The effect of 17% EDTA and QMiX ultrasonic activation on smear layer removal and sealer penetration: ex vivo study

The Effect of Different Compositions and Concentrations of Etidronate-Containing Irrigants on the Antibacterial Activity of Sodium Hypochlorite against Enterococcus faecalis and Candida albicans

We assessed the effect of different compositions and concentrations of two etidronate-containing irrigants on the antibacterial activity of sodium hypochlorite (SH) against Enterococcus faecalis and Candida albicans in vitro. Pure cultures of C. albicans and E. faecalis were isolated from root canal samples. The disc diffusion method was used to compare the antibacterial effect of pure SH and SH mixed with 9%, 15%, and 18% etidronate of two manufactures (dual rinse (DR); IsraDent (ID)) and EDTA. The pH and temperature of the solutions were measured immediately after mixing and within 40 min. The ANOVA revealed a significant influence of the type of irrigating solution on the C. albicans and E. faecalis inhibition zone diameters that ranged from 6.6 to 51.6 mm and from 6.4 to 12.4 mm, respectively. SH with DR 9% exhibited the highest effect against C. albicans. The antifungal activity of the other irrigants was SH = SH + DR15% = SH + DR18% = SH + ID9% > SH + EDTA > SH + ID15% > SH + ID18%. No significant differences in the anti-E. faecalis effect were revealed between the tested solutions except for the mixtures of SH and 15% and 18% ID, which exhibited no antiseptic effect. There was a strong positive correlation between antiseptic activity against both microorganisms and the pH values of the tested solutions. In conclusion, most etidronate formulations did not significantly hamper sodium hypochlorite activity against C. albicans and E. faecalis. The effect was concentration- and manufacturer-dependent.

Effect of EDTA Activation on Blood Clot Structure in Regenerative Endodontics: A Scanning Electron Microscopy Study

INTRODUCTION

EDTA plays a crucial role in regenerative endodontic therapy (RET) because of its significant biological effects. However, EDTA is also recognized as the preferred anticoagulant for hematologic tests. Thus, this study aimed to assess the influence of different EDTA activation techniques on the morphology of blood clots after conditioning the root canal dentin.

METHODS

Forty extracted human teeth were prepared to simulate immature teeth and divided into the following 5 groups: (1) saline solution (negative control), (2) EDTA 17% + saline solution (CNI), (3) CNI + ultrasonic activation, (4) CNI + Easy clean activation, and (5) CNI + XP-endo Finisher activation. After irrigation, the roots were cleaved, and the root canals were filled with human blood to clot formation. The morphology and density of erythrocytes, platelets, and the fibrin network were observed using a scanning electron microscope. The fibrin network density was classified using a 4-point scale. Data were analyzed using the Friedman test and the Kruskal-Wallis test with Bonferroni adjustment (α = 5%).

RESULTS

All groups exhibited consistent blood clot morphology characterized by a high density of erythrocytes, platelets, and white blood cells throughout the entire length of the root canal. The negative control group showed statistically significant high scores of fibrin density compared with the CNI group in all root thirds (P < .05). However, there was no statistical difference in the scores for the fibrin network density between the groups irrigated with EDTA with and without activation (P > .05).

CONCLUSIONS

EDTA may impair the fibrin network formation compared with the saline group. However, EDTA activation did not significantly change the effects on the blood clot in contact with the conditioned intraradicular dentin.

Comparison of Easydo Activator, ultrasonic and needle irrigation techniques on sealer penetration and smear layer removal in vitro

The effects of Easydo Activator (EA), a new sonic irrigation system, on sealer penetration at the root apex were compared to needle irrigation (NI) and passive ultrasonic irrigation (PUI) in this study. Forty-two single-rooted teeth were prepared and randomly divided into three groups (n = 14): group 1: NI; group 2: PUI; and group 3: EA. A solution of 3% sodium hypochlorite (NaOCl) was used for irrigation. Nine teeth in each group were filled with AH Plus sealer mixed with CY5 fluorescent dye and a single gutta-percha cone. The sealer penetration area, maximum penetration depth and percentage of sealer penetration at 5 mm and 1 mm from the apex were analyzed by confocal laser scanning microscopy (CLSM). The remaining 5 teeth in each group were subjected to test smear layer scores by scanning electron microscopy (SEM). The CLSM evaluation showed that increases in the area, depth and percentage of sealer penetration were detected at 1 and 5 mm from the root apex in the PUI group compared with the NI group, and greater increases were observed in the EA group (P < 0.05). The SEM experiment showed that the lowest scores for the smear layer and debris removal were achieved by the EA group when compared with the PUI and NI groups (P < 0.05). In conclusion, EA was superior to PUI and NI regarding sealer penetration at the root apex during endodontic treatment, and it could provide a new technical idea for clinical root canal therapy.

Comparative evaluation of effect of nisin-incorporated ethylenediamine tetraacetic acid and MTAD on endodontic biofilm eradication, smear layer removal, and depth of sealer penetration

OBJECTIVES

To comparatively evaluate the nisin-incorporated ethylenediamine tetraacetic acid (N-EDTA) and MTAD on cytotoxicity, endodontic biofilm eradication potential, smear layer removal ability, and sealer penetration depth.

MATERIALS AND METHODS

N-EDTA was prepared and characterized using high-performance liquid chromatography (HPLC). Minimum inhibitory, minimum bactericidal, and minimum biofilm inhibitory concentration (MBC, MIC, and MBIC) were determined on Enterococcus faecalis (E. faecalis) strain. The cytocompatibility of N-EDTA and MTAD was evaluated using 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based colorimetric assay. Dentin specimens (n = 88 for antibacterial analysis, n = 170 for sealer penetration depth) were prepared and subjected to the classical irrigating strategy and obturation, respectively. The scanning electron microscopic evaluation (SEM) was done for the evaluation of biofilm disruption and smear layer removal. Confocal laser scanning microscopy (CLSM) evaluation was done for determining percentage of bacterial viability and sealer penetration depth. Statistical analysis of one-way ANOVA and Tukey's HSD post hoc tests for bacterial viability and Kruskal-Wallis test and Mann-Whitney test for smear layer removal and depth of penetration were done with the significance level set at p < 0.05.

RESULTS

MTAD and N-EDTA showed cytocompatibility without any statistical differences from each other. For N-EDTA, the MIC and MBC values were 12.5 μg/ml (1:8), and MBIC values were 36 μg/ml. Biofilm disruption and killed bacterial percentage of N-EDTA was statistically higher than MTAD, whereas both the materials showed similar efficacy in the removal of the smear layer and sealer penetration depth.

CONCLUSION

N-EDTA had negligible cytotoxicity with similar smear layer removal ability, sealer penetration, and better antibiofilm potential than MTAD.

CLINICAL RELEVANCE

N-EDTA can serve as a viable alternative endodontic irrigant.

Knowledge, Attitude, and Practice towards Chelating Agents in Endodontic Treatment among Dental Practitioners

The use of chelating agents (CAs) in the endodontic irrigation protocol is required to dissolve the inorganic components of the smear layer. We aimed to assess the knowledge, attitude, and practice of dental professionals regarding the use of CAs during root canal treatment. A cross-sectional anonymous online survey was conducted among specialized endodontists and general dentists who routinely perform endodontic treatment and work in government-funded or private clinics in Moscow. The 8 min survey consisted of four parts: basic demographic data, knowledge (five items), attitude (four items), and practice (five items). We collected 376 completed questionnaires; a majority of the respondents were general dentists (87.5%) and worked in private clinics (77.4%). Most respondents (83.5%) showed a fair knowledge of the CAs used in endodontics, while 16.5% showed a poor knowledge of the topic. Small yet significant differences were found between endodontists and general practitioners and between dentists employed by private and government-funded clinics. A majority of dental practitioners (83%) demonstrated a positive attitude towards the use of CAs in endodontic treatment, and there were no differences among the study subgroups. Almost a third of the respondents always used chelating solutions during endodontic treatment, while 17% of the respondents did not use them at all. There were significant differences in this parameter between dentists working in private and government-funded clinics. Practice significantly correlated with attitude towards chelating agents and with knowledge of the topic. In conclusion, dental practitioners demonstrated a fair knowledge of CAs. Despite a positive attitude, 71% of the respondents did not use CAs for all endodontic patients.

Dentinal Tubule Penetrability and Bond Strength of Two Novel Calcium Silicate-Based Root Canal Sealers

BACKGROUND

Once the chemo-mechanical preparation of root canals is finished, achieving a complete seal of the root canal system becomes crucial in determining the long-term success of endodontic treatment. The important goals of root canal obturation are to minimize leakage and achieve an adequate seal. Thus, a material that possesses satisfactory mechanical characteristics, is biocompatible, and has the ability to penetrate the dentine tubules adequately is needed.

AIM

This study aimed to compare the penetrability and bond strength between two calcium silicate-based sealers and an epoxy resin-based sealer, as well as examine the relationship between penetrability and bond strength for the different sealers.

METHOD AND MATERIALS

Thirty-nine recently extracted single-rooted human premolar teeth were instrumented and divided evenly into three groups (n = 13), according to the sealer used for obturation: AH Plus Jet, EndoSequence, and AH Plus Bioceramic Sealer. Three teeth (30 slices) were randomly selected out of each for analysis using confocal laser scanning microscopy to assess penetrability. The remaining ten teeth (90 slices) in each group were subject to push-out tests using a universal testing machine. All teeth were sectioned into nine transverse slices of 0.9 mm thickness for their respective tests (apical, middle, coronal).

RESULTS

AH Plus Jet exhibited significantly lower penetrability and significantly higher bond strength compared to EndoSequence BC sealer (p = 0.002) and AH Plus Bioceramic Sealer (p = 0.006). There was no significant difference between EndoSequence BC sealer and AH Plus Bioceramic Sealer in terms of either penetrability or bond strength. No correlation was found between penetrability and bond strength.

CONCLUSIONS

Within the limitation of this study and regardless of the location in the canal, the bioceramic based root canal sealers appeared to perform better than the epoxy resin-based sealer in terms of dentinal penetration rate. Further studies are required to compare other biomechanical properties of bioceramic sealers including setting characteristics and bacterial leakage.

Evolution of the combined effect of different irrigation solutions and activation techniques on the removal of smear layer and dentin microhardness in oval-shaped root canal: An in-vitro study

The aim of this in vitro study was to evaluate the effect of three final irrigants, namely QMix, MTAD and EDTA, combined with three irrigation techniques, namely conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI) and photon-induced photoacoustic streaming (PIPS), on smear layer removal, dentin mineral content and microhardness in oval-shaped canals.    130 decoronated premolars with single, oval root canals were equally divided into1 blank control group and 12 treatment groups (n=10) according to the final irrigation protocols. Roots in treatment groups were instrumented with ProTaper Gold to size F4 and subjected to final irrigation. Smear layer removal was assessed by using a four-level scoring system under an environmental scanning electron microscope. Energy dispersive X-ray spectroscopy was performed to measure the dentin mineral content. Dentin microhardness was measured by Knoop microhardness testing. Statistical analysis of the data was performed by using Kruskal-Wallis test, followed by Dunn's post hoc test with Bonferroni correction. PUI- and PIPS-activated QMix and EDTA removed smear layer more effectively than MTAD groups (p<0.05). Regarding the dentin mineral content and microhardness, QMix groups yielded the least calcium (Ca), phosphorus (P)  and Ca/P ratio, followed by EDTA groups and MTAD groups (p<0.05). QMix groups produced significantly lower dentin microhardness values and higher hardness reduction percentages than MTAD groups (p<0.05).  Within the limitations of the present study, it was concluded that QMix and EDTA were superior to MTAD in smear layer removal, especially when activated by PUI and PIPS, but these agents produced more pronounced effect on dentin mineral content and microhardness than MTAD.

Investigation of the effectiveness of sonic, ultrasonic and new laser-assisted irrigation activation methods on smear removal and tubular penetration

The aim of this study was to examine the effectiveness of different irrigation activation methods on smear layer removal and tubular penetration. One hundred-five distal roots of mandibular molar teeth in total; 50 for smear removal efficiency (n = 10) analysis using scanning electron microscopy (SEM), and 55 roots were used to examine tubular penetration using confocal laser scanning microscope (CLSM). Five different irrigation activation methods were used in this study; conventional needle irrigation (CNI), sonic irrigation device of EDDY, passive ultrasonic irrigation (PUI), PIPS and SWEEPS techniques, which are two different laser irrigation activation methods. The obtained data were statistically analyzed and the significance level was determined as p < 0.05. At the apical level, the cleanest canal walls were observed when laser methods PIPS and SWEEPS were used, while in the middle third, there was no difference in smear removal efficiencies between all groups except for the CNI (p > 0.05). Penetration depths and percentages increased from apically to coronally in all groups. The PUI and EDDY generally showed similar penetration depths and percentages to the CNI, except at the coronal root level (p > 0.05). In all groups, when PIPS was used, it showed greater penetration depth and percentage (p < 0.05). PIPS and SWEEPS techniques showed lowest and similar smear scores compared to PUI and EDDY in the apical area where access and effectiveness of the irrigation solution are difficult.

Comparative evaluation of canal cleanliness at apical third using Self-Adjusting File and Wave One File with different irrigants: an in vitro scanning electron microscopic study

Aim

To evaluate the cleaning ability of two single-file rotary systems- Self-Adjusting File (SAF) and Wave one (WO) systems in removing the smear layer using sodium hypochlorite (NaOCl) + ethylene diamine tetraacetic acid (EDTA) and NaOCl + Qmix as irrigants at apical one-third of the root canal.

Methods

Forty extracted human mandibular premolars were selected and working length was determined. The canal was manually instrumented up to a number 25 size K-file. The roots were divided into the following groups with 10 samples each - Group 1 using SAF: Group 1a- 3% NaOCl + 17% EDTA, Group 1b- 3% NaOCl + Qmix. Group2 using WO: Group 2a- 3% NaOCl + 17% EDTA, Group 2b- 3% NaOCl + Qmix. In the SAF group, the irrigation was performed continuously using the special irrigation apparatus. In the WO group, syringe irrigation was done followed by final irrigant activation using passive ultrasonic irrigation (PUI). The roots were sectioned longitudinally and subjected to scanning electron microscopic (SEM) examination. The amount of smear layer was evaluated using a five score index at the apical third level. Statistical analysis was performed using the Chi-square test.

Results

Group 1 (SAF) showed better canal cleanliness at apical third compared to Group 2 (WO) with both irrigant combinations and the results were statistically significant (p<0.05). 3% NaOCl + Qmix was equally as effective as 3% NaOCl + 17% EDTA in removing the smear layer with no significant difference between them.

Conclusion

Within the limitation of this study, SAF in combination with 3% NaOCl + Qmix or 3% NaOCl + 17% EDTA should be used for removing smear layer in critical areas of the root canal.

Impact of antimicrobial photodynamic therapy on the bond-strength and penetration of endodontic sealers: A systematic review

BACKGROUND

Antimicrobial photodynamic therapy (aPDT) has been used for the disinfection of root canals. Studies have been carried out on its effect on the bond-strength and penetration of endodontic sealers. The aim of this systematic review is to critically analyze the literature and summarize the outcomes of these studies.

MATERIALS AND METHODS

An electronic search was conducted on research databases PubMED/Medline, ISI Web of Knowledge, Embase, Scopus and Europe PMC using the following the medical subject headings (MeSH) terms and keywords: [((endodontic sealer) OR (endodontic sealant) OR (root canal sealer)) AND ((anti-microbial photodynamic therapy) OR (laser-assisted) OR (light-assisted) OR (photosensitive dye) OR (photosensitizer)) AND ((bond-strength) OR (penetration))] for all literature published from inception to September 2022. Clinical studies, animal studies, laboratory investigations and case reports were included. Data was extracted and the quality of the included studies was assessed.

RESULTS

Of the 204 studies screen initially, 12 laboratory studies were included in this review. Majority of the outcomes revealed that aPDT does not have an adverse impact on the bond-strength or sealer penetration. Furthermore, AH Plus (an epoxy-based sealer) resulted in higher bond-strengths than other types of sealers (MTA Fillapex, Sealapex and Bioceramics). 11 studies were graded as having 'medium' quality and one study was graded as 'low'.

CONCLUSION

Within the limitations of this review, aPDT does not have a significant impact on the bonding and penetration of endodontic sealers. Future studies should focus on standardization and optimization of aPDT procedures when assessing their impact on the interaction between sealers and dentine.

Comparison of sealer penetration of sonic activation versus conventional needle irrigation: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Most existing studies comparing the efficiency of sonic irrigation (SI) and conventional needle irrigation (CNI) in increasing the penetration of sealers into dentine tubules are controversial; and this study aimed to determine whether the use of SI can lead to greater sealing ability than CNI, during the root canal treatment.

METHODS

The EMBASE, PubMed, and Cochrane Library databases were used to find confocal laser scanning microscopy studies evaluating percentage and maximum depth of sealer penetration following the use of SI or CNI in mature permanent teeth until October 2022. The critical estimative checklist of randomized controlled trials of the standardized Joanna Briggs Institute was adopted to independently score the quality of each study. The random-effect model for meta-analysis was used to analyse for each canal segment (apical, middle, coronal). The results are shown in the forest plots as weighted mean differences (WMDs) with 95% confidence intervals (95% CIs).

RESULTS

Ninety-seven articles were included in the preliminary screening, and nine of them were included in this study. Eight studies were included in the meta-analysis.The meta-analysis exhibited great increases in the coronal (WMD: 8.09, 95% CI 2.78-13.40/WMD: 165.32, 95% CI 128.85-201.80), and middle segments (WMD: 8.81, 95% CI 5.76-11.87/WMD: 132.98, 95% CI 68.71-197.25) for the percentage and maximum depth of sealer penetration, respectively. The percentage of sealer penetration in the apical thirds region was nonsignificant (WMD: 4.73, 95% CI - 2.34-11.80). However, the maximum depth of sealer penetration in the apical thirds region was significant (WMD: 121.46, 95% CI 86.55-156.38). Chi-squared analysis revealed heterogeneity scores of 0.0-70.0% and 44.0-90.0% for the percentage and maximum depth of sealer penetration, respectively.

DISCUSSION

This review verified that SI significantly improves tubular dentin sealer penetration in most areas of the root canal; thus, SI may lead to better filling efficiency and anti-reinfection effects than CNI during and after the root canal therapy. Nevertheless, a large heterogeneity in the current data comparing the irrigation efficiency of SI versus CNI in the apical third of the root canal was found, implying the necessity to standardize root canal irrigation procedures and obtain more accurate results in this area.

TRIAL REGISTRATION

INPLASY database (INPLASY202270116).

Efficacy of Different Endodontic Irrigant Activation Systems on Smear Layer Removal and Canal Cleanliness: Comparative Scanning Electron Microscopic Study

AIM: This study assessed the effectiveness of 5 different irrigant activation systems on canal cleanliness and removal of smear layer from root canals. METHODS: A total of 110 mandibular premolars with straight root canal were assigned to five groups (n = 20): conventional needle irrigation, passive ultrasonic activation, sonic activation with EndoActivator, negative apical pressure EndoVac (EV), or EDDY system, besides a control group (n = 10). All teeth were prepared to size 40, and irrigated with NaOCl (5.25%) according to the respective technique. Roots were split longitudinally and subjected to scanning electron microscopic analysis. The presence of smear layer and debris was evaluated using 5-grade scoring systems with ×1000 and ×400 magnification, respectively. Data were analyzed at 5%. RESULTS: Regarding the smear layer, activation with EV and ED was significantly more effective than other activation groups (p < 0.05). Activation of the irrigant significantly improved removal of debris (p < 0.05). CONCLUSION: No activation technique was able to eliminate smear layer and debris completely from root canals, nevertheless, EDDY is significantly better in removing debris and smear layer from the apical third of the canal.

Influence of chelating solutions on tubular dentin sealer penetration: A systematic review with network meta-analysis

This systematic review assessed the influence of conventional final irrigation with chelating solutions (CS) on tubular dentin sealer penetration (TDSP). The literature search was conducted in eight electronic databases using MeSH, DeCS, EMTREE and free terms. The study protocol followed the PRISMA guidelines and was registered on the PROSPERO database (CRD42020203080). Twelve studies were included, and a qualitative synthesis and network meta-analysis of the data were performed. The risk of bias of the studies was assessed using an adaptation of the JBI Critical Appraisal tool. QMix was the solution with the highest probability of having the highest percentage of TDSP in the apical (34.1%), middle (86.5%) and coronal (97.7%) thirds. Eleven studies presented a moderate risk of bias, whereas one study presented a high risk of bias. In conclusion, CS improves sealer penetration into the dentinal tubules with QMix demonstrating superior results.

Assessment of Real-Time Operative Torque during Nickel–Titanium Instrumentation with Different Lubricants

The aim of the present study is twofold: to assess ex vivo the role of different lubricants on real-time torque generated during intracanal instrumentation and to check whether two different kinds of torque parameters, operative torque (OT) and average peak torque (APT), could produce similar results. Forty extracted single-rooted teeth were selected for the present study and divided into four equal groups (n = 10): Group A, NaCl 0.2%; Group B, NaOCl 5%; Group C, ethylenediaminetetraacetate (EDTA), and Group D, EDTA and hydrogen peroxide. Afterwards, Edge Taper F2 (Edge Endo, Albuquerque, New Mexico) were rotated clockwise at 300 rpm with 3 Ncm maximum torque by an endodontic torque recording motor. In each sample, mean OT and mean APT were recorded and statistically analyzed with one-way ANOVA and a post hoc Bonferroni between groups (p < 0.05). EDTA (12.11 ± 4.45 Ncm) showed statistically significant (p < 0.05) lower values compared with the other tested irrigant for both parameters. Overall, the two different parameters were both able to differentiate between the influence of lubricants on torsional loads.

In vitro Evaluation of the Antimicrobial Effect of N-acetylcysteine and Photodynamic Therapy on Root Canals Infected with Enterococcus faecalis

Introduction

This study aimed to evaluate the in vitro effectiveness of N-acetylcysteine (NAC), photodynamic therapy (PDT) and NAC with supplemental PDT in optimizing the removal of bacteria from infected dentinal tubules of root canals infected with Enterococcus (E.) faecalis biofilm.

Methods and Materials

Eighty human teeth were randomly divided into 5 groups (n=16) according to the intracanal medication used: saline solution (control); calcium hydroxide (CH); NAC; PDT; NAC+PDT. Ten samples from each group were prepared for microbiological culture analysis (CFU/mL) and were inoculated with E. faecalis suspension for 21 days for biofilm development; the other six samples from each group were prepared for scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) and submitted to a 5-days contamination protocol including eight centrifugation cycles on every other day for dentinal tubules infection. For antimicrobial activity analysis by microbiological culture (CFU/mL), the root canals were contaminated with E. faecalis biofilm, instrumented and then medicated according to the experimental groups. Three samples were collected from the root canals: after 21-days of contamination, immediately after the instrumentation and 14-days after the medication according to the experimental groups. The morphology of E. faecalis biofilm on the root canal walls and bacterial cells viability were assessed by means of SEM and CLSM, respectively. One-way ANOVA and Repeated Measures ANOVA tests were used to analyze the obtained data statistically.

Results

CFU/mL analysis showed that CH, NAC and NAC+PDT promoted greater antibacterial activity with statistically significant difference compared to saline solution and PDT (P<0.0001). However, saline solution and PDT were statistically similar (P>0.07). Illustrative images by SEM confirmed partially the CFU/mL results. CLSM showed that all groups were effective eliminating E. faecalis except for the saline solution group.

Conclusions

Based on this in vitro study NAC was bactericidal against E. faecalis biofilms regardless PDT stimulation, presenting similar antimicrobial activity to CH.