Mean Push-out Bond Strength Research Articles

Effect of Dentin Pretreatment with Chlorhexidine on Push-Out Bond Strength of Composite Restorations in Severely Damaged Primary Anterior Teeth

Objectives:Achieving durable restorations with adequate strength in severely damaged primary anterior teeth in children is a priority. The aim of this study was to investigate the effect of dentin pretreatment with chlorhexidine on push-out bond strength of composite restorations.Materials and Methods:In this in vitro experimental study, 56 extracted primary anterior teeth were randomly divided into 4 groups: (1) saline and total-etch bonding agent, (2) chlorhexidine and total-etch bonding agent, (3) saline and self-etch bonding agent, and (4) chlorhexidine and self-etch bonding agent. After the application of bonding agents, the post space was filled with Z250 composite resin. Following thermocycling of the samples, the push-out test was performed using a universal testing machine, and the results were analyzed with two-way ANOVA.Results:The mean push-out bond strength values in groups 1 to 4 were 5.7, 8.39, 5.35, and 7 MPa, respectively. Chlorhexidine groups had significant differences with saline groups in bond strength (P<0.05) but there was no statistically significant difference between the self-etch and total-etch bonding agents in the groups (P>0.05).Conclusion:Both types of bonding agents (self-etch and total-etch) exhibited favorable results in radicular dentin of primary anterior teeth; however, pre-treatment with chlorhexidine increased the push-out bond strength of composite restorations in primary anterior teeth.

Comparative Evaluation of the Push-out bond strength of Nano-formulations of MTA and Portland cement.

Purpose: To investigate and compare the push-out bond strength of nano-formulation of ProRoot MTA (NPMTA) and Portland cement (NPC) with commercially available ProRootMTA (PMTA) and Portland cement (PC) aiming to develop a new root-end filling/ perforation repair material. Methods: Forty root-dentin slices prepared from freshly extracted single-rooted teeth were randomly allocated into four groups (n = 10) according to the tested cements: PMTA, PC, NPMTA and NPC. The root canal lumens were instrumented and filled with the test materials. The Universal testing machine was used for push-out bond strength evaluation. The maximum force employed at the time of dislodgment was recorded and the specimens were inspected under scanning electron microscope at x25 magnification to detect the nature of the bond failure. Kruskal–Wallis test was applied for the comparison between the groups. Mann-Whitney U test was used for pairwise comparison. Results: The mean push-out bond strength ± standard deviation values of PMTA, PC, NPMTA and NPC were 1.33 ± 0.4, 0.91 ± 0.34, 1.1 ± 0.39 and 2.22 ± 0.43 respectively. There was no statistically significant difference between the means of PMTA, PC and NPMTA (p=0.529) but the mean of NPC was significantly higher than the three groups (p=0.012). Under stereomicroscope PMTA, PC and NPMTA groups showed a majority of adhesive failure, while NPC showed a majority of mixed type failure. Conclusions: The force needed for NPMTA displacement is similar to PMTA and PC and significantly lower than the force required for NPC displacement.

Assessment of hybridization and push out bond strength of fiber post after endodontic retreatment. An invitro study

Objective: The aim of this study was to assess hybridization and push out bond strength of fiber post after endodontic retreatment. Materials and methods: 10 freshly extracted human canines were collected having single root canal, samples were decoronated. Endodontic treatment was made to all samples. Samples were inserted into resin blocks. Then randomly divided in to: group I (control group) (5n) drilling to prepare post space followed by post cementation using total etch cement; while in group II (retreatment group) (5n) endodontic retreatment was made followed by drilling and post cementation as group one. Samples were sectioned into six sections of 1.5 mm thickness. Push-out test was performed using universal testing machine. Scanning of the root interface was made by SEM. Results: Group I showed significantly higher mean push-out bond strength (11.55 MPA) than Group II (7.93 MPA). Coronal (13.13 MPA) and middle root levels (9.62 MPA) showed significantly higher mean push-out bond strength than apical level (6.48 MPA). GI showed significantly higher mean push-out bond strength (16.06 MPA) than GII (10.19 MPA) at coronal level. At middle and apical levels; there were no significant difference. SEM showed resin tags and hybridization within dentin in GI while in GII there was an ill-defined hybrid layer at interface. Conclusions: Endodontic retreatment showed significant adverse effect on fiber post push-out bond strength. Root level affected fiber post push-out bond strength only in endodontically treated teeth. Interface of the endodontically treated teeth showed hybrid layer while in endo-retreatment gaps and void were seen.

Effect of different surface treatments on bond strength between zirconia posts and root surfaces

Aim: In recent years, especially with the increase in aesthetic demands, there has been a requirement to use the best aesthetic materials for dental restorations. These restorations are especially needed in those teeth that have crown loss due to a tooth fracture or extreme anterior tooth decay, post-core treatment has been applied as getting support by tooth roots. the aesthetic disadvantages and making use of the strength resistance of various metals. In this case, zirconium, which is a white‑coloured metal, is preferred. In this study, zirconia posts with different surface treatments were cemented to the root canal and bond strength was then evaluated.&#x0D; Materials and Methods: Forty mandibular second premolar teeth were used in this study. Crowns of all teeth were removed to 14 mm from the enamel-cement margin by separation under irrigation. Root canals were cleaned, shaped and filled. Teeth were kept in distilled water while zirconia posts were prepared. Zirconia posts were divided into four groups according to the surface treatment methods as follows: a control group, a CoJet applied group, a sandblasting+laser group and an Er:YAG laser group. The Er:YAG laser was administered at 450 mJ at 10 Hz for 60 seconds with a 100-μs pulse duration. Surface-treated posts were bonded to the root canal with Panavia F cement. Cores were made with the standardized strip crowns. 5000 cycles, 5-55 °C thermal cycle applied with transition time at 5 seconds. For push-out tests, roots were embedded in translucent acrylic resin and coronal, middle third and apical sections were cut into 1.5-mm slices. The maximum load at failure was recorded for each specimen in newtons and then converted into megapascals (MPa). Each specimen was inspected with a scanning electron microscope (SEM) at a magnification of 100 X. Data were analysed using Games‑Howell tests with a significance level of 0.05.&#x0D; Results: The coronal section from Group 3 had the highest mean push-out bond strength (18.01 MPa), while the apical section from Group 1 had the lowest (4.49 MPa). Surface treatments had no significant effect on the mean push-out bond strengths of zirconia posts (p &gt; 0.05). However, dividing the root canal into three sections had a significant effect on bond strength (p &lt; 0.05). When the results were evaluated for all groups, the push-out bond strength was highest in the coronal section, then in the middle third and the lowest in the apical section.&#x0D; &#x0D; How to cite this article:&#x0D; Dündar Yılmaz B, İzgi AD. Effect of different surface treatments on bond strength between zirconia posts and root surfaces. Int Dent Res 2020;10(2):49-54. https://doi.org/10.5577/intdentres.2020.vol10.no2.4&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Effect of Two Different Surface Treatments on Retention of Cosmopost with Two Different Core Materials.

ObjectiveThe objective of this study was to determine the effect of Cosmopost’s two different surface treatments (sandblasting and silica coating) on persistence to various core materials using push-out test set-up.Material and MethodsA total of 30 Cosmoposts was used in this study. Cosmoposts were divided into three groups (10 samples each) according to the post-surface treatment received. Every category was additionally subdivided into two subgroups according to the type of core material (n = 5 samples). A specially designed copper mold was used for construction of different core materials with standardized dimensions around the posts, in such a way to ensure that the posts will be centralized. Surface roughness was estimated for all Cosmoposts, following different surface treatments using SEM. Cylindrical cores were fabricated of either composite resin or heat-pressed zirconia-containing glass-ceramic (IPS Empress Cosmo, Ivoclar Vivadent). Following the construction of different Core materials, samples were subjected to push-out test set-up to Evaluate the impact of various treatments on post/core bond strength. Data were collected, tabulated and statistically analyzed. SEM was performed on Cosmoposts following debonding of different post/core samples to determine their mode of failure.ResultsResults of push-out bond strength revealed that core material, surface treatment and the interaction between the two variables using Two-way ANOVA had a statistically significant effect on mean push-out bond strength. Regarding the effect of type of core material on Push-out bond strength, results showed that IPS Empress Cores showed statistically significant higher mean push-out bond strength to Cosmopost (36.4±9.7MPa) than composite cores (15.8±2.5 MPa).ConclusionWithin the limitations of this study, direct heat-pressed ceramic core was more beneficial for zirconia post buildups, than Composite Cores, since they provided higher bond strength. Thanks to a double improvement: increase in fracture resistance and retentive capacity to post. Also, Tribochemical Silicacoating technique was proved to be more effective in Cosmopost treatments than sandblasting technique.

The Effect of in Vitro Sample Preparation Methods on Bond Strength of Mineral Trioxide Aggregate to Root Dentin.

The aim of this study was to compare the effect of sample preparation methods on push-out bond strength of mineral trioxide aggregate (MTA). Twenty-four extracted human mandibular premolars with single root canal were selected for this in vitro study. After instrumentation, irrigation and drying of root canals, they were randomly divided into two experimental groups (n=12). Group 1: After removing the 3 mm of root ends, 2 mm thick sections were established from the remaining roots. MTA was mixed following the manufacturers' recommendations and root sections were filled. Group 2: The whole root canal was used for filling and packing of MTA and like group 1, after removing the 3 mm of root ends, root sections were provided. Push-out bond strength was measured and analyzed by the independent t-test. Level of statistical significance was set at 0.05. The highest mean push-out bond strength was in apical section of group 2 (4.86±1.31) and the lowest value was in coronal section of group 2 (3.05±1.15). The results of the independent t-test showed a significant difference between two groups only in the apical section (P=0.02). Based on the results of this in vitro study, the highest mean push-out bond strength was in apical section of group 2. It seems that using the whole root canal for MTA application is better for MTA in vitro analysis of bond strength to root dentin because it is more similar to the clinical conditions.

Influence of Er,Cr:YSGG Laser Irradiation on the Push-Out Bond Strength of Zirconia and Glass Fiber Posts with Radicular Dentin.

Objective This in vitro study was designed to evaluate the influence of an Er,Cr:YSGG laser on the bond strength of zirconia and glass fiber posts with root dentin. Materials and methods Ninety extracted single-rooted human teeth were randomized into 6 groups (n = 15/group) on the basis of different posts (zirconia/glass fiber) and Er,Cr:YSGG laser tips (axial and radial). Specimens were prepared for push-out testing with the help of a cutting machine; six slices (2 on each cervical, middle, and apical) of approximately 1 mm thickness were sectioned for all roots on a plane perpendicular to the long axis of the post. All specimens were placed into a universal testing machine with a defined 0.5 mm/min crosshead speed until the maximum failure load was obtained. Results The highest mean push-out bond strength of the glass fiber and zirconia groups was achieved with laser treatment. The highest push-out bond strength was achieved with the axial fiber tip (7.63 ± 1.22 MPa), and the lowest was achieved with a radial fiber tip of the glass fiber group (6.98 ± 0.96 MPa). ANOVA showed a statistically significant difference between the groups (p = 0.041). The mean push-out bond strength was found to be higher with an axial fiber tip for both cervical and apical segments in the glass fiber and zirconia groups (p < 0.05). The independent t-test resulted in the overall highest mean push-out bond strength in the apical segments (p = 0.026). Conclusion Within the limits of the present in vitro research study, an enhancement in the push-out bond strength of resin cement, mainly in the cervical region of the root canal, was achieved after irradiation with an Er,Cr:YSGG laser using an axial fiber tip.

Evaluation of Bond Strength of Aesthetic Type of Posts at Different Regions of Root Canal after Application of Adhesive Resin Cement.

AIM:This study aimed to evaluate the bond strength between esthetic posts and dentin at different regions of the root canal in passive mode or push-out active mode.METHODS:Twenty extracted human bicuspid single canal teeth were used in this study. Teeth were sectioned below the cement-enamel junction. The roots of teeth were endodontically treated. Glass fibre posts (Glassix plus, Harald Nordin SA, Switzerland) and zirconia posts (Zirix, Harald Nordin) were then adhesively luted with total-etch (Variolink N, Ivoclar Vivadent, Schaan, Liechtenstein) and self-adhesive (Multilink Speed, Ivoclar Vivadent) resin cement. The roots were divided into two main groups of 10 samples each, according to the type of post used. Each group subdivided into 2 subgroups of 5 samples each, according to the type of cement used. The specimens were transversally sectioned into three slices of 2 mm thickness to perform the push-out test. The push-out tests were performed at crosshead-speed, 0.5 mm/min). Failure modes were evaluated using a scanning electron microscope at magnification (x 150).RESULTS:The results revealed that push-out bond strengths were significantly affected by the type of luting agent and the type of post (P ≤ 0 .05). The mean push-out bond strength values for fibre post were significantly higher than those for zirconia post independent of the luting strategy used. The score values of total-etch adhesive resin cement were higher than those for self-adhesive resin cement irrespective of other variables. Regarding the effect of the root segment on push-out bond strength, results revealed that bond strength decreased from the coronal to the apical section. The cement-dentin interface found to be the weakest part of the root-cement-post unit.CONCLUSION:Glass fibre posts revealed better results in all root third when they adhesively luted with total-etch or self-etch adhesive resin cement and provided significantly increased bond strength compared to the zirconia posts.

Effect of photodynamic therapy and ErCrYSGG laser irradiation on the push-out bond strength between fiber post and root dentin.

To evaluate the push out bond strength and modes of failure of fiber post by using photodynamic therapy (PDT), Er,Cr:YSGG laser and conventional cleaning and shaping (CCS). Sixty maxillary anterior teeth were sectioned horizontaly 2 mm incisal to the cemento-enamel junction, and root canal were prepared for post space. Tapered fiber posts were placed inside the root canal after post space was made. The fiber posts were subjected to PDT, Er,Cr:YSGG laser and CSS with 20 specimens in each group. The specimens obtained were sectioned in cervical and apical sections. A universal testing machine was used to perform the push out test and the push out bond strength was formulated by σ = C/A, expressed in mega-pascals (MPa). The highest mean push out bond strength was achieved by PDT group (8.08 ± 2.73 MPa) and the lowest was shown by specimens in CCS group (7.45 ± 1.04 MPa). ANOVA showed no statistical difference among the experimental groups (p = 0.481). In the cervical segments, the mean push-out bond strength was found to be slightly higher for all three groups compared to apical segments (P < 0.05). The independent t-tests results showed that the mean push-out bond strength values of the cervical segments were slightly higher than the apical segments in PDT, Er,Cr:YSGG and CSS groups (P < 0.05). Significant differences were observed when mean push-out bond strengths were compared for both cervical (p = 0.037) and apical (p = 0.019) segments between all the groups. Twenty-one failures were found at the interface between the adhesive and the dentin surface, 6 failures were observed at the interface between the adhesive and post, whereas 5 failures were mixed. Push-out bond strength to root canal dentin were not affected by Er,Cr:YSGG compared with conventional cleaning and shaping. However, PDT produced the smallest number of failure modes and slightly higher push-out bond strength to root dentin.

Influence of different endodontic irrigants on the push-out bond strength of an epoxy-resin based sealer and newly introduced bioceramic sealer to root dentin: An in-vitro study

Aim: The present in-vitro study evaluated the influence of different organic and inorganic root canal irrigants used during chemomechanical preparation on the push-out bond strength of an Epoxy-resin based AH Plus sealer and a Bioceramic Endosequence BC sealer. Materials and Methods: Eighty extracted permanent human mandibular single rooted premolar teeth were used and randomly assigned to four major groups [according to irrigation protocol using sodium hypochlorite (NaOCl) with MTAD (mixture of tetracycline, acid and detergent) or ethylenediaminetetraacetic acid (EDTA) or phosphoric acid or normal saline (NS) as control group]. The root canals were instrumented using rotary nickel-titanium Hyflex® CM file system to size 30/0.06 taper, at the working length, as final shaping and finishing file, following different irrigation protocols, as per group allocation. The samples were further subdivided into two groups, with ten samples each (n=10), based on endodontic sealer; roots were obturated with gutta-percha and test sealers (AH-Plus or Endosequence Bioceramic sealer). The teeth were decoronated and obtained samples of eighty obturated roots of eight groups were cut to obtain 2mm thick coronal root slices (10 root section in each group), using hard tissue microtome. Bond strength of sealers was then measured by subjecting each root section to a compressive load via Instron Universal testing machine. The data were tabulated and statistically analyzed using analysis of variance (ANOVA) and Tukey’s HSD along with Bonferroni’s post-hoc test and level of significance set at a p value Results: The highest mean push-out bond strength of 5.38 MPa for AH Plus sealer was obtained in Group 2A followed by 3.94 MPa for Endosequence BC sealer (Group 2B), when phosphoric acid was used as chelating agent. However, mean bond strength of AH Plus sealer was significantly decreased (p Conclusion: The Bioceramic based Endosequence BC sealer and gutta-percha core combination was n

Effect of Relining with Different Composite Resins on the Push-out Bond Strength of Anatomical Fiber Posts to Root Canal Dentin.

Relining fiber posts using composite resins helps the posts adapt to the anatomical space of the root canals. The aim of this study was to evaluate the effect of composite resin type on the push-out bond strength of anatomical fiber posts to intra canal dentin. Forty-eight bovine upper incisors were prepared for post space after root canal therapy and randomly divided in to six groups. Five different types of composite resin (GrandioSO, GrandioSO Heavy Flow, X-tra Fil, X-tra base and everX Posterior) were used for relining the prepared fiber posts. In the control group, the prepared post was cemented into the post space without relining. Cervical, middle and apical cross-sections were achieved from each root and push-out test was conducted at a crosshead speed of 0.5 mm/min. One sample from each group was scanned using a micro-CT scanner which provided views from the apical, middle and coronal thirds. Data were analyzed using Kolmogorov-Smirnov test, repeated measures ANOVA and post hoc tests using SPSS 17 (P<0.05). Statistical analysis showed significant differences in terms of mean push-out bond strengths between different composite resin types and cross-sections (P<0.001). The mean push-out bond strength of the samples relined with Grandio SO composite resin (15.48±2.32) and X-tra Fil Bulk-fill composite resin (14.09±1.98) were significantly higher than that of other groups (P<0.05). The unrelined group had a mean push-out bond strength (5.94±1.45) which was significantly lower than that in other groups (P<0.05). In addition, there was a relationship between cross-sections and composite resin types (P<0.05). This in vitro study showed that the composite resins used for relining can affect the push-out bond strength to intra canal dentin based on their physical and mechanical properties.

Effect of Application Mode on Bond Strength of Adhesively Luted Glass-fiber Bundles Inside the Root Canal.

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. 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). 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. 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.

Effect of different irrigation solutions and techniques on push-out bond strength of resin-based sealer

Aim To evaluate the effect of irrigation solutions [sodium hypochlorite (NaOCl), chlorhexidine (CHX), and normal physiological saline] and different irrigation techniques (conventional needle, EndoVac, and CanalBrush) on push-out bond strength of AH Plus resin-based sealer. Materials and methods Ninety mandibular freshly extracted premolars were selected and divided into three groups according to the irrigation solutions; group I: 5.25% NaOCl, group II: 2% CHX, group III: normal physiological saline solution. Then each group was subdivided into three subgroups according to the irrigation techniques; subgroup A: 27 G side beveled needle, subgroup B: EndoVac irrigating system, subgroup C: medium-sized CanalBrush (30/0.04). Root canals of all groups were prepared using ProTaper Universal Ni-Ti rotary system up to file F4 (40/0.06) and filled by single cone technique using AH Plus sealer. 2 mm thick horizontal sections from the coronal, middle and apical thirds of each root were sliced for the push-out bond strength measurement and tested using universal testing machine. Data were analyzed using one-way analysis of variance in a level of significance (P ≤ 0.05). Results The highest mean push-out bond strength values were recorded for EndoVac system followed by CanalBrush and Needle in all groups and at all root canal levels. In comparison of irrigation solutions in needle subgroup; the highest values were recorded for CHX and least for NaOCl at coronal and middle root levels. While in the apical section, the highest and least mean push-out bond strength values were recorded for CHX and saline respectively. Regarding EndoVac and CanalBrush; the highest push-out bond strength values were recorded for CHX followed by saline and NaOCl at all root canal levels. Conclusions Whenever root canal obturation using AH Plus sealer, it is preferred to use 2% CHX solution throughout and after instrumentation via EndoVac system for improved bond strength. The coronal sections showed higher bond strength than middle and apical sections.

Comparison of Push-out Bond Strength of Three Different Obturating Systems to Intraradicular Dentin: An In vitro Study.

Background:To increase the push-out bond strength of endodontic materials, newer obturation materials and obturation techniques are being introduced.Aim:The present study aimed to evaluate the push-out bond strength of three different obturating materials using a universal testing machine (UTM).Materials and Methods:A total of thirty freshly extracted maxillary anterior teeth were collected and randomly divided into three groups of ten each. Biomechanical preparation was done in all the teeth, and they were then divided into three experimental groups according to the obturation material and technique used, as follows: Group I: gutta-percha (GP) with AH Plus root canal sealer (lateral condensation); Group II: thermoplasticized GP technique – noncarrier based (CALAMUS®) with AH Plus sealer (backfill); and Group III: C-points (self-sealing root canal obturating system) with bioceramic sealer (single cone). Each specimen was subjected to push-out test using the UTM, where the punch moved in an apical to coronal direction at a crosshead speed of 0.5 mm/min, which resulted in the displacement of the filling material. The depth of dye penetration was examined under a stereomicroscope at ×30 magnification.Results:All the analyses were performed using SPSS software version 16. P < 0.05 was considered statistically significant. Comparisons of mean values were done using ANOVA with post hoc Games–Howell test and ANOVA with post hoc Tukey's test. Group III demonstrated the highest mean push-out bond strength and Group I exhibited the least bond strength. A statistically significant difference was found between Group III and Group I with regard to the push-out bond strength assessment.Conclusion:Push-out bond strength differs among different obturation materials and obturation techniques.

The effect of individualization of fiberglass posts using bulk-fill resin-based composites on cementation: an in vitro study.

ObjectivesThis study evaluated the bond strength of various fiberglass post cementation techniques using different resin-based composites.Materials and MethodsThe roots from a total of 100 bovine incisors were randomly assigned to 5 treatment groups: G1, post + Scotchbond Multi-Purpose (SBMP) + RelyX ARC luting agent; G2, relined post (Filtek Z250) + SBMP + RelyX ARC; G3, individualized post (Filtek Z250) + SBMP; G4, individualized post (Filtek Bulk-Fill) + SBMP; G5, individualized post (Filtek Bulk-Fill Flow) + SBMP. The samples were subjected to the push-out (n = 10) and pull-out (n = 10) bond strength tests. Data from the push-out bond strength test were analyzed using 2-way analysis of variance (ANOVA) with the Bonferroni post hoc test, and data from the pull-out bond strength test were analyzed using 1-way ANOVA.ResultsThe data for push-out bond strength presented higher values for G2 and G5, mainly in the cervical and middle thirds, and the data from the apical third showed a lower mean push-out bond strength in all groups. No significant difference was noted for pull-out bond strength among all groups. The most frequent failure modes observed were adhesive failure between dentine and resin and mixed failure.ConclusionsFiberglass post cementation using restorative and flowable bulk-fill composites with the individualization technique may be a promising alternative to existing methods of post cementation.

Effect of Fiber Post-Resin Matrix Composition on Bond Strength of Post-Cement Interface.

Objective To evaluate the influence of 3 different post-resin matrix systems cemented with dual-cure resin cement in simulated root canals made of PMMA acrylic sheet. Methods 3 types of fiber posts (n = 60) with different resin matrixes divided into 3 groups: group 1 cross-linked FRC Postec Plus post (n = 20), group 2 cross-linked Rely X post (n = 20), and group 3 Interpenetrated IPN Everstick post (n = 20). All posts were cemented using Multilink Automix dual-cure cement. Posts were cemented into acrylic blocks in order to purely test the strength of cement-post interface. After one week storage at 37°C, two sections of 1 mm thickness from middle-third were subjected to micro-push-out test at crosshead speed 0.5 mm/min. Results The data were analyzed using one-way analysis of variance (ANOVA). The variable fiber post-matrix system was found to significantly affect the push-out bond strength (p < 0.001). Group 2 exhibited that the highest mean push-out bond strength was (5.36 + 2.3 MPa), and group 3 showed the lowest mean push-out (0.41 + 0.4 MPa). There was significant difference among the groups regarding the failure mode as chi-square test revealed (p < 0.001). Conclusion Prefabricated cross-linked posts with epoxy-based matrix demonstrated higher bond strength than prefabricated cross-linked posts with Bis-GMA-based matrix and posts with semi-IPN matrix when luted with dimethacrylate-based dual-cured resin cement.

Evaluation of the effect of calcium hydroxide and endodontic irrigants on the push-out bond strength of fiber post - an in vitro study.

BackgroundIn recent years, fibre-reinforced composite posts have been proposed for the restoration of root filled teeth as an alternative to pre-fabricated posts or metal dowels.Aims and objectivesThe aim of the study was to analyze the effect of endodontic irrigants used for removal of calcium hydroxide on the push-out bond strength of fiber posts to root canal dentin.MethodsForty human permanent single-rooted mandibular premolars with relatively straight roots were taken and access cavities were prepared and biomechanical preparation done using Rotar Y protaper file till size F2. The samples were divided into Experimental group and Control group. In Experimental groups Intracanal dressing of calcium hydroxide was removed by 2.5% NaOCl and 17% EDTA (Group1), MTAD (Group II) and Qmix (Group III). Control group did not receive Intracanal calcium hydroxide dressing. Canals were obturated using size F2 protaper gutta-percha points and AH plus sealer. After storage for 24 hours, post space was prepared. Forty Tenax fiber post (Coltene) were cemented with Rely X U200 resin. The roots were then transversally sectioned into 3 slices of 1mm thickness corresponding to cervical, middle and apical third. The slices obtained were subjected to micro-push-out bond strength test using a universal testing machine. The data obtained was subjected to statistical analysis using One-Way ANOVA test. P value of .05 was considered as statistically significant level.ResultsThe mean push-out bond strength values for controls, NaOCl/EDTA, MTAD and QMIX group at cervical third were 10.17, 15.84, 20.39 and 20.98 whereas at apical third 4.78, 8.85, 11.66 and 12.10.ConclusionQmix showed higher push-out bond strength values followed by MTAD and NaOCl/EDTA. All the groups showed lowest push-out bond strength values in the apical third followed by middle and the maximum in the cervical region.

Does Adding Various Accelerators to Mineral Trioxide Aggregate Have a Negatively Effect on Push-Out Bond Strength?

Objective: This study compares the effect of the white mineral trioxide aggregate (WMTA) accelerators, including disodium hydrogen orthophosphate (Na₂HPO₄; 2.5 wt%), calcium chloride (CaCl₂; 5 and 10 wt%), and KY jelly, on the push-out bond strength of WMTA. The null hypothesis was that the WMTA accelerators would not affect the push-out bond strength of WMTA. Materials and Methods: Slices (2-mm-thick) were obtained from 75 human mandibular molar distal roots. The slices were enlarged up to size 6 Gates-Glidden burs to obtain a 1.5-mm canal diameter. The slices were randomly divided into 4 experimental groups and a control group (n = 15 in each group). Freshly prepared WMTA mixture was placed into the root slices and stored at 37°C in a 100% humidified atmosphere for 60 days. The force required to dislodge the WMTA cement from the root slice was determined using a universal testing machine. The push-out bond strength was calculated. Results: Push- out bond strength of 5- and 10-wt% CaCl₂, and 2.5-wt% Na₂HPO₄ WMTA groups was significantly lower than in the KY-jelly and control groups (p < 0.05). The mean push-out bond strength of KY jelly was lower than in the control group but not statistically significant. Conclusion: The addition of KY jelly to WMTA did not have an adverse effect on the push-out bond strength of WMTA, in contrast to the other accelerators, including Na₂HPO₄ and CaCl₂, which reduced the push-out bond strength.

Investigating the effect of G-Bond and Z-PRIME Plus on the bond strength between prefabricated zirconia posts and the root canal wall in vitro.

Background. The aim of this study was to analyze the effect of G-Bond and Z-PRIME Plus on the bond strength between prefabricated zirconia posts and the root canal wall. Methods. The study was carried out on 21 premolar teeth with similar conditions. The samples were cut at the CEJ. After root canal treatment of the roots, the post space was prepared up to a length of 10mm. The samples were randomly assigned to two groups of 10. G-Bond was used in one group and Z-PRIME Plus in the other to prepare the posts’ surfaces. After cementation and mounting the samples in polyester, the post was cut from the apical area into three equal sections. The bond strength of the samples was tested using the push-out test on a universal testing machine. Data wereanalyzed using t-test. Results. The meanpush-out bond strengths in the control,G-Bond and Z-PRIME Plus groups were 14.3, 27.6±11.8 and 27.4±13.4N, respectively. There was no statistically significant difference between the two groups (P<0.9). Both methods of surface treatment increased bond strength. The bond strengths were different in different sections such as coronal, middle and apical in each group. Conclusion. There was no significant differencebetween the G-Bond and Z-PRIME Plus groups and both products in-creased the bond strength of prefabricated zirconia posts.

Effect of Final Irrigation Protocol and Etching Mode on Bond Strength of a Multimode Adhesive in the Root Canal.

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