Gutta-percha Removal Research Articles

The efficacy of three different file systems in removal of root filling residue that remains in oval root canal after the use of protaper retreatment files: An In vitro cone-beam computed tomography study

Aims: The aim of this study is to evaluate the efficacy of supplementary file system in the removal of gutta-percha and sealer from the root canal system. Subjects and Methods: Forty-five oval single-rooted mandibular premolars were prepared up to size F2 (DENTSPLY ProTaper) and obturated with gutta-percha and sealer and randomly divided into Group I, Group II and Group III (n = 15). Each group was retreated with ProTaper retreatment files and then additionally retreated with Supplementary files, XP EndoFinisher R file, ProTaper F3 and F4 and WaveOne large, respectively. The cone-beam computed tomography scans were taken after obturation, during the first stage retreatment and second stage retreatment to compare the volume of root filling residue that remained after different stages of retreatment. Statistical Analysis Used: ANOVA and Tukey's multiple comparison tests were used to compare the data. Results: Group I exhibited least root canal residue (P < 0.01) as compared to Group II and Group III that were statistically similar (P > 0.05). Conclusions: The ProTaper retreatment files, coupled with XP EndoFinisher R file, results in the better removal of the root canal fillings during endodontic retreatment procedure.

An assessment of the efficacy of a rotary and a reciprocating retreatment file system for removal of gutta-percha from root canals: An in vitro cone-beam computed tomography study

Aim: The aim of this study was to compare the NeoEndo and WaveOne retreatment systems concerning the effective removal of epoxy resin-based sealer and gutta-percha during the retreatment of straight root canals.Materials and Method: Sixty extracted, human mandibular first premolars with single straight roots were selected based on cone-beam computed tomography (CBCT) evaluations. The root canals were instrumented with the ProTaper system up to the F3 file and filled with gutta-percha and epoxy resin-based sealer using the cold lateral condensation technique. After 1 month, the samples were randomly divided into two groups (n = 30) according to the retreatment system used: NeoEndo and WaveOne. A CBCT device scanned specimen after the root filling and retreatment procedures, and the decrease in the volume of filling material after each retreatment protocol was measured. The results were analyzed using the paired t-test and additional box-and-whisker plots.Results: The WaveOne removed significantly more material than the NeoEndo (P = 0.005) system.Conclusion: The WaveOne system was more effective than the NeoEndo retreatment system during the removal of filling material.

A Comparative Study of the Efficacy of WaveOne and NeoEndo Retreatment File System for the Removal of Gutta Percha from the Root Canal.

Background:Teeth with apical periodontitis that either persisted or developed after initial root canal treatment is most often indicated for retreatment procedure. The present study was conducted to compare the WaveOne and NeoEndo retreatment file system for the removal of gutta-percha from the root canal.Materials and Methods:Fifty extracted mandibular first premolars with single straight roots were divided into two groups, Group I-WaveOne and Group II-NeoEndo. All samples were scanned with cone-beam computed tomography after the root filling and retreatment procedures. The decrease in the volume of filling material after each retreatment protocol was measured.Results:The mean volume of gutta-percha in Group I before retreatment was 5.6 and in Group II was 5.3, after retreatment in Group I was 2.7, and in Group II was 4.2. The mean percentage reduction in Group I was 45.2% and in Group II was 23.8%. The difference was significant (P < 0.05).Conclusion:Both systems failed to completely remove gutta-percha. WaveOne was significantly more effective than the NeoEndo retreatment system.

Chloroform skin injury after endodontic Chloroform skin injury after endodontic retreatment: Case report

A nonsurgical root canal retreatment was initiated for the upper right second premolar in a 35-year-old healthy female patient as part of her comprehensive dental treatment. She reported severe pain during the treatment, and then the procedure was discontinued due to time limitations. The next day, she returned back to the clinic complaining of a skin injury on the right side of her face. According to the patient's history, she felt a burning sensation during the procedure when the treating clinician began using a solution from a syringe. Extraoral clinical examination revealed a dry, pink-brown skin injury extending from the right labial commissure to the middle cheek area. Since the only solution used during the first visit was chloroform, the skin injury was diagnosed as a first-degree chemical burn due to accidental chloroform skin exposure. The patient was reassured and instructed to use petroleum jelly (Vaseline) until healing was complete. After 2 weeks, the burn had healed completely without scarring, with only slight hyperpigmentation remaining in the affected area. Chloroform use should be limited to cases in which mechanical gutta-percha removal is ineffective. It should be handled with extreme caution. Chemical burns can be prevented if exposure is detected immediately and the area washed thoroughly. This clinical case is made to increase the clinicians' awareness of the hazards of chloroform.

Endodontic retreatment

Root canal treatment can last for lifetime, but in case of any recurrent infection and procedural errors endodontic retreatment can save a tooth. Whenever possible it is best to save a natural tooth. In some cases even when treatment has followed the highest standards it still results in endodontic failure. Endodontic failure results from persistent or secondary intra-radicular infection. Extra-radicular infections may be implicated in the failure of some cases. The reason many teeth do not respond to root canal treatment is because of procedural errors. The purpose of this article is to discuss about etiological factors of endodontic failure, removal of gutta percha from canals and different techniques of endodontic retreatment. Keywords: Radicular infections, Overfilling, Coronal Leakage, Gutta percha, Retreatment, Endodontic failure, Curved canals, Rotary Instruments.

In Vitro Comparison of Gutta-Percha Removal Using XP Endo Finisher and ProTaper With or Without Organic Solvent by Scanning Electron Microscope

Introduction: Non-surgical endodontic retreatment is highly dependent on the removal of previous root filling material, bacteria and necrotic tissue. Various techniques and instruments have been used for endodontic retreatment. Recently, the XP-endo Finisher has been introduced in endodontic treatment to clean highly complex morphologies and difficult to reach areas. Aims: a) To compare the effectiveness of XP-endo Finisher and ProTaper universal retreatment system with or without organic solvent in removing gutta-percha. b) To compare the amount of apically extruded debris between the groups. Methods: 24-human- extracted, single-rooted teeth were divided into three groups of 8. The groups were classified as follows: Group I: using a ProTaper universal retreatment system with chloroform. Group II: using a ProTaper universal retreatment system without chloroform. Group III: using a ProTaper universal retreatment system followed by XP-endo Finisher without chloroform. The apically extruded debris was collected during the retreatment and weighted. The roots were split longitudinally. The degree of dentinal tubules patency was evaluated by scanning electron microscopy. Results: The most intensely clear dentinal tubules were observed in group III, followed by group II and group I, respectively. Group I resulted in a debris extrusion, significantly less, as compared with the other groups (P &lt; 0.05). While there was no notable difference between group II and group III (P &gt; 0.05). Conclusion: Under the conditions of the present study, out of all the retreatment techniques that were used, the XPendo Finisher was the most effective in the removal of the gutta-percha in cervical, middle and apical thirds. The use of solvent during retreatment can decrease the amount of the apically extruded debris.

Efficacy of various rotary retreatment instruments for gutta percha removal: An in vitro study

Background: Failure of endodontic treatment may necessitate retreatment by removing gutta percha from root canals. The present study evaluated the efficiency of retreating gutta-percha obturated root canalas with protaper universal retreatment files, endo retreatment files, nrt gpr retreatment files and h files, while using the sealers, ah plus and zinc oxide euginol for obturation. Materials and Methods: Intact single rooted 120 mandibular premolars were decoronated to obtain a standardized root length of 15 mm. Canals were obturated using thermoplasticized gutta percha (GP) with either AH Plus or Endofill as sealer. The roots were randomly divided into 8 groups, with 15 teeth in each group, and gutta percha removal was done using H files, (PTUR Protaper universal retreatment), R Endo and NRT GPR (Nickel titanium gutta percha remover), for studying their efficiency in terms of total operating time and GP remnants left in the canal by using Confocal Raman Microscope. Results: The order of efficiency in terms of time and gutta percha (GP) removal was PTUR > R-Endo > NRT GPR > H-files. The difference in GP removal was not statistically significant but the time taken for removal was statistically significant. The use of AH Plus sealer showed more remnants than Endofill sealer and the file system followed the same order of efficiency, but the difference was not statistically significant. Conclusion: The rotary retreatment system proved to be more efficient than hand files for gutta percha removal.

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.

A comparative evaluation of removal of gutta percha using two retreatment file system: An in vitro study

A comparative evaluation of the efficiency of two retreatment file systems in removing Gutta-percha from the root canals. Forty mandibular premolar teeth with single roots were specifically collected and decoronated with diamond disc so that the root lengths were standardized.Working length (WL) determination was done and root canal preparation done using Hyflex CM rotary files which was followed with meticulous irrigation and obturation was performed with gutta-percha, by the lateral condensation technique. AH-Plus sealer was used. The specimens were then divided in a random manner into two groups, in which retreatment was performed using two retreatment systems, Mtwo and REndo. These were further subdivided into two subgroups groups, i.e. one group using root canal solvent and another without solvent. Retreatment will be considered accomplished when gutta-percha was fully removed from the canal and none could be observed on the retreatment instruments and the same was confirmed radiographically. Longitudinally sectioning was done to split the root in to two halves-Mesial &amp; Distal and was observed for the remnants under scanning electron microscope with 40x and 100x magnification. Photographs of the specimens were taken using a digital camera and the area of the remaining obturating material was determined using the AutoCAD16 software.: The area of remaining guttapercha in mesial and distal half for all the samples were evaluated using the Autocad software(Version 2016) and the mean as well as standard deviation of each group were used for statistical analysis (SPSS 22.00 for windows; SPSS inc, Chicago, USA).Statistical analysis was done using factorial ANOVA and Tukey HSD Post Hoc test. Difference between two groups was determined using student t-test and the level of significance was set at p &amp;#60; 0.05. The results revealed that Mtwo R file system was found to be a more efficient rotary system for endodontic retreatment when compared to REndo(p&amp;#60;0.05) and use of solvent acts as an adjuct for retreatment in both file systems (p&amp;#60;0.05).

NONSURGICAL MANAGEMENT OF ENDODONTIC IATROGENY USING MTA PLUG: A CASE REPORT

Endodontic treatment confronting previous iatrogeny in teeth with incomplete root formation and apical periodontitis is presented as a challenge to the Endodontists. The sanitization and peri-radicular repair can be achieved by the assist of auxiliary materials to biomechanical treatment procedures. MTA is cogitated as a choice for these cases due to its composition, physicochemical, mechanical and biological properties. In this case report, the patient presented tooth 11 with incomplete root formation and peri-radicular radiolucent lesion accompanied by the presence of an inverted gutta-percha cone in an attempt to filling the root canal. Endodontic treatment was accomplished by removal of the previous gutta-percha. After determining the working length, biomechanical preparation was achieved up until #80 K-file. Sequentially application of calcium hydroxide, as intracanal medication, was performed. Six monthly exchanges of intracanal dressing were completed. Apex was sealed with MTA bonded with saline through #4 Paiva condenser, creating an apical plug. The tooth was temporarily sealed, and patient returned after a week to perform the root canal filling with gutta-percha associated to Sealapex. The final radiography shows apical tissue repair with no peri-radicular lesions and clinical signs of successful treatment. This case report highlights the tissue repair and lack of local infection, absence of sensitivity pain or edema. These findings indicated that these approaches could be elect to presence of necrotic lesions achieving tissue repair.

Evaluation of the presence of microorganisms from root canal of teeth submitted to retreatment due to prosthetic reasons and without evidence of apical periodontitis.

The objective of this study was to evaluate the presence of microorganisms in the root canals (RC) of teeth submitted to endodontic retreatment due to prosthetic reasons and without evidence of apical periodontitis. Twenty teeth referred to endodontic retreatment due to prosthetic reasons and without evidence of apical periodontitis were included in this study. Gutta-percha (GP) was collected from each third of the RC. After GP removal, microbial samples were also collected from the full extension of RC using paper points and files. The samples were cultivated in Fastidious Anaerobe Agar and the colony-forming units (CFU/mL) were counted. They were also semi-quantitatively analyzed by checkerboard DNA-DNA hybridization using 40 DNA bacterial probes. Microorganisms were found in all samples. The coronal third of GP was more contaminated than the apical third (p ≤ 0.05). There was prevalence of Enterococcus hirae and Enterococcus faecalis in all RC thirds and also in the samples collected from the full extension of RCs. Microorganisms were found in all cases referred to endodontic retreatment due to prosthetic reasons and without evidence of apical periodontitis. Enterococcus was the genus most frequently detected. An endodontic retreatment should be considered before replacing a prosthesis.

Micro-computed tomographic evaluation of the apical seal of endodontically treated teeth by two obturating techniques and two post space preparation techniques

Aim: This study evaluated apical seal of teeth obturated by two techniques and gutta-percha (GP) removed by two methods for post space preparation, using micro-computed tomography (micro-CT). Materials and Methods: Fifty-six single rooted teeth were decapitated at 15mm from the apex and prepared using ProTaper Universal System. Specimens were divided into two main groups of 28 each according to technique of GP Removal and post space preparation: Group A1, GP removed by a penetrating drill and Group A2, GP removed by hot plugger. Each main group was divided into two subgroups according to obturation technique: single cone (SC) and System B. Each subgroup was further divided into two minor subgroups according to storage time—immediately and one-week post-obturation. Approximately 9mm of GP was removed for post space preparation. All specimens were scanned three times by micro-CT: post-preparation, post-obturation, and after post space preparation. Total mean percentage of voids/gaps in the apical portion was calculated at 1, 3, and 5mm from the apex. Data were explored for normality using Kolmogorov–Smirnov and Shapiro–Wilk tests. Paired sample t-test was used to compare between two groups. Independent sample t-test was used to compare between two groups in non-related samples (significant P ≤ 0.05). Results: It showed that group A2 recorded significantly lower voids than group A1 at the two investigation periods. Voids associated with System B technique were lower than those with SC. Conclusion: An immediate removal of GP by hot plugger would not affect the apical seal.

Apical extrusion of root canal filling material during the removal of gutta-percha and resilon

Introduction. Root canal filling material may be extruded during retreatment through the apical foramen and cause flare-up or chronic infection. The aim of this study was to compare the apical extrusion of gutta-percha and resilon filling materials during retreatment using hand and rotary instruments. Methods. Sixty extracted single-rooted teeth with single, straight canal were selected. Canals were prepared with ProTaper Universal rotary system to a size F2. Two groups (30 teeth in each) were filled with gutta-percha or resilon points, respectively. In both groups teeth were randomly divided into the three subgroups (10 teeth in each), based on the instruments used for retreatment: Hedstrom hand files and two rotary groups- ProTaper and Twisted File instruments. Apical extrusion was detected visually, using a 4-degree scoring system. Mean scores were calculated and analyzed statistically (t-test and ANOVA). The level of significance was set at p &lt; 0.05. Results. Under tested experimental conditions, the type of canal filling material did not have significant effect on the results of apical extrusion during retreatment. Significantly more material was extruded in the resilon group when manual, Hedstrom file was used (1.80 ? 1.13) than rotary ProTaper (0.60 ? 0.70) and Twisted File (0.50 ? 0.71). Conclusions. The use of a rotary technique is recomended to minimize apical extrusion, especially when resilon obturation material is removed during retreatment.

Comparison of the efficacy of different Ni-Ti instruments in the removal of gutta-percha and sealer in root canal retreatment

To evaluate and compare the efficacy of four rotary instrumentation systems in root canal retreatment and to determine retreatment time. To achieve the purpose of this study, canals of 60 distal roots in mandibular molar teeth were selected and randomly divided into four groups A, B, C and D (n = 15). Using step-back technique, the canals were prepared and filled with gutta-percha and AH Plus employing cold lateral compaction technique. The root filling material was removed with the following retreatment systems: Group A: Mtwo R, group B: D-RaCe, group C: ProTaper R and group D: R-Endo. In order to record retreatment time, a stopwatch was used. The samples were split longitudinally, examined under a stereomicroscope, photographed and assessed with AutoCAD software. Finally, the percentages of remaining filling material were calculated and the extracted data were analyzed using one-way ANOVA and Tukey HSD test. All examined groups showed traces of remaining filling material within the canals. No statistically significant difference was found among the four groups in the coronal, middle, and apical thirds. The same result was obtained with regard to retreatment time (P > 0.05). However, within each one of the groups, significant difference was observed in the three regions (P < 0.05). Based on the findings of this study, none of the examined systems could completely remove root filling material from the root canals. However, they were all found to be effective in this regard. The most amount of remaining filling material was found in the apical third.

Entrococcus faecalis elimination in retreatment cases using passive ultrasonic irrigation, manual dynamic activation and photodynamic therapy: a randomized clinical trial

Aim The aim of this in-vivo study was to compare the effect of passive ultrasonic irrigation, manual dynamic activation and photodynamic therapy in reducing Enterococcus faecalis load in retreatment cases by using PCR. Materials and methods Single-rooted, single-canalled 36 teeth with post-treatment apical periodontitis were selected for this study. Teeth were divided into three groups according to the disinfection methods: passive ultrasonic irrigation, manual dynamic activation, and photodynamic therapy (PDT). Microbiological samples were taken after removal of gutta-percha (S1), after preparation of the root canal (S2), and after disinfection method (S3) with sterile paper points. The E. faecalis amounts were measured by using PCR. Results Intragroup analysis revealed that, all groups showed a significant decrease between S1 and S2 (P ≤ 0.05). However, a significant decrease between S2 and S3 was found only with PDT group (P ≤ 0.05). Intergroup analysis revealed that no significant differences were found among disinfection methods for bacterial load of S1, S2 and S3 (P ≥ 0.05). There were no significant differences among disinfection methods in terms of E. faecalis reduction percentages (from S2 to S3) (P ≥ 0.05). Conclusion PDT method significantly enhanced E. faecalis elimination after chemomechanical preparation. All disinfection methods were effective in reducing E. faecalis from infected root canals with no statistical differences.

Comparative evaluation of retreatment techniques by using different file systems from oval-shaped canals.

Introduction:Endodontic failure resolves after complete removal of obturating material followed by disinfection, cleaning, shaping and three-dimensional obturation.Materials and Methods:Seventy single-rooted mandibular premolars, with single oval-shaped root canal were included. They were decoronated at a length of 16 mm from the apex. Shaping and cleaning were performed, and obturation was done using the warm lateral compaction technique. The teeth were divided into seven groups according to retreatment procedures (Hand files; ProTaper Universal retreatment files; MTwo® Retreatment system; R-Endo® Retreatment system; ProTaper Universal retreatment files with solvent and ultrasonics; MTwo® R with solvent, and ultrasonics and R-Endo® with solvent and ultrasonics). The data were obtained and subjected to the statistical analysis.Results:All instrumentation techniques left obturating material with least in Group 6 and maximum Group 5. The mean time taken for complete retreatment procedure was minimum in Group 2 and maximum with Group 1.Conclusion:MTwo® R with solvent and ultrasonics, R-Endo®, and R-Endo® with solvent and ultrasonics were effective in gutta-percha removal from coronal third, middle third, and apical third, respectively. Significance: Nonsurgical endodontic retreatment using rotary files helps in gaining access to infected teeth. During retreatment procedure, this helps disinfectant to reach in critical areas of the root canal system, thereby decreasing the microbial load, leading to achieve healthy periradicular tissues.

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

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). 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). 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). 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.

Evaluation of gutta-percha removal from the dentinal tubules using different instrumentation techniques with or without solvent: An In vitro study

Aim: The cleanliness of dentinal tubules was compared after using different techniques for the removal of root filling material during root canal retreatment with and without solvent. Materials and Methods: Root canals of 90 extracted teeth were prepared and filled in vitro using lateral compaction with gutta-percha and sealer. In the control group (n = 10), the canals were left unfilled. In four experimental groups (n = 20 each), the root fillings were removed after 2 weeks using Hedstrom file, one of two rotary nickel–titanium instruments (ProTaper and Mtwo retreatment files), or a neodymium-doped yttrium aluminum garnet laser with H-file. Each experimental group was further subdivided into two subgroups (n = 10) according to whether the solvent N,N-dimethylformamide was used or not. After final irrigation, the samples were split longitudinally and photographed. The dentinal tubules' cleanliness was evaluated at the microscopic level by a scanning electron microscope in the coronal, middle, and apical thirds of each root half. Results: The number of open tubules was more prevalent in the control group, followed by the nonsolvent subgroups, than in the solvent subgroup (P

In Vitro Comparison of Efficacy of Neolix and ProTaper Universal Retreatment Rotary Systems in Removal of Gutta-Percha Combined with Two Different Sealers

Statement of the Problem:The complete removal of filling material is an important step to regain access to the entire canal and facilitate the disinfection of the root canal system. Rotary nickel-titanium (NiTi) instruments systems have been proposed as an effective removal technique for root canal retreatment. Purpose:The aim of this study was to evaluate the efficacy of Neolix rotary system and ProTaper Universal retreatment system in the removal of gutta-percha combined with two different sealers. Materials and Method: In vivo study, eighty extracted human permanent mandibular premolars were prepared using the ProTaper Universal rotary system to an apical size 30 (F3/0.06). The specimens were randomly divided into 4 groups (n=20) and subsequently filled with lateral condensation of gutta-percha and two sealers: AH-26 and Sure-Seal Root. The teeth were stored for 4 weeks at 37°C and 100% humidity and then retreated by one of the following rotary systems: Neolix or ProTaper Universal retreatment system. Teeth were then grooved and monitored under a stereomicroscope with 8× magnification. The images were transferred to the computer and the amount of filling material that remained on the root canal walls was scored using AutoCAD 2017 version 1.1software. Results were analyzed using one-way analysis of variance test and post hoc Tukey-HSD test (p< 0.05). Results:The mean percentage of remaining gutta-percha and sealer was significantly higher in apical third in all groups (p< 0.01). Post hoc Tukey test showed that there is significantly higher residual filling material in the group filled with gutta-percha and Sure-Seal Root sealer and retreated by Neoniti rotary system compared with other groups in both coronal and middle third of the canal. Conclusion:The Neoniti rotary system was as effective as ProTaper Universal retreatment system in retreatment of gutta-percha and AH-26 sealer but was significantly less effective in groups obturated with Sure-Seal Root sealer.

Comparative Evaluation of Efficacy of ProTaper&amp;reg; Universal Rotary Retreatment System for Gutta-percha Removal from Single Root Canals, Obturated with Two Different Techniques: In Vitro Cone-beam Computed Tomography Study

Comparative Evaluation of Efficacy of ProTaper&amp;reg; Universal Rotary Retreatment System for Gutta-percha Removal from Single Root Canals, Obturated with Two Different Techniques: In Vitro Cone-beam Computed Tomography Study