Purpose: The purpose of this study was to evaluate the bond strength of 3 self-adhesive cements used to cement intraradicular glass fiber posts. The cements all required different application and handling techniques., Material and Methods: Forty-five human maxillary canines were selected and randomly divided into 3 groups n= 15 by drawing lots: Group BIS - Biscem, Group BRE - Breeze, and Group MAX - Maxcem. Each group was divided into 3 subgroups according to application and handling techniques: Sub-group A - Automix/Point tip applicator, Sub-group L - Handmix/Lentulo, and Sub-group C - Handmix/Centrix. Cementation of the posts was performed according to the manufacturers' instructions. The push-out test was performed with a crosshead speed of 0.5 mm/min, and bond strength was expressed in megapascals. The results were evaluated by 2-way ANOVA and the all pairwise multiple comparison procedures (Tukey test) (α=.05)., Results: Breeze cement showed the highest average for the subgroups A, L, and C when compared to the Biscem cement and Maxcem Elite (P<.05). Statistically significant differences among the subgroups were only observed for Biscem., Conclusions: This study shows that application and handling techniques may influence the bond strength of different self-adhesive cements when used for intraradicular post cementation., (Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Introduction: The extension of fiber post cementation often does not seem to influence the fracture resistance of restorations. This study evaluated the effects of cementation depths on the retention of fiber posts submitted to artificial aging., Methods: One hundred and sixty bovine incisors were selected to assess post retention. Following endodontic treatment, the canals were flared with diamonds burs. Postholes were prepared in lengths of 5 or 10 mm, after which fiber posts were relined with composite resin and luted with RelyX ARC or RelyX Unicem. The samples were then submitted to thermal and/or mechanical cycling before testing their pullout bond strengths. Absence of cycling was used as a control. The results of each cement were submitted to two-way and post hoc Tukey tests (α=0.05)., Results: Independent of the aging protocol, a depth of 10 mm showed higher pullout bond strength than did 5 mm, except for RelyX Unicem without cycling. For RelyX ARC, thermomechanical cycling resulted in lower values than in the absence of cycling. Mechanical cycling alone promoted the highest bond strength when the posts were luted with RelyX Unicem., Conclusion: The effect of artificial aging on the pullout bond strength is dependent on the type of material and the depth.

Objective: This study aimed to investigate the effect of dentin surface moisture and curing mode on microtensile bond strength (MTBS) and nanoindentation characteristics of a self-adhesive resin cement., Methods: Forty-four extracted human molars were distributed into four groups according to dentin surface moisture (dry or wet) and curing mode of the resin cement (light or chemical). Clearfil SA Cement (Kuraray Noritake Dental, Japan) was used for cementation of composite cores to the pulp chamber dentin. The specimens were sectioned into beams for MTBS test at the pulpal floor. Nanoindentation hardness and creep of the cement layer were measured under 100 mN load with 30s hold segment. Data were statistically analyzed using two-way ANOVA and Weibull distribution of MTBS (α=0.05)., Results: Moisture, curing mode or their interaction did not significantly affect mean MTBS values that ranged 17.6-22.6 MPa (p>0.05); however, the lowest characteristic strength was found in moist chemically cured group. Hardness ranged 437-512 MPa, and was not affected by the experimental factors (p>0.05). Nanoindentation creep ranged 9.3-10.9% with the chemically cured groups showing the highest values, indicating lower cross-linking and deformation resistance of their polymer network., Significance: Additional moisture on dentin surface did not contribute to adhesion of the anhydrous self-adhesive resin cement to dentin. Light-curing, despite attenuation through the composite core, was beneficial and improved nanoindentation creep resistance of the cement. The difference was not, however, reflected in the mean bond strength or hardness values., (Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

Purpose: To evaluate the effects of different glass-fiber post surface treatments on the bond strength to root dentin., Materials and Methods: Fifty bovine incisors were used in this study. After removing the crowns, the teeth were endodontically treated. The roots were randomly divided into five groups according to post surface treatment. The groups were as follows: CO (Control) - no treatment; G1 - RelyX Ceramic Primer (silane) only; G2 - silane and Solobond M; G3 - silane and Scotchbond Adhesive; G4 - silane and Excite. For post cementation, RelyX Unicem was used according to the manufacturer's recommendation and the roots were stored in a light-proof container with 100% relative humidity for 24 h. The specimens were transversally sectioned. Subsequently, the cervical, middle, and apical regions of the root were positioned in a push-out device and tested at 0.5 mm/min using a universal testing machine (Instron). The data were statistically analyzed with two-way ANOVA and Tukey's post-hoc test. The fractured specimens were then observed under a stereoscopic loupe at 60X magnification., Results: No significant difference in bond strength was found among the groups that received a silane or silane plus an adhesive system (p > 0.05). However, the CO (no silane) showed the lowest bond strength. Regarding G1, G2, G3, and G4, the cervical region of the root canal attained better bond strengths than did the middle or apical regions. The most frequent failure mode occurred at the cement/dentin interface., Conclusion: Silane application may be necessary to improve the adhesion of fiber posts luted with the self-adhesive resin cement evaluated here. The application of an adhesive layer between the fiber post and resin cement did not have any influence on the bond strength when the silane coupling was previously used.

The purpose of this study was to compare the retention of fiber-reinforced composite (FRC) posts luted with either conventional or self-adhesive resin cement. The FRC posts and core resin were built up in bovine teeth. The posts were luted with standard etch-andrinse cement, self-etch cement, or one of two self-adhesive cements. The samples were stored in water for 1 or 14 days or subjected to thermal cycling (TC). Retention value was measured with the pull-out test using a universal testing machine. Conventional adhesive resin cement yielded significantly greater retention than self-adhesive resin cement at 1 day. No significant difference was observed in retention among the adhesive systems tested at 14 days or after TC. During the early luting stage, self-adhesive resin cement yielded lower retention value than conventional resin cement. After 14 days storage or TC, retention was comparable to that with conventional resin cement.

Purpose: To investigate the bond of endodontic post materials, with and without grit blasting, to a resin composite cement and a core material using push-out bond strength tests., Materials and Methods: Fiber-reinforced composite (FRC) posts containing carbon (C) or glass (A) fiber and a steel (S) post were cemented into cylinders of polymerized restorative composite without surface treatment (as controls) and after grit blasting for 8, 16, and 32 seconds. Additional steel post samples were sputter-coated with gold before cementation to prevent chemical interaction with the cement. Cylindrical composite cores were bonded to other samples. After sectioning into discs, bond strengths were determined using push-out testing. Profilometry and electron microscopy were used to assess the effect of grit blasting on surface topography., Results: Mean (standard deviation) bond strength values (MPa) for untreated posts to resin cement were 8.41 (2.80) for C, 9.61(1.88) for A, and 19.90 (3.61) for S. Prolonged grit blasting increased bond strength for FRC posts but produced only a minimal increase for S. After 32 seconds, mean values were 20.65 (4.91) for C, 20.41 (2.93) for A, and 22.97 (2.87) for S. Gold-coated steel samples produced the lowest bond strength value, 7.84 (1.40). Mean bond strengths for untreated posts bonded to composite cores were 6.19 (0.95) for C, 13.22 (1.61) for A, and 8.82 (1.18) for S, and after 32 seconds of grit blasting the values were 17.30 (2.02) for C, 26.47 (3.09) for A, and 20.61 (2.67) for S. FRC materials recorded higher roughness values before and after grit blasting than S. With prolonged grit blasting, roughness increased for A and C, but not for S., Conclusions: There was no evidence of significant bonding to untreated FRC posts, but significant bonding occurred between untreated steel posts and the resin cement. Increases in the roughness of FRC samples were material dependent and roughening significantly increased bond strength values (p<0.05). Surface roughening of the tested FRC posts is required for effective bonding.

Purpose: To compare the microhardness of several dual-cure, self-adhesive resin cements used to lute fiber posts at 24 hours and seven days after cementation., Methods: Bovine incisors were selected to lute 15 fiber posts that were 12 mm long (FRC Postec Plus size 3, Ivoclar-Vivadent). Five resin cements were tested: Multilink Automix (Ivoclar-Vivadent), without light-curing, and the self-adhesive resin cements Maxcem Elite (Kerr), RelyX Unicem (3M ESPE), G-Cem (GC), and Smartcem 2 (Dentsply), which were light-cured for 40 seconds (LED Bluephase, Ivoclar-Vivadent). Each root was embedded in chemically cured acrylic resin and stored at 37°C for 24 hours. The roots were transversally sectioned into nine specimens that were each 1 mm thick, with three specimens corresponding to each root third. Indentations (100g, 30 seconds) were performed on each section in the resin cement, at 24 hours and seven days after cementation, using a Vickers digital microdurometer (Buehler). Data were analyzed by two-way analysis of variance, Student-Newman-Keuls test, and paired t-test (p<0.05)., Results: A significant influence was found (p<0.05) for the resin cement evaluated, the root third, and their interactions on microhardness values at 24 hours and seven days after post cementation. RelyX Unicem and G-Cem exhibited the highest microhardness values, whereas Multilink Automix presented the lowest. All resin cements suffered a decrease in microhardness according to root canal depth, with the exception of G-Cem and Multilink Automix at 24 hours and Smartcem 2 after seven days. After seven days, the evaluated resin cements showed a significant increase in microhardness values, with the exception of Maxcem Elite and Smartcem 2 at the coronal third., Conclusions: Microhardness of the self-adhesive resin cements when used to lute fiber posts was material-dependent and higher values were obtained in the coronal third, revealing their sensitivity to light irradiation. More information regarding the polymerization reaction of these cements is warranted. According to the current results, microhardness values were significantly higher one week after post luting.

Objective: To compare push-out bond strength of fiber-posts luted with different adhesive approaches to root canal dentin., Materials and Methods: Forty maxillary first incisors were decoronated and endodontically treated. Specimens were randomly distributed into five groups (n = 8) and fiber-posts (DentinPost coated, Komet) were inserted using five different luting materials: etch-and-rinse adhesive systems and corresponding core-and-post material in groups 1 (DentinBond/DentinBuild, Komet) and 2 (XP Bond + SCA/Core-X flow, Densply), self-adhesive resin cements in groups 3 (RelyX Unicem, 3M Espe) and 4 (SmartCem 2, Dentsply) and a self-etch adhesive/resin cement in group 5 (ED-Primer II/Panavia F 2.0, Kuraray). The roots were sectioned into eight 1 mm thick serial slices and within 48 h push-out bond strength was investigated. Statistical analyses were performed using non-parametrical Kruskal-Wallis H-test and Mann-Whitney U-test for differences between experimental groups at p < 0.05. The failure modes were analyzed using Chi square test., Results: The bond strength [MPa] (mean/min-max) for groups 3 (12.35/3.60-32.44), 4 (13.52/4.48-30.69) and 2 (11.15/5.23-35.58) were significantly higher (p < 0.001) compared to groups 1 (6.66/2.34-24.89) and 5 (7.41/0.28-34.18). Adhesive failure between dentin and luting agent was the most frequent failure mode., Conclusions: Bond strength of fiber-posts adhesively luted to root canal dentin was significantly higher when self-adhesive resin cements were used. One (group 2) of the tested core-and-post materials/etch-and-rinse adhesive achieved comparable bond strength values.

Purpose: To evaluate the effect of mechanical cycling and cementation strategies on the push-out bond strength between fiber posts and root dentin and the polymerization stresses produced using three resin cements., Materials and Methods: Eighty bovine mandibular teeth were sectioned to a length of 16 mm, prepared to 12 mm, and embedded in self-curing acrylic resin. The specimens were then distributed into 8 groups (n = 10): Gr1 - Scotchbond Multi Purpose + RelyX ARC; Gr2 - Scotchbond Multi Purpose + RelyX ARC + mechanical cycling; Gr3 - AdheSE + Multilink Automix; Gr4 - AdheSE + Multilink Automix + mechanical cycling; Gr5 - phosphoric acid + RelyX U100 (self-adhesive cement); Gr6 - phosphoric acid+ RelyX U100 + mechanical cycling; Gr7 - RelyX U100; Gr8 - RelyX U100 + mechanical cycling. The values obtained from the push-out bond strength test were submitted to two-way ANOVA and Tukey's test (p = 0.05), while the values obtained from the polymerization stress test were subjected to one-way ANOVA and Tukey's test (α = 0.05)., Results: Mechanical cycling did not affect the bond strength values (p = 0.236), while cementation strategies affected the push-out bond strength (p < 0.001). Luting with RelyX U100 and Scotch Bond Multi Purpose + RelyX ARC yielded higher push-out bond strength values. The polymerization stress results were affected by the factor "cement" (p = 0.0104): the self-adhesive cement RelyX U100 exhibited the lowest values, RelyX ARC resulted in the highest values, while Multilink Automix presented values statistically similar to the other two cements., Conclusion: The self-adhesive cement appears to be a good alternative for luting fiber posts due to the high push-out bond strengths and lower polymerization stress values.

The aim of this study was to investigate the effect of thermomechanical loading (TML) on the bond strength of fiber posts luted with three different resin cements. Sixty-six extracted human anterior teeth were endodontically treated and restored with fiber posts (RelyX Fiber Posts, 3M ESPE) using three commercially available resin cements and three corresponding core build-up materials (n=22 each): Panavia F 2.0/Clearfil DC Core Automix (Kuraray), Variolink II/Multicore Flow (Ivoclar Vivadent), and RelyX Unicem/Filtek Z250 (3M ESPE). Twelve specimens of each group received all-ceramic crowns and were subjected to TML. The other 10 specimens were stored in saline solution for 24 hours. The roots were sectioned and bond strength was measured using a push-out test. Adhesive interfaces of two specimens of each group subjected to TML were analyzed using field emission scanning electron microscopy (FESEM). Bond strengths of fiber posts were significantly affected by the type of resin cement (p<0.0005) and TML (p<0.0005; two-way analysis of variance). TML significantly reduced bond strengths for all materials ((6.0 (6.2) MPa)) compared with initial bond strengths ((14.9 (10.4) MPa)). RelyX Unicem resulted in significantly higher bond strengths before ((18.3 (10.3) MPa)) and after TML ((9.8 (7.5) MPa)) compared with the other materials (p<0.0005; Tukey HSD). Using FESEM, Variolink II and Panavia F demonstrated a hybrid layer partly detached from the underlying resin cement, whereas no hybrid layer was observed for RelyX Unicem. The decrease in bond strength after TML suggests that retention of fiber posts may be reduced after clinical function. Therefore, endodontically treated teeth that are restored using fiber posts may benefit from additional reinforcement via coronal restorations using adequate ferrules and/or adhesive techniques.

The aim of this research is to evaluate bond strength between translucent fibre posts (White Post DC, FGM or FRC Postec Plus, Ivoclar/Vivadent) and intraradicular dentin at three different levels (cervical, middle and apical) using a dual-cure (AllCem, FGM) or self-curing (Multilink, Ivoclar/Vivadent) resin cement. Also, the fracture type after push-out test was analysed under SEM. Thirty-two extracted single-root teeth were selected. After undergoing endodontic therapy, they were randomly divided into four groups according to their post type and resin cement. Root canals were etched using 37% phosphoric acid, and Excite DSC adhesive (Ivoclar/Vivadent) was applied in all groups. The root was sectioned to obtain nine 1-mm-thick slices (three per third: coronal, middle, apical). All slices were subjected to push-out tests. Data were analysed using two-way anova. The mean bond strengths vary from 6.6 (4.6) MPa [apical] to 11.9 (5.9) MPa [cervical]. There were no significant differences between groups. Pearson χ(2)-test revealed significant differences in fracture types for all groups (P < 0.0001). The apical third had the lowest bond strengths and it was also shown to be the most critical region for luting fibre posts., (© 2010 The Authors. Australian Endodontic Journal © 2010 Australian Society of Endodontology.)

Introduction: The aim of this study was to evaluate the push-out bond strengths of a new polyfiber post system and a fiber post that were adhesively luted with a dual-cure resin cement., Methods: Forty single-rooted human maxillary teeth were sectioned below the cementoenamel junction, and the roots were endodontically treated. The roots were randomly divided into 2 groups of 20 specimens each according to the post type used: SpiraPost (group A; DMG, Englewood, NJ) and DT Light-Post Illusion X-RO (group B; Bisco Inc, Schaumburg, IL). All posts were cemented with dual-cure resin cement. Bonded specimens were cut into 1-mm-thick sections, and push-out tests were performed using a universal testing machine. All specimens were loaded until fracture, and the failure modes were evaluated with a stereomicroscope at 50× magnification. Representative specimens were analyzed by scanning electron microscopy., Results: Push-out bond strength was significantly affected by the type of post (P < .05). In all root sections, the SpiraPost push-out bond strength values were significantly higher than that those of DT Light-Post Illusion X-RO (P < .05). Cohesive failure within the post was the most frequent type of failure for the SpiraPost system., Conclusions: In all root segments, the SpiraPost system provided significantly increased post retention compared with the fiber post., (Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim: To compare by means of a push-out test the interfacial strength of a dual-curing resin cement and a light-curing self-adhering resin composite when used in translucent fibre post cementation., Methodology: Thirty-four extracted human premolars with single canals were selected and root filled. Translucent fibre posts (RelyX Fiber Post) were luted into the root canal using two resinous luting systems (n = 17). Dual-Curing Technique (DC): the specimens were treated with Excite DSC and RelyX ARC, which were light-cured simultaneously through the post for 60 s. Light-Curing Self-Adhering Technique (LCSA): the specimens were treated with Vertise Flow, which was light-cured through the post for 60 s. The specimens were sectioned transversally into six slices to perform the push-out test at the coronal, middle and apical regions of the root canals. Data were analysed by two-way anova. All specimens were analysed by stereomicroscopy and SEM to determine fracture patterns., Results: There were no significant differences between the DC and LCSA techniques (P = 0.703) in any of the canal regions. Root region was not a significant factor for push-out values (P = 0.255) and group-region interactions were not significant (P = 0.740). For the DC technique, the majority of the fracture patterns (73.3%) were adhesive at the interface between dual-curing resin cement and adhesive. For the LCSA technique, the majority of the fracture patterns (71.7%) were adhesive at the interface between light-curing self-adhering resin composite and dentine., Conclusions: The interfacial strength between light-curing self-adhering resin composite and root canal walls is equivalent to the interfacial strength between dual-curing cement and root canal walls., (© 2011 International Endodontic Journal.)

Aim: To evaluate the effect of luting agent and fibreglass post design on bond strength to root dentine at different depths within the canal., Methodology: Ninety single-rooted teeth were root filled and prepared to receive either a parallel-sided and serrated fibreglass post (Reforpost no. 2) or a tapered and smooth fibreglass post (Exato Cônico). The posts were cemented with the following resin cements: dual-cured resin cement (Rely X ARC), two self-adhesive resin cements (Rely X Unicem and MaxCem) and a self-cured resin cement (Cement-Post). The roots were cross-sectioned to obtain two 1-mm-thick discs for each cervical, middle and apical third of the prepared root portion. The posts were submitted to a micropush-out test at a speed of 0.5 mm min(-1), and the bond strength values (MPa) were submitted to anova in a split-plot arrangement and Tukey's test (P < 0.05)., Results: The RelyX Unicem demonstrated significantly higher bond strength values (P < 0.001) along the root dentine. The RelyX ARC and Cement-Post had similar bond strength values in the cervical third; however, the bond strength decreased significantly (P < 0.001) in an apical direction for the RelyX ARC. Significantly lower bond strength values (P < 0.001), irrespective of canal region, were found for MaxCem cement. The bond strength was similar for both post configurations irrespective of the resin cement and canal region., Conclusions: The retention of glass fibre posts remained unaffected by surface roughness but was influenced by resin cement type. The self-adhesive cement RelyX Unicem yielded a significantly greater (P < 0.001) bond strength value when cementing the fibreglass posts., (© 2011 International Endodontic Journal.)