Cleanliness of Canal Walls following Gutta-Percha Removal with Hand Files, RaCe and RaCe plus XP-Endo Finisher Instruments: A Photographic in Vitro Analysis

In Vitro Cone Beam CT Analysis of the Efficacy of Three Supplementary Steps In the Removal of Obturation Material in Endodontic Retreatment

OBJECTIVES

To evaluate and compare the efficacy of XP-endo Finisher R (FKG Dentaire, Le Locle, Neuchatel, Switzerland), EDDY (VDW Dental, Munich, Germany), and passive ultrasonic irrigation (PUI) as supplementary steps following the D-RaCe retreatment file system (FKG Dentaire) in the removal of root canal obturation material using cone beam CT.

MATERIALS AND METHODS

A total of 45 two-rooted permanent maxillary first premolars were selected. Following access preparation, cleaning, and shaping with Hero Shaper (Micro Mega, Besançon, BFC, France) rotary file up to 25/04%, thermoplasticized obturation was performed with TotalFill BC sealer (FKG Dentaire) and gutta-percha. The specimens were subjected to routine retreatment using the D-RaCe retreatment file system. Cone beam computed tomography (CBCT) and volumetric analysis were performed before and after this procedure. The samples were divided into group A (XP-endo Finisher R: n=15), group B (EDDY: n=15), and group C (PUI: n=15). Finally, a third CBCT was taken and a volumetric analysis was done. Statistical analysis was done using SPSS Statistics version 26.0 (IBM Corp., Armonk, NY, USA).

RESULTS

The lowest mean residual volume of obturation material was seen with XP-endo Finisher R (1.6 mm3), followed by PUI (1.7 mm3). The EDDY showed the least efficiency in complete debridement of the root canals (3.6 mm3). This difference in values was statistically significant.

CONCLUSION

The XP-endo Finisher R and PUI showed superior performance than EDDY in the removal of remaining obturation material from the root canal system after retreatment with the D-RaCe retreatment file system. However, none of the systems were able to completely remove the root canal obturation materials.

Comparative Analysis of the Efficacy of Various Retreatment File Systems in the Removal of Gutta-Percha in Retreatment Cases and Time Taken During the Procedure: An In Vitro Cone Beam CT Study

Background Removing gutta-percha manually can be a challenging task, especially when addressing densely packed root-filling material, particularly in cases where resin-based sealers are employed for obturation. The use of nickel-titanium (NiTi) rotary instruments not only effectively shapes the root canal but also efficiently removes the endodontic filling from the curved canal during retreatment. Hence, incorporating rotary NiTi instruments in retreatment cases can alleviate fatigue for both patients and operators. Objectives This study aims to compare the efficacy of Neo-Endo retreatment files, R-Endo retreatment files, and K and H files in the removal of endodontic filling material. Additionally, the remnants of gutta-percha in root canals are evaluated using cone beam computed tomography (CBCT). Materials and methods A total of 60 extracted first maxillary molar teeth were selected for this study. Canal preparation was conducted using the step-back method up to an apical size of 40 K-file. The obturation process involved the use of gutta-percha points and AH Plus sealer in a lateral compaction technique. Post-operative CBCT scans were taken. The samples were randomly divided according to the retreatment files used: group I included Neo-Endo retreatment files, group II included R-Endo retreatment files, and group III included conventional K-files and Hedstroem files (H-Files). The retreatment procedure was considered complete when the last instrument easily reached the working-length range and was physically clean. A stopwatch was used to record the time taken by each file to remove the obturating material. T1 represented the total time (including irrigation and change of file) required to reach the apex, while T2 indicated the complete removal of materials from the canal with the last instrument. The overall time recorded (TT) was calculated as T1 + T2. The removal process was analyzed with CBCT scans. Results The Neo-Endo retreatment files removed the filling materials better and more quickly than the other files. Conclusions Despite the presence of residual filling material in all samples, the Neo-Endo retreatment files left the least amount of residual filling material and achieved the shortest completion time.

Comparative analysis of novel heat-treated retreatment file system on the removal of obturating material using nano-computed tomography

Introduction

The aim of nonsurgical retreatment is to remove the previous filling material followed by chemo-mechanical preparation of the canal to achieve proper disinfection of the root canal system. This is then followed by re-obturation. This study evaluates the time taken to retrieve the gutta-percha and the quantity of remaining filling material after retreatment with two different file systems. The quantity of remaining filling material was assessed using nano-computed tomography (CT) due to its increased accuracy.

Materials and Methods

Forty extracted single-rooted teeth were split into two groups at random and decoronated and obturated at a standard root length of 16 mm. Solite RS3 (SRS-3) Retreatment and ProTaper Universal Retreatment (PTUR) systems were used to retrieve the gutta-percha after a preoperative nano-CT scan. Postoperative nano-CT scan was taken and both the scans were superimposed to quantify the remaining filling material. The time taken to remove gutta-percha was measured using a stopwatch. The statistical analysis comparing the two groups was conducted using the independent t-test.

Results

The quantitative analysis of remaining filling material using nano-CT showed no statistical difference between both the file systems used (P > 0.05). However, SRS-3 took significantly less time in the removal of gutta-percha (P < 0.05).

Conclusion

Hence, we can conclude that there is no significant difference in the amount of remaining filling material between both the file systems. However, time taken to remove the gutta-percha was lesser in SRS-3 compared to PTUR file system.

Evaluation of the efficacy of TruNatomy, ProTaper retreatment, and RaCe file systems in retreatment of moderately curved mandibular molars: An in vitro study

Context

Endodontic retreatment is the first line of treatment in cases of failed primary endodontic treatment. Although associated with challenges such as incomplete removal of obturating material, increased clinical time, and extrusion of apical debris, endodontic retreatment still has considerable success rate in the general population.

Aims

The aim of this study was to evaluate and compare the efficacy of TruNatomy, ProTaper retreatment, and RaCe file systems to remove the obturating material, time taken to remove the obturating material, and apical extrusion of debris using cone-beam computed tomography (CBCT).

Settings and Design

In vitro study.

Subjects and Methods

Forty-five moderately curved mesiobuccal roots of the mandibular molars were instrumented up to #25, 4% taper and obturated with bioceramic sealer and lateral compaction technique. Teeth were divided randomly into three groups (n = 15). Teeth were retreated with TruNatomy, ProTaper retreatment, and RaCe file systems, respectively. Preretreatment and postretreatment CBCT scans were recorded and percentage of obturating material removed was calculated. Time taken to remove the obturating material and apical extrusion of debris was noted.

Statistical Analysis Used

Descriptive statistics including percentage, mean, standard deviation, Tukey's post hoc test, Kruskal-Wallis test, and Mann-Whitney Post hoc test were used.

Results

The total time needed for the removal of obturating material was comparatively shorter in the RaCe group, followed by the ProTaper retreatment group and TruNatomy group (P < 0.001). TruNatomy files were significantly better in removing the obturating material than the ProTaper retreatment files (P = 0.04). Statically, no difference between RaCe and TruNatomy files was noted. Apically extruded debris was more in the TruNatomy group than in the RaCe and ProTaper retreatment groups (P = 0.01).

Conclusions

All tested endodontic files were effective in removal of obturating material, although none could completely remove the filling material and no system could completely eliminate apical extrusion.

Buckling resistance, torque, and force generation during retreatment with D-RaCe, HyFlex Remover, and Mtwo retreatment files

Objectives

This study compared the buckling resistance of 3 nickel-titanium (NiTi) retreatment file systems and the torque/force generated during retreatment.

Materials and Methods

The buckling resistance was compared among the D-RaCe (DR2), HyFlex Remover, and Mtwo R25/05 retreatment systems. J-shaped canals within resin blocks were prepared with ProTaper NEXT X3 and obturated by the single-cone technique with AH Plus. After 4 weeks, 4 mm of gutta-percha in the coronal aspect was removed with Gates-Glidden drills. Retreatment was then performed using DR1 (size 30, 10% taper) followed by DR2 (size 25, 4% taper), HyFlex Remover (size 30, 7% taper), or Mtrwo R25/05 (size 25, 5% taper) (15 specimens in each group). Further apical preparation was performed with WaveOne Gold Primary. The clockwise torque and upward force generated during retreatment were recorded. After retreatment, resin blocks were examined using stereomicroscopy, and the percentage of residual filling material in the canal area was calculated. Data were analyzed using 1-way analysis of variance with the Tukey test.

Results

The HyFlex Remover files exhibited the greatest buckling resistance (p < 0.05), followed by the Mtwo R25/05. The HyFlex Remover and Mtwo R25/05 files generated the highest maximum clockwise torque and upward force, respectively (p < 0.05). The DR1 and DR2 files generated the least upward force and torque (p < 0.05). The percentage of residual filling material after retreatment was not significantly different between file systems (p > 0.05).

Conclusions

NiTi retreatment instruments with higher buckling resistance generated greater clockwise torque and upward force.

Postoperative Endodontic Pain after Treatment Using XP-endo Finisher: A Randomized Clinical Trial

Introduction

This randomized clinical trial aimed to determine whether the XP-endo finisher combined with or without foraminal enlargement has any significant effect on the incidence and intensity of postoperative pain in necrotic pulps.

Materials and Methods

Clinical pain levels were measured after 6, 12, 24, 48, and 72 hours and at 7 postoperative days. All treatments were performed by an endodontist in a single visit. One hundred and twenty patients were included. All patients had a single tooth treated. The patients were divided into four groups: No FE (None Foraminal Enlargement) (n=30), FE (Foraminal Enlargement) (n=30), No FE+XPF (None Foraminal Enlargement+XP-endo Finisher) (n=30) and XPF+FE (XP-endo Finisher and Foraminal Enlargement) (n=30). The canals were irrigated with sodium hypochlorite, shaped using WaveOne Gold Medium file, and then filled by using a matching single cone and AH-Plus sealer. The cavity was filled using glass ionomer cement. Pain intensity was assessed using the visual analog scale. The data were analyzed with the ANOVA and Games-Howell test. The significance level was 5%.

Results

The XPF+FE group experienced a higher level of pain, being classified on the visual analog scale as moderate for 48 postoperative hours and mild for 7 postoperative days (P<0.05). In the other groups, the pain was mild, only with different time intervals (P>0.05).

Conclusions

Foraminal enlargement associated with XP-endo Finisher may cause moderate postoperative pain.

Full counterclockwise rotary motion kinematics enhances the removal of gutta-percha and bioceramic sealer from root canals: A computed tomographic study

Background and Aim

Complete removal of gutta-percha and sealer is an important step during retreatment. The aim of this study was to assess the efficacy and time taken by full counterclockwise rotary motion of a reciprocating file in the removal of gutta-percha and BioRoot™ RCS bioceramic sealer.

Materials and Methods

Thirty-six extracted human mandibular premolars were instrumented with Mtwo rotary files and obturated using lateral condensation technique with gutta-percha and BioRoot™ RCS bioceramic sealer. The teeth were divided into three retreatment groups (n = 12) based on the kinematics used: Group I, Mtwo retreatment (Mtwo-R) files; Group II, Reciproc files used in reciprocation mode (Reciproc-R); and Group III, Reciproc files used in full counterclockwise motion (Reciproc-CCW). The efficacy of gutta-percha and bioceramic sealer removal was assessed by volume of gutta-percha removed using cone-beam computed tomography and area of remaining gutta-percha and bioceramic sealer using ImageJ software after longitudinal sectioning. Statistical analysis was done by one-way analysis of variance test and Tukey's multiple post hoc tests.

Results

Reciproc-CCW motion was significantly efficient in the removal of gutta-percha and bioceramic sealer in comparison to Mtwo-R files and Reciproc-R. The time taken for gutta-percha and sealer removal was least for Reciproc-R (325.5 ± 101.68 seconds) and was statistically significant in comparison to the other groups.

Conclusion

Within the limitations of the study, Reciproc-CCW was an effective method of removal of gutta-percha and bioceramic sealer during retreatment.

Simulated Evaluation of Tooth Fracture Resistance during Instrumentation with Single-and Multi-file Rotary Systems

Introduction

Use of rotary files in root canal preparation is inevitable due to their high speed and reduced duration of treatment. However, microcracks and even root fracture may sometimes occur in teeth where canal(s) is/are prepared using these devices. The purpose of the current study was to compare NeoNiti single-file with RaCe multi-file rotary systems.

Materials and Methods

An accurate scanner designed detailed three-dimensional file models, and a simulated model was developed using canal-specific features; including dentin thickness, root canal length, taper rate and root canal curvature. Cleaning and shaping conditions were simulated with appropriate speed and crack conditions for both types of files on the computer. Strain accumulation sites in the root dentin wall where microcracks was likely to occur were simulated and investigated. Abaqus and ANSYS software were used to perform finite element simulations.

Results

RaCe files with 0.04 taper caused the lowest level of stress (34.33 MPa) to the simulated canal. Conversely, the highest level of stress (62.35 MPa) was applied by 8% NeoNiti file to the simulated canal.

Conclusions

Based on the present experimental study, it can be concluded that RaCe multi-file rotary system may better be used in endodontic therapy, and the risk of microcracks in the tooth wall is less than that of NeoNiti single-file rotary system.

Irrigant Agitation Techniques versus Passive Ultrasonic Irrigation for Removing Debris from Curved Root Canals: An Environmental Scanning Electron Microscopic Study

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.

A Maxillary Second Premolar with Four Canals: A Case Report

Profound knowledge of the internal anatomy and configuration of the teeth plays a pivotal role in the success of standard root canal treatment. The presence of unexpected extra root canals has been reported in all the teeth, making root canal treatment a challenge for every clinician. Although the maxillary second premolar is no exception to this rule, the presence of a variety of multiple canals is relatively rare. In fact, the presence of three separate root canals has been reported in only 1-6% of cases. A 33-year-old male was referred for root canal retreatment of his left maxillary second premolar. An intraoral periapical radiograph revealed previous substandard endodontic treatment. Retreatment was performed under an operating microscope, and four root canals were found, which is, in fact, very rare. This case highlights another variation in the morphology of such teeth and it does highlight the importance of using magnification, especially an operating microscope in endodontic treatment.

Removal of Obturation Material from Root Canals Using a Combination of Reciprocal Instrumentation and Different Final Irrigation Techniques

Introduction

The predictability of successful non-surgical endodontic retreatment is directly related to it's ability to completely cleanse and remove obturation material from the canal system. The purpose of this study was to evaluate the removal of gutta-percha from curved canals using three final irrigation methods: passive ultrasonic irrigation (PUI) with a 20/01 E1 insert (Irrisonic); XP-endo Finisher (XPF); and Easy Clean (EC).

Methods and Materials

Forty mesial roots of mandibular molars with an angle of curvature between 10^° and 20^°, two canals, and independent foramina were cut into 16-mm sections. The canals were instrumented using the Reciproc system (R25) and filled with a #25 gutta-percha cone and AH-Plus sealer by the continuous-wave condensation technique. The roots were double-sealed with Coltosol and photopolymerizable resin and stored at 37^°C and 100% humidity for 30 days. They were then randomized into 4 groups (n=10): control (C), PUI, XPF, and EC. All specimens were scanned using cone-beam computed tomography (CBCT), and fill volume data (in square pixels) were calculated before retreatment, after retreatment, and after final irrigation. The images were analyzed using Tps Dig software 2.32 by two blinded, calibrated examiners (intra-class correlation coefficient=0.9967). The results were analyzed in BioEstat 4.0. The nonparametric Kruskal-Wallis test with Dunn's post-hoc and Friedman comparison were applied. Significance was accepted at 5% (P<0.05).

Results

None of the final irrigation protocols completely removed remnants of obturation material from the root canal systems (P>0.05). On comparative analysis with specimens divided into thirds, all methods were found to remove material equally, with no significant differences (P>0.05).

Conclusion

Based on this in vitro study, the additional cleaning methods tested were equivalent to each other and did not lead to an improvement in the removal of residual obturation material.

Cleaning Efficacy of the XP-Endo® Finisher Instrument Compared to Other Irrigation Activation Procedures: A Systematic Review

Background. One of the most important aims of an endodontic treatment is to obtain the complete removal or reduction of root canal remaining filling material: Smear layer, bacteria, intra-canal medicaments. To meet this requirement, several irrigation activation techniques have been proposed. Our systematic review examined studies which analyzed the XP-endo Finisher (XPF) instrument efficacy in removing root canal debris during initial endodontic treatment or retreatment, comparing it with the efficacy of other irrigation activation protocols, such as passive ultrasonic irrigation (PUI), laser activation procedure (Er:YAG), and Self-Adjusting File system (SAF). Methods. A systematic review was conducted using PubMed, Chocrane Library, and Scopus databases, identifying 51 items. Thirty-four articles were excluded based on title, abstract, full text, and language. Seventeen randomized controlled trials were selected and consequently submitted to quality assessment and data collection. Results. Conventional needle irrigation (CNI) is the less effective irrigation technique, but it is still unclear whether XPF is able to guarantee greater debris removal than the PUI technique. Er:YAG laser has been proven to be more effective in apical third than XPF instrument. Conclusions. Further investigations are needed in order to establish which final irrigation activation procedure could reach the maximum root canal debris reduction.

Smear layer removal evaluation of different protocol of Bio Race file and XP- endo Finisher file in corporation with EDTA 17% and NaOCl

Background

The aim of the present study was to compare the amount of the smear layer remaining in prepared root canals with different protocols of Bio RaCe files and XP-endo Finisher file (XPF) in association with 17% EDTA and sodium hypochlorite solution.

Material and Methods

A total of 68 extracted single-rooted teeth were randomly divided into 4 experimental groups (n=14) and two control groups (n=6). The root canals were prepared with Bio RaCe files (FKG Dentaire, Switzerland) using the crown-down technique based on manufacturer’s instructions and irrigated according to the following irrigation techniques: Group 1: XPF with 2 mL of 2.5% NaOCl for 1 minute. Group 2:, XPF with 1 mL of 17% EDTA for one minute. Group 3: XPF was used for 1 minute in association with normal saline solution. Group 4: XP-endo Finisher file for 30 seconds in association with 2.5% NaOCl and 17% EDTA for 30 seconds. The negative control group: NaOCl (2.5%) was used during root canal preparation, followed by irrigation with 17% EDTA at the end of root canal preparation. The positive control group: Normal saline solution was used for irrigation during root canal preparation. In all the groups, during preparation of the root canals with Bio RaCe file, 20 mL of 2.5% NaOCl was used for root canal irrigation and at the end of the procedural steps 20 mL of normal saline solution was used as a final irrigant. The samples were analyzed under SEM at ×1000‒2000 magnification and evaluated using Torabinejad scoring system. Data were analyzed with non-parametric Kruskal-Wallis test and post hoc Mann-Whitney U test, using SPSS. Statistical significant was defined at P<0.05.

Results

The results of the study showed the least amount of the smear layer at coronal, middle and apical thirds of the root canals in groups 2, which was not significantly different from the negative control group (P<0.5).

Conclusions

Under the limitations of the present study, use of a combination of NaOCl and EDTA in association with XPF exhibited the best efficacy for the removal of the smear layer.

Key words:Smear layer, XP-endo Finisher file, EDTA, Sodium hypochlorite.

Micro-CT Evaluation of Gutta-Percha Removal by Two Retreatment Systems

INTRODUCTION

The aim of the present ex vivo research was to compare the remaining filling material and the volumes of dentine removed after retreatment of curved canals with two rotary systems naming ProTaper Universal Retreatment and Mani NRT-GPR using micro-computed tomography (micro-CT).

METHODS AND MATERIAL

Forty mandibular molars containing two completely separated canals, with curvature angle of 25-35° and a curvature radius <10 mm were prepared to the Mtwo instrument 35/0.04 and filled with warm gutta-percha and AH-Plus sealer. The teeth were randomly divided into 2 groups (n=20), according to the retreatment system evaluated: ProTaper Universal Retreatment (PR group) or Mani NRT-GPR (MR group). Retreatment was considered complete when the working length was reached and when smooth dentinal walls were observed, with no evidence of filling material adhered to instruments or in the irrigating solution. Preoperative and postoperative micro-CT images were obtained with an isotropic voxel size of 11.88 µm to observe the volume of residual filling material in the canals and dentine removed after retreatment. Statistical analysis was performed by Student's t-test (P<0.05).

RESULTS

The mean percentage of remaining filling material was 12.96% for PR group and 24.26% for MR group (P=0.0056). The percentage of dentin removal was greater in the PR group (5.02%) than MR group (1.36%) (P=0.0028). Both systems failed to completely remove the filling material from the canals.

CONCLUSION

ProTaper Universal Retreatment system was more effective than Mani NRT-GPR system regarding removal of root filling material and also removed significantly more dentine after retreatment of curved mesial root canals of mandibular molars.