Influence of passive ultrasonic irrigation on the efficiency of various irrigation solutions in removing smear layer: a scanning electron microscope study

Did in-between rinsing and agitating with distilled water prevents precipitate formation by the interaction between sodium hypochlorite and chlorhexidine canal irrigants?

The interaction of sodium hypochlorite (NaOCl) and chlorhexidine gluconate (CHX) produces an orange-brown precipitate. The present study evaluated the influence of distilled water (H2 O) in different irrigation protocols designed to prevent the formation of precipitate with NaOCl and CHX. Fifty canine teeth were instrumented and split longitudinally. The canal was examined with a stereomicroscope and photographed by canal-thirds. The tooth halves were repositioned and distributed randomly into five groups, according to the final irrigation protocol (n = 10): G1 (control)-Ethylenediaminetetraacetic acid (EDTA) + NaOCl + CHX, conventional irrigation (CI); G2-EDTA + NaOCl + CHX, activated with passive ultrasonic irrigation (PUI); G3-EDTA (PUI) + NaOCl (PUI) + H2 O (CI) + CHX (PUI); G4-EDTA + NaOCl + H2 O + CHX (PUI); G5-EDTA (PUI) + NaOCl (PUI) + H2 O (continuous ultrasonic irrigation [CUI]) + CHX (PUI). The specimens were evaluated with a stereomicroscope and scanning electron microscope (SEM). Energy dispersive x-ray spectroscopy analysis was performed to identify the elemental profile of the irrigated canal walls. The images were scored according to the extensiveness of precipitate. Data were analyzed (Kruskal-Wallis test, α = 5%). Under the stereomicroscope, G1 had significantly higher scores than all the other groups in all canal-thirds (p < .05). All four experimental groups showed similar scores (p > .05). There were no significant differences in precipitate formation among root-thirds in intragroup analysis (p > .05). Upon SEM examination, overall, only G5 had lower scores than G1 (p < .05). Analysis by canal-thirds showed no significant difference among groups and among canal-thirds in the intragroup analysis (p > .05). G1 showed high Cl peaks. In-between irrigation with H2 O activated by CUI is effective in preventing precipitate formation during canal debridement with NaOCl and CHX. RESEARCH HIGHLIGHTS: Continuous ultrasonic irrigation with distilled water was capable to prevent the precipitate formation. The precipitate can be classified as a chemical smear layer.

Effect of Different Irrigant Activation Techniques on the Penetration of Calcium Hydroxide, an Intracanal Medicament: An In Vitro Study

Background and objective The main goal of root canal treatment is to eliminate microorganisms from the canal and to prevent re-infection. To achieve these goals, instrumentation must be combined with adequate irrigation and the placement of intracanal medicament. This study aims to compare the effect of different irrigation activation techniques, i.e., passive ultrasonic irrigation (PUI), EndoActivator (EA), and conventional needle irrigation on the penetration of calcium hydroxide (CH), an intracanal medicament into dentinal tubules. Methodology A total of 60 single-rooted extracted human teeth were selected, which were de-coronated to standardize the root length of 12 mm. An access cavity was prepared, and biomechanical preparation was done. The samples were randomly assigned to three experimental groups: Group I received conventional needle irrigation, Group II underwent EA irrigation, and Group III was subjected to PUI. All the samples were filled with CH paste mixed with Rhodamine B dye, and the orifice openings were sealed with Cavit. The samples were stored in an incubator for 24 hours and were subsequently sectioned horizontally at the coronal, middle, and apical thirds using a hard tissue microtome. These were observed under a confocal laser scanning microscope to evaluate the depth of medicament penetration. Statistical analysis was performed using IBM SPSS Statistics for Windows, Version 25.0 (IBM Corp., Armonk, NY). The Shapiro-Wilk test was employed to assess normality, while ANOVA and Tukey's post hoc analysis were utilized to determine significance. Results It was observed that the depth of penetration of CH into dentinal tubules was highest in Group III (PUI), followed by Group II (EA irrigation), with the least penetration observed in Group I (conventional needle irrigation). All the groups showed maximum penetration at the coronal third followed by the middle and apical third. Conclusions Passive ultrasonic irrigant activation resulted in more penetration of CH into the dentinal tubules followed by EA irrigant activation.

Evaluating the Effectiveness of Different Irrigant Activation Techniques in Removing the Smear Layer and Opening the Dentinal Canals: A Scanning Electron Microscopic Study

Background Although irrigation is one of the most important stages during root canal treatment, it is not possible to guarantee the entry of irrigants to all the areas in the root canal, especially in the apical third. Therefore, the activation of irrigants can stimulate and help the irrigants to access hard-to-reach places within the root canal system. Therefore, this study aimed to evaluate the opening of the dentinal canals with scanning electron microscopy (SEM) using different irrigant activation techniques, such as intracanal heating activation, sonic activation, and ultrasonic activation, along the walls of the root canals in the coronal, middle, and apical thirds. Methodology The study sample consisted of 36 single-canal premolars, which were randomly divided into the following three equal groups according to the method of activation used: group 1 (n = 12), which involved heating activation inside the root canals, group 2 (n = 12), which involved sonic activation, and group 3 (control; n = 12), which involved ultrasonic activation. Afterward, dental crowns were cut to standardize the working length by 18 mm and were then prepared using the ProTaper Next system up to size X2. Moreover, the irrigant was activated for each group separately, and the teeth were extracted and prepared for SEM. Three images were taken for each sample (i.e., coronal third, middle third, and apical third) at ×2,000 magnification. Data were analyzed using the Mann-Whitney U test. Results When studying the removal of the smear layer and the opening of the dentinal canal under ×2,000 magnification, there were no statistically significant differences in the coronal and middle third between the three studied groups. However, statistically significant differences were found in the apical third, where the ultrasonic activation group was the best, followed by the sonic activation group, and the heating activation group. Conclusions All methods of activation were effective in removing the smear layer and opening the dentinal canals with the advantage of ultrasonic activation in the rest of the groups. The intracanal heating irrigant activation proved to be similar to the effectiveness of sonic activation and close to ultrasonic activation.

Efficient removal of 2,6-xylidine precipitate using different agitation protocols: An in vitro field emission scanning electron microscopic study

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Effect of different irrigation protocols for applications in regenerative endodontics on mechanical properties of root dentin

The objective of this study was to evaluate the effect of different concentrations of NaOCl with and without passive ultrasonic irrigation (PUI) on mechanical properties of human dentin for applications in regenerative endodontics (RE). Sixty single-rooted teeth were sectioned into 2 halves (n = 120). Dentin bars were produced from one half for flexural strength and the other half was used for microhardness. Specimens were randomly assigned into 10 groups: G1 and G2 (control): distilled water for 30 and 60 min, respectively; G3: 1.5%NaOCl for 30 min; G4:1.5%NaOCl for 60 min; G5: 1.5%NaOCl + PUI for 30 min; G6: 1.5%NaOCl + PUI for 60 min; G7: 5.25%NaOCl for 30 min; G8: 5.25%NaOCl for 60 min; G9: 5.25%NaOCl + PUI for 30 min; G10: 5.25%NaOCl + PUI for 60 min. An increase in NaOCl concentration showed highly significant reduction in mechanical properties. There was no significant difference between 1.5% NaOCl and control group except for specimens treated with PUI for 60 min. NaOCl in concentrations recommended for RE did not have a significant effect on mechanical properties of dentin. However, PUI with increased irrigation time might have an effect even with low NaOCl concentration.

Smear Layer Removal Using Passive Ultrasonic Irrigation and Different Concentrations of Sodium Hypochlorite

INTRODUCTION

The present study evaluated the effect of passive ultrasonic activation (PUI) of EDTA solution followed by conventional irrigation with 2 concentrations of sodium hypochlorite (NaOCl) on smear layer removal.

METHODS

Fifty single-root mandibular premolars were chemomechanically prepared with ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium rotary instruments and 1% NaOCl. The roots were cleaved, and the dentin surfaces were analyzed with scanning electron microscopy operated at a low vacuum. Images were obtained from previously demarcated areas in each root canal third. The teeth were reassembled and distributed into 5 groups according to the final irrigation protocols (n = 10): group 1, EDTA/PUI + 1% NaOCl; group 2, EDTA/PUI + 5% NaOCl; group 3, EDTA/CI + 1% NaOCl; group 4, EDTA/CI + 5% NaOCl; and group 5 (negative control), saline solution/PUI. After irrigation, the teeth were reseparated and prepared for conventional high-vacuum scanning electron microscopy of the same dentin surface that was previously analyzed. The amount of debris was classified using a 4-point scoring system. Data were analyzed with Kruskal-Wallis and Dunn tests at α = 0.05.

RESULTS

Groups 1 and 2, which used PUI and different concentrations of NaOCl, were not significantly different; however, they differed significantly from group 3 (P < .05). With respect to canal cleanliness at different root thirds, all groups showed the worst cleaning at the apical third.

CONCLUSIONS

PUI activation of the EDTA irrigant is required when canal debridement is performed with EDTA and a lower concentration of NaOCl.

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

This study aimed to compare the effect of conventional irrigation (CI) and passive ultrasonic irrigation (PUI) with 17% EDTA and QMiX on the maximum depth and percentage of sealer penetration into the dentinal tubules by confocal laser scanning microscopy (CLSM) and to describe the cleaning of root canal walls by scanning electron microscopy (SEM). Eighty single-rooted human mandibular premolars were instrumented and randomly assigned to four groups (n = 20): EDTA + CI, QMiX + CI, EDTA + PUI, and QMiX + PUI. Ten samples from each group were examined by SEM (2,000×) and the remaining 40 roots were filled with a single gutta-percha cone and AH Plus sealer mixed with 0.1% rhodamine B for analysis by CLSM (10×). Images were assessed at distances of 2 mm (apical), 5 mm (middle), and 8 mm (coronal) from the apex with the Leica Application Suite V4.10 software. The EDTA + PUI and QMiX + PUI protocols presented higher rates of debris/smear layer removal in the apical and middle thirds. The PUI was superior to CI in the maximum depth of sealer penetration at the middle third. The QMiX + PUI group had a higher percentage of sealer penetration at the apical third. The PUI and QMiX protocol improved debris/smear layer removal and tubular dentin sealer penetration.

Effect of QMix irrigant in removal of smear layer in root canal system: a systematic review of in vitro studies

Objectives

To evaluate the outcome of in vitro studies comparing the effectiveness of QMix irrigant in removing the smear layer in the root canal system compared with other irrigants.

Materials and Methods

The research question was developed by using Population, Intervention, Comparison, Outcome and Study design framework. Literature search was performed using 3 electronic databases PubMed, Scopus, and EBSCOhost until October 2019. Two reviewers were independently involved in the selection of the articles and data extraction process. Risk of bias of the studies was independently appraised using revised Cochrane Risk of Bias tool (RoB 2.0) based on 5 domains.

Results

Thirteen studies fulfilled the selection criteria. The overall risk of bias was moderate. QMix was found to have better smear layer removal ability than mixture of tetracycline isonomer, an acid and a detergent (MTAD), sodium hypochlorite (NaOCl), and phytic acid. The efficacy was less effective than 7% maleic acid and 10% citric acid. No conclusive results could be drawn between QMix and 17% ethylenediaminetetraacetic acid due to conflicting results. QMix was more effective when used for 3 minutes than 1 minute.

Conclusions

QMix has better smear layer removal ability compared to MTAD, NaOCl, Tubulicid Plus, and Phytic acid. In order to remove the smear layer more effectively with QMix, it is recommended to use it for a longer duration.

Effect of ultrasonic and Nd: Yag laser activation on irrigants on the push-out bond strength of fiber post to the root canal

OBJECTIVE

This in vitro study aimed to compare the efficacy of irrigants using various irrigation activation methods to the push-out bond strengths of fiber post to root canal luted with self-adhesive resin cement (SARC).

METHODOLOGY

Forty-eight decoronated human canines were used. The specimens were divided into four groups corresponding with the post-space irrigation process and were treated as follows: distilled water (DW) (Control) group received 15 mL of DW; sodium hypochlorite (NaOCl)+ethylenediaminetetraacetic acid (EDTA) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of DW; passive ultrasonic irrigation (PUI) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of DW, and each irrigant was agitated with an ultrasonic file; and laser activated irrigation (LAI) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of DW, and each irrigant was irradiated with Nd: YAG laser. Fiber posts were luted with SARC, and a push-out test was performed. Data was analyzed using one-way analysis of variance and Tukey HSD test.

RESULTS

The bond strength values for the groups obtained were as follows: Control (10.04 MPa), NaOCl+EDTA (11.07 MPa), PUI (11.85 MPa), and LAI (11.63 MPa). No statistically significant differences were found among all experimental groups (p>0.05). The coronal (12.66 MPa) and middle (11.63 MPa) root regions indicated a significantly higher bond strength compared with the apical (9.16 MPa) region (p<0.05).

CONCLUSIONS

Irrigant activation methods did not increase the bond strength of fiber post to canal.

Passive Ultrasonic Irrigation Efficacy in the Vapor Lock Removal: Systematic Review and Meta-Analysis

Passive Ultrasonic Irrigation (PUI) represents one of the most used systems to improve the endodontic irrigants activity. PUI acts increasing the reaction rate of NaOCl, with an increase of dentinal debris and smear layer removal. There is a stronger shear stress and a vapor lock reduction. Aim of this systematic review was to figure out the effects of the PUI on the vapor lock removal, during irrigation. Literature research has been carried out by two reviewers, consulting online databases such as PubMed, EBSCO, and Google Scholar, using keywords like Vapor Lock, Vapour Lock, and Vapor Lock Endodontic. The articles list has been screened based on titles and abstracts, applying eligibility and inclusion criteria. The three articles were eligible for quantitative and statistical analysis, by using RevManager Software Version 5.3. Results show statistical heterogeneity (P=0.08; I² index=61%) in the vapor lock elimination between the use of PUI and PPI, with an overall Odds Ratio=0.08, CI=95% [0.03;0.25]. PUI resulted to be a useful technique to improve NaOCl activity for vapor lock removal, despite PPI alone using a needle.