Retreatment Procedures Research Articles

Outcome of buccal mucosa urethroplasty in the management of urethral strictures.

The objective of the study is to report the outcome of buccal mucosal urethroplasty. The follow up data of 15 patients undergoing single stage urethroplasty from September 2010 to September 2015 were retropectively reviewed. They received buccal mucosa graft for urethroplasty. The patients were followed for complications and outcome. Mean age was 53.7 ± 13.6 The stricture length ranged from 3 to 6 cm (mean 4.4 ± 0.8). The success rate for buccal mucosa urethroplasty (BMU) was 67.7% at 12th month. Three patients presenting with voiding difficulty in the 3rd month and one in the next 12 months, had urethral restenosis. One patient had fistula formation at 6th month postoperatively. Five patients underwent retreatment procedures such as internal urethrotomy, urethroplasty and/or internal urethrotomy. The buccal mucosa is easy to obtain and handle, therefore BMU can be safely and effectively managed outside high volume institutions.

Comparison of Apically Extruded Debris during Retreatment Procedure by Two Types of Endodontic Instruments

Abstract Introduction: During root canal treatment, canal debris is inadvertently extruded through the apex during shaping and cleaning. This happens not only during the routine endodontic cases, but also during the retreatment cases. Objective: This study analyzed in vitro the amount of debris extruded through the foramen using two instrumentation techniques during endodontic retreatment. Materials and methods: Sixty roots of mandibular first premolars were selected, instrumented with anatomical diameter up to size number 40 International Organization for Standardization (ISO) file, and then obturated with gutta-percha and zinc-oxide eugenol sealer by lateral condensation. They were then divided into two groups of 30 each. The first group was instrumented with ISO K-files for gutta-percha removal and the second group was instrumented with Protaper retreatment files and gutta-percha was removed. All teeth were irrigated with distilled water. The debris extruded through the foramen were collected and weighed by an analytical balance. Results: Group II had the lowest average for material extrusion through the foramen followed by group I. When Tukey test for statistical analysis was applied, significant differences among groups were found (p = 0.02). Conclusion: It can be concluded that Protaper retreatment files produce significantly less debris as compared with K-files.

Efficacy of Ethylenediamine Tetraacetic Acid and Calcium Hydroxide in the Removal of Root Canal Filling During Retreatment

Objective: To compare the effect of Ethylenediamine tetraacetic acid (EDTA) and calcium hydroxide [Ca(OH) 2 ] in the removal of root canal filling material during retreatment procedure. Methodology: Eighty extracted, single-rooted human teeth were used. Root canals were shaped with a crown-down technique using Ni-Ti rotary instruments (ProTaper, Dentsply Maillefer, Switzerland) and filled with a cold lateral condensation method. AH Plus was used as a sealer. After filling, the teeth were divided into 4 groups and root fillings were removed by ProTaper Universal rotary retreatment system. In each group different irrigation and disinfection protocols were followed; Group I. Sodium hypochlorite (5.25%) + EDTA (17%-1 min.) Group II. Sodium hypochlorite (5.25%) Group III. Sodium hypochlorite (5.25%) + Ca (OH)2 Group IV. Sodium hypochlorite (5.25%) + Ca(OH) 2 + EDTA (17%-1 min.). Irrigation with 17% EDTA was performed only before D 3 -Retreatment instrumentation in all groups. AutoCAD system was used to detect the amount of residual root canal filling material. The results were statistically analyzed by SPSS (Statistical Package for Social Sciences) for Windows 15.0, one way ANOVA and Tukey’s HSD tests. The significance was evaluated at the level of p 0.05). Conclusions: Irrigating the canals with EDTA enhanced the removal of root canal filling during retreatment. However, disinfecting the canals with Ca(OH) 2 had no effect in the removal of filling material. Keywords: Retreatment, Sodium Hypochlorite, Ethylenediamine tetraacetic acid, calcium hydroxide.

Apically Extruded Debris after Retreatment Procedure with Reciproc, ProTaper Next, and Twisted File Adaptive Instruments

IntroductionThe aim of this study was to compare the amount of debris extruded from the apex during retreatment procedures with ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (RCP; VDW, Munich, Germany), and Twisted File Adaptive (TFA; SybronEndo, Orange, CA) files and the duration of these retreatment procedures. MethodsNinety upper central incisor teeth were prepared and filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany) using the vertical compaction technique. The teeth were randomly divided into 3 groups of 30 for removal of the root filling material with PTN, RCP, and TFA files. The apically extruded debris was collected in preweighed Eppendorf tubes. The time for gutta-percha removal was recorded. Data were statistically analyzed using Kruskal-Wallis and 1-way analysis of variance tests. ResultsThe amount of debris extruded was RPC > TFA > PTN, respectively. Compared with the PTN group, the amount of debris extruded in the RPC group was statistically significantly higher (P < .001). There was no statistically significant difference among the RCP, TFA, and PTN groups regarding the time for retreatment (P > .05). ConclusionsWithin the limitations of this in vitro study, all groups were associated with debris extrusion from the apex. The RCP file system led to higher levels of apical extrusion in proportion to the PTN file system. In addition, there was no significant difference among groups in the duration of the retreatment procedures.

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.

Clinical and Patient-centered Outcomes of Nonsurgical Root Canal Retreatment in First Molars Using Contemporary Techniques

IntroductionThere have been many recent technical advances in modern endodontics that have the potential to affect treatment outcomes. Reports on treatment outcomes using contemporary techniques are relatively scarce, especially in the field of nonsurgical retreatment. The purpose of this study was to determine the success of nonsurgical root canal retreatment in molars using contemporary endodontic techniques. MethodsSixty-three patients referred for retreatment in first molars were enrolled in the study. The retreatment procedures were performed by endodontic residents using a semistandardized treatment protocol. Patients were followed-up at 6, 12, and 24 months. Treatment outcomes were categorized into healed, healing, or nonhealing based on clinical and radiographic criteria. Healed and healing were considered as successes, and nonhealing was considered a failure. Outcomes were also evaluated using patient-centered criteria that included oral health–related quality of life scores and subjective chewing ability. ResultsFifty-two of the 63 patients were available for final analysis. Five cases (9.6%) were determined to be nonhealing at the last follow-up with new or persistent periapical lesions. Thirty-seven (71.2%) patients had complete resolution of apical periodontitis, and the remaining 10 (19.2%) remained asymptomatic and showed radiographic evidence of healing. Oral health–related quality of life scores and chewing ability improved significantly over time (P < .05), with the biggest increase observed within the first week of treatment completion. ConclusionsThis study showed that endodontic retreatment using contemporary techniques significantly improved patients' quality of life and chewing ability over time, with a success rate of 90.4% after 2 years.

Diversity of Enterococcus faecalis Genotypes from Multiple Oral Sites Associated with Endodontic Failure Using Repetitive Sequence-based Polymerase Chain Reaction and Arbitrarily Primed Polymerase Chain Reaction

IntroductionThe aim of this study was to evaluate the diversity and similarity of Enterococcus faecalis genotype isolates from multiple oral sites using repetitive sequence-based polymerase chain reaction and arbitrarily primed polymerase chain reaction (AP-PCR). MethodsForty-two endodontically treated teeth with apical periodontitis were selected. A total of 126 microbial samples were collected from 3 different sites (saliva, pulp chamber, and root canals, all n = 42) during the nonsurgical retreatment procedures. After growth on m-Enterococcus agar, the colonies were isolated, characterized as gram-positive catalase negative cocci, and identified using an API 20 Strep kit (bioMérieux, Marcy-l'Etoile, France). Seventy-four colonies from 10 patients were confirmed as E. faecalis by polymerase chain reaction (16S ribosomal RNA). Repetitive sequence-based polymerase chain reactions using ERIC and AP-PCR using RW3A primers were performed in all 74 colonies. Fingerprints were analyzed and separated into genotypic groups based on the Dice coefficient percentage of similarity (82% or greater) as determined by ERIC reproducibility assays involving E. faecalis controls. ResultsSeven different E. faecalis genotypes (GTs) (GT1 = 27%, GT2 = 17.6%, GT3 = 1.3%, GT4 = 18.9%, GT5 = 9.5%, GT6 = 14.9%, and GT7 = 10.8%) were observed in different subjects and oral sites associated with endodontic failure. Remarkably, in 4 of 5 patients, the same GTs present in the infected root canals were also isolated from either the pulp chamber or the saliva samples. In particular, GT6 was detected in all 3 oral sites of patient 37. ConclusionsE. faecalis GTs isolated from saliva, the pulp chamber, and the root canal were similar using the Rep-PCR and AP-PCR methods. These findings suggest that coronal microleakage is a conceivable cause of endodontic failure.

Effect of solvents on apically extruded debris and irrigant during root canal retreatment using reciprocating instruments.

To evaluate the effect of several solvents on the weight of apically extruded debris and irrigant during retreatment using a novel agar gel model. Orange oil, turpentine oil and chloroform were used as solvents. Eighty single straight-rooted extracted human mandibular premolar teeth with a single root canal were divided into four groups (n=20). All specimens were root canal-filled and weighed prior to their insertion into a prepared 1.5% agar gel model. The mean initial weights were measured by subtracting the weight of the specimen from the weight of the test apparatus and recorded. Following the removal of the coronal 4mm of root filling, the test solvent was applied onto the root filling. No solvent was used in the control group. A Reciproc R25 instrument was used to remove the root filling in all groups. Apically extruded debris and test solvent were collected during retreatment procedures. The mean weights of apically extruded debris and irrigant were calculated by subtracting the mean initial weights from the weights of test apparatus without the Teflon tape and the specimen following the retreatment procedures. Data were statistically analysed using one-way analysis of variance. Use of solvents resulted in significantly less extruded debris and irrigant compared to the control group (P<0.05). Chloroform extruded significantly more debris than orange oil and turpentine oil (P<0.05). Use of solvents during root filling removal was associated with less apically extruded debris and irrigant when compared to no solvent.

Effect of different nickel-titanium rotary files on dentinal crack formation during retreatment procedure.

Background. The aim of this study was to compare the dentinal defects caused by Reciproc, TF Adaptive and ProTaper Next NiTi rotary file systems during the retreatment procedure. Methods. A total of 150 mandibular incisors with straight and single root canals were included in the present study. All the root canals were prepared up to an apical diameter 0.40 mm using stainless steel files. Thirty teeth were randomly stored as the negative control group. A total of 120 specimens were obturated with gutta-percha and AH Plus sealer using vertical compaction technique. Thirty specimens with root canal filling were randomly separated for the only-filled group. Then the teeth were randomly divided into 3 groups; Reciproc, TF Adaptive and ProTaper Next. The retreatment procedure was performed with these NiTi files. Then 150 specimens were cut perpendicular to tooth axis at 3-, 6-, and 9-mm distances from the apex, and examined to determine the presence of any cracks at ×25 under a stereomicroscope. Chi-squared test was used at 5% significance level. Results. All the tested NiTi file systems were found to cause significantly more dentinal defects compared to unprepared and only-filled groups (P<0.05). No statistically significant differences were found between the groups in terms of dentinal defects (P>0.05). No correlation was found between the slice levels and the dentinal defect distribution (P>0.05). Conclusion. Within the limitations of present study, all the tested NiTi file systems were found to cause significantly more dentinal defects compared to unprepared and only-filled groups.

Incidence of apical crack formation and propagation during removal of root canal filling materials with different engine driven nickel-titanium instruments.

ObjectivesTo determine the incidence of crack formation and propagation in apical root dentin after retreatment procedures performed using ProTaper Universal Retreatment (PTR), Mtwo-R, ProTaper Next (PTN), and Twisted File Adaptive (TFA) systems.Materials and MethodsThe study consisted of 120 extracted mandibular premolars. One millimeter from the apex of each tooth was ground perpendicular to the long axis of the tooth, and the apical surface was polished. Twenty teeth served as the negative control group. One hundred teeth were prepared, obturated, and then divided into 5 retreatment groups. The retreatment procedures were performed using the following files: PTR, Mtwo-R, PTN, TFA, and hand files. After filling material removal, apical enlargement was done using apical size 0.50 mm ProTaper Universal (PTU), Mtwo, PTN, TFA, and hand files. Digital images of the apical root surfaces were recorded before preparation, after preparation, after obturation, after filling removal, and after apical enlargement using a stereomicroscope. The images were then inspected for the presence of new apical cracks and crack propagation. Data were analyzed with χ2 tests using SPSS 21.0 software.ResultsNew cracks and crack propagation occurred in all the experimental groups during the retreatment process. Nickel-titanium rotary file systems caused significantly more apical crack formation and propagation than the hand files. The PTU system caused significantly more apical cracks than the other groups after the apical enlargement stage.ConclusionsThis study showed that retreatment procedures and apical enlargement after the use of retreatment files can cause crack formation and propagation in apical dentin.

Comparison of the Smear Layer Removal Ability of Four Different Final Activation Techniques after Retreatment Procedures: a SEM Investigation

Comparison of the Smear Layer Removal Ability of Four Different Final Activation Techniques after Retreatment Procedures: a SEM Investigation

A Single Center Experience with Coil Embolization for Cerebral Aneurysms Greater than 10 mm in the Internal Carotid Artery.

We investigated endovascular treatment for 10 mm or larger aneurysms in the internal carotid artery (IC), including the cavernous portion, the paraclinoid portion, and the posterior communication artery (PC). Between 2011 and 2014 at our hospital, there were 35 cases of aneurysms that were 10 mm or larger in the carotid artery. We analyzed these 35 cases retrospectively based on the size and location of the aneurysms, method of treatment, number of coils implanted, use of a stent, complications, rupture after treatment, ophthalmologic symptoms, and need for re-treatment. There was no bleeding after treatment. Of the 35 cases, four cases (11%) had permanent complications. Re-treatment was indicated in 11 cases (31%), including eight cases localized in the paraclinoid portion, two cases in the IC-PC, and one case in the cavernous portion. Among these re-treatment cases, two cases required a third treatment. Of the 16 cases with paraclinoid aneurysms, half required re-treatment. Of the 12 cases with ophthalmologic symptoms prior to treatment, 9 (75%) improved or had no change and 3 (25%) became worse. There were no complications in the 13 re-treatment procedures. Re-treatment is not uncommon, and a scheduled follow-up is needed. Coil embolization has been one of the main options for aneurysms that are 10 mm or larger in the IC. In the future, these large aneurysms will be treated with a flow diverter stent (FD).

Potential to induce dentinal cracks during retreatment procedures of teeth treated with “Russian red”: An ex vivo study

ObjectiveThe aim of this study was to compare the impact of treatment procedures on roots previously treated with resorcinol–formaldehyde resin and analyze the effectiveness of dye and magnification for the detection of dentin cracks. Materials and methodsDistal roots of 80 permanent first mandibular molars with a single canal were sectioned at 3mm and 9mm from the anatomical apex. Two groups were formed according to the method used for root canal penetration: group 1 (K-file and Pro Taper instruments) and group 2 (Ultrasound with Pro Ultra and Pro Taper files). Before and after the completion of procedures, photographs of the roots were taken for examination for cracks or/and infraction lines with two levels of magnification and with or without a dye. ResultsIn groups 1 and 2, either with dye or without it, there were statistically significant differences (P<0.001) with more fractures observed in the coronal than in the apical part of specimens. Statistically significant proportional differences regarding the location of fractures were observed at both magnifications.When the dye was used, there were no statistically significant differences between the two magnifications in the detection of cracks. In the specimens where the dye was not used, differences between the groups were statistically significant at both magnifications with more complete and intra-dental fractures observed in group 2. ConclusionsRetreatment methods had a damaging effect on the root dentin of teeth previously treated with resorcinol–formaldehyde resin. At magnification ×16, the efficacy of using the dye for the detection of cracks was higher than detection without the dye.

EVALUAREA MATERIALULUI DE OBTURAŢIE DE CANAL RESTANT DUPĂ DEZOBTURARE, FOLOSIND PROTAPER ROTATIV CU SAU FĂRĂ SOLVENŢI

The purposes of retreatment are to eliminate the cause for failure of initial endodontic treatment and to preserve the tooth as well. The aim of this study is a comparative evaluation of efficacy of Protaper rotaty retreatment instruments for gutta-percha removal with or without solvents specific both to the sealer and gutta-percha. Materials and methods: Forty single-rooted extracted teeth were randomly divided into 4 groups according to different methods of retreatment. The teeth were prepared with Protaper Universal system (Dentsply-Maillefer, Ballaigues, Switzerland) and filled using lateral condensation of gutta-percha and AH Plus (Dentsply DeTrey, Konstanz, Germany). All root canal fillings were removed using Protaper Universal Retreatment system (Dentsply-Maillefer, Ballaigues, Switzerland). During the retreatment procedure, in group 1 Resosolv (Pierre Rolland, Merignac, France) was used; in group 2 eucalyptol was used, in group 3 Endosolv E (Septodont, Paris, France) was used and in group 4 no solvent was used. The times required for retreatments and radiographycal evaluation after retreatment were recorded. Results: All root canals showed filling material remnants and group 1 with specific solvent for AH Plus recorded the shortest time. Conclusions: Although it is not possible to eliminate the entire filling material on the canal walls, the duration of retreatment was reduced by the use of a solvent specific to the sealer compared with a gutta-percha solvent or no solvent.

Efficacy of CM-Wire, M-Wire, and Nickel-Titanium Instruments for Removing Filling Material from Curved Root Canals: A Micro–Computed Tomography Study

IntroductionThe aim of this ex vivo study was to evaluate the removal of filling material after using CM-wire, M-wire, and nickel-titanium instruments in both reciprocating and rotary motions in curved canals. MethodsThirty maxillary lateral incisors were divided into 9 groups according to retreatment procedures: Reciproc R25 followed by Mtwo 40/.04 and ProDesign Logic 50/.01 files; ProDesign R 25/.06 followed by ProDesign Logic 40/.05 and ProDesign Logic 50/.01 files; and Gates-Glidden drills, Hedström files, and K-files up to apical size 30 followed by K-file 40 and K-file 50 up to the working length. Micro–computed tomography scans were performed before and after each reinstrumentation procedure to evaluate root canal filling removal. Statistical analysis was performed with Kruskal-Wallis, Friedman, and Wilcoxon tests (P < .05). ResultsNo significant differences in filling material removal were found in the 3 groups of teeth. The use of Mtwo and ProDesign Logic 40/.05 rotary files did not enhance filling material removal after the use of reciprocating files. The use of ProDesign Logic 50/.01 files significantly reduced the amount of filling material at the apical levels compared with the use of reciprocating files. ConclusionsAssociation of reciprocating and rotary files was capable of removing a large amount of filling material in the retreatment of curved canals, irrespective of the type of alloy of the instruments. The use of a ProDesign Logic 50/.01 file for apical preparation significantly reduced the amount of remnant material in the apical portion when compared with reciprocating instruments.

Effect of different gutta-percha solvents on the microtensile bond strength of various adhesive systems to pulp chamber dentin.

The aim of this study was to evaluate the effect of different endodontic solvents on the microtensile bond strength (μTBS) of various adhesives to pulp chamber dentin. A total of 120 human third molars were selected. Canals were prepared with the ProTaper Universal system and obturated. The access cavities were then restored with resin composite. After 1week, a retreatment procedure was applied as follows: control, no solvent was applied to the pulp chamber and experimental groups, three different solvents (chloroform, eucalyptol, and orange oil) were applied to the pulp chamber for 2min. The canal filling was removed and calcium hydroxide (Ca[OH]2) was placed into the canals. After 7days, the Ca(OH)2 was removed from the canals and the canals were re-obturated. Teeth were then divided into three subgroups according to the adhesive used. The samples were restored with a nanohybrid resin composite using three different adhesives: Clearfil SE Bond (CSE), Adper Easy One (AEO), and Single Bond 2 (SB2). The samples were aged with thermocycling. Teeth were sectioned, and a total of 20 dentin sticks were obtained for each subgroup. μTBS testing was then performed. The debonded surfaces were evaluated using scanning electron microscopy (SEM) analysis. Data were analyzed using two-way ANOVA and Tukey's post hoc tests. Chloroform showed statistically lower mean μTBS values (14±7.2MPa) than control group did (19.2±6.1MPa) (p<0.05). Orange oil (18.1±6.3MPa) and eucalyptol (16.9±6.8MPa) did not reduce the mean μTBS statistically (p>0.05). Chloroform showed significantly lower bond strength for all adhesives (p<0.05). Whereas orange oil did not reduce the mean μTBS values of all adhesive systems significantly (p>0.05), eucalyptol reduced the μTBS values of all the groups, but the results were only statistically significant for SB2 (p<0.05). CSE showed statistically higher bond strength (20.4±6.8MPa) than AEO (14.6±5.3MPa) and SB2 (16.3±7.2MPa) did (p<0.05). There were no statistical differences between AEO and SB2 (p>0.05). According to the SEM analysis of the debonded surfaces, adhesive failures were the most common type in all the groups, followed by mixed failures. While chloroform reduced the mean bond strength of the adhesive resins, orange oil did not affect the bond strength of the adhesives. The effect of eucalyptol on bond strength depended on the type of adhesive system. This study shows that endodontic solvents could affect the microtensile bond strength of adhesives to pulp chamber dentin.

Analysis of the key points in the micro-endodontic treatment

Micro-endodontic treatment refers to the microscope-assisted endodontic treatment techniques. The microscope offers a stereoscopic, enlarged image under great magnification and illumination at a comfortable working position. It will greatly promote the precision and improve the outcomes of endodontic treatment through enhancing the ability to detect the complexity of the root canal system of teeth that probably cannot be seen by the naked eyes, remove the infectious substances in root canal more efficiently, provide a tight root canal obturation and carry out effective retreatment procedures. The requirements of micro-endodontic treatment are different from the conventional root canal therapy carried out without microscope due to the complicated structure of the microscope. In order to make the use of microscope easier, it is of great importance to learn how to adjust the position of the operator and the patient, preset the angle of objective lens and the eyepiece, select the proper magnification and instruments, practice eye-hand cooperation under the microscope, etc. The purpose of this article was to analyze the key points in the applications of the microscope in endodontic treatment by reviewing the literature together with the author's clinical experience.

A Comparative Evaluation of Guttapercha Removal by Various Rotary Files: An in Vitro Study

Aim: To compare the efficacy of different rotary instruments for removing obturating material from root canals. Materials and Methods: Thirty extracted human premolar teeth having a single canal were selected. The biomechanical preparation of the root canals was done with Protaperrotary file and obturation was done with corresponding guttapercha cone. The samples were divided into three groups according to the rotary file used for removing the obturating material: Group I – Neoniti; Group II – Protaper D; Group III – Hyflex. The amount of remaining filling material after the retreatment procedure was checked under stereomicroscope. The data was statistically analysed by One way Anova test. Results: Group I(Neoniti) left less remaining filling material compared with group II (Protaper D) and group III (Hyflex). Conclusion: The Neoniti file was most effective in removing the gutta-percha from the root canal.

A Comparison of the Effectiveness of Reciprocating System with Continuous Rotary Systems in Non-Surgical Endodontic Retreatment : An in Vitro Study

Background: Optimal root canal retreatment was required safe and efficient removal of filling material from root canal. The aim of this in vitro study was to compare the efficacy of reciprocating and continuous motion of four retreatment systems in removal of root canal filling material. Materials and Methods: Forty distal roots of the mandibular first molars teeth were used in this study, these roots were embedded in cold clear acrylic,roots were instrumented using crown down technique and rotary ProTaper systemize Sx to size F2 ,instrumentation were done with copiousirrigation of 2.5% sodium hypochlorite and 17% buffered solution of EDTA was used as final irrigant followed by distilledwater, roots were obturated with AH26 sealer and Protaper gutta-percha point F2 and medium fine accessory gutta-percha using lateral condensation technique,roots were left for 7 days with 100% humidity at 37oC in an incubator. Roots were randomly divided into four groups according to technique used for removing the root filling material (ten teeth for each group): group I: reciprocating technique and Wave One system, group II: continuous technique and ProTaper retreatment system, group III: continuous technique and R-Endo system, group IV: continuous technique and D–RaCere treatment system. All the roots were radiographed before and after removal of gutta-percha from both bucco-lingual and mesiodistal directions using custom made platform and digital radiograph system RVG to havea digitized images. The total surface area of all root canals was measured before removal ofthe gutta-percha and the area of the remaining gutta-percha filling in the canals after retreatment procedure from both directions. These measurements were analyzed with Adobe Photoshop CS6 software, the percentage of removed gutta-percha calculated. Results: Statistical analysis was performed and the result showed group Ihad the highest mean values in removal of root canal filling material in both bucco-lingual and mesiodistal direction of dental radiograph and there were significant difference between group I and most of the other groups ,there were non significant difference between group II,group III and group IV. Conclusion: This study was showed all the used retreatment systems did notcompletely remove the root canal filling material. The reciprocating technique was most effective method for removing gutta-percha and sealer than continuous rotary technique. Key words: Retreatment, reciprocating motion, root canal filling, rotary instrument.

Efficacy of Combined Use of Different Nickel-Titanium Files on Removing Root Canal Filling Materials

IntroductionThe aim of this study was to estimate the remaining amount of residual filling materials in root canals after retreatment using ProTaper Universal Retreatment (PTUR) files (Dentsply Maillefer, Ballaigues, Switzerland) alone or with the additional use of the Self-Adjusting File (SAF; ReDent-Nova, Ra'anana, Israel), Reciproc (VDW, Munich, Germany), or Hedström-files (H-file; VDW, Antaeos, Munich, Germany) with volumetric estimation using the stereologic method via cone-beam computed tomographic images. MethodsForty-eight mandibular premolars with single canals were used. The canals were instrumented with ProTaper rotary instruments up to F4 and filled with gutta-percha and AH26 sealer (Dentsply De Trey, Johnson City, TN). All the samples were placed into the silicone models. Samples were scanned with cone-beam computed tomographic imaging and assigned into 4 groups (n = 12) according to retreatment files: the PTUR system group, the PTUR system plus SAF group, the PTUR system plus Reciproc group, and the PTUR system plus H-file group. The specimens were rescanned after retreatment procedures, and the volume estimations of the remaining filling materials were performed using the stereologic method. Data were analyzed using Kruskal-Wallis and Dunn tests. ResultsThere was no significant difference among the groups regarding mean percentage volumes of the filling materials before retreatment procedures (P > .05). None of the retreatment procedures provided complete removal of the filling materials. The additional use of the SAF did not significantly improve the removal of filling materials when compared with the PTUR system alone (P > .05). However, the additional use of Reciproc or hand H-files significantly improved the removal of filling materials when compared with the PTUR system alone (P < .05). ConclusionsThe additional use of files with different motion kinetics improved the removal of root canal fillings; however, none of the systems completely removed the root canal filling material from the root canals.