The efficacy of five techniques for removing root filling material: microscopic versus radiographic evaluation

Effectiveness of H-files and Pro-Taper universal systems in removing Gutta-percha during endodontic retreatment: A comparative study

Objective

This research was aimed at assessing the effectiveness of manual H-files versus a combination of a Pro-Taper universal rotary canal preparation system and retreatment system in removing gutta-percha (GP) during endodontic retreatment, by using a digital radiography technique.

Methods

This ex vivo study used a non-probability consecutive sampling technique. The study sample comprised 60 extracted anterior permanent teeth, each with one root with a straight root canal (RC). After preparation, RCs were obturated with GP and sealer. Subsequently, teeth were stored for 2 weeks in a humid environment at 37 °C. Thirty teeth each were randomly assigned to the control (group I), and experimental (group II) groups. GP removal was performed with H-files {group I) or a combination of a Pro-Taper universal rotary canal preparation system and retreatment system (group 2). Digital radiographs were acquired with Carestream digital radiovisiography software (Kodak; version-VER.6.10.8.3-A), and the presence of residual GP was analyzed. AutoCAD (2006) software was used to demarcate the RC and residual root filling. The residual GP in both groups was compared with independent sample t-tests.

Results

The remaining root filling did not significantly differ when GP was removed with conventional Hedstrom files versus a combination of Pro-Taper Universal preparation and retreatment file systems. The residual GP was confined to the apical third of the canals in both groups.

Conclusions

Pro-Taper Universal preparation and retreatment file systems have similar effectiveness to manual H-files in GP removal in straight canals.

Innovative ex vivo exploration: A comparative study of novel approaches of root canal filling material removal efficiency

Introduction

Retention of the natural tooth without any symptoms in the oral cavity is one of the prime desires of endodontic treatment. Root canal therapy usually leads to failure when treatment is not up to the mark of acceptable standards. To address these deficiencies, non-surgical endodontic retreatment is the most accepted option with the success rate ranging from 65% to 83%. Forty-five single-rooted mandibular premolars with undeviated canals (as per Schneider's criteria) were obtained and divided further into three groups with 15 specimens along with resin-based sealer solvent in each group: Group 1 - Retreatment rotary file system, Group 2 - Ultrasonics, and Group 3 - Diode laser. Specimens were then evaluated under a stereomicroscope at ×10 after cutting in two halves followed by evaluation of the remaining filling material using Hulsmann and Bluhm criteria.

Context

Nonsurgical retreatment.

Aims

The aim of the study was to evaluate and compare the efficacy of various retreatment techniques for the elimination of root canal filling material.

Settings and Design

The sample size was determined using the formula n = (Zα/2)2 s2/d2. The design of the study is in vitro experimental study.

Subjects and Methods

A sum of 45 single-rooted extracted human permanent mandibular premolars were included in this study. All teeth were biomechanically prepared and obturated followed by decoronating the samples. All specimens were randomly divided into 3 groups comprising 15 specimens along with solvent based on the technique for the filling material elimination from the root canal, i.e. Group I: retreatment rotary files, Group II: ultrasonics, and Group III: diode laser.

Statistical Analysis Used

The Tukey's post hoc tests and one-way analysis of variance were used for comparison of the study parameters among the groups.

Results

Results revealed that ultrasonics showed the least amount of remaining filling material within the root canal which had a significant difference from other groups, i.e. retreatment rotary files and diode laser.

Conclusions

Ultrasonics with a resin-based sealer solvent can be considered a preferred option for nonsurgical retreatment. However, none of the groups shows complete elimination of filling material inside the root canal system.

Efficacy of Endoscope and Periapical Radiography to Detect Residual Root Canal Filling Using Micro-CT as Reference

INTRODUCTION

To evaluate the efficacy of examinations by endoscope of root canals to determine residual root canal filling materials by comparison with microcomputed tomographic (micro-CT) images as reference.

METHODS

Thirty maxillary second premolars with oval canals received root canal treatment. Then D-Race retreatment files were used to remove the root canal fillings supplemented by XP-endo Finisher. Samples were scanned to reconstruct micro-CT reference images. Images were obtained of all samples from the mesiodistal and buccolingual directions by digital radiography. Then the root canals of specimens mounted in manikins were assessed by endoscope. The radiographic and endoscopic results were scored following comparison with the micro-CT images, which served as a reference, by 2 blinded observers. The interexaminer reliability of the assessments was evaluated by kappa test and the accuracy of endoscopic visualization according to the presence of residual root canal filling materials was compared using Kruskal-Wallis H test and Spearman's rank order correlation with the level of significance set at 5%.

RESULTS

The efficiency of the periapical radiography and endoscopy to determine residual root canal filling material was similar in every third of the root canal (P > .05).

CONCLUSIONS

The endoscope detected residual root canal filling material as efficiently as periapical radiography.

Retreatment of XP-endo Shaper and R-Endo files in curved root canals

OBJECTIVES

To compare the retreatment efficiency of XP-endo Shaper and R-Endo files in curved root canals using ImageJ software.

METHODS

Forty extracted mandibular first molars with curved mesial canals (25°-35°) were chosen. Access cavities, preparation and obturation of root canals were performed. Roots were randomly distributed into two groups corresponding to the retreatment files used. Group 1 retreated with XP-endo Shaper file, and group 2 retreated with R-Endo files. Each root was sectioned and photographed. ImageJ software was used to estimate the percentage of residual filling material that existed on the three root canal segments. Mann-Whitney U and the Kruskal-Wallis tests were used to compare the percentages of residual filling material between the teeth segments (P < .05).

RESULTS

The R-Endo group showed a significantly higher median percentage of residual filling material than the XP-endo Shaper group. In both groups, the coronal segments had the highest median of the residual filling material, followed by the middle and apical segments.

CONCLUSION

XP-endo Shaper is significantly more effective than R-Endo in removing root canal filling materials in the coronal, middle, and apical segments.

Effectiveness of the REvision System and Sonic Irrigation in the Removal of Root Canal Filling Material from Oval Canals: An In Vitro Study

This study aimed to evaluate the effectiveness of the Endostar REvision system (Poldent, Warsaw, Poland) in the removal of filling materials from oval root canals using sonic irrigation as an additional cleaning method. Thirty human-extracted mandibular premolars with oval canals were prepared using the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland) up to instrument F1 (20/.07), and then filled by the continuous wave vertical compaction technique using pulp canal sealer EWT (Sybron Dental Specialties, Orange, CA, USA). The teeth were randomly divided into two groups (n = 15) according to the instrumentation system and the additional cleaning method, as follows: REvision (30/.08, 25/.06) with EQ-S sonic activation (Meta Biomed, Chungcheongbuk-do, Korea), REvision (30/.08, 25/.06) without additional activation. All specimens were sectioned longitudinally at 3 and 7 mm from the apex, and analyzed using digital microscopy (KEYENCE, Osaka, Japan) to measure the total area of the residual obturation materials, followed by SEM analysis. The data on the percentage of remaining filling material were analyzed by Kruskal−Wallis one-way Analysis of Variance on ranks. None of the retreatment protocols completely removed the filling material from the root canals (p > 0.05); the retreatment technique using sonic activation showed statistically less residual filling materials than the retreatment technique using irrigants without activation at the coronal third (p < 0.05), whilst no significant difference was found between both tested groups at the apical and middle thirds (p > 0.05). The REvision system showed promising results in the removal of filling materials from oval canals.

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.

A micro-computed tomographic evaluation of retreatability of BioRoot RCS in comparison with AH Plus

This study compared the retreatability of filling material from canals filled with BioRoot RCS (Septodont, Saint-Maur-des-Fosses, France) and AH Plus (Dentsply DeTrey, Konstanz, Germany) combined with gutta-percha using micro-computed tomography for evaluation. Thirty-four mandibular premolars were divided into two groups according to the sealer used. Thirty days after obturation, canals were retreated with a ProTaper Universal retreatment system (Dentsply Maillefer, Ballaigues, Switzerland) followed by passive ultrasonic irrigation (PUI). The time taken for retreatment was recorded. The roots were scanned after obturation, after retreatment and after PUI. Data were analysed using the Mann-Whitney and Wilcoxon tests. Canals filled with BioRoot RCS exhibited significantly less remaining filling material than canals filled with AH Plus (P < 0.05). The addition of PUI resulted in a significant decrease in the residual material in both groups (P < 0.05). A significantly shorter retreatment time was reported for the AH Plus group than the BioRoot RCS group (P < 0.05).

Comparative Assessment of Canal Transportation, Dentin Loss, and Remaining Root Filling Material by Different Retreatment Files An In vitro Cross-Sectional Study

Aim:

The purpose of this study was to evaluate the centering ability, canal transportation and efficacy of re-treatment rotary and hand files in removing Gutta Percha from root canals using Cone Beam Computed Tomography(CBCT).

Materials and Methods:

Sixty extracted human maxillary anteriors were obturated and randomly divided into three groups. Root fillings were removed with ProTaper Universal retreatment system, R-Endo system, and Hedstrom files. CBCT scans were taken.

Statistical Analysis and Results:

The data were analyzed using the Statistical Package for the Social Sciences (SPSS 15.0, IBM). The mean and standard deviation among the groups was calculated by one-way analysis of variance, Kruskal–Wallis, and Mann– Whitney U-tests, and the comparison among the various groups was done by post hoc Tukey's test. A statistically significant amount of remaining root canal filling material and canal transportation was noted (P < 0.05).

Conclusion:

No system completely removed the root filling material from root canals. Manual instrumentation resulted in more dentin loss and canal transportation than rotary file system.

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.

Evaluation of the amount of remained sealer in the dentinal tubules following re-treatment with and without solvent

Background:

The effect of solvent and sealer type (BioRoot RCS [BRRCS], mineral trioxide aggregate [MTA] Fillapex, and AH26) on the root canal residues was evaluated by confocal laser scanning microscopy (CLSM).

Materials and Methods:

Distal root canals of 60 mandibular molars prepared up to ProTaper-F4 were filled using one of the sealers labeled with 0.1% rhodamine-B (n = 20 per sealer). Samples were divided into two according to reprocessing methods as follows: ProTaper Universal Reprocessing System (PTUR) or solvent plus PTUR. Samples were sectioned at 2–5 and 8 mm from the apex and the samples were observed under CLSM. Penetration depth, percent penetration depth, and percent penetration into canal walls were evaluated. Statistical analysis was performed using the repeated measures of the two-way ANOVA and Bonferroni post hoc test at P = 0.05.

Results:

The highest penetration depth was measured in BRRCS in all root canal thirds with or without chloroform addition. Percentage of penetration depth values of MTA Fillapex and BRRCS was statistically similar and higher than AH26 in all sections, except the apical section re-treated with the addition of chloroform.

Conclusion:

None of the sealers were completely removed. The type of sealant and the use of chloroform changed the amount of sealant remaining in the root canal system.

Does the ultrasonic activation of sealer hinder the root canal retreatment?

OBJECTIVES

To evaluate if the ultrasonic activation of sealer hinders the root canal retreatment.

MATERIALS AND METHODS

Thirty mandibular premolars were prepared using the ProTaper Universal system (Dentsply) until the instrument F3 (0.30/0.09). The canals were distributed into 2 groups (n = 15), according to the filling technique: NUact group - sealer without ultrasonic activation + gutta-percha cones and Uact group - sealer with ultrasonic activation + gutta-percha cones. The canals were re-instrumented with Largo burs, followed by the instrument R50 (0.50/0.05) of the Reciproc system. The time required to perform re-instrumentation was recorded (s). The roots were longitudinally cleaved, and the total area of root canal and remaining filling material were quantified (%). The ANOVA test was applied to the data and complemented by Student's t test (P < 0.05).

RESULTS

Uact group had higher percentage of remaining filling material than NUact group (P < 0.05). When the root thirds were considered, there was statistically significant difference only for Uact group at the apical third (P < 0.05). There was no difference between groups regarding the time required to perform re-instrumentation (P > 0.05).

CONCLUSIONS

Ultrasonic activation of sealer leads to a higher percentage of remaining filling material attached to the root canal walls. However, it did not affect the retreatment time.

CLINICAL SIGNIFICANCE

Ultrasonic activation increases sealer penetration into dentinal tubules, improving its resistance to dislodgement. However, there is no scientific evidence to prove if ultrasonic activation of sealer hinders its removal when root canal retreatment is necessary.

Comparative Analysis of Root Canal Filling Debris and Smear Layer Removal Efficacy Using Various Root Canal Activation Systems during Endodontic Retreatment

Background and objectives: The complete removal of obturation material can be a challenge in nonsurgical root canal retreatment. The insufficient removal of obturation material is a reason for root canal retreatment failure. Materials and Methods: The purpose of this study was to assess the efficacy of different final root canal irrigation activation methods in removing debris and smear layers in the apical and middle portions of root canals during retreatment. Sixty-six distal roots of freshly extracted molars were randomly divided into six groups: (1) primary root canal treatment with no obturation (negative control); (2) retreatment with only conventional instrumentation and irrigation (positive control); (3) retreatment with additional ultrasonic irrigation using the Piezon Master 700; (4) ultrasonic irrigation with the ENDOSONIC Blue; (5) sonic irrigation with the EDDY; and (6) multisonic irrigation with the GentleWave system. Roots were split and prepared for scanning electron microscopic (SEM) evaluation. Acquired images were assessed to quantify the amount of debris and smear remaining. Results: Among the treatment groups, Group 6 had a significantly lower debris score than Group 2 (positive control) in both the middle and apical regions (p = 0.004, p = 0.012). All treatment groups showed significantly lower smear scores than Group 2 in the middle and apical regions (p < 0.05). Conclusions: The GentleWave multisonic System showed a more optimal cleaning efficacy of the root canal debris but did not differ significantly with the tested passive ultrasonic or sonic irrigation method.

The use of solvents for gutta-percha dissolution/removal during endodontic retreatments: A scoping review

This scoping review study aimed to map the evidence about solvents' use for gutta-percha dissolution and removal during endodontic retreatments. The study protocol followed the Joanna Briggs Institute guidelines, available online (https://osf.io/5vy8n/). Reporting was based on PRISMA Extension for Scoping Reviews. We selected dentistry studies that considered the effectiveness of solvents in gutta-percha dissolution in endodontic retreatments and compared their performance to the use of instrumentation techniques without solvents. The search and study screening were performed in PubMed and Scopus databases by two independent researchers. A descriptive analysis considered the study design, method/technique used for obturation, method/technique used for instrumentation during retreatment, solvent solutions tested, exposure time, and main findings. A total of 41 studies were included. Despite that, most studies suggested that solvents' use may complicate root canal cleanliness, regardless of the type of instrumentation used, and facilitate the presence of gutta-percha remnants in the root surface. Thus, the use of solvents should be avoided and its use should only be considered if the previous working length was not possible to access without it. Despite that, high heterogeneity was observed, further studies are still encouraged comparing the performance and effects of different solvents in different clinical scenarios.

Effect of different obturating techniques and sealers on the removal of filling materials during endodontic retreatment

Background:

Adequate removal of previous root filling materials is an important objective during endodontic retreatment.

Aim:

This study was aimed to evaluate the influence of obturation quality and sealer type on the removal of root filling materials during endodontic retreatment using micro-computed tomography (μ-CT).

Materials and Methods:

Ninety extracted mandibular premolars were randomly assigned to two groups (n = 45) based on the type of sealer (AH Plus and BioRoot RCS) and three sub-groups based on the obturating technique used, i.e., cold lateral condensation, warm vertical compaction, and thermoplasticized injectable techniques. Specimens were scanned using μ-CT before and after retreatment to assess the amount of filling material, and time taken for removal was recorded.

Statistical Analysis:

Data were analyzed using two-way analysis of variance and Tukey's multiple post hoc test at 5% significance level.

Results:

Filling debris percentage and retreatment time were not significantly affected by the type of sealer (P ≥ 0.05). The percentage of remaining filling material was higher in teeth obturated with thermoplasticized technique (P < 0.05). Significantly more filling material debris was observed in apical third (P < 0.05).

Conclusions:

The type of obturating technique used for initial root canal treatment has influenced the amount of remaining filling material and retreatment time. Retreatability of the BioRoot RCS sealer was similar to the AH Plus sealer.

Effect of Sonic Agitation of a Binary Mixture of Solvents on Filling Remnants Removal as an Alternative to Apical Enlargement-A Micro-CT Study

BACKGROUND

This work aimed to evaluate the efficacy of sonic agitation of a binary mixture of solvents (methyl ethyl ketone/tetrachloroethylene) on filling remnants removal and compare the effects of solvent agitation with the enlargement to the next instrument size.

METHODS

Twenty-four mandibular incisors were prepared with ProTaper Next (X1, X2) and obturated with the single-cone technique and AH Plus sealer. The teeth were retreated with ProTaper Universal Retreatment and ProTaper Next and divided into two groups (n = 12) according to the final instrument (X3 or X4). All canals were submitted to a supplementary procedure consisting of a mixture of solvents-methyl ethyl ketone/tetrachloroethylene, agitated with EndoActivator. The volume of filling remnants was assessed through micro-computed tomography in the apical 5 mm. Statistical analysis was performed with a significance level of 5%.

RESULTS

The supplementary procedure of agitation of the solvent mixture was beneficial in both groups (p < 0.05). There were no statistically significant differences between canals re-prepared until X4 and canals re-prepared until X3 plus solvent (p > 0.05).

CONCLUSIONS

An additional step with a two-solvent solution potentiated by EndoActivator showed to be very effective for the removal of gutta-percha and resinous sealer remnants from apical root canals of mandibular incisors, avoiding further enlargement.

Efficacy and Cytotoxicity of Binary Mixtures as Root Canal Filling Solvents

OBJECTIVES

This study reports the efficacy of two solvent mixtures on the dissolution of gutta-percha and AH Plus sealer, together with the cytotoxicity.

METHODS

Methyl ethyl ketone (MEK), orange oil, tetrachloroethylene, MEK/tetrachloroethylene (1:1), MEK/orange oil (1:1), and chloroform (control) were tested. Twelve groups (n = 15) of standardized stainless-steel molds filled with softened gutta-percha cones and twelve (n = 15) filled with AH Plus were immersed in the corresponding mixture or individual solvent, in an ultrasonic bath, for either 2 or 5 min. The effect of the solvents was assessed qualitatively by a topographical analysis (scanning electron microscopy) and chemical analysis (Fourier transform infrared spectroscopy), and quantitatively by a weight loss and viscoelastic property (dynamic mechanical analysis) evaluation. The cytotoxicity was assessed on MG63 human osteoblastic cells.

RESULTS

The mixtures did not show the formation of new compounds. Both presented significantly higher efficacies compared to their individual solvents, suggesting a synergistic effect. Their dissolution efficacy was similar to that of chloroform, showing high cytocompatibility.

CONCLUSIONS

The proposed strategy, incorporating ultrasound agitation and profiting from the synergy of adequate solvents, might enhance root canal cleanliness allowing a single-step procedure to dissolve gutta-percha and the sealer remnants, while assuring cytocompatibility with the periapical tissues.

The retreatment abilities of ProTaper Next and F6 Skytaper: a micro-computed tomography study

Purpose

The aim of this study was to evaluate the retreatment abilities of the ProTaper Next (PTN) and F6 SkyTaper (F6) systems by using micro-computed tomography (microct), radiographic and microscopic imaging techniques.

Materials and methods

The root canals of twenty-six extracted mandibular premolar teeth were prepared and obturated. For the retreatment procedure, the teeth were randomly divided into two equal groups according to endodontic instruments: PTN (X4) and F6 (#40/.06). Pre- and post-operative filling material volumes were measured with micro-ct, and areas were measured with radiographic and microscopic imaging techniques. The percentages of residual material were calculated, and then statistically compared. The significance level was set at p<0.05.

Results

There was no statistically significant difference between F6 and PTN for retreatment efficacy in the micro-ct and radiographic imaging techniques (p>0.05). PTN demonstrated better cleaning ability when evaluated by microscopic imaging. (p<0.05). The correlation was moderate between micro-ct and radiographic, and micro-ct and microscopic imaging groups; however, it was strong between radiographic and microscopic imaging methods.

Conclusion

The PTN and F6 files had similar effects in the removal of filling material with microct evaluation. The radiographic imaging method gave similar results with micro-ct imaging.

A Comparative Evaluation of Two Commonly Used GP Solvents on Different Epoxy Resin-based Sealers: An In Vitro Study

AIM

This study evaluates epoxy resin-based sealers after their final set, immersed in Endosolve-R or xylene for 1-2 minutes, for its easy removal mechanically after softening.

MATERIALS AND METHODS

Sixty Teflon molds were grouped with 20 samples in each of the three commercially available sealers, i.e., AH 26, AH Plus, and Adseal. The sealers were put in the specific molds after their manipulation as per the instructions given in the literature by the manufacturer. They were allowed to harden for 2 weeks at 37°C in 100% humidity. Two subgroups, A-Xylene and B-Endosolv-R, of 10 samples each, were formed from 20 set specimens based on solvents to which they were immersed for 1 and 2 minutes, respectively. The data obtained was subjected to the Mauchly's test one-way ANOVA and two-way ANOVA for analysis.

RESULTS

It was proved that for all the sealers immersed in solvents, there was a significant reduction in the mean Vickers hardness as the time increases. There was a significant difference in the initial hardness between the mentioned sealers with AH plus showing the highest followed by AH 26 and Adseal showing the lowest. AH Plus and Adseal sealers were softened by xylene after 2 minutes of their initial microhardness (p < 0.001); least effect was seen on AH 26. After 2 minutes, Endosolv-R softened initial microhardness of all the three sealers (p < 0.001).

CONCLUSION

It was concluded that Endosolv-R was more effective in softening the epoxy-based resin sealer than xylene, after 2 minutes of exposure.

HOW TO CITE THIS ARTICLE

Tyagi S, Choudhary E, Choudhary A, et al. A Comparative Evaluation of Two Commonly Used GP Solvents on Different Epoxy Resin-based Sealers: An In Vitro Study. Int J Clin Pediatr Dent 2020;13(1):35-37.

Evaluation of two shaping systems and two sonic irrigation devices in removing root canal filling material from distal roots of mandibular molars assessed by micro CT

AIM

To compare two preparation systems and two sonic irrigation devices during the removal of root filling material from oval distal canals of extracted mandibular molars.

METHODOLOGY

The distal canals in 40 extracted mandibular molars were shaped using the ProTaper Next system (Dentslpy Sirona, Ballaigues, Switzerland), filled with Gutta Percha X2 (Dentsply Sirona), along with AH Plus sealer (Dentsply De Trey, Konstanz, Germany) and randomly divided into two groups (n = 20) according to volume of initial filling, preparation diameter and working length. One group was retreated using the Reciproc system (VDW, Munich, Germany), and the other using the 2Shape system (Micro-Mega, Besançon, France). A micro-CT scan was taken after the initial root filling and after retreatment to evaluate the volume of filling material remnants. The teeth were divided into four groups to test the supplementary effect of two sonic irrigation devices on removing filling material: Eddy (VDW) and MM1500 (Micro-Mega). In the first and second groups, 2Shape was followed subsequently by MM1500 and Eddy; in the third and fourth groups, Reciproc was followed by MM1500 and Eddy. A third micro-CT was taken to compare the remaining root filling material in all groups. Wilcoxon's signed rank tests, Mann-Whitney and Kruskal-Wallis tests were used for statistical analysis.

RESULTS

No significant difference was found for the volume of filling material removed between the Reciproc and 2Shape in the entire canal (P = 0.355). The volume dropped significantly from its initial value after removing the bulk of the root filling by 95.8% (from 4.71 to 0.22 mm³ ) with the 2Shape (P < 0.001) and by 94.0% (from 5.05 to 0.33 mm³ ) with the Reciproc (P < 0.001). Sonic activation significantly decreased the residual volume of filling material remnants by 3.21% (P = 0.013) in the first group, 1.38% (P = 0.012) in the second group, 1.83% (P = 0.008) in the third group and 1.83% (P = 0.012) in the fourth group. At the end, the percentage of residual material was not significantly different among the groups in the entire canal (P = 0.163).

CONCLUSION

In the distal oval canals of extracted mandibular molar teeth, there was no significant difference between the 2Shape and Reciproc systems in removing gutta-percha/sealer. Sonic activation with MM1500 and Eddy significantly improved filling material removal.

Evaluation of Two Shaping Systems and Two Ultrasonic Irrigation Devices in Removing Root Canal Filling Material from Mesial Roots of Mandibular Molars: A Micro CT Study

We assessed the efficiency of two shaping file systems and two passive ultrasonic irrigation (PUI) devices for removing filling material during retreatment. The mesial canals from 44 extracted mandibular molars were prepared and obturated. The teeth were randomly divided into two groups, and then one group was retreated with Reciproc R25 (VDW, Munich, Germany) (n = 44) and the other group was retreated with 2Shape (TS, Micro Mega, Besançon, France) (n = 44). A micro-computed tomography (CT) scan was taken before and after the retreatment to assess the volume of the filling material remnants. The teeth were then randomly divided into four groups to test two different PUI devices: Irrisafe (Satelec Acteon Group, Merignac, France) and Endo Ultra (Vista Dental Products, Racine, WI, USA). The teeth in Group A were retreated with 2Shape to test the Endo Ultra (n = 22) device, the teeth in Group B were retreated with 2Shape in order to test the Irrisafe (n = 22) device, the teeth in Group C were retreated with Reciproc to test the Endo Ultra (n = 22) device, and Group D was retreated with Reciproc to test the Irrisafe (n = 22) device. A third micro-CT scan was taken after the retreatment to test the PUIs. The percentage of Gutta-Percha (GP) and sealer removed was 94.75% for TS2 (p < 0.001) and 89.3% for R25 (p < 0.001). The PUI significantly enhanced the removal of the filling material by 0.76% for Group A (p < 0.001), 1.47% for Group B (p < 0.001), 2.61% for Group C (p < 0.001), and by 1.66% for Group D (p < 0.001). 2Shape was more effective at removing the GP and sealer during retreatment (p = 0.018). The supplementary approach with PUI significantly improved filling material removal, with no statistical difference between the four groups (p = 0.106).

Influence of solvent and a supplementary step with a finishing instrument on filling material removal from canals connected by an isthmus

AIM

To evaluate the effectiveness of a solvent (eucalyptol) in improving filling material removal from canals connected by isthmuses, and the additional cleaning effect of a finishing instrument.

METHODOLOGY

The mesial canals from 32 mandibular molars (Vertucci's type II morphology) were instrumented and filled with the single-cone technique using Reciproc R25 gutta-percha points (VDW, Munich, Germany) combined with Sealer 26 (Dentsply, Petrópolis, RJ, Brazil). Each root was then subjected to retreatment using the Mtwo instrument system (VDW), with or without a solvent (n = 16 per group). The volume of filling material in the canals was assessed by micro-computed tomographic (micro-CT) scans taken before and after retreatment. Canals with remnants of filling material received a supplementary procedure with the XP-endo Finisher R instrument (FKG Dentaire, La Chaux-de-Fonds, Switzerland), with or without eucalyptol, and another micro-CT scan was taken. All retreatment procedures were performed inside a cabinet under a controlled temperature (37 °C). Filling material removal was evaluated in the 5-mm apical canal system for the canal+isthmus space or the isthmus alone. Statistical analyses were performed to compare the removal of filling material with and without eucalyptol, and after a supplementary approach with XP-endo Finisher R. The level of significance was set at 5% for all statistical tests (P < 0.05).

RESULTS

The amount of filling material removed from the canal+isthmus with Mtwo instruments was 83.2% when no solvent was used and 83.8% using the solvent (P > 0.05). When the isthmus area was evaluated separately, most specimens were associated with a reduction in the filling material, with no significant difference between the groups with or without using a solvent (P > 0.05). The supplementary step with XP-endo Finisher R significantly improved removal of filling material from both canal and isthmus area (P < 0.05), regardless of the use of a solvent (P > 0.05).

CONCLUSION

The use of eucalyptol did not improve filling material removal from Vertucci's type II molar mesial canals and isthmuses. XP-endo Finisher R significantly enhanced removal of filling material from the canals and isthmuses.

Comparative Evaluation of Apical Transportation and Canal Centric Ability in Apical Region of Newer nickel-titanium File Systems Using cone-beam computed tomography on Extracted Molars: An In Vitro Study

Background:

Objective in root canal preparation is to develop a shape that tapers from apical to coronal, maintaining the original canal shape. With advent of instruments manufactured from nickel-titanium (NiTi) alloys, there was a significant improvement of quality of root canal shaping, with predictable results and less iatrogenic damage.

Aim:

The aim of the study was to evaluate the canal centric ability and apical transportation in apical region of newer NiTi file system in root canal using cone-beam computed tomography (CBCT) on extracted molars.

Materials and Methods:

Root canal of thirty extracted human permanent teeth with mature root apices with 20°–40° of curvature were collected and divided into three groups after initial bio-mechanical preparation: Group 1: canal prepared using ProTaperNext (PTN) file system; Group 2: canal prepared using Mani silk system; and Group 3: canal prepared using V-taper file system. All samples were scanned before and after biomechanical preparation using CBCT. The data collected were evaluated using the Kruskal–Wallis analysis of variance test and Mann–Whitney U-test.

Results:

It was observed that in apical region Group I (PTN) showed significantly lower mean apical transportation and canal centric ability as compared to Group II (Mani Silk) and Group III (V-taper).

Conclusion:

It was concluded that PTN rotary system has no canal transportation and maintained centric ability in comparison to Mani and V-taper rotary file system in apical region of curved root canal.

The efficacy of retreatment and new reciprocating systems in removing a gutta-percha-based filling material

Objectives

To investigate the efficacy of retreatment and reciprocating rotary systems in removing gutta-percha filling material from root-canal systems.

Methods

A total of 90 single-canal human teeth were instrumented using a F3 ProTaper file and obturated with gutta-percha and the Tubliseal sealer using the lateral-compaction technique. They were divided into five groups according to the rotary system used to remove the filling material: Reciproc, which used the Reciproc-R25 file; WaveOne, which used the WaveOne-Primary file; S1, which used the S1 (25/.06) file; ProTaper-R, which used the ProTaper-Retreatment system; and Mtwo-R, which used the Mtwo®-Retreatment system. The time required to remove the filling material (min) and the associated instrument separation, if any, were recorded. Teeth were cleaved longitudinally and photographed with a high-resolution camera. Images were imported to the AutoCAD application to measure the remaining filling material and the root-canal space. Data were analysed using the one-way analysis of variance and Chi-squared tests.

Results

The Mtwo-R group showed the highest mean remaining filling material (51%) (p < 0.001), with no significant differences among the other groups. The ProTaper group required the least time for filling-material removal (4.95 min), with significant differences compared to the other groups (p < 0.05), except the WaveOne group (5.83 min; p = 1.000). Overall, 13 instruments (15.9%) were used for filling-material removal, with a significantly greater proportion in the Mtwo-R group (33.3%) compared to the other groups (p = 0.009).

Conclusions

Within the limitations of this in vitro study, reciprocating rotary systems were as effective as retreatment rotary systems in removing root-canal filling material. The Mtwo-R system showed the poorest performance with respect to removal effectiveness and instrument separation.

Comparative evaluation of three different rotary instrumentation systems for removal of gutta-percha from root canal during endodontic retreatment: An in vitro study

Context:

Endodontic retreatment is performed in teeth with endodontic failures. The main goal of retreatment is cleaning and shaping of the root canal with removal of old root filling material. Hand instruments and rotary instruments are mainly used for removing this filling material.

Aim of Study:

To compare the relative efficacy of three rotary instrumentation systems for removal of gutta-percha from root canal during endodontic retreatment.

Objective of Study:

To find out which NiTi system is more efficacious in retreatment and to check out the efficacy of retreatment with and without use of solvent.

Materials and Methods:

Sixty freshly extracted, single-rooted human mandibular premolars were instrumented with K-files, and each root canal was filled with gutta-percha and AH Plus (Dentsply Detrey, Konstanz, Germany) sealer using lateral compaction. Specimens were then divided into three experimental groups with twenty specimens each. Groups were then subdivided into ten specimens each. Groups were then retreated either with or without solvent. The removal of gutta-percha was performed using ProTaper retreatment files, Mtwo retreatment files, and R-Endo files after 2 weeks. The amount of root canal filling material remnant in the coronal, middle, and apical thirds was measured using stereomicroscope and computer image analysis program.

Statistical Analysis Used:

Data were evaluated statistically using analysis of variance.

Results:

ProTaper group was found to have less remnant filling material as compared to the other groups in coronal and middle thirds, but a significant difference was observed between ProTaper and Mtwo and Mtwo and R-Endo in the nonsolvent groups (P < 0.05). Mtwo group demonstrated less amount of remaining filling material in the nonsolvent group.

Conclusions:

Both nickel–titanium systems and ProTaper and Mtwo retreatment file systems, were found to be effective in the removal of root canal filling material. However, complete removal of gutta-percha from root canals did not occur with any of the experimental groups.

Apically extruded debris in filling removal of curved canals using 3 NiTi systems and hand files

Abstract The aim of this study was to assess the amount of apically extruded debris during filling removal with WaveOne Gold (WOG), ProTaper Universal Retreatment (PTR), D-RaCe Retreatment (DRR) or hand files (HF), to compare the working time during filling removal, and to describe failures of NiTi instruments. Forty mesiobuccal roots of maxillary first molars were prepared with WOG Primary, obturated and divided into 4 groups (n=10), according to the instruments used: WOG, PTR, DRR or HF. Distilled water was used as irrigant and the extruded debris were collected in Eppendorf tubes and dried. The amount of extruded debris was determined by subtracting the final from the initial weight. The time of filling removal for each canal was recorded and the instruments used were analyzed pre and post-operatively by SEM. Kruskal-Wallis and Dunn’s test analyzed extruded debris data and ANOVA, followed by Tukey’s test, compared the working time data (a=0.05). Instrument deformation and fracture were described. WOG produced significantly less debris compared with HF and DRR (p<0.05), and similar to PTR (p>0.05). HF, PTR and DRR showed no significant difference (p>0.05). Working time in HF group was significantly higher than others (p<0.05). SEM analyses showed, from the 18 instruments evaluated, 3 fractures and 10 deformations. All instruments tested caused debris extrusion. WOG was associated with less extrusion than DRR and HF. Filling removal with HF was slower than with the other instruments. All NiTi systems presented fracture and deformation.

Evaluation of 3 Different Retreatment Techniques in Maxillary Molar Teeth by Using Micro-computed Tomography

INTRODUCTION

Nonsurgical retreatment procedure involves the complete removal of the previous filling material to allow thorough instrumentation, disinfection, and refilling of root canal system. We aimed to determine the residuals of the root-filling material by using 3 different retreatment techniques with the aid of micro-computed tomography.

METHODS

Thirty extracted human maxillary molar teeth were included. All root canals were also obturated with F2 ProTaper single cones and AH Plus sealer. The following retreatment techniques were performed: group 1, ProTaper retreatment files; group 2, Mtwo retreatment files; and group 3, ProFile files. For the assessment of residual filling material, preoperative and postoperative micro-computed tomography scans were compared with each other, and the working time was recorded. One-way analysis of variance was used to analyze the differences between the groups. The significance level was set at P < .05.

RESULTS

None of the retreatment techniques were capable of removing the whole filling material. The percentages of the residual filling materials for groups 1, 2, and 3 were 34.45, 45.43, and 23.63, respectively. There was a statistically significant difference between groups 2 and 3 (P < .05). ProTaper and ProFile instruments required less time for the removal of filling materials when compared with Mtwo instrument.

CONCLUSIONS

ProFile files revealed the best results for endodontic retreatment in terms of both removing capacity and time requirement.

Efficacy of ProTaper NEXT Compared with Reciproc in Removing Obturation Material from Severely Curved Root Canals: A Micro-Computed Tomography Study

INTRODUCTION

The aim of this study was to compare the remaining root canal obturation, volume of dentin removed, and apical transportation after retreatment of severely curved root canals by using Reciproc (REC) or ProTaper NEXT (PTN) systems.

METHODS

Twenty-eight mesial canals of mandibular molars were instrumented and then obturated with gutta-percha and sealer and allocated into 2 balanced groups (n = 14), the REC group (R25 file) and the PTN group (X3 and X2 files). Micro-computed tomography analysis was performed to assess the percentage of residual obturation material, the amount of dentin removed, and apical transportation. The effective time for the removal of obturation and procedural errors were recorded.

RESULTS

Obturation was effectively removed from the root canal in the REC and PTN groups (P ≤ .001), and the percentages of remaining obturation material were similar between both groups (84.8% PTN vs 86.5% REC) (P > .05). The amount of dentin removed (3.17 ± 2.64 mm(3) PTN versus 3.50 ± 2.82 mm(3) REC), apical transportation (at 1 mm: 0.096 ± 0.189 mm PTN versus 0.093 ± 0.186 mm REC; at 3 mm: 0.059 ± 0.069 mm PTN versus 0.082 ± 0.080 mm REC; at 5 mm: 0.097 ± 0.093 mm PTN versus 0.133 ± 0.138 mm REC), and the working time (269.69 ± 19.25 seconds PTN versus 268.62 ± 16.37 seconds REC) were also similar in both groups (P > .05). One file fractured in the REC group.

CONCLUSIONS

Both systems were equally effective in the removal of obturation from severely curved canals and can be used for retreatment. Neither system could completely remove the obturation material; therefore, additional techniques are needed to improve cleaning of the root canal.

Evaluation of Apically Extruded Debris during Root Canal Retreatment Using ProTaper Next and Reciproc in Severely Curved Canals

INTRODUCTION

To compare the apical extrusion of debris produced during root obturating material removal from severely curved root canals using either Reciproc (REC) or ProTaper Next (PTN) systems.

METHODS AND MATERIALS

Twenty-six mesial canals of lower molars were instrumented, filled and allocated into two groups (n=13). Micro-computed tomographic images were performed to determine the root canal configuration (Vertucci's type IV) and initial volume of obturation. One Eppendorf tube was assigned per canal and weighed (10^-4g) before and after removal of the obturating material. The difference between the initial and final weights was calculated and statistically evaluated.

RESULTS

Apical extrusion of debris was confirmed in all samples, and the mean amount of apical extrusion was similar between both groups (0.061±0.014 g in PTN vs. 0.065±0.016 g in REC samples) (P<0.05).

CONCLUSION

Both systems caused apical extrusion of debris with no differences between PTN and REC systems.

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

INTRODUCTION

Gutta-percha must be removed from the root canal space during retreatment to ensure a more favorable outcome. The aim of this study was to compare the efficacy of hand instruments, RaCe and RaCe plus XP-endo finisher instruments in removal of gutta-percha from root canal walls during retreatment.

METHODS AND MATERIALS

Thirty single-rooted premolars were prepared, obturated, and divided into three groups according to retreatment method; in group 1, retreatment was carried out by hand instruments, while in groups 2 and 3 retreatment was done using RaCe rotary files alone or accompanied by XP-endo finisher instruments, respectively. After retreatment, teeth were sectioned longitudinally and photographic images were taken. The amount of remaining gutta-percha in coronal, middle and apical thirds was quantified using Image J software. The two-way ANOVA and post hoc Tukey's tests were used to analyze data. The level of significance was set at 0.05.

RESULTS

RaCe cleaned the apical third significantly better than hand instrumentation. In the coronal third, RaCe+XP-endo finisher was more effective than RaCe. RaCe+XP-endo finisher was more effective than hand instrumentation in the entire root canal. The amount of remaining gutta-percha was the least in the apical part and increased toward the coronal part with the use of XP-endo finisher (P<0.05).

CONCLUSION

Rotary instrumentation was more effective in removing gutta-percha from the canal walls. Furthermore, use of XP-endo finisher file resulted in cleaner canal walls and was more effective in removing gutta-percha from the coronal toward the apical part of the canal.

Postoperative pain after the removal of root canal filling material using different techniques in teeth with failed root canal therapy: a randomized clinical trial

OBJECTIVES

This study evaluated the intensity and duration of postoperative pain after the removal of root canal filling material in retreatment procedures of upper incisor teeth with chronic apical periodontitis, using different techniques.

MATERIALS AND METHODS

One hundred and thirty-five patients requiring retreatment of upper incisor teeth with chronic apical periodontitis were included in the study. The patients were assigned to three groups of 45 patients, according to the method used to remove old canal filling material. In group 1, canal filling material was removed using hand files. In group 2, the canal filling material was removed with ProTaper universal retreatment (PTUR) instruments. In group 3, Reciproc instruments were used to remove canal filling material. Teeth were then medicated with calcium hydroxide and sealed using temporary filling material. The presence of postoperative pain was assessed after 6, 12, 24, 48 and 72 h, 7 days, and finally after 10 days.

RESULTS

In all time intervals, except for 72 h, 7 days and 10 days, group 1 participants reported more intense postoperative pain than those in groups 2 and 3 (p = 0.02). In all time intervals, there was no difference in the pain scores between groups 2 and 3 (p = 0.08). In all groups, the intensity of postoperative pain decreased over time. The required time to remove canal filling material was less for the Reciproc group compared to the hand and ProTaper retreatment groups (p = 0.032).

CONCLUSIONS

Hand files caused greater postoperative pain after non-surgical endodontic retreatment (NSER) of upper incisor teeth with chronic apical periodontitis compared to the ProTaper retreatment and Reciproc files.

Efficacy of protaper next and protaper universal retreatment systems in removing gutta-percha in curved root canals during root canal retreatment

Purpose:

The aim of this study was to compare the cleanliness of root canal walls after retreatment using ProTaper Next (PTN), ProTaper Universal Retreatment (PTR) nickel-titanium (NiTi) systems and Hedström hand files in curved mesial canals of mandibular molar teeth and the time required for gutta-percha and sealer removal.

Materials and Methods:

Ninety mandibular molar teeth with curved mesial roots were instrumented up to #35.04 with Mtwo NiTi rotary instruments and obturated using the continuous wave of condensation technique. Removal of gutta-percha and sealer was performed using one of the following: PTN and PTR NiTi systems and Hedström hand files. Samples were placed on the VistaScan phosphor plates in the mesio-distal direction and the radiographs were taken. The digital radiographs were analyzed using AutoCAD software. Also, the total time required for gutta-percha removal was calculated by a chronometer.

Results:

The total retreatment time was significantly shorter in the PTN and PTR groups compared with the manual group (p<0.05). There was a significant difference between the groups according to the total residual gutta-percha and sealer (p<0.05). The PTN and PTR groups left significantly less gutta-percha and sealer remnant than the manual group (p<0.001).

Conclusion:

Within the limitations of this study, the PTN and PTR groups showed less residual gutta-percha and sealer than the manual group. The NiTi rotary systems were significantly faster than the manual group in the time required for gutta-percha and sealer removal.

Effectiveness of the ProTaper Next and Reciproc Systems in Removing Root Canal Filling Material with Sonic or Ultrasonic Irrigation: A Micro-computed Tomographic Study

INTRODUCTION

The aim of this study was to evaluate the effectiveness of ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) and Reciproc (VDW, Munich, Germany) systems in removing filling material from oval root canals using sonic or ultrasonic irrigation as additional cleaning methods.

METHODS

Thirty-two human extracted mandibular premolars with oval canals were prepared using the ProTaper Universal system (Dentsply Maillefer) up to instrument F4 (40/.06) and then filled by the single-cone technique using Endofill sealer (Dentsply Maillefer). The teeth were randomly divided into 4 groups (n = 8) according to the instrumentation system and the additional cleaning method as follows: Reciproc 40 with ultrasonic activation, Reciproc 40 with sonic agitation, ProTaper Next (X2, X3, and X4) with ultrasonic activation, and ProTaper Next (X2, X3, and X4) with sonic agitation. All specimens were analyzed using micro-computed tomographic imaging before and after removal of the filling material and also after applying the additional cleaning methods. The data, in mm³ of remaining filling material, were analyzed by the Kruskal-Wallis, Dunn, and Mann-Whitney tests.

RESULTS

None of the retreatment protocols completely removed the filling material from the root canals, and there was no significant difference between the instrumentation systems or between root thirds assessed in terms of the average volume of remaining filling material (P > .05). Likewise, no significant difference was observed between the additional cleaning methods in any of the root canal thirds assessed (P > .05).

CONCLUSIONS

The ProTaper Next and Reciproc systems were equivalent with respect to effectiveness in removing filling material regardless of the additional cleaning method used. The additional cleaning methods were also equivalent and did not improve the removal of filling material significantly.

Influence of solvents on the bond strength of resin sealer to intraradicular dentin after retreatment

This study evaluated the removal of filling material with ProTaper Universal Rotary Retreatment system (PTR) combined with solvents and the influence of solvents on the bond strength (PBS) of sealer to intraradicular dentin after canal reobturation. Roots were endodontically treated and distributed to five groups (n = 12). The control group was not retreated. In the four experimental groups, canals were retreated with PTR alone or in combination with xylol, orange oil, and eucalyptol. After filling material removal, two specimens of each group were analysed by SEM and µCT to verify the presence of filling remnants on root canal walls. The other roots were reobturated and sectioned in 1-mm-thick dentin slices that were subjected to the push-out test. Data were analysed by two-way ANOVA and Tukey's test (α = 0.05). SEM and µCT analysis revealed that all retreatment techniques left filling remnants on canal walls. The control group (3.47 ± 1.21) presented significantly higher (p < 0.05) PBS than the experimental groups. The groups retreated with PTR alone (2.59 ± 0.99) or combined with xylol (2.54 ± 0.77) and orange oil (2.32 ± 0.93) presented similar bond strength (p > 0.05), and differed significantly from the group with eucalyptol (1.89 ± 0.63). The solvents reduced the PBS of the sealer to dentin and no retreatment technique promoted complete removal of filling material.

Comparison of the Effectiveness of Different Techniques for Supportive Removal of Root Canal Filling Material

Objective:

To compare the cleanliness of oval cross-sectioned root canals after using different supportive techniques for removal of root canal filling material as part of retreatment process.

Methods:

One hundred mandibular canine teeth with flat oval cross-sectioned canals were instrumented up to #40.06 and obturated using the warm vertical compaction technique. Removal of the gutta-percha and sealer was performed using the D-RaCe nickel-titanium retreatment instruments. The roots were randomly divided into four groups of 25 teeth, and the activation processes were applied: XP-endo Finisher (XP), EndoActivator (EA) and IrrıSafe (IS). Conventional needle irrigation (CI) was used as the control group. The teeth were sectioned, and digital images were captured. The photographs were analysed using AutoCAD software regarding the area of residual root filling. Kruskal–Wallis and post hoc Dunn’s tests were performed for statistical analysis.

Results:

There was significantly less gutta-percha and sealer remnant in the XP group than in the other groups (P<0.05). The CI group contained significantly more gutta-percha and sealer remnant than the other groups (P<0.05). The apical third of the CI group had significantly more residual gutta-percha and sealer when compared to that of the other groups (P<0.05).

Conclusion:

Within the limitations of this study, the amount of gutta-percha and sealer in the XP group was lower than that in the EA, IS, and CI groups.

Micro-Computed Tomography Study of Filling Material Removal from Oval-shaped Canals by Using Rotary, Reciprocating, and Adaptive Motion Systems

INTRODUCTION

This study evaluated filling material removal from distal oval-shaped canals of mandibular molars with rotary, reciprocating, and adaptive motion systems by using micro-computed tomography.

METHODS

After cone-beam computed tomography scanning, 21 teeth were selected, prepared up to a size 40 file, root filled, and divided into 3 groups (n = 7) according to the filling material removal technique: group PTUR, ProTaper Universal Retreatment combined with ProTaper Universal F2, F3, F4, and F5 files; group RP, Reciproc R50 file; and group TFA: TF Adaptive 50.04 files. The specimens were scanned preoperatively and postoperatively to assess filling material removal by using micro-computed tomography imaging, and the percent volume of residual filling material was calculated.

RESULTS

The statistical analysis showed the lowest percent volume of residual filling material at the coronal third in all groups (P < .05). There was no significant difference among the systems in the coronal third (P > .05). In the middle third, group TFA (31.2 ± 10.1) showed lower volume of residual filling material than group RP (52.4 ± 14.1) (P < .05). In the apical third, groups TFA (44.8 ± 20.6) and PTUR (48.6 ± 16.8) presented a lower percent volume of filling material than group RP (70.6 ± 7.2) (P < .05), as confirmed by the qualitative analysis.

CONCLUSIONS

The use of the adaptive motion increased the amount of root filling removed in the middle and apical thirds compared with the reciprocating motion. However, no technique was able to completely remove the filling material from the canals.

The efficacy of the Self-Adjusting File versus WaveOne in removal of root filling residue that remains in oval canals after the use of ProTaper retreatment files: A cone-beam computed tomography study

Aim:

The current ex vivo study compared the efficacy of removing root fillings using ProTaper retreatment files followed by either WaveOne reciprocating file or the Self-Adjusting File (SAF).

Materials and Methods:

Forty maxillary canines with single oval root canal were selected and sectioned to obtain 18-mm root segments. The root canals were instrumented with WaveOne primary files, followed by obturation using warm lateral compaction, and the sealer was allowed to fully set. The teeth were then divided into two equal groups (N = 20). Initial removal of the bulk of root filling material was performed with ProTaper retreatment files, followed by either WaveOne files (Group 1) or SAF (Group 2). Endosolv R was used as a gutta-percha softener. Preoperative and postoperative high-resolution cone-beam computed tomography (CBCT) was used to measure the volume of the root filling residue that was left after the procedure. Statistical analysis was performed using t-test.

Results:

The mean volume of root filling residue in Group 1 was 9.4 (±0.5) mm³, whereas in Group 2 the residue volume was 2.6 (±0.4) mm³, (P < 0.001; t-test).

Conclusions:

When SAF was used after ProTaper retreatment files, significantly less root filling residue was left in the canals compared to when WaveOne was used.

Efficacy of Different Nickel-Titanium Instruments in Removing Gutta-percha during Root Canal Retreatment

INTRODUCTION

The aim of this study was to compare the cleanliness of root canal walls after retreatment using ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), Twisted File Adaptive (TFA; Axis/SybronEndo, Orange, CA), Reciproc (PRC; VDW, Munich, Germany), and ProTaper Universal retreatment (PTR, Dentsply Maillefer) nickel-titanium systems and the time required for gutta-percha and sealer removal.

METHODS

Eighty human maxillary central incisors with single and straight root canals were instrumented up to #40.02 with manual K-files (Dentsply Maillefer) and obturated using the continuous wave of condensation technique. Removal of the gutta-percha and sealer was performed using 1 of the following nickel-titanium systems: PTN, TFA, RPC, or PTR. The teeth were sectioned, and digital images were captured. The photographs were analyzed using AutoCAD software (Autodesk, San Rafael, CA). Also, the total time required for gutta-percha removal was calculated by a chronometer.

RESULTS

The total retreatment time was significantly shorter in the PTR group compared with the other groups (P < .05). There was a significant difference between the groups according to the total residual gutta-percha and sealer (P < .05). The PTN and PTR groups left significantly less gutta-percha and sealer remnant than the TFA and RPC groups (P < .05).

CONCLUSIONS

Within the limitations of this study, the PTN and the PTR groups showed less residual gutta-percha and sealer than the TFA and RPC groups. The time required for gutta-percha and sealer removal was similar for all the groups, except for the PTR group.

Efficacy of passive ultrasonic irrigation in removing root filling material during endodontic retreatment

Abstract Introduction The aim of endodontic retreatment is to remove the previous root filling materials completely to allow for the subsequent steps of cleaning, canal shaping and filling replacement. Objective To evaluate the efficacy of passive ultrasonic irrigation (PUI) in the removal of residual root filling material after removing the bulk of the root filling with nickel-titanium rotary instruments. Material and method Eighteen mesial isthmus-containing roots of human mandibular molars were prepared and filled. The root canal filling was removed with the ProTaper Retreatment system and K-files. The specimens were randomized into 2 groups (n = 9), both irrigated with 2.5% NaOCl and 17% EDTA. In the conventional group, an irrigation syringe was used. In the PUI group, the PUI technique was used. The roots were sectioned longitudinally and evaluated under stereomicroscopy. Student’s t test was used to compare groups and the general linear model was used to compare the apical, cervical, and middle root thirds within each group, in regard to the percentages of remaining residual filling material. Result There was no statistically significant intergroup difference, irrespective of which root third was evaluated (P > 0.05). In the PUI group, the apical third showed a significantly higher percentage of residual filling material, in comparison with the cervical (P = 0.038) and middle (P = 0.029) thirds. Conclusion The PUI technique was not more effective than the conventional irrigation technique in removing residual root filling material during endodontic retreatment in root canals with a complex anatomy.

Do the Sealer Solvents Used Affect Apically Extruded Debris in Retreatment?

INTRODUCTION

We evaluated apically extruded debris in the retreatment of root canals filled with different root canal sealers and gutta-percha using different solvents.

METHODS

Ninety human mandibular central and lateral teeth were prepared using the Reciproc #25 .08 nickel-titanium system (VDW GmbH, Munich, Germany) and were divided randomly into 6 groups. In groups 1, 2, and 3, root canals were filled with epoxy resin-based sealer and gutta-percha, and in groups 4, 5, and 6, root canals were filled with zinc oxide-eugenol-based sealer and gutta-percha. Each tooth was placed in a glass vial experimental apparatus. All root canal fillings were removed with the ProTaper Retreatment nickel-titanium system (Dentsply Maillefer, Ballaigues, Switzerland). During the retreatment procedure, in group 1, Resosolv (Pierre Rolland, Merignac, France) was used; in group 4, Endosolv E (Septodont, Paris, France) was used; and in groups 2 and 5, Guttasolv (Septodont) was used as the solvent. In the control groups (groups 3 and 6), no solvent was used. Reciproc #40 .06 was used for the final preparation. The times required for retreatments were recorded.

RESULTS

The weight of the extruded debris and the time required for retreatment were decreased significantly in the groups in which a solvent that was intended specifically for the root canal sealer was used (groups 1 and 4). In the Guttasolv groups (groups 2 and 5), the amount of apically extruded debris and the time required decreased for both root canal sealers.

CONCLUSIONS

The amount of apically extruded debris and the duration of retreatment were reduced by the use of a solvent specific to the sealer compared with a gutta-percha solvent or no solvent.

Comparison of retreatment ability of full-sequence reciprocating instrumentation and 360° rotary instrumentation

OBJECTIVES

The purpose of the present study was to investigate the amount of root canal filling material after root canal filling removal with 360° rotary instrumentation or reciprocating motion with the same file sequence.

MATERIALS AND METHODS

Root canals of the 36 mandibular premolars were shaped with ProTaper Universal instruments up to size F2 and filled with corresponding single gutta-percha cone and sealer. The teeth were assigned to two retreatment groups (n = 18): group 1 360° rotational motion and group 2 reciprocating motion of ATR Tecnika motors (1310° clockwise and 578° counterclockwise). Retreatment procedure was performed with ProTaper Universal retreatment files with a sequence of D1-3 and ProTaper Universal F3 instruments. Total time required to remove filling material were recorded. Remaining filling material was examined under stereomicroscope at ×8 magnification. The data were analysed statistically using the Mann-Whitney U test, and testing was performed at 95 % confidence level (p < 0.05).

RESULTS

There were no significant differences between the groups (p > 0.05) in terms of remaining filling material. The total time required for retreatment was shorter in 360° rotational motion group compared to reciprocating motion group (p < 0.05).

CONCLUSION

Both continuous rotation and reciprocating motion showed similar effectiveness in terms of root canal filling material removal.

CLINICAL RELEVANCE

Using ProTaper Universal retreatment instruments with reciprocating motion of ATR motor and conventional rotary motion have similar efficacy in root canal filling removal.

Comparison of Time Required by D-RaCe, R-Endo and Mtwo Instruments for Retreatment: An in vitro Study

INTRODUCTION

To evaluate and compare the amount of time required by three rotary NiTi instruments in removing gutta-percha from root canal during retreatment with hand file as control.

MATERIALS AND METHODS

Eighty human mandibular premolars with single straight root canals were prepared and obturated by cold lateral condensation with gutta-percha and AH Plus sealer. After two weeks, the 80 teeth were divided into one control group and 3 retreatment groups (n = 20 each). Gutta-percha was removed using H-files, the D-RaCe, or the Mtwo or the R-Endo retreatment systems. Retreatment time was calculated using stopwatch.

RESULTS

D-RaCe and Mtwo required significantly less time than R-Endo and hand file. Hand file took maximum time, which was significantly slower than all groups. However, D-RaCe and Mtwo retreatment time was statistically insignificant.

CONCLUSION

D-RaCe and Mtwo remove gutta-percha faster than R-Endo and Hand files.

Efficacy of reciprocating and rotary systems for removing root filling material: a micro-computed tomography study

This study aimed to use micro-computed tomography (micro-CT) imaging to evaluate the efficacy of the reciprocating and rotary systems for the removal of root filling materials in comparison with hand files. Thirty maxillary incisor teeth were prepared with ProTaper Universal (PTU) system, filled using cold lateral condensation and randomly divided into three groups of ten teeth each. The root fillings were removed with WaveOne Reciprocating and ProTaper Universal Re-treatment (PTU-R) systems and hand files. Micro-CT was used to scan the specimens before and after each treatment step. Percentage of volume of residual root filling was measured. The operating time was recorded. PTU-R instruments yielded better results for removing filling material, even though there was no statistically significant difference between PTU-R and WaveOne groups. Reciprocating and rotary systems showed similar performances in terms of efficacy and operating time for root filling removal.