Micro‐CT evaluation of the removal of root fillings using the ProTaper Universal Retreatment system supplemented by the XP‐Endo Finisher file

The Effect of Different Obturation Techniques Using Different Root Canal Sealers on the Residual Filling Material After Retreatment Procedures

BACKGROUND

This study aimed to compare the effect of different obturation techniques with root canal sealers on the residual filling material after retreatment using SEM.

MATERIAL AND METHOD

Sixty (60) single rooted mandibular premolars were selected and instrumented with rotary files using the Mtwo system up to file size 30/.05 taper. The samples were randomly divided to two groups based on the type of sealer and three sub-groups (n=10) based on the obturating technique used. The root fillings were removed using the PTUR system files and the specimens were longitudinally sectioned while digital images were obtained from the root canals with SEM. The time required to reach working lenght were recorded.

RESULTS

There was no difference in terms of the smear score when comparing both sealer and obturation technique groups in the apical third. Smear scores were significantly affected by the type of sealer and obturation technique in the medium and coronal thirds of root canals (p<0.05). Higher smear scores were obtained with GFB than AH Plus (p<0.05). The time required to reach working length with GFB was longer than AH Plus (p<0.05).

CONCLUSION

Residual filling material was observed in all samples, regardless of the root canal sealer or the obturation technique used. There was a significantly lower smear scores in the AH Plus groups as compared to the GFB.

Effectiveness of different supplementary protocols for remaining filling material removal in endodontic reintervention: an integrative review

The aim of this study was to perform an integrative review to identify the most effective supplementary protocols used after filling material (FM) removal and root canal reinstrumentation, during endodontic reintervention. The literature search was performed on the electronic databases PubMed and Latin American and Caribbean Health Sciences Literature (LILACS), using a combination of specific scientific descriptors. Selection criteria accepted articles published in English, Spanish and Portuguese languages, up to August 2021, involving in vitro and ex vivo studies. After applying the eligibility criteria, 46 articles were included for qualitative analysis. The tool for qualitative analysis of quasi-experimental studies of the Joanna Briggs Institute was used to determine the risk of bias of the included articles. The selected articles provided important data regarding the following supplementary protocols: sonic and ultrasonic activation of the irrigating solution; the use of ultrasonic inserts, XP-endo system instruments, and photon-induced photoacoustic streaming for mechanical debridement; and new devices as GentleWave system, and the self-adjusting file. Overall, all supplementary protocols demonstrated efficacy in removing the remaining FM. The implementation of various supplementary protocols can effectively remove the remaining FM from the root canal walls, although complete removal is not always achieved. However, it was not possible to determine the most effective protocol. Conversely, their association can enhance remaining FM removal. Remaining FM attached to root canal walls hinders proper chemical-mechanical preparation during endodontic reintervention. Supplementary protocols optimize the remaining FM removal, enhancing cleaning and disinfection of root canal.

A scientometric, bibliometric, and thematic map analysis of hydraulic calcium silicate root canal sealers

Objectives

This scientometric and bibliometric analysis explored scientific publications related to hydraulic calcium silicate-based (HCSB) sealers used in endodontology, aiming to describe basic bibliometric indicators and analyze current research trends.

Materials and Methods

A comprehensive search was conducted in Web of Science and Scopus using specific HCSB sealer and general endodontic-related terms. Basic research parameters were collected, including publication year, authorship, countries, institutions, journals, level of evidence, study design and topic of interest, title terms, author keywords, citation counts, and density.

Results

In total, 498 articles published in 136 journals were retrieved for the period 2008-2023. Brazil was the leading country, and the universities of Bologna in Italy and Sao Paolo in Brazil were represented equally as leading institutions. The most frequently occurring keywords were "calcium silicate," "root canal sealer MTA-Fillapex," and "biocompatibility," while title terms such as "calcium," "sealers," "root," "canal," "silicate based," and "endodontic" occurred most often. According to the thematic map analysis, "solubility" appeared as a basic theme of concentrated research interest, and "single-cone technique" was identified as an emerging, inadequately developed theme. The co-occurrence analysis revealed 4 major clusters centered on sealers' biological and physicochemical properties, obturation techniques, retreatability, and adhesion.

Conclusions

This analysis presents bibliographic features and outlines changing trends in HCSB sealer research. The research output is dominated by basic science articles scrutinizing the biological and specific physicochemical properties of commonly used HCSB sealers. Future research needs to be guided by studies with a high level of evidence that utilize innovative, sophisticated technologies.

Micro-CT evaluation of the removal of root fillings using rotary and reciprocating systems supplemented by XP-Endo Finisher, the Self-Adjusting File, or Er,Cr:YSGG laser

Objectives

This study aimed to compare the effectiveness of a single-file reciprocating system (WaveOne Gold, WOG) and a multi-file rotary system (ProTaper Universal Retreatment, PTUR) in removing canal filling from severely curved canals and to evaluate the possible adjunctive effects of XP-Endo Finisher (XPF), the Self-Adjusting File (SAF), and an erbium, chromium: yttrium, scandium, gallium garnet (Er,Cr:YSGG) laser using micro-computed tomography (μCT).

Materials and Methods

Sixty-six curved mandibular molars were divided into 2 groups based on the retreatment technique and then into 3 based on the supplementary method. The residual filling volumes and root canals were evaluated with μCT before and after retreatment, and after the supplementary steps. The data were statistically analyzed with the t-test, Mann-Whitney U test, analysis of covariance, and factorial analysis of variance (p < 0.05).

Results

PTUR and WOG showed no significant difference in removing filling materials (p > 0.05). The supplementary techniques were significantly more effective than reciprocating or rotary systems only (p < 0.01). The supplementary steps showed no significant differences in canal filling removal effectiveness (p > 0.05), but XPF showed less dentin reduction than the SAF and Er,Cr:YSGG laser (p < 0.01).

Conclusions

The supplementary methods significantly decreased the volume of residual filling materials. XPF caused minimal changes in root canal volume and might be preferred for retreatment in curved root canals. Supplementary approaches after retreatment procedures may improve root canal cleanliness.

The supplementary use of XP-endo Finisher R after Reciproc enhances the removal of a bioceramic sealer in oval root canals

This study compared the performance of Reciproc and Reciproc Blue endodontic files in retreatment time and re-establishment of apical patency, plus removal of a bioceramic sealer from the canal surface with the supplementary use of the XP-endo Finisher R. Following preparation, slightly curved oval root canals in mandibular incisors were filled using a corresponding gutta-percha point and a bioceramic sealer. Apical patency achievement was assessed and the time required to reach the original working length was recorded. The samples were split longitudinally and were photographed to assess the material remaining on the canal walls. No significant differences were observed regarding patency achievement or retreatment times when comparing Reciproc and Reciproc Blue. Significant less material remained on the canal walls when Reciproc was followed by XP-endo compared with Reciproc alone, and when the data for Reciproc and Reciproc Blue were pooled.

Effect of Additional Apical Preparation on Retreatment of Curved Root Canals Filled with Different Sealers

OBJECTIVE

 This study assessed the influence of additional apical preparation on material removal during retreatment of curved root canals filled with different sealers.

MATERIALS AND METHODS

 Twelve mesial roots of mandibular molars with two separate canals and curvature between 25 and 35 degrees were selected. The working length was established 1-mm short of the apical foramen, and all the root canals were prepared using ProDesign R (PDR) 25/0.06. After preparation, the root canals were divided in two groups (n = 12) and filled by continuous wave condensation technique with NeoMTA Plus or AH Plus. All the root canals were retreated using rotary ProDesign Logic RT 25/0.08, reciprocating PDR 25/0.06 and apical preparation with PDR 35/0.05. Additional apical preparation was performed with ProDesign Logic (PDL) 50/0.01. The samples were scanned using a Skycan 1176 micro-computed tomography (micro-CT), voxel size 8.74 µm, before and after the retreatment procedures. Percentages of remaining filling material were evaluated.

STATISTICAL ANALYSIS

 The data were submitted to paired and unpaired t-tests (α = 0.05).

RESULTS

 Percentage of remaining filling material was similar between the root canals filled with NeoMTA Plus or AH Plus sealer after retreatment using PDR 35/0.05, and after additional apical preparation using PDL 50/0.01 (p > 0.05). However, PDL 50/0.01 significantly decreased the percentage of remaining filling material in the apical third after the additional apical preparation for both sealers (p < 0.05).

CONCLUSION

 NeoMTA Plus or AH Plus did not influence the retreatment of curved root canals. ProDesign Logic 50/0.01 promoted greater filling material removal in the apical third.

Sonic irrigation for removal of calcium hydroxide in the apical root canal: A micro-CT and light-coupled tracking analysis

Objective

This study aimed to evaluate the efficacy of three sonic irrigation systems for removal of calcium hydroxide dressing from the apical root canal.

Materials and methods

A total of 96 single-rooted teeth in three categories of root canal curvatures (straight: 0–5°, moderate: 6–20°, and severe: > 20°) were allocated to four groups: conventional needle irrigation, EndoActivator, EQ-S, and Vibringe. The root canals were instrumented using Protaper NEXT and filled with calcium hydroxide. After removal of calcium hydroxide, the remaining volume of calcium hydroxide was measured by micro-CT analysis. Data were compared among root canal curvatures and irrigation systems using the Kruskal-Wallis test and Mann-Whitney test (p < .05). The oscillating range of each irrigation system was measured using light-coupled motion tracking.

Results

The volumes of calcium hydroxide remaining in the canals with severe curvature were significantly higher than in those of straight curvature (p < .05). In the canals of moderate or severe curvature, EQ-S showed the highest removal percentage, followed by EndoActivator, Vibringe, and needle irrigation (p < .05). Light-coupled tracking showed the largest oscillating range in EQ-S (p < .05).

Conclusions

Sonically activated irrigation systems with a flexible tip can be beneficial for calcium hydroxide intracanal dressing removal in the curved apical canals.

Evaluation of irrigation techniques in the removal of root canal filling material: Micro-CT and SEM study

Background/Aim: This study aimed to compare the different irrigation activation methods in retreatment of oval-shaped root canals. Material and Methods: Forty distal canals from mandibular molars were filled. After the removal of filling material, specimens were assigned to four groups as follows; control, passive ultrasonic irrigation (PUI), self-adjusting file (SAF), and XP-endo Finisher (XPF). The amount of residual filling material was assessed by micro-computed tomography (micro-CT) and root canal walls were examined by using scanning electrom microscopy (SEM). Data were analyzed using the Kruskal-Wallis and Dunn test. Results: None of the activation techniques removed root canal remnants completely. The amount of filling material significantly decreased in all activation techniques compared to the control group (p<0.05). There was no significant difference between the PUI, SAF, and XPF groups in the micro-CT analysis (p>0.05). SEM evaluation showed higher scores in the apical region in all groups (p<0.05). Conclusions: The use of activation methods reduces the amount of residual filling material.

Critical analysis of research methods and experimental models to study removal of root filling materials

Despite enjoying high favourable outcome rates, root canal treatment is not always successful. Root canal retreatment is a widely practised option for managing a non-healing root treated tooth. A basic distinction between retreatment and initial treatment is the requirement to remove the existing root filling material occupying the root canal space. Only then, can the technical deficiencies and possible causes of failure be addressed. Hence, the successful removal of the root filling material is critical to achieving the objectives of retreatment. Many different materials and techniques have been used for root canal filling, which have been documented in a plethora of studies; these are mainly laboratory studies investigating the removal of root filling materials. To help guide future research, which may then better inform clinical practice in relation to retreatment procedures, the focus of this narrative review is on the research methods and experimental models employed to study the removal of root filling materials. The current available literature demonstrates great variation in the research methodologies used to study the removal of root filling material, including direct visualization by splitting tooth samples or clearing, three-dimensional radiographic imaging including using microcomputed tomography or cone-beam computed tomography, and a combination of these techniques. Depending on the research method employed, variation also exists in quantification of root filling material removal; these include measurements of surface area, volume or weight, and criteria-based (semi-quantitative) assessment. Experimental models, using human teeth or resin models, differ with respect to standardization techniques and replication of the clinical scenario including initial sample preparation, canal filling, allocation and technical aspects of retreatment procedures. Future models should replicate, as closely as possible, the clinical scenario. Currently, microcomputed tomography provides a highly detailed, non-invasive and non-destructive method of objectively assessing and quantifying root filling removal.

PRILE 2021 guidelines for reporting laboratory studies in Endodontology: explanation and elaboration

Guidance to authors is needed to prevent their waste of talent, time and resources in writing manuscripts that will never be published in the highest-quality journals. Laboratory studies are probably the most common type of endodontic research projects because they make up the majority of manuscripts submitted for publication. Unfortunately, most of these manuscripts fail the peer-review process, primarily due to critical flaws in the reporting of the methods and results. Here, in order to guide authors, the Preferred Reporting Items for study Designs in Endodontology (PRIDE) team developed new reporting guidelines for laboratory-based studies: the Preferred Reporting Items for Laboratory studies in Endodontology (PRILE) 2021 guidelines. The PRILE 2021 guidelines were developed exclusively for the area of Endodontology by integrating and adapting the modified CONSORT checklist of items for reporting in vitro studies of dental materials and the Clinical and Laboratory Images in Publications (CLIP) principles. The process of developing the PRILE 2021 guidelines followed the recommendations of the Guidance for Developers of Health Research Reporting Guidelines. The aim of the current document is to provide authors with an explanation for each of the items in the PRILE 2021 checklist and flowchart with examples from the literature, and to provide advice from peer-reviewers and editors about how to solve each problem in manuscripts prior to their peer-review. The Preferred Reporting Items for study Designs in Endodontology (PRIDE) website (http://pride-endodonticguidelines.org/prile/) provides a link to the PRILE 2021 explanation and elaboration document as well as to the checklist and flowchart.

Efficacy of Removing Thermafil and GuttaCore from Straight Root Canal Systems Using a Novel Non-Surgical Root Canal Re-Treatment System: A Micro-Computed Tomography Analysis

The present study aims to evaluate the effectiveness of an XP-endo non-surgical root canal re-treatment system in removing both GuttaCore and Thermafil gutta-percha carrier-based root canal filling materials from straight root canal systems using micro-computed tomography (micro-CT) analysis. The study was performed on 20 single-rooted upper teeth, which were randomly allocated into the following study groups: Group A, Thermafil and AH Plus sealer (n = 10); Group B, GuttaCore and AH Plus sealer (n = 10). Before and after the non-surgical root canal re-treatment procedure, the samples were submitted for a micro-CT analysis. The volume of the root canal filling material (mm³), the volume of the remaining root canal filling material (mm³) and the time (minutes) needed to remove the root canal filling material were also recorded. Student's t-test was used to analyze the results. No statistically significant differences were found between the volume of the remaining root canal filling material in the GuttaCore and Thermafil root canal filling systems at the coronal third (p = 0.782), middle third (p = 0.838) or apical third (p = 0.882) of the straight root canal systems; however, the GuttaCore required a statistically significant (p = 0.037) shorter amount of time (4.72 ± 0.76 min) to be removed than the Thermafil carrier-based root canal filling material (5.92 ± 1.42 min). The XP-endo Finisher non-surgical endodontic re-treatment system removes both GuttaCore and Thermafil gutta-percha carrier-based root canal filling materials from straight root canal systems, although removal of the GuttaCore gutta-percha carrier-based root canal filling material required less time.

Contribution of XP-Endo files to the root canal filling removal: A systematic review and meta-analysis of in vitro studies

This review was designed to analyse whether the supplementary use of XP-Endo Finisher and XP-Endo Finisher R contributes to the removal of root canal filling materials. Databases were searched up to November 2020. Studies were critically assessed according to inclusion and exclusion criteria. Risk of bias evaluation was performed. Pooled standardised mean differences (SMD) and 95% confidence intervals (95% CI) were calculated. Ten studies involving 192 teeth were eligible for systematic review and meta-analysis could be performed with eight of these studies. Strong evidence showed that XP-Endo Finisher R file contributed significantly to filling material removal from root canals (SMD (95% CI): 0.41 (0.06-0.76)). Although the evidence was conflicting, XP-Endo Finisher R file was superior than other irrigant activation techniques (SMD (95% CI): 0.47 (0.02-0.93)). The supplementary use of XP-Endo Finisher and XP-Endo Finisher R is beneficial in further removal of root canal filling materials from root canal system.

A Digital Microscopic Inspection of Dentinal Defects after Using Endodontic Retreatment Files

Aim

The study aimed at evaluating the incidence of dentinal defects after root canal retreatment with ProTaper Universal retreatment (PTUR) and XP-endo Shaper and Finisher R (XP).

Materials and Methods

Sixty extracted single-rooted human premolars were selected and divided into 4 groups of 15 teeth each. In the negative control group, the teeth were left unprepared. In the positive control group, the teeth were prepared with ProTaper Next and obturated with no further retreatment. In the PTUR and XP groups, the teeth were prepared and obturated followed by removal of the filling material at body temperature using PTUR and XP instruments, respectively. The roots were then sectioned at 3, 6, and 9 mm from the apex and observed under a digital microscope to detect defects.

Results

PTUR group showed significantly higher (p value <0.05) incidence of defects than the other groups. Comparison of no defects versus defects between groups in different areas of root canals demonstrated significant difference among the groups in the apical and cervical regions.

Conclusion

Within the limitations of the present study, PTUR files created significantly more dentinal defects than XP files, with most of those defects at the cervical and apical areas of the root canals.

Retrievability of bioceramic-based sealers in comparison with epoxy resin-based sealer assessed using microcomputed tomography: A systematic review of laboratory-based studies

Aim:

The objective was to evaluate the retrievability of bioceramic sealers in comparison with epoxy resin-based sealers assessed using microcomputed tomography.

Materials and Methods:

Four reviewers independently conducted a systematic literature search in four electronic databases. The risk of bias was assessed using modified Joanna Briggs Institute Critical Appraisal tools for Quasi-Experimental Studies.

Results:

Ten articles were included in this review and all had a moderate risk of bias. The results across the included articles were inconsistent with some indicating easier/difficult removal of bioceramic sealers, while others indicate no difference. The studies varied in terms of the type of bioceramic sealer used, root canal anatomy, and retreatment techniques followed. Due to heterogeneity, only a qualitative analysis was performed and no meta-analysis was conducted.

Conclusion:

The quality of evidence is low and no definitive conclusion could be derived regarding the retrievability of bioceramic sealer/AH plus sealer from the root canals during retreatment procedures.

Micro-CT evaluation of filling of flattened root canals using a new premixed ready-to-use calcium silicate sealer by single-cone technique

The aim of this study was to evaluate the filling ability of a new premixed ready-to-use calcium silicate-based sealer, in comparison with an epoxy resin-based sealer by the single-cone technique in flattened root canals. Thirty-two flattened root canals of maxillary second premolars with buccal-lingual diameter 4 or more times larger than the mesio-distal diameter at 9 mm from the radiographic apex were selected. Root canals were prepared using Hyflex EDM 25/0.08 and additional preparation with ultrasonic tip Flatsonic and ProDesign Logic 25/0.03. After preparation, the root canals were filled with two root canal sealers (n = 16): Bio-C Sealer or AH Plus using the single-cone technique. Scanning was performed before and after root canal obturation using a Skycan 1176 micro-computed tomography (micro-CT) with an isotropic voxel size of 8.74 μm. The percentage of voids was analyzed in the cervical/middle thirds and in the apical third. Data were submitted to the Mann-Whitney test at a significance level of 5%. There was no statistical difference between Bio-C Sealer and AH Plus (p > .05). The percentage of voids in the cervical/middle thirds was 8.94% (1.33-39.95) for Bio-C Sealer and 9.30% (1.19-18.00) for AH Plus (p > .05). In the apical third, this percentage was 11.84% (4.85-27.00) for Bio-C Sealer and 9.21% (1.34-28.78) for AH Plus (p > .05). By using the single-cone technique, neither Bio-C Sealer nor AH Plus provided a voids-free root canal filling. Both sealers had similar filling ability in flattened root canals.

In vitro comparative evaluation of efficiency of XP-endo shaper, XP-endo finisher, and XP-endo finisher-R files in terms of residual root filling material, preservation of root dentin, and time during retreatment procedures in oval canals - A cone-beam computed tomography analysis

Background:

In an oval-shaped canal, no single instrumentation systems were effective in absolute removing obturation.

Aim:

The aim of the study was to evaluate the performance of ProTaper Universal Retreatment (PTUR) system, XP-endo Shaper (XPS), XP-endo Finisher (XPF), and XP-endo Finisher-R (XPF-R) in removing root-canal filling material and preservation of sound dentin during retreatment procedure.

Methodology:

Root-canal preparation was performed on 60 mandibular premolars with oval-shaped canals using the ProTaper Gold file system. Preobturation scans were performed to measure canal volume of the canal and recorded. Obturation was performed and the samples were randomly assigned into four groups according to the retreatment protocol used (n = 15): H-file, PTUR files, PTUR followed by XPF file, and XPS supplemented with XPF-R file. After retreatment, the specimens were re-scanned and volumetric analysis of remaining root filling material, volume of the canal space were measured using EZ-3Di Software Version 5.0.0.2. All the data were subjected to one-way ANOVA and post hoc Tukey's test with a significance of 5%.

Results:

XPS + XPF-R showed promising results in the removal of obturating material and preservation of root dentin than any other group. The difference is statistically significant.

Conclusion:

XPS + XPF-R removed gutta-percha more significantly without sacrificing the sound dentin along with instrumentation.

Micro-computed Tomographic Assessment of Supplementary Cleaning Techniques for Removing Bioceramic Sealer and Gutta-percha in Oval Canals

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.