Higher Push-out Bond Strength Research Articles

Influence of Natural Dentin Biomodification Agent on Push-Out Bond Strength and Nanoleakage of Self-Adhesive Resin Cement Luting of Glass-Fiber Posts.

To evaluate the plant-derived compound lignin (LIG) as a pretreatment of intraradicular dentin in combination with EDTA on push-out bond strength (PBS) and nanoleakage of the glass fiber posts (GFPs) cemented using adhesive resin cement. Twenty-eight human incisor roots were prepared for GFP cementation and divided based on dentin pretreatment: (1) CONTROL: no pretreatment, (2) EDTA: 17% EDTA for 3 min, (3) EDTA-LIG: 17% EDTA and 2% lignin for 3 min, (4) EDTA-PAC: 17% EDTA and 2% lignin for 3 min. The GFPs were cemented using the self-adhesive resin cement Multilink Speed. The roots (n = 7) were sectioned into 1 mm-thick discs and subjected to PBS testing after 1 week or 6 months. Nanoleakage was analyzed by SEM. Statistical analysis was performed using two-factor ANOVA and Tukey's test (p < 0.05). Higher PBS was identified for the CONTROL group (p < 0.001). After 6 months, the EDTA-LIG maintained the bond strength with a predominance of mixed failures, while the EDTA-PAC, EDTA, and CONTROL groups showed reduction of bond strength, with a predominance of adhesive failures along with severe silver infiltration in the interface. LIG associated with EDTA as a pretreatment for intraradicular dentin shows significant potential for attaining stable bond strength and interfacial integrity of self-adhesive resin cement to intraradicular dentin.

Comparative Evaluation of the Effect of Various Irrigating Solutions on the Push-Out Bond Strength of Biodentine and Mineral Trioxide Aggregate: An In Vitro Study

Introduction: A successful endodontic treatment is ba¬sed on combination of adequate instrumentation, irrigation and obturation of canal system. The objectives of endodontic irrigants are lubrication of root canal, removal of microorganisms, pulp, dentinal remnants and dissolution of tissues. The objective of root-end filling is establishment of proper apical hermetic seal. Aim: To evaluate and compare the effect of various irrigating solutions on push-out bond strength of Biodentine and Mineral trioxide aggregate (MTA). Materials and Method: Sixty-four extracted human single rooted teeth were decoronated 1.5-2 mm coronal to cemento-enamel junction. The root canals were prepared and divided into four groups (n=16): Group I- Normal Saline (Control group), Group II- Triple antibiotic solution, Group III- 2% Chlorhexidine, Group IV- Morinda citrifolia solution. Mid root dentin was sectioned horizontally and irrigated further with respective irrigating solutions for 5 minutes and divided into 2 subgroups: Subgroup A- Biodentine and Subgroup B- MTA. The root-end filling material was incrementally placed and embedded in acrylic blocks. Samples were tested for push-out bond strength using universal testing machine. Results: The highest push-out bond strength was shown by 2% Chlorhexidine group when used with Biodentine and lowest when normal saline was used with Biodentine. Conclusion: All experimental irrigating solutions increased the push-out bond strength of MTA and Biodentine.

Microhardness and Pushout Bond Strength of Glass Fiber Post-to-Canal Dentin Irrigated with Boric Acid, Nd: YAP, AgNPs, and Curcumin Activated with Microbubble Emulsion. A SEM, EDX Analysis

This study aimed to assess the microhardness (MH) and push-out bond strength (PBS) of fiber post-to-canal dentin when boric acid (BA), Nd: YAP, silver nanoparticles (AgNPs), and microbubble emulsion (MBE) with curcumin were used as irrigants. Canal therapy was performed and the post space was prepared. Prior to glass fiber post (GFP) insertion, the post space was irrigated using 2.5% NaOCl+17% EDTA, 10% BA+EDTA, Nd: YAP laser+EDTA, AgNP+EDTA, and MBE (curcumin)+EDTA. Following disinfection, microhardness was evaluated. GFP was then inserted and PBS was assessed at the coronal, middle, and apical levels, along with the examination of debonded surfaces via stereomicroscope. The data were analyzed using ANOVA and a Post Hoc Tukey HSD test. The results showed that MH was highest in the group treated with AgNP+EDTA and lowest in the group treated with 10% BA+EDTA. Within the cervical region, the Nd: YAP laser+EDTA group showed the lowest PBS, while the highest PBS was observed in the group treated with MBE (curcumin)+EDTA. In the middle region, the GFP bonded to canal dentin disinfected with 2.5% NaOCl+EDTA was comparable to that treated with Nd: YAP laser+EDTA. In the apical region, the PBS of GFP was highest in the canal disinfected with MBE (curcumin)+EDTA. The study concluded that silver nanoparticles+EDTA and curcumin photosensitizer via microbubble emulsion+EDTA have the potential to be used as alternatives to conventional methods for improving the adhesion of glass fiber post-to-canal dentin, along with enhancing microhardness.

In Vitro Effects of Chlorhexidine and Isopropyl Alcohol Conditioning Agents on Immediate and Late Bond Strength of Fiber Posts Dentin.

Objectives: This study assessed the effect of chlorhexidine (CHX) and isopropyl alcohol (IA) on immediate and late pushout bond strength (PBS) of fiber posts to dentin. Materials and Methods: In this in vitro study, 54 single-canal premolars were endodontically treated, and randomly assigned to 3 groups (N=18) for root dentin conditioning with distilled water (control), 2% CHX, and 70% IA after post space preparation. Fiber posts were cemented with TheraCem self-adhesive cement, and each group was subdivided into two subgroups (N=9) for PBS measurement immediately after bonding, and after 5000 thermal cycles (5-55°C). The roots were then sectioned, and their PBS was measured. The mode of failure was evaluated under a stereomicroscope at ×40 magnification. Data were analyzed by repeated measures ANOVA and Tukey's test (alpha=0.05). Results: The highest PBS was noted in the IA group (21.12 MPa) after 24 hours and the lowest PBS belonged to the control group after thermocycling (7.48 MPa). The immediate and post-thermocycling PBS were significantly lower in the control group than the CHX group (P<0.05). The PBS in both the control and CHX groups was lower than that in the IA group (P<0.001). Regardless of the type of detergent, a significant reduction in PBS was observed after thermocycling (P<0.003). The PBS significantly decreased from the cervical towards the apical region in all groups (P<0.001). Conclusion: According to the results, application of IA before the self-adhesive cement effectively improved the immediate and late PBS, and was significantly more effective than CHX.

Push-Out Bond Strength of Glass Fiber Endodontic Posts with Different Diameters.

(1) Background: The retention of intraradicular posts is an important factor for the prognosis of endodontically treated teeth. The purpose of this study was to evaluate the push-out bond strength (PBS) of the posts relating to their diameter and region of the root. (2) Methods: A total of 40 premolar teeth (decoronated and root canal-filled) were divided into four groups (n = 10). After post-space preparation, different sizes (1.0, 1.2, 1.5, and 2.0 mm) of glass fiber posts were luted with resin cement into the root canals. After placement, 2 mm thick slices were cut from the roots according to their apical, middle, and coronal regions (n = 116). Push-out tests were carried out in a universal testing machine on each slice. A statistical evaluation of the data was applied. (3) Results: When comparing the diameter, the 2.0 mm posts had the highest PBS (111.99 ± 10.40 N), while the 1.0 mm posts had the lowest PBS (99.98 ± 8.05 N). Divided by the surface of the bonded area, the average PBS value was the highest for the 1.0 mm posts (18.20 ± 1.67 MPa) and the lowest for the 2.0 mm posts (12.08 ± 1.05 MPa). (4) Conclusions: Within the limitations of the study, when comparing the regions of the roots, no significant differences were found among the PBS values of the three regions (p = 0.219). When comparing the diameters, significant differences were shown between the PBS values of the four groups (p = 0.023 and p = 0.003, respectively).

Adjunctive use of different lasers Er, Cr: YSGG, femtosecond, potassium titanyl phosphate and photodynamic therapy on radicular disinfection bonded to glass fiber post.

The aim of this study was to evaluate and compare the effect of different laser prototypes [Er, Cr: YSGG laser (ECYL), potassium titanyl phosphate laser (KTP), and Femtosecond laser (FSL)]and curcumin photosensitizer (CP) activated by Photodynamic therapy (PDT) on the bond strength of Pre-fabricated fiber reinforced composite (PFRC) post-bonded to radicular dentin. A total of fifty mandibular single-rooted closed apex teeth were extracted carefully, assembled, and decoronated up to the cementoenamel junction. The working length of all specimens was determined by using a 10 K patency file and later, were cleaned and shaped with Protaper NiTi system using the crown down approach, dried, and obturated with gutta-percha using an AH Plus sealer. Post space was prepared by guiding peeso-reamer. Based on the method of disinfection, the samples were allocated to five groups (n=10) at random: samples in group 1: curcumin photosensitizer (CP) activated by PDT, samples in group 2 disinfected using 5.25% NaOCl+17% EDTA, samples in group 3 disinfected using 5.25% NaOCl+17% EDTA+FSL, specimens in group 4 sterilized using 5.25% NaOCl+17% EDTA+KTP and samples in group 5 cleaned with 5.25% NaOCl+17% EDTA+ECYL. The fiber post was cemented via self-etch resin cement into the post space. All specimens with posts were dissected perpendicularly into apical, middle, and coronal dentin and subjected to the universal testing machine for push-out bond strength (PBS) testing. Statistical analysis was performed using a One-Way analysis of variance and Post Hoc Tukey multiple comparison tests. The highest PBS was corroborated when the radicular canal was disinfected with 5.25% NaOCl +17% EDTA+ ECYL at all three root levels (coronal, middle, and apical) and the lowest was adjudicated by decontamination with CP activated by PDT at all inspected root levels. Intergroup comparison presented that specimens in group 2: 5.25% NaOCl+17% EDTA (control) and group 4: 5.25% NaOCl+17% EDTA+KTP revealed comparable PBS outcome to group 5 (p>0.05) while samples in group 3 revealed the equivalent PBS values to group 1 (p<0.05) at all three root levels. Er, Cr: YSGG laser and potassium titanyl phosphate laser when used in combination with the conventional canal disinfection 5.25% NaOCl and 17% EDTA demonstrated the highest push-out bond strength values at coronal, middle, and apical levels of the root.

Does radiation therapy affect adhesion of tricalcium silicate cements to root dentin?

This study aimed to analyze the effect of irradiation on the push-out bond strength of mineral trioxide aggregate (MTA) and Biodentine to radicular dentin. A total of 60 extracted mature human teeth with single root canals were categorized into two groups (irradiated and non-irradiated) (n=30). Each group was further divided into two sub-groups based on cements used (Biodentine and MTA). Then, a cumulative radiation dose of 60 Gy was divided into 30 fractions (two Gy for every fraction) and administered for five successive days per week over six weeks. Obturation was then performed using MTA and Biodentine. Afterwards, 1.5 mm thick horizontal sections were procured from the middle one-third of all the specimens and then subjected to push-out bond test. Results were analyzed using one-way analysis of variance with post-hoc Tukey's test. The bond strength of Biodentine and MTA to irradiated teeth was lower than non-irradiated teeth. Highest push-out bond strength was observed in non-irradiated specimens filled with Biodentine (p=0), followed by irradiated specimens filled with Biodentine (p=0); non-irradiated specimens filled with MTA (p=0); and irradiated specimens filled with MTA (p=0.9). The push-out bond strength of Biodentine and MTA to root canal dentin decreased significantly post irradiation.

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.

In Situ Zymography Analysis of Matrix Metalloproteinases Activity Following Endodontic Irrigation Protocols and Correlation to Root Dentine Bond Strength.

The objective was to evaluate the effect of different root canal irrigating solutions on the activity of matrix metalloproteinases (MMPs), and correlation to the push-out bond strength (PBS) and nanoleakage expression (NL) in the root dentin. Seventy-two single-rooted teeth were treated endodontically and distributed into four groups (n = 6 for in-situ zymography, n = 10 for PBS, and n = 2 for NL per group) according to the irrigating solutions used: (I) saline (S); (II) 5.25% sodium hypochlorite (SH); (III) 5.25% SH + 10% citric acid (CA); and (IV) 5.25% SH + 10% CA + 0.2% chlorhexidine (CHX). After root canal obturation, post space was prepared to receive the glass fiber post. Dual-cure resin was used for luting and light polymerization was performed. The root/fiber post assemblies were sectioned and subjected to in situ zymography, and PBS and NL expression analysis tests. The enzymatic activity was quantified and expressed as a percentage of the green fluorescence, while fractographic evaluation was performed after PBS with a stereomicroscope, and data were statistically analyzed at p < 0.05. The zymography analysis shows high expression of MMPs in the middle third of the root in all groups, while the most abundant activity of MMPs following the irrigating solutions is observed in groups I and III, where saline and citric acid are used, respectively. Inversely, group IV, where chlorhexidine is the final rinse, records the lowest MMP activity with the highest PBS, and the statistical analysis of the groups are ranked as: IV > II > III > I (p < 0.05). The combination of SH, CA, and CHX results in lower expression of MMPs and higher push-out bond strength of fiber posts to root dentin, with no difference seen in the nanoleakage expression (p > 0.05); hence, this irrigation regime with chlorhexidine as a final rinse is more favorable than other combinations in ensuring optimal adhesion to root dentine.

Push-Out Bond Strength and Dentinal Penetration of a Novel Herbal-Based Pulp Capping Agent: An In vitro Study

Background: Pulp capping agents should have proper sealing effect to enhance dental pulp tissue healing.&#x0D; Aim: The purpose of this study was to compare the effectiveness of grape seed extract (GSE) and Mineral trioxide aggregate (MTA) to penetrate to dentin and their push-out bond strength at two time intervals (1 and 3 months) when used as pulp capping agents either singly or combined to each other.&#x0D; Materials and Methods: This study was conducted on 120 human single-rooted anterior teeth. Sixty dentin discs were randomly divided into three groups (n=20) based on the material used; MTA, GSE, and a combination of MTA and GSE. A universal testing machine was used to determine the push-out bond strength for one and three months. At the same time intervals, extra 60 teeth with the same groups were utilized to quantify the degree of capping material penetration within the dentinal tubules using scanning electron microscopy (SEM). ANOVA with multiple comparison Post hoc test was used to evaluate the data where the p value was &lt; 0.05.&#x0D; Results: MTA had the highest push-out bond strength and penetration depth measurement into dentinal tubules at one month, followed by MTA combined with GSE, while GSE had the lowest push-out bond strength and penetration depth measurement. Nevertheless, GSE had the greatest values in both tests at 3 months, followed by MTA, while MTA coupled with GSE had the lowest value in both tests.&#x0D; Conclusion: Push out bond strength and dentinal penetration depth were improved with time except for the MTA group testing its dentinal penetration depth. GSE shows good push out bond strength and dentinal penetration depth.

Evaluation of pretreatments on intra-radicular dentin bond strength of self-adhesive resin cements.

To evaluate the influence of dentin pretreatments on the push-out bond strength (POBS) of self-adhesive resin cements (SARCs) to radicular dentin. Two experimental pretreatments (2.5% titanium tetrafluoride (TiF4 ) and 26% polyacrylic acid (PA)) and two SARCs: Maxcem Elite (MAX) and Calibra Universal (CAL) were used. For each cement, a control group was applied as indicated by the manufacturer. Sixty bovine incisors were restored (n = 10) and subjected to POBS evaluation. Failure mode, adhesive interface and surface morphology were analyzed by a Scanning Electron Microscopy (SEM) and resin infiltration was performed by confocal laser scanning microscopy (CLSM). Data for POBS and CLSM were analyzed by three-way ANOVA and Bonferroni post-hoc (α = 0.05). For MAX, both experimental pretreatments resulted in increased POBS in the cervical third, and for CAL, only the PA resulted in higher POBS in the cervical third. The most failures occurred between the dentin and the resin cement, except when TiF4 was applied. For PA, analysis of surface morphology showed open dentinal tubules, while TiF4 presented particle agglomerates. SEM and CLSM images confirmed presence of resin tags for both pretreatments. Pretreating radicular dentin with PA and TiF4 solutions improves the bond strength of SARCs.

Radicular canal disinfection using photon-induced photoacoustic streaming and riboflavin photosensitizer to silver diamine fluoride and diode laser bonded to fiber post: An assessment of extrusion bond strength

AimThe present study aimed to estimate and compare the effectiveness of different innovative canal cleansing approaches photon induced photoacoustic streaming (PIPS) Riboflavin Photosensitizer (RF), Diode Laser, and silver diamine fluoride (SDF) on push out bond strength (PBS) of fiber post cemented to radicular dentin Material and methodsForty extracted premolars were disinfected and decoronated up to the cement-o-enamel junction. Canals of all specimens were cleaned and shaped utilizing a reciprocating system. Post space was created by employing peso-reamers and samples were randomized into four groups based on methods of disinfection (n = 10). Group 1 (PIPS), group 2 (Diode Laser), group 3 (RP), and group 4 (SDF) canal disinfection. Fiber posts were cemented via Self etch resin cement (SERC) in a radicular dentin post space area and root was segmented at three levels (coronal, middle and apical). PBS analysis was performed, and a stereomicroscope was used to assess the failure mode. The means and standard deviations of PBS among studied groups were measured using one-way analysis of variance (ANOVA) after exposure. The means of bonding strength were compared by Tukey multiple comparison tests (p > 0.05). ResultsRF had the highest PBS at all three root levels, coronal (8.31 ± 0.64 MPa), middle (8.13 ± 0.11 MPa) and apical (5.68 ± 0.54 MPa) while group 4 SDF samples showed lowest PBS at all root portions, coronal (6.14 ± 0.78 MPa), middle (5.18 ± 0.15 MPa) and apical (3.15 ± 0.19 MPa), respectively. Intergroup comparison unveiled comparable PBS at all three root levels for group 1 (PIPS) and group 3 RF (p > 0.05). Intragroup comparison displayed a significant decline in PBS values from coronal, middle to the apical direction in all studied groups ConclusionDisinfection of radicular dentin with Riboflavin Photosensitizer and photon-induced photoacoustic streaming bonded to fiber post have the greatest PBS at all three levels cervical, middle and apical.

Push-out bond strength of mineral trioxide aggregate with addition of titanium dioxide, silver, and silicon dioxide nanoparticles: An in vitro comparative study.

The ultimate goal of endodontic therapy is to eliminate all microorganisms present inside root canal and thereby sealing all the possible communicating pathways between pulpal and periradicular tissues, which prevents all the factors that cause recontamination and reinfection of the root canal system. If endodontic treatment fails, next approach is surgical endodontics. Bioceramics are recently introduced materials specifically designed for their potential use in medical field and dentistry. To evaluate and compare the push-out bond strength of mineral trioxide aggregate (MTA) by adding titanium dioxide (TiO2), silver, and silicon dioxide nanoparticles. Totally, 60 single-rooted human teeth were used. Middle third of the root was sectioned to obtain 2-mm thick root section. Acrylic was adapted to the section to obtain disks of 5 mm diameter and 2 mm thickness. Canal was prepared by GG Drill. Samples were divided into four groups of 15 each (n = 15): • Group I (control): MTA • Group II: MTA + TiO2 nanoparticles. • Group III: MTA + silver nanoparticles. • Group IV: MTA + silicon dioxide nanoparticles. The cement mixture was compacted into the canal. Samples were subjected to push-out bond strength using universal testing machine. The data were analyzed statistically by analysis of variance and post hoc comparison by Tukey's t-test. The highest push-out bond strength was shown by Group II (MTA with TiO2 nanoparticles), followed by Group III (MTA with silver nanoparticles) and Group I (MTA control group). The lowest push-out bond strength was shown by Group III (MTA with silicon dioxide nanoparticles). TiO2 and silver nanoparticles when added into MTA lead to an increase in push-out bond strength of MTA.

Comparative evaluation of push-out bond strength of bioceramic and epoxy sealers after using various final irrigants: An in vitro study.

Aim:The aim of the study is to compare the push-out bond strength of bioceramic and epoxy sealers after using various final irrigants.Materials and Methods:Hundred single-rooted teeth were divided into two groups (n = 50) according to the sealer used: Group A: Bio C (bioceramic sealer), Group B: Dia-Proseal (epoxy sealer). Each group was subdivided into five subgroups (n = 10) according to the final irrigation protocol: Group A1 and B1 – 5% glycolic acid (GA), Group A2 and B2 – 17% GA, Group A3 and B3 – 0.2% chitosan, Group A4 and B4 – 17% ethylenediaminetetraacetic acid, and Group A5 and B5 – 0.9% saline. Samples were obturated in combination with one of the mentioned sealers and were allowed to set for 1 week. Two horizontal slices were obtained from each sample and subjected to push-out test.Statistical Analysis:The data were statistically analyzed using two-way ANOVA and independent Student's t-test.Results:Both the sealers exhibited higher push-out bond strength after treatment with GA with no significant difference between 5% and 17% GA. Bio C sealer with GA as final irrigant showed higher bond strength than Dia-Proseal (P < 0.05).Conclusion:The push-out bond strength of the sealer was significantly affected by the final irrigation solution used. The highest push-out bond strength was seen with Bio C sealer after treatment with GA with no significant difference between 5% and 17% GA.

Effect of exposure to etidronic acid on the bond strength of calcium silicate-based cements after 1 and 21\xa0days: an in vitro study

BackgroundAfter reparation of root perforations with calcium silicate-based cements (CSBC), the surface of the material is expected to be exposed to root canal irrigants (RCI) while resuming the root canal treatment.MethodsThe aim of this study was to compare the effect of exposure to a mixture of sodium hypochlorite (NaOCl) and etidronic acid (HEBP) or other irrigants on the Push Out Bond Strength (POBS) of CSBC after two different setting times. 240 root slices 1 mm thick were obtained from single-rooted human teeth. A 1.4 mm diameter perforation was performed on each slice and filled with Biodentine (BD) or ProRoot MTA (PMTA). After 1 or 21 days they were exposed to 17% ethylenediaminetetraacetic acid, 5.25% NaOCl, a mixture of 5.25% NaOCl and 9% HEBP (NaOCl + HEBP) or saline (n = 15) and submitted to a push-out test. POBS results were analysed with ANOVA and Tukey tests.ResultsBD showed higher POBS than PMTA after 1 day (p < .05). After 21 days no differences were found between materials. After 1 day exposure to NaOCl + HEBP resulted in higher POBS, compared to the other irrigants (p < .05).ConclusionPOBS results are influenced by the cement, the setting time and the exposure to irrigants.

Bond strength and Weibull analysis of fiber posts luted with different cement types and mechanically aged

This study aimed to evaluate the influence of cement type and mechanical cycling on the push-out bond strength (σ) of fiber posts luted to root canals. Eighty bovine single-root teeth were prepared and the roots were included with chemically cured acrylic resin. The specimens were allocated into 8 groups (n = 10) considering the factors ‘cement’ (glass ionomer cement – GIC, resin reinforced glass ionomer cement – RRGIC, conventional dual-cure resin cement – CRC, and self-adhesive resin cement – SARC) and ‘mechanical cycling’ (non-aged and aged – mc). The fiber posts and roots dentin were treated according to the cement type and luted to root canals. Composite-cores were made for the groups submitted to mechanical cycling (1,000,000 cycles, 84 N, 4 Hz). Each root were cut into 4 disk-samples of 1.8 mm (thickness) and submitted to push-out testing. Data (MPa) were analyzed using two-way ANOVA, Tukey test (5%), and Weibull analysis. ANOVA revealed that cement (p < 0.001) was significant; however, the mechanical cycling had no effect on bond strength (p = 0.895). The CRC (4.36 ± 1.15 MPa), CRCmc (4.13 ± 0.75 MPa), GIC (4.29 ± 2.14 MPa), and GICmc (4.04 ± 1.18 MPa) groups showed higher (σ) than RRGIC (2.36 ± 1.00 MPa). Weibull Characteristic strength of the CRC and CRCmc were significantly higher than RRGICmc, and RRGIC. The mixed type of failure was the most common. Conventional dual-cure resin cement and glass ionomer cement presented higher push-out bond strength to root dentin regardless of mechanical cycling.

Effect of indirect ultrasonic activation of modified bioceramic materials on the bond strength and tubular penetration in root canals

To maintain the integrity of the interface between root canal filling and radicular dentin an ideal endodontic biomaterial should have good adhesion. This study was aimed to evaluate the bond strength and tubular penetration of modified bioceramic materials by indirect ultrasonic activation. In the present in vitro experimental study, 120 coronal root slices of 2 mm were prepared from mandibular premolars and randomly divided into six groups (n = 20) in accordance to placement techniques: Group I: Nano Biodentine-manual, Group II: CaCl2 modified ProRootMTA-manual (MM), Group III: Biodentine-manual, Group IV: Nano Biodentine: Ultrasonic, Group V: CaCl2 modified ProRootMTA-ultrasonic, and Group VI: Biodentine-ultrasonic (BDU). The samples were kept in humidifier for 4 days at 37°C and push out bond strength, sealer penetration were evaluated using an universal testing machine and confocal laser scanning microscope respectively. Data were subjected to statistical analysis using SPSS software by using One-way ANOVA for overall significance and Tukey's multiple post hoc test for intergroup comparison (P < 0.05). Highest push out bond strength and greater tubular penetration were observed with Group VI (BDU), while the lowest bond strength and tubular penetration were associated with Group II (MM). Within the limitations of current study it was observed that Biodentine with indirect ultrasonic activation has resulted in highest pushout bond strength among all the study groups.

Constituents, properties and clinical applications of OrthoMTA & RetroMTA: A systematic review.

OrthoMTA and RetroMTA are newly developed mineral trioxide aggregates that were developed to achieve maximum benefits and clinical performance. This systematic review aimed at assessing and describing the constituents, properties and uses of OrthoMTA and RetroMTA. Literature search was performed using the keywords, "OrthoMTA", "RetroMTA", "BioMTA", "constituents" and "properties" in the databases, PubMed, Cochrane, Semantic scholar and Europe PubMed Central. Original articles in English describing the properties, constituents, uses/indications, history and recent advances on OrthoMTA and RetroMTA were considered for the study. A total of 35 articles were selected for the systematic review based on keywords selected. Among the 35 articles, 5 articles described the composition and properties of OrthoMTA and RetroMTA, 7 articles depicted the usage of OrthoMTA and RetroMTA and the remaining articles discussed on the various properties of both OrthoMTA and RetroMTA. The present review confirmed that RetroMTA exhibits an excellent property, namely, short setting time, less tooth discoloration, high compressive strength, higher shear bond strength with time, higher push-out bond strength, low solubility, low cytotoxicity, biocompatibility, antibacterial property, and can be used in reparative processes in case of blood contamination. However, even OrthoMTA showed less microleakage, is biocompatible and possesses antibacterial properties.

Influence of Propolis, Ozone and Photodynamic therapy in root canal disinfection on resin bond strength to radicular dentin.

The aim of the present study was to assess post space disinfection using different irrigants and their effect on radicular dentin bond to SERC. Forty single rooted mandibular 2nd premolars were collected and disinfected. All samples were decoronated maintaining root length of 12 mm and embedded vertically in acrylic resin. Shaping of the canal was performed using reciprocating system. Canals were dried using paper points and obturated with gutta percha via lateral condensation. Peso-reamers were used to create post space up to 10 mm. The post space was irrigated with 1% NaOCl before being randomly allocated into four groups (n = 10) according to different methods of canal disinfection. Samples in group 1 were subjected to photoactivated disinfection (PAD), group 2 irrigated with ethanol based propolis group 3 disinfected using ozone and group 4 irrigated with 2.25 % NaOCl with 17 % EDTA and ECL. GFP was fitted using SERC. Each sample was cut into 1 mm from coronal, middle and apical and subjected to pushout bond strength (PBS) via universal testing machine. Fracture analysis were confirmed by stereomicroscope at 40x magnification. For comparison of means, Analysis of variance (ANOVA) and Tukey multiple comparison test was used maintaining the level of significance at p < 0.05. The highest PBS at all three levels were found in group 4, canal disinfected with 2.5 % NaOCl with 17 % EDTA and ECYL. Whereas, the lowest PBS was observed in group 1. Inter group comparison, prosthetic space disinfected with propolis extract showed no significant difference to group 4 canal disinfected with 2.5 % NaOCl with 17 % EDTA and ECYL at all three levels (p > 0.05). Intra group comparison in all experimental groups showed no significant difference was noted in coronal and middle thirds of group 1, group 2 and group 3 respectively (p > 0.05). 2.5 % NaOCl with EDTA and ECL treatment (group 4) remains the gold standard when used as a final canal irrigant. Propolis can be used as potential irrigant for canal disinfectant provided if the composition becomes standardized.

Evaluation of Push-out Bond Strength of a Resin Sealer to Dentin after a Final Flush of Three Irrigants

To evaluate the push-out bond strength of resin-based sealer to root dentin after a final flush of three different irrigants. Thirty extracted human mandibular premolars were sectioned 4 mm below the cement-enamel junction and 60 horizontal disks of 2 mm from middle one-third of the root were prepared. The disks were immersed in 3% sodium hypochlorite for 1 minute, and after drying the disks, they were finally flushed with the following irrigants: group I-Chitosan solution, group II-Morinda citrifolia juice (MCJ), and group III-ethylenediaminetetraacetic acid (EDTA). The disks were filled with AH Plus sealer, and after 7 days, the disks were subjected to push-out bond strength using a universal testing machine. EDTA had the highest push-out bond strength followed by MCJ and then chitosan. Chitosan and MCJ can be used as alternative irrigants as a final flush during the cleaning and shaping of the root canals. EDTA, chitosan solution, and MCJ are efficient in smear layer removal which thereby increases better sealer penetration and prevents the dislocation of obturating materials.