Influence of Root Canal Curvature on the Accuracy of Root ZX Electronic Foramen Locator: An In Vitro Study

Introduction: The aim of this in vitro study was to evaluate the correlation between accuracy of Root ZX electronic foramen locator and root canal curvature. Methods and Materials: One hundred and ten extracted mandibular molars were selected. Access cavity was prepared and coronal enlargement of mesiobuccal canal was performed. A #10 Flexofile was inserted into the mesiobuccal canal, and a radiography was taken to measure the degree of curvature by Schneider's method. The actual working length (AWL) was defined by inserting the file until its tip could be observed at a place tangential to the major apical foramen and then 0.5 mm was subtracted from this measurement. For the electronic working length (EWL) measurement, the apical 3 or 4 mm of the root was embedded in alginate as the electrolyte material. The file was inserted into the root canal to the major foramen, until the APEX reading was shown on the electronic device and then pulled back until the visual display showed the 0.5-mm mark. The AWL was subtracted from the EWL to define the distance between the file tip and the point 0.5 mm coronal to the major apical foramen. Data were analyzed using the Pearson’s correlation coefficient. Results: The accuracy of Root ZX within ±0.1 mm and ±0.5 mm was 38.2% and 94.6%, respectively. There was no correlation between the distance from the EWL to the AWL and the degree of root canal curvature (r=0.097, P=0.317). Conclusion: Root canal curvature did not influence the accuracy of Root ZX foramen locator.Keywords: Accuracy; Curved Root Canals; Electronic Apex Locator; Working Lengt

Radiographic Evaluation of Errors during the Root Canal Treatment by 5thand 6thYear Undergraduate Students of Islamic Azad University of Isfahan (Khorasgan) from 2015 to 2018

Quality of rootcanal treatment is considered as an important prognostic factor for endodontic therapy success.The aim of this study is to evaluate radiographic errors during the root canal treatment by 5thand 6thyear undergraduate students of Islamic Azad university of Isfahan (Khorasgan) from 2015 to 2018.Materials & Methods:In this study records of 860 cases of endodontic treatment of patients referred to the General Endodontics Department and the Comprehensive Treatment Department of Isfahan Azad University (Khorasgan) during 2015-2018 including 1903 root canals that had received root canal treatment were examined. Periapical radiography was used to evaluate errors during access cavity preparation, canal preparation, and canal filling by two endodontic specialists and it was recorded in pre-prepared forms. In the access cavity preparation: furcation perforation, low access cavity expansion, high access cavity expansion were evaluated. During the canal preparation phase, errors such as missing of canal, ledge, transport, perforation types and broken instruments were investigated. Length and density of root filing were the criteria evaluated at the canal filling stage. The analysis was performed at both descriptive and inferential levels. Statistical analysis was performed by Chi-Square test and exact Fisher's test.Results:Frequency of acceptable root canal treatment (without errors) was 37.5%. Lower first molars showed the highest error rate (40.7%). Furcation perforation was reported with 9.4% highest error of access cavity preparation. The highest error rate was reported transport (7.8%) in the preparation phase. Inadequate density (gap) of 36.9% and under filling of 31.1% had the highest error in filling stage.Conclusion:According to the results of this study, it can be stated that general endodontics department needs careful planning to increase the quality of root canal treatments performed by student

Micro-CT Evaluation of Four Root Canal Obturation Techniques

Purpose. The aim of this in vitro study was to evaluate the quality of four root canal obturation techniques using microcomputed tomography (micro-CT). Materials and Methods. A total of 36 mandibular first premolars with mostly round canals were decoronated, then instrumented up to a size F3 rotary file, and dressed with an epoxy resin-based sealer. Subsequently, they were divided into 4 different groups (n=9) based on the method of obturation: lateral condensation using 0.02 tapered master cone (LC2), lateral condensation using 0.04 tapered master cone (LC4), matched single-cone technique (MS), and matched single cone-mediated ultrasonic activation (MSUA). All the teeth were scanned using micro-CT (resolution of 19 μm), and the percentage volume of voids was calculated. One-way analysis of variance and Tukey test were used to analyze the data (α=0.05). Results. The total percentage volume of voids was significantly lower in the MSUA group compared to all other groups (P<0.05). The total percentage volume of voids was significantly lower in the MS group compared to the LC4 (P<0.001) and LC2 (P<0.001) groups. However, there was no significant difference between the LC2 and LC4 groups (P<0.65). Conclusions. MSUA, significantly, showed the least root canal filling voids amongst all the obturation techniques studied. MSUA can be considered an effective method for the filling of the round root canals. In general, lateral condensation using either 0.02 or 0.04 tapered master cones had significantly the highest volume percentage of voids amongst the experimental groups

Comparative Evaluation of Apically Extruded Debris During Root Canal Preparation Using Three Different File Systems Applied Under 2.5% Sodium Hypochlorite or 2% CHX Irrigation

The chemomechanical cleaning of the root canal system is performed using manual and rotary files. This study aimed to compare the effect of ProTaper, Reciproc and HyFlex rotary files considering 2.5% sodium hypochlorite and 2% chlorhexidine (CHX) as irrigating solutions on apical extrusion of intracanal debris. Single-canal mandibular premolars (N=165) were evaluated. The teeth were divided into 6 experimental groups (N=25) for root canal instrumentation using 3 file systems, (Reciproc, HyFlex and ProTaper) and two irrigation solutions, namely 2.5% sodium hypochlorite or 2% CHX. Fifteen teeth were also assigned into three control groups (n=5) with saline as irrigation solution. Eppendorf tubes were weighed and the teeth were placed inside. The canals were instrumented and the tubes weighed to determine the dry weight of extruded debris. Data were analyzed using one-way ANOVA and Bonferroni test (α=0.05). The mean amount of extruded debris using the sodium hypochlorite solution was significantly higher than other irrigating solutions (p⟨0.001). The mean amount of extruded debris using the Reciproc file system was significantly higher compared to ProTaper and HyFlex (p⟨0.001). The use of the sodium hypochlorite solution, single-file systems and reciprocal movement are associated with higher debris extrusion and might be associated with higher risk of postoperative pain