Push-out Bond Strength Research Articles

Comparison of push out bond strength of various root perforation repair materials

Background/ Aims: High bond strength of root perforation repair materials is essential for success of endodontic therapy. The aims of current study were to assist the push-out bond strength of 4 types of root perforation repair materials (Biodentine , Mineral trioxide aggregate, glass ionomer cement, and calcium hydroxide paste) from dentin, and to determine the modes of failure at debonded surfaces.
 Materials and Methods: Forty lower premolars with a straight single root canal and matured apex were utilized. Then the teeth decorated 15 mm from the apex, and the middle third of the roots were cut perpendicular to their long axis in order to obtain sections with 1 mm thick. After that instrumentation for the canal of the dentin discs with Gates Glidden was done from sizes 2-5 to result into standardized cavities with 1.3 mm diameter. After that, specimens were divided randomly into 4groups with 10 specimens in every group as follows: group I: Bio (Biodentine), group II: Mineral trioxide aggregate ( MTA), group III: GI (glass ionomer), and group IV: calcium hydroxide paste (Ca(OH)2). Prepared cavity was then filled with each of the material tested according to the corresponding groups. after setting of the tested materials the specimens stored for one week and then push-out bond strength test preformed.
 Results: push-out bond strength of Biodentine was significantly higher than other tested materials. Followed by Mineral trioxide aggregate, which exhibited significantly higher bond strength than glass ionomer and MTA materials, while the Ca(OH)2 showed the lowest value of push-out bond strength.
 Conclusions: push-out bond strength Biodentine, was significantly greater than MTA, GI, and Ca(OH)2. Therefore, BIO can be used successfully for treatment of root perforation that might occur during endodontic therapy of the root canal.

Effect of three different photosensitizers in photodynamic therapy on bond strength of a calcium silicate-based sealer to radicular dentin.

To evaluate the effect of the photodynamic therapy (PDT) using with different photosensitizers on the bond strength of BioRoot RCS (BR) to radicular dentin by comparing with AH Plus (AH). The shaped root canals of 80 human mandibular premolars were divided into four groups based on the final disinfection protocol: NaOCl/EDTA, PDT with methylene Blue (MB), PDT with curcumin (CUR) and PDT with toluidine blue O (TBO) (n=20). Each group was randomly divided into two subgroups (n=10), according to the endodontic sealer used for obturation (n=10). The test of push-out bond strength (PBS) was performed using an universal test machine. The data were analysed using ANOVA, Tukey post-hoc, and independent sample t-test (α=0.05). MB-BR group showed the highest PBS at the cervical level (p < 0.05). The selection of the photosensitizer in PDT influenced adhesion of root canal sealers to radicular dentin.

The effects of different root canal irrigation protocols and artificial aging procedures on the bond strength between dentin and hybrid ceramic posts

The purpose of this study is to investigate the effects of different root canal irrigation protocols applied to the dentin and artificial aging procedures on the micro pushout bond strength (mPBS) between dentin and hybrid ceramic posts. Seventy-five single-rooted mandibular premolar teeth were divided into 5 groups (Gr1-5). 50 of the teeth were used for the mPBS tests (n = 10), whereas 25 were used for the smear layer examinations (n = 5). Post space were prepared and irrigated with different irrigation-protocols in each group. (Gr1:[SS], Gr2:[NaOCl] + SS, Gr3:[EDTA] + NaOCl + SS, Gr4:[MA] + NaOCl + SS, Gr5:[Ch] + NaOCl + SS). Post and core pattern were fabricated with pattern resin and a fiber post, after scanning, the posts were milled with Vita Enamic resin ceramic block, and cemented. After 7 days the roots were sliced at thicknesses of 1mm; half of them were subjected to mPBS test, while the other half were tested after undergoing mechanical cycling for artificial aging. For data analysis, the Shapiro-Wilk test was utilized to test normal distributions, 3-way analysis of variance was used to compare mPBS, and Tukey's HSD test was conducted for multiple comparisons. SEM analysis was performed for examination of failure modes and smear layer removal. Different root canal irrigation protocols affected mPBS significantly. While Gr4 had the highest mPBS, Gr1 had the lowest. Regarding to different zones, the highest mPBS was in coronal zone, and the lowest one was in the apical zone. The aging procedure also led to a statistically-significant decrease in mPBS. Most frequent failure modes were cohesive failure in dentin and mixed failure. Irrigation with 7%MA (Gr4) showed better performance than 17% EDTA (Gr3) in smear layer removal, especially at the apical zone of the tooth. This is critical for the success of root canal treatment and increased the mPBS to a higher extent in all zones of the tooth.

Push-Out Bond Strength Failure Analysis of Gutta-Percha and Martens Hardness of Radicular Dentin Disinfected Using Rose Bengal, Er, Cr: YSGG, Sealed with a Novel Bio-Ceramic Sealer

Push-out bond strength (POBS) and failure analysis of gutta-percha and Martens hardness (MH) of canal dentin sealed with Bio-ceramic sealer (BCS). Specimens underwent endodontic treatment. Based on the method of disinfectants, specimens were classified into 4 groups. Group 1:5.25% NaOCl+Q-mix, group 2:ECYL+Q-mix, group 3:LGE+Q-mix, and group 4:RBP+Q-mix. Before obturation MH was assessed using a microhardness tester. Canals were obturated, and sealed with Bio-Root RCS. Each root was cut horizontally in 2 mm thickness and placed under the indenter of the universal testing machine. One-way analysis of variance and the Post Hoc Tukey test for group comparisons as statistical analysis. Samples with (5.25% NaOCl+Q-mix) displayed the highest bond integrity of BCS (8.00±0.24 MPa). The lowest POBS was demonstrated by the apical section of group 4 (RBP+Q-mix 2 in 1) (4.10±0.94 MPa) specimens. Group 2 (ECYL+Q-mix) and group 3 (LGE+Q-mix) exhibited comparable outcomes of bond scores to group 1 specimens (p &gt; 0.05). MH was significantly lower in group 4 compared to group 1, group 2, and group 3 (p &lt;0.05). The bond strength of BCS and MH of canal dentin is influenced by the type of irrigation.

EXPERIMENTAL INVESTIGATION AND COMPARATIVE EVALUATION OF PUSH-OUT BOND STRENGTH FIBER POST CEMENTED WITH DIFFERENT ADHESIVE RESIN CEMENTS: AN IN-VITRO STUDY

This article present an experimental investigation of push-out bond strength of fiber post that are cemented with various adhesive resin cements. Various modes of failure are also studied and discussed herein. Three resins namely Fluorocore 2+, Rely-X U200 and G-Cem are used in this study. The study is carried out on forth five single rooted teeth randomly divided into three groups. The teeth specimens were prepared by chemo-mechanical procedure and cemented with various adhesive resin cement. These teeth are further sliced at coronal, middle and apical levels for experimental testing of bond strength. These samples further tested on universal spring testing machine until the post was dislodged. Using Chi square, Mann Whitney U and Kruskal Wallis test, the obtained results were analyzed with significance level of p = 0.05. Bond strength of Fluorocore 2+ showed highest as compared to others. Rely-X U200 and G-Cem showed insignificant variation in bond strength at coronal, middle and apical levels.

Evaluation of the Bond Strength of Epoxy Resin-based Sealer Following Different Calcium Hydroxide Paste Removal Methods in Oval-shaped Root Canal

The study aimed to investigate the bond strength of epoxy resin-based sealer following five different calcium hydroxide paste removal methods in oval-shaped root canals. Sixty single-rooted human mandibular premolars having an oval-shaped root canal as evidenced by radiographs were decoronated and instrumented to size 40/0.04, medicated with calcium hydroxide paste for 7 days, before being randomly assigned to the conventional needle irrigation (CNI), manual dynamic agitation (MDA), sonic irrigation (SI), passive ultrasonic irrigation (PUI), and XP-endo Finisher (XP) groups to be irrigated using different irrigation systems. All specimens were then obturated using an epoxy resin-based root canal sealer and warm vertical compaction obturation technique. After 7 days, each specimen was sectioned into 1 mm root slices at the coronal, middle, and apical third of the root canal and tested for the push-out bond strength using a universal testing machine. The XP group was the only group that had comparable bond strength to the control group at every level of the root canal following removal of calcium hydroxide medicament (p >0.05). The control group had higher bond strength than the CNI group at every level of the root canal (p < 0.05). Calcium hydroxide interfered with the bonding of epoxy resin-based sealer to root canal walls. Irrigation with the XP increased the bonding sealer at every level of the root canal. The XP was efficacious as a final rinse agitation technique to promote the bonding of the epoxy resin-based sealer at every level of the root canal following calcium hydroxide medication.

Evaluation of structural integrity effect on adhesion strength of root dentin with a multi-functional irrigation strategy.

To evaluate effects of a novel auxiliary irrigation strategy, proanthocyanidin (PA) + carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) nanocomplexes, on maintaining the organic-inorganic structural integrity and hence optimizing the adhesion strength of root dentin. Dentin specimens (n = 150) were prepared and subjected to the classical irrigating strategy with or without PA and CMC/ACP. The ultrastructure and biomechanical behaviour of dentin were characterized by scanning electron microscopy and atomic force microscope, respectively. Forty single root-canal premolars were employed for push-out bond strength testing. Besides, the antibacterial effects against Enterococcus faecalis were evaluated with confocal laser scanning microscopy. Statistical differences were verified with one-way ANOVA and Tukey's post-tests. The organic-inorganic structural integrity of root dentin was repaired with the synergetic use of PA and CMC/ACP. Correspondingly, the bond stability between the root canal wall and the AH-Plus sealer was significantly reinforced (P < 0.05). Meanwhile, the tissue biomechanical properties and antibacterial behaviour were enhanced compared to that of control group (P < 0.05). The synergistic utilization of PA and CMC/ACP can preserve the structural integrity of root dentin, contributing to optimizing the sealing effects of root canal. Moreover, the novel irrigation strategy demonstrated a favourable antimicrobial activity. The combination of PA and CMC/ACP can serve as a promising auxiliary irrigation strategy to optimize the outcomes of chemical preparation, enhance the sealing effects of root canal and hence improve the success rate of treatment.

Comparison of the push-out bond strength of AH Plus sealer to dentin after using different herbal irrigation solutions as the final rinse.

The aim of the present study was to evaluate the push-out bond strength of AH Plus sealer to dentin treated with the essential oils of Cumimum cyminum and Cinnamomum zeylanicum as herbal final irrigants. Forty human mandibular first premolars were selected. After smear layer removal, the samples were divided into 4 groups and irrigated with experimental solutions for 1 min and later with distilled water. G1: Cinnamomum zeylanicum (CZ) in minimum inhibitory concentration (MIC); G2: Sodium hypochlorite 2.5%; G3: Sodium hypochlorite in MIC; G4: Cuminum cyminum (CC) in MIC. After obturation, the roots were sectioned in order to obtain 1-mm discs for push-out assessment. The push-out test was performed using a universal testing machine. The slices were examined using a stereomicroscope at 30× to determine the mode of failure. The data were analyzed using one-way analysis of variance and Tukey's post-hoc test. The teeth irrigated with CZ showed significantly lower push-out resistance than those irrigated with NaOCl 2.5% and NaOCl at MIC. The other groups had no significant difference. The modes of failure were predominantly mixed. Under the limitations of the present study, CC does not have adverse effects on the bond strength of AH Plus and can be used as a good alternative for currently used final irrigants.

Use of photosensitizers activated by photodynamic therapy on the canal disinfection of radicular dentin bonded to Dimethacrylate-based glass fiber post: an assessment of pushout bond strength.

The present lab-based investigation aimed at evaluating the canal disinfectants using photodynamic therapy (PDT) using different photosensitizers, conventional NaOCl, a mixture of doxycycline, citric acid, and a detergent (MTAD) and their impact on the bond strength of glass fiber post to radicular dentin. Forty extracted human premolars were gathered and disinfected. The decoration was performed up to the cementoenamel junction. Using the crown down technique cleaning of the canal was done following rinse with distilled water. All canals were dried with paper points and obturated with gutta-percha. Post space was prepared using peso reamers and samples were randomly allocated into four groups following different disinfection regimes: Group 1 - Methylene blue photosensitizer (MBP) + MTAD; Group 2 - RBP (Rose Bengal photosensitizer) + MTAD; Group 3 - CP (curcumin photosensitizer) + MTAD and Group 4 - 2.25% NaOCl + MTAD (control). Following disinfection, the canals were dried and the post was placed and cemented within the canal. Samples were dissected at coronal, middle, and apical third and placed in a universal testing machine for push-out bond strength (PBS). Debonded surfaces were evaluated for failure modes. PBS was examined using a one-way analysis of variance (ANOVA). The means of PBS were compared using Tukey multiple comparison tests with a significance threshold of (p<0.05). Group 3 canals disinfected with CP and MTAD had the highest PBS at two levels: cervical (9.57±1.21 MPa), middle (6.37±0.79 MPa), and group 2 canal space disinfected by RBP and MTAD had the maximum PBS in apical portion (5.35±0.42 MPa). No significant difference at all root levels between group 2 (RBP + MTAD) and group 3 (p>0.05). Canal irrigation with group 1 (MBP + MTAD) and group 4 control (2.25% NaOCl + MTAD) exhibited comparable PBS at all three levels of the root. CP, MTAD, RBP and MTAD for canal disinfection and bonding of glass fiber post to radicular dentin demonstrated comparable bond values at all three root levels and can be recommended in clinical settings after further investigations.

Effect of the Viscosity and Application Time of Different Phosphoric Acids on the Bond Strength and Nanoleakage of Fiber Posts to Root Dentin.

To evaluate the effect of application time and viscosity of meta-phosphoric acid (MPA) and ortho-phosphoric acid (OPA) on the push-out resin-dentin bond strength (PBS) and nanoleakage (NL) at the adhesive-root dentin interface. Ninety-six roots of premolars were endodontically prepared and randomly assigned into groups according to the (i) acid (OPA and MPA), (ii) viscosity (gel and liquid), and (iii) application time (7 and 15 seconds). Fiber posts were cemented to the roots, which were then transversally sectioned into serial slices. The slices (cervical, medium, and apical) were subjected to PBS or NL. Analysis of the dentin etching pattern was performed using scanning electron microscopy (SEM). The PBS (MPa) and NL (%) data were subjected to three-way repeated-measures analysis of variance (ANOVA) and Tukey's test (α=0.05). The cross-product interaction was significant for both PBS and NL (p<0.001). No significant difference in the PBS was observed with the use of OPA compared to MPA (p>0.05). Higher PBS values were observed in the groups etched for 15 seconds compared to 7 seconds, regardless of the acid, viscosity, or root third (p<0.05). Lower NL was observed for MPA etching when compared to OPA etching (p<0.05), and these values were not affected by increasing the application time or acid viscosity (p>0.05). A more pronounced etching pattern was observed with OPA than MPA regardless of the acid viscosity. The use of 40% meta-phosphoric acid promoted adequate bond strength without increasing dentin demineralization or void spaces in the hybrid layer.

An In-Vitro Study Comparing The Push Out Bond Strength Of A Fiber Post System Employing Four Different Resin Cements.

Background: Debonding is one of the common reasons for failure in fiber-reinforced composite posts, and it tends to occur at the post space-dentin adhesive contact. The goal of this investigation was to evaluate the push-out bond strength of a fiber-reinforced post system by using four distinct types of resin cement.Materials and Methods: This in-vitro research used a decoronation technique on forty mandibular premolars, and endodontic treatment was performed on the roots. After the post space preparation was complete, the root specimens were divided up into four groups of ten each and categorized accordingly. The following are the names of the four resin cement systems that were used to cement fiber-reinforced composite posts: (a) Multilink Speed, (b) Rely X Unicem, (c) Calibra, and (d) Permaflo DC. Three portions of each root were cut to a thickness of three millimeters, and these parts were prepared. The bond strength values were determined by performing a push-out test using a universal testing machine at a crosshead speed of one millimeter per minute (mm/min). After compiling the results, a post-hoc Scheffe test and multivariate analysis of variance (MANOVA) were carried out on the data.Result: The product with the greatest mean push-out bond strength was Rely X Unicem, followed by Multilink Speed and then Permaflo DC. Calibra was found to have the mean push-out bond strength that was the lowest. Using the MANOVA and post-hoc Scheffe tests, we discovered that the push-out bond strength of resin cement varied significantly across the various root canal areas. These variations were statistically significant.Conclusion: The mean push-out bond strength of Rely X Unicem was the greatest, followed by Multilink Speed and Permaflo DC in that order. When compared to Calibra, the mean push-out bond strength was found to be the weakest.

Effects of calcium hydroxide intracanal medicament on push-out bond strength of endodontic sealers: A systematic review and meta-analysis.

To investigate the effect of calcium hydroxide intracanal medicament on the push-out bond strength of resin-based and calcium silicate-based endodontic sealers. A comprehensive search of was conducted for all relevant in-vitro studies. All randomized controlled in-vitro studies that evaluated the effect of calcium hydroxide on the push-out bond strength of resin-based or calcium silicate-based endodontic sealers were assessed. The variables of interest were extracted, and the risk of the included studies was evaluated. The standardized mean difference was calculated and the significance level was set at p value <0.05. A total of 26 studies were eligible for analysis. There were 45 independent comparison groups and 1009 recruited teeth. The pooled data showed no significant difference in push-out bond strength between calcium hydroxide and control group in the resin-based group (SMD=0.03; 95% CI=-0.55, 0.60; p=0.93), and calcium silicate-based group (SMD=0.02; 95% CI=-0.31, 0.35; p=0.90). Most of the studies (21 out of 26) were at medium risk of bias and five studies showed a low risk of bias. The available evidence suggests that calcium hydroxide used as intracanal medication does not influence the push-out bond strength of the resin- and calcium silicate-based endodontic sealers. The results of this meta-analysis suggest that calcium hydroxide used as intracanal medication does not influence the push-out bond strength of resin-based and calcium silicate-based endodontic sealers.

Evaluation of microleakage and push-out bond strength of various composite resins for sealing the screw-access channel in implant-supported restorations

Statement of problemMicroleakage and loss of the composite resin sealing the screw-access channel are frequent complications of screw-retained implant-supported prostheses. How the screw-access channel should be best restored to reduce such complications is unclear. PurposeThe purpose of this in vitro study was to evaluate the microleakage and bond strength of 3 types of composite resins (flowable, packable, and bulk-fill) with or without a bonding agent treatment to seal the screw-access channel of 2 types of restorative materials (zirconia and Co-Cr alloy) with or without thermocycling. Material and methodsIn total, 240 yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) specimens (IPS e.max ZirCAD) and 240 Co-Cr alloy (Vera PDS) specimens were prepared with a Ø3×3-mm cylindrical cavity at the center to simulate the screw-access channel. Three types of composite resins (flowable, packable, and bulk-fill resin) (Filtek Z350 XT Flowable Restorative, Filtek Z350 XT Universal Restorative, and Filtek One Bulk Fill Restorative) were applied to restore the access channel of the zirconia and Co-Cr specimens with or without a bonding agent (Single Bond Universal Adhesive). Microleakage and push-out bond strength were determined and compared by dividing the specimens into experimental groups with or without thermocycling (1000 times with 30 seconds at 5 ±2 °C and 55 ±2 °C). The results were analyzed by using a 1-way ANOVA and 4-way ANOVA. Adjustment for multiple comparisons was made with the Tukey Honestly Significant Difference (HSD) test. ResultsThe specimens subjected to thermocycling showed a lower bond strength (P<.001) and higher microleakage (P<.001) than specimens stored in a constant-temperature water bath. Specimens treated with bonding agents showed a higher bond strength (P<.001) and lower microleakage (P<.001) than specimens not treated with a bonding agent. Higher bond strengths were observed in the order of bulk-fill resin, packable resin, and flowable resin (P<.001). Packable resin showed higher microleakage than flowable resin and bulk-fill resin (P<.05). No significant difference in microleakage was found between the flowable resin and bulk-fill resin (P>.05). ConclusionsHigher bond strengths were observed in the order of bulk-fill resin, packable resin, and flowable resin. Less microleakage was observed in the flowable resin and bulk-fill resin than in the packable composite resin. Bonding agent treatment was effective in increasing bond strength and decreasing microleakage. Zirconia and Co-Cr showed a bond strength similar to that of composite resins, but zirconia showed higher microleakage than Co-Cr. Restoring the screw-access channel with the bulk-fill resin should increase bond strength and reduce microleakage.

Evaluation of Adaptability and Push-out Bond Strength of a Novel Bio-ceramic Sealer Using Two Different Obturation Techniques. (In vitro study)

Evaluation of Adaptability and Push-out Bond Strength of a Novel Bio-ceramic Sealer Using Two Different Obturation Techniques. (In vitro study)

Push-out Bond Strength of Endoseal MTA and AH Plus Sealers After Using Apple Vinegar as Final Irrigating Solution

Push-out Bond Strength of Endoseal MTA and AH Plus Sealers After Using Apple Vinegar as Final Irrigating Solution

Push-Out Bond Strength of Endodontic Posts Cemented to Extracted Teeth: An In-Vitro Evaluation.

(1) Background: An ideal bond strength between endodontic posts and root canal dentin is essential for optimal retention and good prognosis. This study aimed to evaluate the push-out bond strength (PBS) of prefabricated fiber and metal posts, luted with resin cement to natural dentin. (2) Methods: Extracted premolars with similar root dimensions were assigned into two groups of 30 each for the metal and fiber posts. Teeth were mounted in acrylic blocks exposing 2 mm of the coronal root. Teeth were subjected to endodontic treatment and post-space preparations. Two groups were further subdivided into three sub-groups (n = 10) according to the size of the posts (# 4, 5 and 6). Posts were cemented with resin cement. Specimens were sectioned into 4 mm slices and subjected to the PBS test. (3) Results: The mean PBS was similar for the metal and fiber posts bonded with resin cement, showing a statistically significant result. An increase in post size increased the bond strength initially, but a further increase in size did not show any marked difference. A total of 71.66% of tested specimens failed with the adhesive failure mode. (4) Conclusions: Metal posts showed slightly higher retention compared to the fiber posts, although the p-value was similar for both types. An increase in the size of posts showed increased retention. The most common mode of failure was adhesive failure between cement and dentin.

The effect of 400 nm femtosecond laser and Zn(II)chlorin e6 methyl ester (Zn(II)e6Me) photosensitizer on disinfection of radicular dentin bonded to glass fiber post

AimTo assess and compare push-out bond strength (PBS) when canal disinfected with 5.25% NaOCl, 400 nm femtosecond laser, and natural PS activated by PDT (CP and Zn (II) Ce6 methyl ester) on bond efficacy of radicular dentin bonded to glass fiber post. Material and methodsA sum of 40 non-traumatic, cautiously extracted with closed apex human mandibular premolars were collected and decoronated up to the cement-o-enamel junction. Canals of all specimens were cleaned and shaped using a Protaper universal NiTi system via a crown-down approach, then finally dried out and obturated with gutta-percha. Post alignment space was formed with peso reamers and sanitized. Then samples were randomly allocated into four groups as per the radicular dentin designated disinfection protocols. Group 1 disinfected with curcumin photosensitizer + EDTA, group 2: 5.25% NaOCl and EDTA, group 3: Zn (II) Ce6 methyl ester and EDTA and group 4 sanitized with 400 nm fs-laser + EDTA. GFP was cemented into the radicular canal space and specimens were placed in a thermocycler. Segmentation of the root was done at three levels (coronal, middle, and apical) and positioned in a universal testing machine for PBS analysis. Failure mode analysis was performed using a stereomicroscope and statistical analysis was executed by one-way ANOVA and Tukey multiple comparison tests at a statistically significant level of p < 0.05. ResultsThe highest PBS was revealed by group 2 canal disinfected with 5.25% NaOCl +17% EDTA (control) at coronal (9.49 ± 1.42 MPa) and middle (7.545 ± 0.15 MPa) root levels. Whereas, the lowest PBS was displayed by group 3: Zn (II) Ce6 methyl ester +17% EDTA at coronal (6.31 ± 0.54 MPa) middle (4.85 ± 0.11 MPa) root levels respectively. Intergroup comparison presented that radicular dentin disinfected with 400 nm femtosecond laser + 17% EDTA substantiated comparable PBS result to group 2 (control) at all three root levels (p > 0.05). Likewise, root surface disinfection with Curcumin activated by PDT+17% EDTA unveiled no statistically significant result for specimens disinfected with Zn(II) Ce6 methyl ester +17% EDTA(p > 0.05). Furthermore, apical root segments in all groups showed a substantial decrease in PBS value and were comparable (p > 0.05). ConclusionThe bond efficacy of glass fiber post to radicular dentin disinfected with 400 nm femtosecond laser has the potential to be used as an alternative to conventional sodium hypochlorite.

The push out bond strength of bioceramic seal-er (Total Fill) after warm and cold obturation tech-niques An in vitro comparative study

Background: The goal of a root canal treatment is three dimensional obturation with a complete seal of the root canal system. The aim of this study was to evaluate and compare the effect of two warm obturation techniques, warm vertical compaction (WVC) and, carrier based obturation technique Gutta Core (GC), versus two cold obturation techniques, cold lateral compaction (CLC) and, single cone (SC) on push-out bond strength of bioceramic sealer (Total Fill) at three different root levels. Materials and Methods: Forty extracted maxillary first molars teeth with a straight round palatal root canal and mature apices were selected for this study. After sectioning the palatal roots to 11 mm from the root apex, the canals were prepared with EDGEENDO X7 rotary system file from size 20 up to size 40 taper 04. The samples were then randomly separated into four groups based on obturation procedures (each group n = 10), with group A: obturated by WVC, group B: GC, group C: CLC, and group D: SC. Following obturation, the teeth were kept in an incubator at 37°C and 100% humidity for two weeks. Three slices of 2 mm thickness were cut horizontally at 2, 4.5, and 7 mm from the root apex in each of the three sections (apical, middle and coronal). The data were investigated using one-way ANOVA and Tukey's test with a significance level (p&lt; 0.05). A digital microscope with a magnification of 60 X was used to establish the failure mode. Results: There was a significant increase in push-out bond strength following canal obturation with GC and WVC, particularly at the apical third (9.48, and 8.11 MPa, respectively) , compared to canals obturated with SC and CLC in all root levels except the middle third, at the (p&lt; 0.05) significance level. The cohesive mode of failure was the most prevalent in all groups. Conclusio: BC (TotalFill) sealer showed higher bond strength when used in WVC and GC compared to other techniques. SC and CLC were showed comparable bond strength values.

Push-out Bond Strength Evaluation for Different Endodontic Sealers (A Comparative Study).

Aims: The aim of this study was to compare the push-out bond strength values between four different types of sealers. Materials and method: Forty extracted straight, single-rooted, sound human mandibular first premolar teeth were selected for this study. The crown portion of each tooth was decoronated to the level of the cement-enamel junction (CEJ) to standardize the root length to 16 mm. The working length was measured and the canals were instrumented using Nickel-Titanium ProTaper Universal Rotary System up to size F3. The canals were rinsed with 2.5% sodium hypochlorite followed by 17% EDTA, then the samples were divided into four groups (n=10) according to the sealer to be used with F3 gutta-percha. These are (AH Plus, GuttaFlow 2, GuttaFlow Bioseal and MTA Fillapex) sealers. The push-out bond strength test was performed and the data were analyzed using one way ANOVA, and post hoc Duncan’s multiple range tests at (p ≤ 0.05). Results: There was a statistically significant difference in the push-out bond strength among the four sealers’ groups at (p ≤ 0.05). The highest mean value of bond strength (3.605) MPa was shown in the AH Plus group. Bioseal group produced (1.833) MPa followed by (0.822) MPa for GuttaFlow2 group. The lowest value (0.645) MPa was shown in MTA Fillapex group. Conclusion: Based on the findings of this study, AH Plus sealer revealed the highest bond-strength value followed by GuttaFlow Bioseal and GuttaFlow 2, whereas MTA Fillapex showed the least bond value.

The Effect of Smear Layer on the Push-out Bond Strength of Silicone-based Root Canal Sealers

Aims: The study aimed to evaluate the effect of smear layer on the push-out bond strength of silicone-based root canal sealers. Materials and methods: Sixty extracted, single-rooted, sound human mandibular first premolar teeth were selected for this study. The Crown portion of each tooth was decoronated to the level of cement-enamel junction to standardize the root length to 16 mm. The working length was measured by subtracting 1mm from the visually determined canal length and the canals were instrumented using ProTaper universal rotary system up to size F3. The canals were divided into two groups according to the irrigating solutions used. Group.1 was rinsed with 2.5% sodium hypochlorite followed by 17% EDTA to ensure complete smear layer removal. Group.2 was rinsed using 0.9% normal saline to keep the smear layer. Then the samples were subdivided into three subgroups according to the sealer used with gutta-percha. These include AH Plus, GuttaFlow 2, and GuttaFlow Bioseal groups. The push-out bond strength test was performed using the universal testing machine and the data were analyzed using independent sample T-test at (p ≤ 0.05) to compare the results of each sealer group in the presence and absence of the smear layer. Results: For all sealers’ groups the results has shown a statistically significant difference in the bond strength at (p ≤ 0.05) between group 1 (without smear layer) and group 2 (with smear layer). The smear layer removal produced higher bond strength in AH Plus sealer, whereas the bond strength of both GuttaFlow 2 and GuttaFlow Bioseal was decreased when the smear layer was removed. Conclusion:Smear layer removal has a positive effect on the bond strength value of AH Plus sealer. The bond strength of GuttaFlow 2 and GuttaFlow Bioseal was not improved following smear layer removal.