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Cleaning and shaping the root canal system are essential steps for performing successful endodontic therapy, and are challenging procedures in the apical region. This study aimed to conduct an ex vivo assessment of the debridement ability of the WaveOne Gold (Medium 35/.06) and TruNatomy (Medium 36/.03) systems in the apical third of round root canals of mandibular premolars. Forty-eight teeth, extracted for orthodontic or periodontal reasons, were divided into three groups (n=16), as follows: Group C, control (without instrumentation or irrigation); Group WOG, instrumentation with WaveOne Gold; Group TN, instrumentation with TruNatomy. A total of 40 mL of 2.5% sodium hypochlorite and 5 mL of 17% ethylenediamine tetraacetic acid were used per root canal in all the groups. Ten 0.5-μm serial cross-sections per specimen were obtained every 0.2 mm from a 2-mm segment of the apical region, extending from 1 to 3 mm short of the root apex. The sections were stained with hematoxylin-eosin and analyzed under a digital microscope (100x). The percentages of unprepared walls and remaining debris were quantified using ImageJ software. Generalized linear models were used to analyze the results (α=5%). Groups WOG and TN had significantly lower percentages of unprepared walls and remaining debris than Group C (p<0.05). There was no significant difference between groups WOG and TN for either of the variables studied (p>0.05). Instrumentation with the WaveOne Gold Medium and TruNatomy Medium instruments was associated with equivalent percentages of unprepared walls and remaining debris in the apical third of round canals of mandibular premolars.

To use scanning electron microscopy and energy dispersive X-ray spectroscopy to evaluate the metallurgical-chemical changes of WaveOne Gold (WOG) and R-Motion (RM), after multiple uses. The instruments were divided into groups (n = 8): WOG and RM-control groups, new instruments; WOG1 and RM1; WOG2 and RM2; WOG3 and RM3 after instrumentation of 1, 2 or 3 molars, respectively. Burrs occurred mainly in the control group and after the first use. The RM files were found to have a higher nickel content, which increased during reuse, and a decrease in oxygen content with increasing reuse, in addition to calcium impregnation, which occurred in greater amounts in the corrosion areas in the WOG files. The presence of topographic and chemical changes was demonstrated, indicating that caution should be taken when reusing endodontic instruments to avoid fractures., (© 2024 Australian Society of Endodontology Inc.)

Introduction: This study aimed to compare the effectiveness of two endodontic cleaning techniques, passive ultrasonic irrigation (PUI) and the XP-endo Finisher R (XPR) system, in removing residual filling material during endodontic retreatment procedures., Materials and Methods: Forty mandibular premolars with oval canals were divided into four groups based on the sealer used (AH-Plus or Bio-C Sealer) and the cleaning technique employed (PUI or XPR). To ensure uniformity of canal volume among groups, initial micro-CT scans were conducted. The canals were instrumented, filled, and then re-instrumented before undergoing either PUI or XPR cleaning techniques. Residual filling material volumes were assessed through micro-CT scans, and statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney U tests., Results: Following instrumentation, there was no significant difference in residual filling material volumes between AH-Plus and Bio-C Sealer groups (1.35 mm 3 and 1.02 mm 3 , respectively; P >0.05). However, after supplementary cleaning techniques, XPR-cleaned specimens exhibited significantly less residual material compared to PUI-cleaned specimens (0.01 mm 3 and 0.29 mm 3 for Bio-C Sealer, and 0.07 mm 3 and. 0.30 mm 3  for AH-Plus, P <0.05)., Conclusion: The XPR system was found to be more effective than PUI in removing residual filling material from Bio-C Sealer-filled root canals. This highlights its potential as a useful supplementary cleaning technique in endodontic retreatment procedures., Competing Interests: None.

The aim of this study was to histologically verify the performance of pulp-derived stem cells used in the pulp-dentin complex regeneration. Maxillary molars of 12 immunosuppressed rats were divided into two groups: the SC (stem cells) group, and the PBS (just standard phosphate-buffered saline) group. After pulpectomy and canal preparation, the teeth received the designated materials, and the cavities were sealed. After 12 weeks, the animals were euthanized, and the specimens underwent histological processing and qualitative evaluation of intracanal connective tissue, odontoblast-like cells, intracanal mineralized tissue, and periapical inflammatory infiltrate. Immunohistochemical evaluation was performed to detect dentin matrix protein 1 (DMP1). In the PBS group, an amorphous substance and remnants of mineralized tissue were observed throughout the canal, and abundant inflammatory cells were observed in the periapical region. In the SC group, an amorphous substance and remnants of mineralized tissue were observed throughout the canal; odontoblasts-like cells immunopositive for DMP1 and mineral plug were observed in the apical region of the canal; and a mild inflammatory infiltrate, intense vascularization, and neoformation of organized connective tissue were observed in the periapical region. In conclusion, the transplantation of human pulp stem cells promoted partial pulp tissue neoformation in adult rat molars.

This study assessed the influence of apical preparation size and final irrigation protocol on the debridement of the apical third of oval root canals of mandibular molars. Seventy-seven distal roots were divided into 7 groups (n = 11): Control: without instrumentation or irrigation; Group 30CI: ProTaper Next (up to size 30; PTN) + conventional irrigation (CI); Group 30UAI: PTN + ultrasonically activated irrigation (UAI); Group 30XPF: PTN + XP-endo Finisher (XPF); Group 40CI: PTN + ProDesign Logic (up to size 40; PDL) + CI; Group 40UAI: PTN + PDL + UAI; and Group 40XPF: PTN + PDL + XPF. The total volume of irrigating solutions used per root canal in all the experimental groups was 33 mL of 2.5% sodium hypochlorite (NaOCl) and 6 mL of 17% ethylenediaminetetraacetic acid (EDTA). After specimen processing and histological analysis under a digital microscope (100x), the percentages of untouched canal walls (UCW) and remaining debris (RD) were assessed using Image J software. A descriptive and exploratory analysis was conducted, indicating that the data failed to meet the assumptions of an analysis of variance. Therefore, generalized linear models were used to assess the effects of the different instrumentation and irrigation protocols, as well as the interaction among them, on the percentage of UCW and RD. No significant difference was found among the irrigation protocols regarding the percentage of UCW, irrespective of apical preparation size (p>0.05). However, UCW and RD were significantly lower in groups 40CI, 40UAI and 40XPF than in groups 30CI, 30UAI and 30XPF (p<0.05). The percentage of RD was significantly lower in the UAI and XPF groups than in the CI groups, irrespective of apical preparation size (p<0.05). The difference between preparation sizes 30 and 40, with respect to RD, was higher when CI was used (p<0.05). In conclusion, instrumentation up to apical preparation size 40 resulted in lower percentages of UCW and RD than up to apical preparation size 30. Use of UAI or XPF resulted in lower percentages of RD than CI.

Introduction: The aim of this study was to compare the efficacy of passive ultrasonic irrigation (PUI) versus mechanical agitation of the irrigant promoted by the EasyClean (EC) and XP-Endo Finisher (XP-F) systems in removing debris from root canal walls, using environmental scanning electron microscopy (ESEM)., Methods and Materials: Twelve curved mesiobuccal canals of mandibular molars were prepared with the ProTaper Next system up to file X2 (25/0.06). The specimens were embedded in flasks containing silicone putty, sectioned lengthwise, and a 4-mm long groove was made on the canal wall of the buccal half of the specimen, extending from 2 mm up to 6 mm short of the apex. Five cross-sectional markings were made along this groove to establish standardized locations for imaging. The same specimens were used to prepare a negative control group (without debris), a positive control group (completely covered by debris), and 3 experimental groups according to the final irrigation protocol employed: PUI, EC or XP-F. ESEM images were obtained and evaluated by 3 examiners. The amount of debris observed on the images was classified according to a 4-category scoring system. The kappa test was used to assess inter-examiner agreement, and the Kruskal-Wallis and Dunn tests were used to compare the scores ( P <0.05)., Results: The scores attributed to the PUI, EC, and XP-F groups were statistically similar to those attributed to the negative control group ( P >0.05)., Conclusion: Based on this in-vitro study, the mechanical agitation of the irrigant promoted by EC and XP-F was as effective as using PUI to remove debris from the root canal walls., Competing Interests: ‘None declared’., (© The Author(s).)

Introduction: The aim of this study was to conduct a micro-computed tomographic assessment of the effectiveness of 3 supplementary cleaning techniques in reducing the residual volume of gutta-percha and a bioceramic sealer after performing endodontic retreatment procedures in teeth with oval canals., Methods: Thirty-six mandibular premolars were instrumented with the ProTaper Next system (instruments X1-X3; Dentsply Maillefer, Ballaigues, Switzerland) and filled with gutta-percha and Bio-C Sealer (Angelus, Londrina, PR, Brazil) using the single-cone technique. The teeth were reinstrumented with the Reciproc R40 instrument (VDW, Munich, Germany) and divided into 3 groups according to the supplementary cleaning technique used (n = 12): ultrasonic-assisted irrigation (UAI), EndoActivator (Dentsply Tulsa Dental Specialties, Tulsa, OK) irrigation (EAI), or the XP-endo Finisher R system (XPR; FKG Dentaire, La Chaux-de-Fonds, Switzerland). Micro-computed tomographic imaging was used to quantify the residual volume of filling material. One-way analysis of variance complemented by the Tukey test was used to perform the statistical analysis (P < .05)., Results: Significant reductions were obtained in the residual filling material after supplementary cleaning (P < .05). XPR (47.5%) led to significantly greater (P < .05) filling material removal than UAI (16.6%) or EAI (22.6%). The removal values of the 2 latter systems were not significantly different., Conclusions: XPR was more effective than UAI and EAI in removing filling material in mandibular premolars with oval canals. None of the tested supplementary cleaning techniques completely removed the residual filling material., (Copyright © 2020 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to compare the root canal instrumentation techniques that involve foraminal enlargement versus those not involving it, in regard to the apical extrusion of filling material, using micro-computed tomography (micro-CT). Twenty-two premolars with single canals were instrumented using the ProTaper Universal System and then randomly divided into two groups (n = 11): Group NFE, without foraminal enlargement, and Group FE, with foraminal enlargement. Instrumentation was performed up to 1 mm short of the apical foramen, and foraminal patency was maintained at each instrument change in both groups. Prior to obturation, the apical portion of the specimens was wrapped in adhesive paper to ensure complete separation between apex and extruded material. The canals were filled according to the continuous wave of condensation technique. The apically extruded material was collected and measured using micro-CT. Extrusion in Group FE was significantly higher than in Group NFE (0.928 mm 3 vs. 0.148 mm 3 ; P < 0.001)., (© 2020 Australian Society of Endodontology Inc.)

Aim: To compare the shaping ability of four instrumentation systems in curved molar root canals, using computerized microtomography (micro-CT)., Methodology: Forty mesial roots of mandibular molars were submitted first to radiographic examination to determine their curvature and then to a micro-CT scan to analyse other initial morphological characteristics. The specimens were distributed into four experimental groups, according to the endodontic instrumentation system used (n = 10): Group R, Reciproc; Group PTN, ProTaper Next; Group WOG, WaveOne Gold; Group PDL, ProDesign Logic. After root canal instrumentation, the specimens were submitted to a second micro-CT scan, and the pre- and postoperative data were examined to evaluate the following parameters: volume of dentine removed (DR), increase in root canal volume (VI), untouched root canal surface area (UA), volume of accumulated hard tissue debris (AD) and structure model index (SMI). The data observed for these parameters after instrumentation were analysed using generalized linear models. R software was used for the analyses, and the level of significance adopted was 5%., Results: There were no significant differences among the instrumentation systems regarding the DR, VI, UA and AD parameters (P > 0.05). PTN and WOG systems were associated with greater increases in SMI than the PDL system (P < 0.05)., Conclusions: The four systems evaluated were similar regarding the parameters analysed, with the exception of the SMI, with the rate of variation of this parameter being greater after using the PTN and WOG systems than after using the PDL system. These results indicate that the four systems perform similarly in terms of their shaping ability, but that the PTN and WOG systems produced more rounded preparations than the PDL system., (© 2019 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Introduction: The objective of this study was to compare the methods of micro-computed tomography (micro-CT) and cross-sectioning followed by stereomicroscopy in assessing dentinal defects after instrumentation with different mechanized systems., Methods: Forty mesial roots of mandibular molars were scanned and divided into 4 groups (n = 10): Group R, Reciproc; Group PTN, ProTaper Next; Group WOG, WaveOne Gold; Group PDL, ProDesign Logic. After instrumentation, the roots were once again submitted to a micro-CT scan, and then sectioned at 3, 6, and 9 mm from the apex, and assessed for the presence of complete and incomplete dentinal defects under a stereomicroscope. The nonparametric Kruskal-Wallis, Friedman, and Wilcoxon tests were used in the statistical analysis. The study used a significance level of 5%., Results: The total number of defects observed by cross-sectioning followed by stereomicroscopy was significantly higher than that observed by micro-CT, in all of the experimental groups (P ≤ .05). All of the defects identified in the postoperative period were already present in the corresponding preoperative period. There was no significant difference among the instrumentation systems as to the median numbers of defects, for either cross-sectioning followed by stereomicroscopy or micro-CT, at all the root levels (P > .05). In the micro-CT analysis, no significant difference was found between the median numbers of pre- and postinstrumentation defects, regardless of the instrumentation system (P > .05)., Conclusion: None of the evaluated instrumentation systems led to the formation of new dentin defects. All of the defects identified in the stereomicroscopic analysis were already present before instrumentation, or were absent at both time points in the micro-CT analysis, indicating that the formation of new defects resulted from the sectioning procedure performed before stereomicroscopy and not from instrumentation., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)