Effect of Different Irrigation Protocols on Resin Sealer Bond Strength to Dentin

Formulations of NaOCl-based in liquid, gel form or with surfactants on dentin deproteinization before fiber post cementation

The objective of the study was to evaluate the effects of dentin deproteinization protocols for post space using different formulations containing sodium hypochlorite before fiber post cementation with self-adhesive resinous cement. The groups were divided according to the irrigation protocol (DWC, SHS, SHT and SHG). The residue cleanliness, bond strength, adhesive failure pattern, and tag formation at the adhesive interface between the self-adhesive cement and the dentin were evaluated. For this, analysis in scanning electron microscope, push-out test and confocal laser scanning microscopy were performed. The SHT protocol showed the highest residue cleanliness on the dentin surface of the post space (p<0.05). In addition, SHT protocol showed highest bond strength and tag formation in the cervical and middle thirds (p<0.05). Dentin deproteinization with sodium hypochlorite with surfactant provided the best dentin cleaning of residues, bond strength and tag formation after cementation of the fiber post with self-adhesive cement.

Effect of sodium hypochlorite-based formulations on the adhesion interface after fiber post cementation

The study evaluated the persistence of residues, bond strength and tags formation of a cementation system after post-space irrigation with different sodium hypochlorite-based irrigants. The groups were divided according to the irrigation protocol (DW: distilled water; SHS: sodium hypochlorite solution; SHG: sodium hypochlorite gel; and, SHT: sodium hypochlorite with surfactant). Forty roots (n=10) were used to evaluate the persistence of residues by scanning electron microscopy. Other forty roots were used to the push-out bond strength test, failure mode and tag formation analyses. Non-parametric data were submitted to Kruskal Wallis and Dunn tests, while parametric data were evaluated by one-way ANOVA. No difference was observed in the persistence of residues. DW showed the highest bond strength and tag formation. Type 2 failure mode was the most frequent in the experimental groups. Compared to control, SHT showed the best performance, since less negative effects on adhesive interface was observed.

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.

Effect of cleaning materials on microtensile bond strength of resin composite to primary dentin contaminated with root canal sealers

BACKGROUND

There have been no studies on the bond strength of adhesives with dentin surfaces contaminated with root canal sealers in primary teeth without underlying permanent teeth germs. This study investigated the cleaning materials used for primary tooth dentin contaminated with root canal sealers. The aim was to increase the success rate of root canal treatment in pedodontics clinics and retain the teeth for longer.

METHODS

The occlusal enamel layer was removed, followed by the application of root canal sealers (AH Plus or MTA Fillapex) to the dentin and cleaning using different irrigation solutions (saline, NaOCl, and ethanol). The specimens were restored using a self-etch adhesive and composite. Sticks with a thickness of approximately 1 mm were obtained from each sample, and the bond strengths were measured using a microtensile testing device. The interfacial morphology of the bonded space was evaluated using scanning electron microscopy.

RESULTS

The control and AH Plus saline groups had the highest bond strengths. The groups cleaned using ethanol had the lowest bond strengths (p < 0.01).

CONCLUSION

Cleaning the dentin with saline-soaked cotton pellets provided the best bond strengths. Therefore, saline is the most effective material for removing both epoxy resin- and calcium silicate-based root canal sealers from the access cavity.

The effect of different acidic irrigation solutions on the pushout bond strength of root canal filling

Background

This study investigated the effects of different acidic solutions used as the final irrigation on the push-out bond strength (PBS) of resin-based and bioceramic-based root canal sealers.

Methods

100 single root and canal human incisors were selected and decorated. Root canal shaping was done with ProTaper Next rotary files up to X4 and rinsed with 5 mL of 5.25% NaOCl between each file. Then, teeth were divided into five main groups according to the final irrigation (n=20). Group 1: glycolic acid; Group 2: phosphoric acid; Group 3: citric acid; Group 4: EDTA and group 5: saline. Then, each group was divided into two subgroups according to the canal sealer used (n=10). The groups filled with bioceramic-based sealer (bioserra) were named A, and the groups filled with resin-based sealer (AH Plus) were called B. PBS test was applied to one of the two samples obtained from the coronal third of each root. The data were statistically analyzed using a two-way analysis of variance and Tukey's HSD test (α=0.05).

Results

Statistically, the highest PBS value was obtained in group 2A (4.81±0.03 MPa), which was irrigated with phosphoric acid and filled with bioserra, and the lowest PBS value was obtained in group 5B (1.10±0,03), which was irrigated with saline and filled with AH Plus (P<0.05). There was a statistical difference between all groups except group 1A and group 3A (P<0.05).

Conclusion

The bioceramic-based root canal sealer (bioserra) bond strength is superior to resin-based (AH Plus). Phosphoric acid, glycolic acid, and citric acid can be an alternative to EDTA.

The Effect of Photodynamic Therapy Applied with Different Photosensitizers on Dentin Hardness in Comparison with Conventional Irrigation

Objective: The aim of this study was to examine the effect of photodynamic therapy (PDT) using toluidine blue O (TBO), curcumin (CUR) and methylene blue (MB) photosensitizers on root canal dentin microhardness by comparing it with sodium hypochlorite (NaOCl) + ethylenediamine tetraacetic acid (EDTA). Materials and methods: The root canals of 100 human premolar teeth were shaped by the R25 file (Reciproc; VDW, Munich, Germany). The working length of the teeth was determined by using a #10 K-file, keeping it 1mm shorter than the tooth apex. The R25 file was used to prepare the root canals. After every three pecking motions, irrigation was performed and a total of 10 mm of distilled water was used. The specimens were randomly distributed according to the disinfection method; NaOCl+EDTA, PDT with TBO, PDT with CUR, PDT with MB and distilled water (DS) (n=20). Grooves were prepared on the buccal and lingual surfaces of the prepared teeth, parallel to the long axis of the tooth, without touching the root canals. The roots were divided into two parts by means of a cement spatula placed in these grooves. Root canal dentin microhardness was evaluated by the Vickers test method. Three measurements were made by applying 300 g of force for 15 seconds and the average was calculated. It was recorded as the Vickers hardness value. The data were analyzed by using the one-way ANOVA and Dunnett’s post hoc tests (α=0.05). Results: All photosensitizer groups showed significantly higher microhardness value than the groups of DS and NaOCl + EDTA (p0.05). Conclusions: PDT with CUR obtained the highest radicular dentin microhardness.

Influence of 2% chlorhexidine on the dislodgement resistance of AH plus, bioroot RCS, and GuttaFlow 2 sealer to dentin and sealer-dentin interface

Aim

To find out the effects of 2% chlorhexidine (CHX) gel intracanal medicament on the dislodgement resistance of AH Plus, BioRoot RCS, and GuttaFlow 2 Sealer to dentin and on sealer-dentin interface.

Materials and Methods

Sixty single-rooted maxillary canine were taken and divided into two groups based on the treatment: Group 1 - control group (no medicament) (n = 30) and Group 2 - (GLUCO-CHeX 2% Gel) (n = 30). Further, the groups were divided according to the sealer used, namely (A) AH Plus sealer, (B) BioRoot RCS Sealer, and (c) Gutta Flow 2 sealer. Teeth were prepared using rotary instrumentation of file size 35 with a taper of 0.06 and obturation was done. 1 mm thick sections were obtained from the roots. All the sections were checked for push out bond strength using Universal testing machine and mode of failure using stereomicroscope. Some samples were evaluated for sealer-dentin interface using field emission scanning electron microscope.

Results

AH Plus showed higher bond strength compared to BioRoot RCS and GuttaFlow 2. There was no significant difference in the push out bond strength with or without the prior use of 2% CHX medicament (P > 0.05) and also CHX did not affect the mode of failure. However, sealer-dentin interface gap was increased with application of medicament.

Conclusion

Dislodgement resistance of AH Plus sealer is significantly higher than BioRoot RCS and GuttaFlow 2 sealer. The application of 2% CHX intracanal medicament before root canal obturation did not significantly affect the dislodgement resistance of the three tested sealers. 2% CHX medicament did not affect the failure mode of the sealers. Sealer-dentin interface is affected by the use of 2% CHX gel medicament.

Effect of triple antibiotic paste on the bond strength of epoxy and methacrylate resin-based sealers to root canal dentin

Purpose:

This study aimed to evaluate the effect of triple antibiotic paste (TAP) as an endodontic intracanal medicament on the bond strength of epoxy and methacrylate resin-based sealers to root canal dentin.

Materials and Methods:

In this in vitro study, 80 single-rooted human mandibular premolars were prepared using ProTaper rotary system. The specimens were randomly divided into a control group (without intracanal dressing) and an experimental group receiving TAP (n = 40). The intracanal dressing was removed after 3 weeks. Then, samples of each group were randomly divided into four subgroups (n = 10) and obturated with gutta-percha and different resin-based sealers. G1: AH Plus, G2: Syntex, G3: EndoREZ, and G4: MetaSEAL. After 1 week, 16 slices of 1 ± 0.1 mm thickness were obtained from the midroots of teeth in each subgroup, and a push-out test was used to measure the bond strength. Slices were examined using a stereomicroscope at 30 × to determine the mode of failure. The data were analyzed using two-way analysis of variance, one-way analysis of variance, and Tukey post hoc tests (α = 0.05).

Results:

Compared to control group, TAP significantly increased the bond strength of MetaSEAL and EndoREZ (P < 0.05). In the control group, epoxy resin-based sealers showed higher bond strength compared to methacrylate ones (P = 0.00). In TAP group, Syntex and EndoREZ showed significantly the greatest and the lowest bond strengths, respectively, (P < 0.05). The analysis of failure modes revealed a predominance of mixed failures in all groups except for Syntex group in which most failures were cohesive.

Conclusions:

TAP significantly increased the bond strength of methacrylate resin-based sealers.

Influence of the use of chelating agents as final irrigant on the push-out bond strength of epoxy resin-based root canal sealers: A systematic review

This systematic review (PROSPERO - CRD42020150722) was performed to answer the following question: Does the use of chelating agents affect the dislodgment resistance of epoxy resin-based root canal sealers? A search was conducted in PubMed, EMBASE, Scopus, LILACS and Web of Science, hand searching of two endodontic journals and grey literature until September 2020. Extracted data included: teeth used, sample size, root canal preparation, irrigant, chelating solution, neutralisation solution, type of resin-based sealer and obturation approach, storage method and duration, root third and slice thickness, plunger dimension and loading direction and the push-out testing parameters and values. The search retrieved a total of 2.389 studies. After analysis, 12 studies fulfilled the eligibility criteria and were included. Most of the final irrigation protocols with chelating agents had a positive impact and promoted an improvement in the dislodgment resistance of epoxy resin-based sealers to the root dentin.

Investigation of the effect of different chelation solutions on penetration of resin-based and bioceramic sealers with a novel method

This study aimed to investigate the effects of different chelation solutions on the penetration of resin-based and bioceramic root canal sealers into dentinal tubules using a device that assembles conventional microplate detection with automated digital microscopy. Eighty-four single-rooted teeth were prepared with 30.07 nickel-titanium instruments and divided into four groups of 21 according to the final irrigation solutions used: saline (control), ethylenediaminetetraacetic acid (EDTA), maleic acid (MA), and etidronic acid (HEBP). The samples were obturated with AH Plus, MTA Fillapex, or EndoSequence BC Sealer using the single-cone technique. The roots were then sectioned horizontally at 2, 6, and 10 mm and examined using a Cytation 5 reader and Gen5 software. Data were compared using two-way analysis of variance followed by univariate analyses and Tukey's multiple comparison test (p < .05). The mean penetration depth in the apical thirds was higher in the MA group than in the other groups (p = .013). The mean depth in the middle and coronal thirds was almost equal in the EDTA and HEBP groups. The mean depth was significantly higher in the coronal thirds of the root canals than in any other section in all final irrigation solution groups (p < .001). EndoSequence BC Sealer displayed higher penetration depth than AH Plus and MTA Fillapex, although the differences between the examined sealers were not statistically significant. The chelation solutions increased root canal sealer penetration into the dentinal tubule.

Comparative evaluation of push-out bond strength of gutta-percha using different sealers with lateral condensation and thermoplasticized obturation technique: An in vitro study

Aim:

The study aimed to evaluate and compare the push-out bond strength of gutta-percha using AH plus, Endosequence BC, and Roeko seal sealer with lateral condensation and thermoplasticized obturation technique.

Materials and Methods:

Sixty single-rooted premolars were instrumented and samples were randomly assigned into three groups based on the sealer used (Group A-AH Plus, Group B-Endosequence BC, Group C-Roeko Seal) which were further divided into two subgroups-A1, B1, and C1 were obturated by the lateral condensation technique and A2, B2, and C2 using the thermoplasticized technique. Each sample was sectioned horizontally using a diamond disc, representing apical, middle, and coronal thirds, respectively. Root segments were then mounted on an acrylic block, and push-out bond strength of each sample was tested using the universal testing machine.

Statistical Analysis:

One-way ANOVA, Tukey's test, and unpaired t-test.

Results:

For mandibular premolar teeth with a single canal using lateral condensation technique, the highest push-out bond strength was found in the A1 group (7.30 ± 0.61 MPa) at the apical level. While using the thermoplasticized technique, the highest push-out bond strength was found in the B2 group (3.71 ± 0.81 MPa) at the apical level. Overall results showed that the lateral condensation technique showed significantly higher push-out bond strength than thermoplasticized technique (P < 0.028).

Conclusions:

The push-out bond strength of AH Plus sealer was higher than the Endosequence BC sealer and Roeko seal sealer. Lateral condensation technique has shown higher push-out bond strength than the thermoplasticized technique.

The Effect of Silver, Zinc Oxide, and Titanium Dioxide Nanoparticles Used as Final Irrigation Solutions on the Fracture Resistance of Root-Filled Teeth

Aim

This study was conducted to evaluate the effect of three nanoparticle solutions used as final root canal irrigants on the fracture resistance of endodontically treated roots.

Materials and Methods

Sixty intact single-rooted premolar teeth were used after removing the crowns below the cementum–enamel junction to standardize the length of the remaining roots to 13 mm. After instrumenting the roots using ProTaper Universal rotary instruments up to size F4, the roots were randomly divided into six groups (n=10) according to the final irrigating solutions: Group 1: normal saline; Group 2: 2% chlorhexidine (CHX); Group 3: 17% EDTA+2.5% NaOCl; Group 4: 17% EDTA+0.1% silver nanoparticle (SNP) solution; Group 5: 17% EDTA+0.1% titanium dioxide nanoparticle (TNP) solution; Group 6: 17% EDTA+0.1% zinc oxide nanoparticle (ZNP) solution. After filling the root canals with gutta-percha and AH Plus sealer, the fracture resistance (FR) values were measured. The data were subjected to the one-way analysis of variance and the Tamhane post hoc test (p=0.05).

Results

EDTA + NaOCl had the lowest FR value, followed by normal saline and CHX (p values < 0.05). No significant difference was found between the FR of roots irrigated with CHX and normal saline (p > 0.05). The application of nanoparticles (SNP, TNP, and ZNP) was associated with a significantly greater FR than that of other irrigation solutions (p values < 0.05).

Conclusion

The final irrigation of root canals with nanoparticles enhanced the fracture resistance of the endodontically treated roots. The lowest FR value was observed for NaOCl.

Design Variability of the Push-out Bond Test in Endodontic Research: A Systematic Review

INTRODUCTION

There is limited literature on the impact of testing variables on the push-out bond test (POBT). This review identified designs of the POBT used in the endodontic literature and aimed to determine which experimental variables may influence the push-out bond strength (POBS).

METHODS

A systematic review based on PRISMA guidelines was performed by searching the PubMed, SCOPUS, and Cochrane library databases using terms including push-out and dislocation resistance and descriptions of endodontic materials. Test variables assessed included method of root preparation, timing of sectioning compared with filling, thickness, diameter and taper of sections, and plunger size and velocity. The POBS of 3 common materials (gutta-percha and AH Plus, mineral trioxide aggregate, and Biodentine) were collected from investigations, and a comparison was attempted.

RESULTS

One hundred thirty-three studies assessed the POBS of root-filling materials, 68 assessed root repair cements/root-end filling materials, and 16 assessed orifice barrier materials other than mineral trioxide aggregate. There was significant variation in all of the assessed variables, resulting in a large range of reported values for the POBS of the various materials. Because of this heterogeneity in study design, no further statistical analysis of the impact of the test variables on POBS was possible.

CONCLUSIONS

There was considerable variation in the POBT design used in endodontic research. Greater standardization is required for future research as well as accurate reporting for all test variables to assess the impact of specific design variables on POBS.

Effect of Root Dentin Conditioning on the Pushout Bond Strength of Biodentine

INTRODUCTION

Sodium hypochlorite (NaOCl) is the main irrigant to clean root canals. Decalcifying agents are advocated as additional means to condition the root dentin. The aim of this study was to evaluate the effect of alternating (EDTA) or continuous 1-hydroxyethane 1,1-diphosphonic (HEDP) chelation in conjunction with NaOCl irrigation on the pushout bond strength of Biodentine (Septodont, Saint Maur des Fosses, France).

METHODS

Single root canals of 50 extracted, mature human teeth were divided into 5 groups (n = 10) and enlarged using rotary instruments. Canals were irrigated with 5 mL irrigant after each instrument and then with 5 mL after mechanical preparation as follows: 2.5% NaOCl during and then 2.5% NaOCl, 17% EDTA, or 17% EDTA followed by 2.5% NaOCl after preparation. Continuous chelation with 2.5% NaOCl/9% Dual Rinse HEDP (Medcem GmbH, Weinfelden, Switzerland) during and after preparation. The control group was irrigated with water during and after preparation. Canals were then filled with Biodentine. A horizontal section of 1.5-mm thickness was taken from the middle root third, and a pushout bond test was performed. Data were statistically analyzed using 1-way analysis of variance/Tukey honest significant different test.

RESULTS

The pushout bond strength of Biodentine was significantly higher when the root canal was irrigated with 2.5% NaOCl/9% Dual Rinse HEDP (19.6 ± 2.3 MPa) than with NaOCl alone (15.5 ± 1.5 MPa) or the NaOCl/EDTA sequences (15.7 ± 2.2 MPa and 16.9 ± 2.9 MPa) (P < .05), which did not differ among each other (P > .05). The lowest pushout bond strength values were found with water irrigation (11.5 ± 0.5 MPa) (P < .05 to all other groups).

CONCLUSIONS

Irrigation with 2.5% NaOCl/9% Dual Rinse HEDP significantly improved the pushout bond strength of Biodentine to the root canal dentin.

Effect of photodynamic therapy and non-thermal plasma on root canal filling: analysis of adhesion and sealer penetration

Objective

The aim of this study was to evaluate the effect of photodynamic therapy (PDT) and non-thermal plasma (NTP) on adhesion and sealer penetration in root canals.

Material and Methods

Sixty single-rooted premolars were used. The teeth were prepared using a crown-down technique. NaOCl and EDTA were used for irrigation and smear layer removal, respectively. The root canals were divided into three groups: control, PDT, and NTP. After treatments, the roots were filled using gutta-percha and either AH Plus (AHP) or MTA Fillapex (MTAF) sealers. Samples were sectioned at 4, 8, and 12 mm from the apex (1-mm slices)and analyzed by the push-out bond strength test (adhesion) and confocal laser scanning microscopy (sealer penetration). Data were statistically evaluated using Kruskal-Wallis, Dunn’s, and Spearman’s tests.

Results

Regarding AHP, bond strength was similar in the NTP group and in the control group, but significantly lower in the PDT group. As to MTAF, both therapies showed lower values than the control group. In the confocal analysis of AHP, maximum and mean penetration, and penetrated area were statistically higher in the control group than in the PDT and NTP groups. Penetrated perimeter was similar among groups. Regarding MTAF, all parameters yielded better results in the NTP than in the control group. The PDT and control groups showed similar results except for penetrated area.

Conclusion

PDT and plasma therapy affected the adhesion and sealer penetration of root canals filled with AH Plus and MTA Fillapex and there is no positive correlation between adhesion and sealer penetration.

Effect of Intermediate Flush Using Different Devices to Prevent Chemical Smear Layer Formation

This study compared the effect of intermediate flush with distilled water delivered by conventional irrigation, EndoVac microcannula or Self-Adjusting File (SAF) system in the prevention of chemical smear layer (CSL) formation. Thirty human premolars were used. Canals were prepared with Reciproc system and 5.25% NaOCl. After chemomechanical preparation, samples were divided in 3 groups (n=10) according to the intermediate irrigation protocol with distilled water using: conventional irrigation, EndoVac microcannula or SAF. A final flush with 2% chlorhexidine solution was used and scanning electron microscopy was performed to assess protocol effectiveness. Two calibrated evaluators attributed scores according the presence or absence of CSL on the surface of the root canal walls at the coronal, middle and apical thirds, as follows: (1) no CSL; (2) small amounts of CSL; (3) moderate CSL; and (4) heavy CSL. Differences between protocols were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. SAF resulted in less formation of CSL when compared with the conventional irrigation and EndoVac microcannula (p<0.05). When root canal thirds were analyzed, conventional irrigation and EndoVac groups showed less CSL formation at coronal and middle thirds in comparison to the apical third (p<0.05). In SAF group, there was no difference among the thirds (p>0.05). It may be concluded that an intermediate flush of distilled water, delivered by the SAF system resulted in a better reduction of CSL formation during chemomechanical preparation.

Effects of different intra canal medicaments on the push out bond strength of endodontic sealers

BACKGROUND

One of the essential properties of the root canal sealers is the adhesion to root canal dentin and their higher bond strength decreases the microleakage. The aim of the present study was to compare the effect of Different Intracanal medicaments on the push out bond strength of AH26 and MTA Fillapex sealers.

MATERIAL AND METHODS

A total of 104 one-rooted extracted human teeth were divided into 4 (n=26) experimental groups. After the cleaning and shaping, the root canals were filled with Ca(OH)2, triantibiotic paste (TAP), Metapex or 2% chlorhexidine gel for two weeks. Then, intracanal medicaments were rinsed away and the samples in the sub-groups were obturated with gutta-percha and AH26 or MTA Fillapex sealers. After two weeks incubation, 2-mm-thick middle section of each root was then subjected to push-out testing. Data were analyzed with two-way ANOVA and LSD test.

RESULTS

With all the intracanal medicaments, the overall mean of bond strength values were significantly higher with AH26 compared to MTA Fillapex (p<0.05). With the use of MTA Fillapex the maximum and minimum means of bond strength values were recorded with CHX and Metapex and for AH26 were recorded with Ca(OH)2 and chlorhexidine, respectively.

CONCLUSIONS

The bond strengths of sealers to dentin are under the influence of pre-treatment with intracanal medicaments. Under the limitations of the present study, the effect of TAP on the bond strength of endodontic sealers was not negative. Key words:AH26, medicament, MTA Fillapex, push-out bond.

Effects of auxiliary device use on smear layer removal

This study evaluated the effects of different auxiliary irrigation devices on smear layer removal with a chelating solution (QMix). Fifty single-rooted permanent human teeth were shaped with a sequence of nickel-titanium instruments. A 2% chlorhexidine gel was used as a chemical auxiliary substance during preparation. Samples were assigned to five groups (n = 10 each) according to final irrigation protocol, namely, distilled water (control group), QMix 1 min, QMix + passive ultrasonic irrigation (PUI), QMix + plastic endodontic finishing file (EC), and QMix 3 min. Teeth were prepared and evaluated by scanning electron microscopy, and three photomicrographs (magnification, 1,000×) were obtained for each root third. Two blinded and precalibrated evaluators analyzed and scored the images, and the data were statistically analyzed by the Kruskal-Wallis and Dunn tests (P < 0.05). Groups were ranked according to the extent of smear layer removal. The total area of the root canal walls and apical root thirds was calculated, and the groups ranked PUI > EC = QMix 3 min > QMix 1 min > control. QMix 1 min was effective for smear layer removal only when used with auxiliary devices, and QMix + passive ultrasonic irrigation yielded the best results, particularly for the apical third.(J Oral Sci 58, 561-567, 2016).

Epigallocatechin-3-gallate increased the push out bond strength of an epoxy resin sealer to root dentin

This study aimed to investigate the effect of epigallocatechin-3-gallate (EGCG) from green tea extract on the push out bond strength of an epoxy resin sealer to root dentin. Seventy single root canal premolars were decoronated and instrumented. The roots were randomly irrigated with different final irrigation protocols (n=16): 17%EDTA (EDTA), 17%EDTA followed by 2.5%NaOCl (EDTA+NaOCl), 17%EDTA followed by 1 mg/mL EGCG (EDTA+EGCG) and 1 mg/mL EGCG (EGCG). Other six root canals were received only 2.5%NaOCl as a control group. One root from each group (n=1) was excluded and prepared for SEM investigation. All root canals were then obturated and horizontally sectioned to perform the push out test. EDTA+EGCG group had the highest bond strength (p<0.05). EGCG group showed higher bond strength than EDTA group (p<0.05). The use of EGCG as a final irrigant significantly increased the push out bond strength of an epoxy resin sealer to root dentin.

Evaluation of bond strength of various epoxy resin based sealers in oval shaped root canals

Background

The aim of this study was to evaluate the bond strength of AH plus, Acroseal, and Adseal to the root canal dentin.

Methods

A total of 36 single-rooted, mandibular premolar teeth were used. Root canal shaping procedures were performed with ProTaper rotary instruments (Dentsply Maillefer) up to size F4. The prepared samples were then randomly assembled into 3 groups (n = 12). For each group, an ultrasonic tip (size 15, 0.02 taper) which was also coated with an epoxy resin based sealer and placed 2 mm shorter than the working length. The sealer was then activated for 10 s. A push-out test was used to measure the bond strength between the root canal dentine and the sealer. Kruskal-Wallis test to evaluate the push-out bond strength of epoxy based sealer (P = 0.05). The failure mode data were statistically analyzed using Pearson’s chi square test (P = 0.05).

Results

Kruskal-Wallis test indicated that there were no statistically significant difference among the push out bond strength values of 3 mm (p = 0.123) and 6 mm (P = 0.057) for groups, there was statistically significant difference push out bond strength value of 9 mm (P = 0.032). Pearson’s chi square test showed statistically significant differences for the failure types among the groups.

Conclusion

Various epoxy resin based sealers activated ultrasonically showed similar bond strength in oval shaped root canals. Apical sections for all groups have higher push out bond strength values than middle and coronal sections.

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-016-0301-1) contains supplementary material, which is available to authorized users.

Efeito do plasma de oxigênio na dentina previamente exposta ao NaOCl

Resumo Introdução O tratamento de plasma é uma tecnologia eficaz que pode manter as propriedades internas dos materiais inalteradas após o tratamento, modificando apenas a superfície. Objetivo Avaliar o efeito do plasma de oxigênio na dentina previamente exposta ao NaOCl 6%. Material e método Foram utilizados 60 incisivos bovinos. A coroa foi removida, a raiz foi dividida e as faces planificadas, totalizando 120 segmentos referentes ao terço cervical. As amostras foram divididas em dois grupos: controle (imersa em NaOCl 6%, lavada com água destilada, seca, imersa em EDTA 17%, lavada e seca) e plasma de oxigênio (após tratamento descrito no grupo controle, plasma de oxigênio foi aplicado por 30 s). As amostras foram avaliadas qualitativamente em relação à topografia por microscopia eletrônica de varredura, utilizando-se microfotografias com ampliação de 1.000×. O goniômetro Ramé-hart foi utilizado para a mensuração do ângulo de contato entre as superfícies e as seguintes soluções foram utilizadas: água, etilenoglicol e di-iodometano. Em seguida, a energia de superfície, representada pelas componentes polar e dispersiva, foi calculada. Avaliou-se também o escoamento dos cimentos Pulp Canal Sealer EWT (PCS) e Real Sal SE (RS) na superfície dentinária. Os dados foram analisados estatisticamente utilizando os testes Kruskal-Wallis e Mann-Whitney U (p<0,05). Resultado O tratamento com plasma levou à formação de uma camada semelhante à smear layer na superfície dentinária. Este tratamento levou a um aumento da energia de superfície e da componente polar, favorecendo a hidrofilicidade da superfície. Entretanto, desfavoreceu o escoamento do cimento PCS e não influenciou no escoamento do cimento RS. Conclusão O plasma de oxigênio ocasionou mudanças topográficas na superfície dentinária, favorecendo a hidrofilicidade desta. Contudo, não favoreceu o escoamento dos cimentos endodônticos na dentina.

Effect of final irrigation procedures on fracture resistance of root filled teeth: an ex vivo study

AIM

To evaluate the effect of chlorhexidine (CHX) on fracture resistance of roots treated with different concentrations of ethylenediaminetetraacetic acid (EDTA).

METHODOLOGY

One hundred and twenty intact single-rooted premolar teeth were sectioned below the cementum-enamel junction to standardize the length of the teeth to 12 mm. The canals of one hundred specimens were instrumented with ProTaper Universal rotary instruments up to size F4 and were randomly divided into five groups (n = 20) according to the final irrigating solutions: Group 1: distilled water (DW); Group 2: 5% EDTA and 2.5% NaOCl; Group 3: 17% EDTA and 2.5% NaOCl; Group 4: 5% EDTA, 2.5% NaOCl, DW and 2% CHX; Group 5: 17% EDTA and 2.5% NaOCl, DW and 2% CHX. Root canals were filled with gutta-percha and epoxy resin-based root canal sealer using a single-cone technique. Twenty teeth served as negative controls and were not instrumented nor root filled (Group 6). All specimens were embedded in self-curing acrylic resin and loaded vertically at 0.5 mm min^-1 until fracture occurred. The data were evaluated statistically using one-way anova test followed by Holm-Sidak's multiple comparison test (P < 0.05).

RESULTS

Group 1 (only DW) had the lowest vertical fracture strength, followed by Group 3 (17% EDTA and 2.5% NaOCl; P < 0.05). Group 6 (negative control group) had the highest fracture resistance. Final irrigation with CHX following irrigation with 17% EDTA or 5% EDTA and 2.5% NaOCl (groups 4 and 5) significantly increased the fracture resistance of roots (P < 0.05). However, the difference between Group 4 and Group 5 was not significant (P > 0.05).

CONCLUSIONS

Intracanal CHX rinse of EDTA/NaOCl-treated root dentine enhanced the fracture resistance of roots filled with AH Plus.

Evaluation of the bond strength of root-end placed mineral trioxide aggregate and Biodentine in the absence/presence of blood contamination

Objective:

Mineral trioxide aggregate (MTA) has been accepted as an appropriate root-end filling material in endodontic microsurgery because of setting ability in the wet environment. The aim of this study was to assess the bond strength of root-end placed MTA and Biodentine (Septodont, Saint Maur des Fossés, France) in the absence/presence of blood contamination.

Materials and Methods:

Forty-eight single-rooted maxillary incisors were used. subsequent to root-end resection and apical preparation using ultrasonic retro-tips, the specimens were randomly separated into two groups according to the root-end filling materials: MTA (Cerkamed Medical Company, Stalowa, Poland) or Biodentine. The specimens were then separated into two subgroups according to storage condition (absence/presence of blood) (n = 12). After obtaining 2.0 ± 0.1 mm slices, push-out tests were performed. Each slice was examined under a stereomicroscope to evaluate the failure mode. The data were analyzed using two-way analysis of variance and Tukey's post hoc test for multiple comparisons. The failure modes were analyzed using the Chi-square test (P = 0.05).

Results:

The bond strength was significantly affected by the presence of blood contamination and root-end filling material type (P < 0.001). Biodentine had better bond strength than MTA (P < 0.001). The most common failure type was adhesive failure. According to the Chi-square test, there were no statistically significant differences among the groups (P = 0.394).

Conclusions:

Biodentine had better bond strength values compared to MTA, and the bond strength of both MTA and Biodentine as root-end filling materials was negatively affected by the presence of blood.

Influence of antimicrobial solutions in the decontamination and adhesion of glass-fiber posts to root canals

Objective

This study evaluated the effect of root canal disinfectants on the elimination of bacteria from the root canals, as well as their effect on glass-fiber posts bond strength.

Material and Methods

Fifty-three endodontically treated root canals had post spaces of 11 mm in length prepared and contaminated with E. faecalis. For CFU/ml analysis, eight teeth were contaminated for 1 h or 30 days (n=4). Teeth were decontaminated with 5% NaOCl, 2% CHX, or distilled water. As control, no decontamination was conducted. After decontamination, sterile paper points were used to collect samples, and CFU/ml were counted. For push-out, three groups were evaluated (n=15): irrigation with 2.5% NaOCl, 2% CHX, or sterile distilled water. A bonding agent was applied to root canal dentin, and a glass-fiber post was cemented with a dual-cured cement. After 24 h, 1-mm-thick slices of the middle portion of root canals were obtained and submitted to the push-out evaluation. Three specimens of each group were evaluated in scanning electron microscopy (SEM). Data were analyzed with one-way ANOVA and Dunnett’s T3 test (α=0.05).

Results

The number of CFU/ml increased from 1 h to 30 days of contamination in control and sterile distilled water groups. Decontamination with NaOCl was effective only when teeth were contaminated for 1 h. CHX was effective at both contamination times. NaOCl did not influence the bond strength (p>0.05). Higher values were observed with CHX (p<0.05). SEM showed formation of resin tags in all groups.

Conclusion

CHX showed better results for the irrigation of contaminated root canals both in reducing the bacterial contamination and in improving the glass-fiber post bonding.

The Effect of Increased Temperatures of QMix and EDTA on the Push-out Bond Strength of an Epoxy-resin Based Sealer

BACKGROUND

Bond strength of root canal sealers is mainly influenced by the surface tension of the root canal wall. Heat, or the use of a surfactant might reduce surface tension and it is known that surface tension of an EDTA solution significantly affected from temperature rise. QMix is a novel endodontic irrigant for smear layer removal containing EDTA, chlorhexidine and a detergent. There is no data regarding the influence of the temperature of the EDTA and QMix on the push-out bond strength of root canal sealers.

AIM

To evaluate effect of temperatures of QMix and EDTA on the bond-strength of AH Plus.

MATERIALS AND METHODS

Sixty premolars were prepared with ProTaper F4. During preparation 3% NaOCl was performed. Specimens were divided into 4 groups as follows: 5-mL 17% EDTA at 22°C and 37°C; 5-mL QMix at 22°C and 37°C. Three specimens from each group were prepared for observation using SEM. Remaining roots were obturated and prepared for a push-out test. Data was analysed using Anova and Bonferroni tests (p<0.05).

RESULTS

Samples irrigated with QMix had higher push-out bond strength values than those irrigated with EDTA (p=0.01), regardless of temperature. Samples irrigated with 37°C EDTA resulted in higher bond-strength values than those irrigated with 22°C EDTA (p<0.001).

CONCLUSION

Temperature of the final irrigant does affect the bond strength values of AH plus to root dentin irrigated with EDTA. Bond strength of AH Plus sealer to root canal dentin may improve with QMix.

Antimicrobial and cytotoxic effects of phosphoric acid solution compared to other root canal irrigants

Phosphoric acid has been suggested as an irrigant due to its effectiveness in removing the smear layer.

In vitro study of the apical microleakage with resilon root canal filling using different final endodontic irrigants

Background

Endodontic microleakage or microfiltration refers to the percolation of fluids and micro-organisms at the interface of the obturation material and the walls of the root canal system. The aim of this in vitro study was to compare apical microfiltration of Resilon root canal filling by employing three different final irrigant solutions.

Material and Methods

128 single-rooted teeth were employed. The crowns were sectioned horizontally at the cemento-enamel junction and instrumented with 5.25% sodium hypochlorite (NaOCl) and 17% EDTA gel to obtain an instrumented 040 apical caliber. An intermediate irrigation was performed with distilled water. The roots were then randomly assigned to three experimental groups with three different final irrigants: (A) 20% citric acid (CA); (B) 2% chlorhexidine digluconate (CHX); and (C) 5.25% NaOCl, plus two control groups (positive and negative). They were then dried, obturated with RealSeal™, and cleared by Robertson’s technique. Apical microleakage was measured by the dye penetration method and assessed with a 4.5x stereomicroscope. Data were statistically analyzed by one way ANOVA and post hoc analysis for multiple comparisons.

Results

Mean and standard deviations for apical microleakage were: 2% CHX (0.24 mm ± 0.22), 20% CA (0.25 mm ± 0.20), and 5.25% NaOCl (0.87 mm ± 0.32). Significant differences were reported among the group irrigated with NaOCl, CHX and CA (P<0.001).

Conclusions

A higher rate of apical microleakage was observed when the final irrigation was performed with NaOCl whilst lower rates were reported for CHX and CA.

Key words:Apical filtration, endodontic irrigation, resin-based sealers, adhesion, root canal filling.

Dentin wettability enhancement for three irrigating solutions and their effect on push out bond strength of gutta percha / AH Plus

Background

The aim of this study was to investigate the effect of wettability enhancement for 17% EDTA, 2.5% sodium hypochlorite and 7% maleic acid solutions on push out bond strength of gutta percha /AH Plus to root dentin.

Material and Methods

One hundred and eight extracted single rooted human lower premolars were instrumented up to Protaper Universal F5 then irrigated with 3ml of 2.5% NaOCl after each file. Irrigants were prepared and a pilot study for determination of Tween 80 concentration yielding the lowest surface tension value in every solution was conducted. Samples were randomly divided into a control group and two experimental groups (17% EDTA and 7% Maleate), further split into eight subgroups (n=12), according to Tween 80 implementation sequence. Roots were obturated using gutta percha and AH plus by lateral condensation. Bond strength was measured by push out test. Mode of failure was then evaluated quantitatively by stereomicroscopy. Data were statistically analyzed using one way ANOVA followed by Tukey-Kramer for multiple comparisons.

Results

Control group showed the lowest values. Maleic acid subgroups showed significantly higher overall values than EDTA subgroups (P<0.05). Protocols implementing surfactant containing NaOCl showed significantly lower values than plain counterparts. Failure pattern was predominantly cohesive for plain regimens and the ones implementing Tween 80 in maleic acid solutions with plain NaOCl.

Conclusions

Tween 80 addition to demineralizing irrigants increased the bond strength values. Surfactant containing NaOCl solutions yielded lower bond strength than plain ones.

Key words:Wettability enhancement for three irrigants vs. corresponding gutta percha/AH Plus bonding.

A microleakage study of gutta-percha/AH Plus and Resilon/Real self-etch systems after different irrigation protocols

The development and maintenance of the sealing of the root canal system is the key to the success of root canal treatment. The resin-based adhesive material has the potential to reduce the microleakage of the root canal because of its adhesive properties and penetration into dentinal walls. Moreover, the irrigation protocols may have an influence on the adhesiveness of resin-based sealers to root dentin.

Influence of chlorhexidine application time on the bond strength between fiber posts and dentin

INTRODUCTION

The aim of this study was to investigate the effects of chlorhexidine (CHX) application time on the bond strength and durability of the adhesion of fiber posts relined with resin composite to the root dentin.

METHODS

Eighty bovine incisor roots were divided into 4 groups after root preparation: control group (irrigation with physiological solution) and experimental groups, CHX for 30 seconds, CHX for 60 seconds, and CHX for 120 seconds. Fiber posts relined with resin composite were cemented with RelyX ARC. The Scotchbond Multi-Purpose total-etching adhesive system was used in half of the samples of each group, and the Clearfil SE Bond self-etching adhesive system was used in the other half. The samples were randomly divided into 2 subgroups, 24 hours of storage and 12 months of storage. All roots were sectioned transversely, and push-out tests were performed. Bond strength means were analyzed by analysis of variance and Tukey test (α = 0.05). Failure mode was determined by examining specimen's surfaces under scanning electron microscope, and its distribution was evaluated by using χ(2) test (α = 0.05).

RESULTS

CHX pretreatment resulted in homogeneous bond strength values at 24 hours and 12 months of storage, irrespective of the CHX application time and adhesive system (P < .05). A significant bond strength decrease was noticed after 12 months of storage when irrigation was performed with physiological solution in the control groups (P > .05). Significant differences were observed for fracture patterns (P < .001).

CONCLUSIONS

The use of CHX pretreatment could preserve the bond strength of the fiber post relined with resin composite to root dentin for 12 months, irrespective of the CHX application time and adhesive system used.

Push-out bond strength of a self-adhesive resin cement used as endodontic sealer

OBJECTIVES

The aim of the present study was to investigate the bond strength of RelyX Unicem (3M) to root canal dentin when used as an endodontic sealer.

MATERIALS AND METHODS

Samples of 24 single-rooted teeth were prepared with Gates Glidden drills and K3 files. After that, the roots were randomly assigned to three experimental groups (n = 8) according to the filling material, (1) AH Plus (Dentsply De Trey GmbH)/Gutta-Percha cone; (2) Epiphany SE (Pentron)/Resilon cone; (3) RelyX Unicem/Gutta-Percha cone. All roots were filled using a single cone technique associated to vertical condensation. After the filling procedures, each tooth was prepared for a push-out bond strenght test by cutting 1 mm-thick root slices. Loading was performed on a universal testing machine at a speed of 0.5 mm/min. One-way analysis of variance and Tukey test for multiple comparisons were used to compare the results among the experimental groups.

RESULTS

Epiphany SE/Resilon showed significantly lower push-out bond strength than both AH Plus/Gutta-Percha and RelyX Unicem/Gutta-Percha (p < 0.05). There was no significant difference in bond strength between AH Plus/Gutta-Percha and RelyX Unicem/Gutta-Percha (p > 0.05).

CONCLUSIONS

Under the present in vitro conditions, bond strength to root dentin promoted by RelyX Unicem was similar to AH Plus. Epiphany SE/Resilon resulted in lower bond strength values when compared to both materials.

Effect of calcium hydroxide and double and triple antibiotic pastes on the bond strength of epoxy resin-based sealer to root canal dentin

INTRODUCTION

The aim of this study was to evaluate the effects of calcium hydroxide (CH) and triple (TAP) and double (DAP) antibiotic pastes on the bond strength of an epoxy resin-based sealer (AH Plus Jet; Dentsply DeTrey, Konstanz, Germany) to the root canal dentin.

METHODS

Sixty-four single-rooted human mandibular premolars were decoronated and prepared using the rotary system to size 40. The specimens were randomly divided into a control group (without intracanal dressing) and 3 experimental groups that received an intracanal dressing with either CH, DAP, or TAP (n = 16). The intracanal dressing was removed by rinsing with 10 mL 17% EDTA followed by 10 mL 2.5% sodium hypochlorite. The root canals were then obturated with gutta-percha and AH Plus Jet sealer. A push-out test was used to measure the bond strength between the root canal dentin and the sealer. The data were analyzed using 2-way analysis of variance and Tukey post hoc tests to detect the effect of the independent variables (intracanal medicaments and root canal thirds) and their interactions on the push-out bond strength of the root canal filling material to the root dentin (P = .05).

RESULTS

The push-out bond strength values were significantly affected by the intracanal medicaments (P < .001) but not by the root canal thirds (P > .05). In the middle and apical third, the bond strength of the TAP group was higher than those of the CH and DAP groups (P < .05).

CONCLUSIONS

The DAP and CH did not affect the bond strength of the epoxy resin-based sealer. Additionally, the TAP improved the bond strength of the epoxy resin-based sealer in the middle and apical thirds.

Lack of correlation between tubular dentine cement penetration, adhesiveness and leakage in roots filled with gutta percha and an endodontic cement based on epoxy amine resin

Objective

To analyze possible correlations among tubular dentine cement penetration, adhesiveness and apical leakage in fillings performed with gutta percha and an endodontic cement based on epoxy amine resin.

Material and Methods

Sixty similar, extracted human mandibular central incisors were irrigated, instrumented and filled following the same protocol. First, apical leakage was quantified by fluid filtration tests. Then, these same specimens were sectioned for analysis of tubular dentine cement penetration and the middle thirds were submitted to push-out tests to analyze the adhesiveness of the fillings.

Results

In brief, the means and standard deviations with a confidence interval of 95% were as follows: tubular dentine cement penetration (8.875±4.540), adhesiveness (4.441±2.683) and apical leakage (0.318±0.215). The data were confronted using the Pearson's test (P>0.05), and it was possible to prove that there was no correlation between (1) tubular dentine cement penetration and apical leakage (r²: 0.08276), (2) tubular dentine cement penetration and adhesiveness (r²: -0.2412) and (3) adhesiveness and apical leakage (r²: 0.1340).

Conclusion

After analysis of these data, it could be observed that there exists no correlation among the variables analyzed in this study.

Efeito de diferentes soluções utilizadas como irrigante final na superfície dentinária: análise de rugosidade

INTRODUÇÃO: O uso de irrigantes pode gerar alterações microestruturais na superfície dentinária, entre as quais alterações na rugosidade. Essas alterações podem influenciar o processo de união dos materiais obturadores à dentina. OBJETIVO: O objetivo do presente trabalho foi avaliar o efeito das soluções de EDTA, hipoclorito de sódio (NaOCl) e clorexidina, como irrigante final, na rugosidade da superfície dentinária. MATERIAL E MÉTODO: Foram utilizadas raízes distais de seis terceiros molares inferiores, que foram planificadas com o auxílio de disco de lixa e cortadas em segmentos, totalizando 18 amostras. A análise inicial foi realizada utilizando-se o perfilômetro Dektak. Foram realizadas cinco varreduras por amostra. Em seguida, as amostras foram irrigadas com NaOCl para simular o preparo químico-mecânico e lavadas com água destilada. Foram então divididas em seis grupos de acordo com o protocolo de irrigação final: Água destilada; NaOCl 5,25%; clorexidina 2%; EDTA17%; EDTA 17% + NaOCl 5,25%, e EDTA 17% + clorexidina 2%. Novamente, em cada amostra, foram realizadas cinco varreduras, totalizando 15 varreduras por grupo. Os dados foram analisados estatisticamente pelos testes de Kruskal-Wallis e Mann-Whitney (p<0,05). RESULTADO: Foi encontrada alteração significativa da rugosidade somente no grupo em que houve a combinação do agente quelante com o NaOCl. CONCLUSÃO: Os protocolos de irrigação final apresentam diferentes efeitos na rugosidade da superfície dentinária.