Introduction: The purpose of this study was to evaluate the effectiveness of different irrigating methods in removing the smear layer at 1, 3, 5, and 8 mm from the apex of endodontic canals. Methods: Sixty-five extracted single-rooted human mandibular premolars were decoronated to a standardized length of 16 mm. Specimens were shaped to ProTaper F4 (Dentsply Maillefer, Ballaigues, Switzerland) and irrigated with 5.25% NaOCl at 37 C. Teeth were divided into 5 groups (2 control groups [n = 10] and 3 test groups [n = 15]) according to the final irrigant activation/delivering technique (ie, sonic irrigation, passive ultrasonic irrigation [PUI], or apical negative pressure). Root canals were then split longitudinally and observed by field emission scanning electron microscopy. The presence of debris and a smear layer at 1, 3, 5, and 8 mm from the apex was evaluated. Scores were analyzed by KruskalWallis and Mann-Whitney U tests. Results: The EndoActivator System (Dentsply Tulsa Dental Specialties, Tulsa, OK) was significantly more efficient than PUI and the control groups in removing the smear layer at 3, 5, and 8 mm from the apex. The EndoVac System (Discus Dental, Culver City, CA) removed statistically significantly more smear layer than all groups at 1, 3, 5, and 8 mm from the apex. At 5 and 8 mm from the apex, PUI and the EndoVac did not differ statistically significantly, but both performed statistically better than the control groups. Conclusions: In our study, none of the activation/delivery systems completely removed the smear layer from the endodontic dentine walls; nevertheless, the EndoActivator and EndoVac showed the best results at 3, 5, and 8 mm (EndoActivator) and 1, 3, 5, and 8 mm (EndoVac) from the apex.

Introduction: This study compared the efficacy of BioPure MTAD (Dentsply Tulsa, Tulsa, OK), 17% EDTA, and 42% citric acid in endodontic smear layer removal and degree of erosion in the apical third of endodontic canals. Methods: Ninety-six extracted single-rooted human teeth were randomized into four groups (n = 24) and instrumented using System GT nickel-titanium rotary instruments (Dentsply Tulsa, Tulsa, OK). Each canal was irrigated with one of the following solutions: BioPure MTAD, 17% EDTA, 42% citric acid, or 5.25% NaOCl (control). Next, all specimens were irrigated with 5.25% NaOCl. Results: Evaluation by scanning electron microscopy showed no significant differences among test irrigants in removing the smear layer. However, the efficacy of BioPure MTAD and 17% EDTA in removing the smear layer was significantly greater than 5.25% NaOCl (control). The erosive effects of irrigating solutions could not be evaluated. Conclusions: In conclusion, the protocols used in this study were not sufficient to completely remove the smear layer in the apical third of prepared root canals. (J Endod 2009;35:900-903)

Introduction: This study compared (1) the accuracy of three different electronic apex locators (EALs) in detecting the apical foramen ex vivo under clinical conditions; (2) the accuracy of digital radiography and EALs in determining the working length (WL) with visible control under a microscope; and (3) the precision of #10, #15, and #20 K-files in electronic measurements.

In our study, none of the activation/delivery systems completely removed the smear layer from the root canal walls; nevertheless, EV and EA showed, respectively, statistically significant better results at 1, 3, 5, and 8 mm and 3, 5, and 8 mm from the apex.

Introduction: The aim of this study was to determine in anterior teeth, bicuspids, and molars (1) the accuracy of 3 different electronic apex locators (EALs) in detecting the apical foramen and (2) the accuracy of digital radiography in determining the working length (WL), compared with visible control under a microscope. Methods: By using radiovideography (RVG), we measured the lengths of 120 root canals with 3 different EALs (Endex, ProPex II, and Root ZX) and compared them with the actual lengths. The accuracy of EALs and RVG was related to each dental category. An endodontic training kit (Pro-Train) was used during experimental procedures. Results: Statistical analysis showed that the 3 EALs and RVG were less accurate in anterior teeth and molars than in bicuspids. The paired-sample t test showed no statistically significant difference between mesiodistal plane and buccolingual plane digital radiography in all groups. Conclusions: The 3 EALs tested were more accurate in detecting the apical foramen in bicuspids than in both molars and anterior teeth. Radiographic measurements were not reliable for determining WL in all dental groups in both radiographic planes. (J Endod 2011;37:684-687)