Introduction: The present study was set to investigate the training quality and its association with the quality of Root Canal therapy performed by fifth year dentistry students. Methods and Materials: A total number of 432 records of endodontic treatment performed by fifth year dentistry students were qualified to be further investigated. Radiographs were assessed by two independent endodontists. Apical transportation, apical perforation, gouging, ledge formation, and the quality of temporary restoration were error types investigated in the present study. Results: the prevalence of apical transportation, ledge formation, and apical perforation errors were significantly higher in molars in comparison with other types of teeth. The most prevalent type of error was the apical transportation, which was significantly higher in mandibular teeth. There was no significant differences among teeth in terms of other types of errors. Conclusion: The quality of training provided for dentistry students should be improved and endodontic curriculum should be modified.

Introduction: Cleaning and shaping of the Root Canal system is an important objective of Root Canal therapy. Many automatic devices have been produced to simplify the preparation and to decrease Instrumentation time. One of these automatic devices is the new reciprocal handpiece (TEP-E10R) known as general name "Endogripper". The purpose of this study was to compare Canal transportation with hand Instrumentation technique and reciprocal Instrumentation technique with TEP-E10R handpiece.Materials & Methods: In this invitro study 60 human mandibular first and second molars were selected and divided into four groups.Radiographs with initial file inserted to working length were taken in all specimens with constant conditions. In group one, the preparations were made by Ni-Ti files and hand Instrumentation technique. In group two, the preparation were made by stainless steel files and the same technique in group one, in group three preparation were made by Ni-Ti files and TEP-E10R reciprocal handpiece and in group four, the preparation were made by stainless steel files and the same handpiece in group three. Instrumentation technique in all four groups was crown down preparation. After finishing of the Instrumentation in latter four groups, additional radiographs were taken while the master apical files (MAF) were inserted in the Canals with the same constant conditions recorded for intial file radiographs. The MAF radiographs were compared with initial file radiographs for Canal trans portation. The amount of dentin removal was also calculated by measuring instrumented surface in the final radiographs. Data were collected by SPSS10. One way ANOVA analysis was used to compare four groups and tukey test was used to compare couple groups.Results: All of specimens showed degrees of transportation. Group two had the most mean degree of transportation that was significantly different from group one (P=0.001). None of the groups had statistically significant difference between amount of dentin removed from Canal walls (P=0.83).Conclusion: Reciprocal handpices with NiTi files had acceptable results for Canal preparation.

Introduction: The aim of this study was to analyze the effect of rotation speed on the Instrumentation time of Root Canals with different curvatures using Mtwo NiTi rotary instruments. Methods and Materials: Forty Root Canals were selected and divided into 2 groups, according to the angle of curvature (group A>30° , group B<30° ). Both groups were divided into 2 subgroups (n=10), according to the rotational speed used for Root Canal Instrumentation (150 rpm: group A1 and B1; 250 rpm: group A2 and B2). The total Instrumentation time and the total number of Instrumentation cycles (NCI) required to complete Root Canal preparation were registered for each Canal. The mean and standard deviation were then calculated. Data were then statistically analyzed using two-way ANOVA and interaction effect P-values (P<0. 05). Results: During Root Canal Instrumentation, there were no file fractures. Total Instrumentation time of the low speed groups A1 (150 rpm) and B1 (150 rpm) were significantly higher (P<0. 05) than that of the high speed groups, A2 (250 rpm) and B2 (250 rpm); however, there was no statistically significant difference in terms of NCI between the different groups (P>0. 05). Statistical difference was not found between the different angles of curvature, group A1 vs B1 and A2 vs B2 in terms of total Instrumentation time (P>0. 05) and NCI (P>0. 05). Conclusions: This ex-vivo study showed that Canal preparation with Mtwo rotary files could be completed safely with an increase of the Instrumentation time at low rotational speed independently of the Root Canal curvature.

Introduction: Pulpectomy of primary teeth is commonly carried out with hand files and broaches; a tricky and time consuming procedure. The purpose of this in vitro study was to compare the cleaning efficacy and time taken for Instrumentation of deciduous molars using hand K-files and Flex Master rotary system.Materials and Methods: In this study, 68 Canals of 23 extracted primary molars with at least two third intact Roots and 7-12 mm length were selected. After preparing an access cavity, K-file size #15 was introduced into the Root Canal and India ink was injected with an insulin syringe. Sixty samples were randomly divided in to experimental groups in group I (n=30), Root Canals were prepared with hand K-files; in group II (n=30), rotary Flex Master files were used for Instrumentation, and in group III 8 remained samples were considered as negative controls. After clearing and Root sectioning, the removal of India ink from cervical, middle, and apical thirds was scored. Data was analyzed using student's T-test and Mann-Whitney U test. Results: There was no significant difference between experimental groups cleaning efficacy at the cervical, middle and apical Root Canal thirds. Only the coronal third scored higher in the hand instrumented group (P<0.001). Instrumentation with Flex Master rotary files was significantly less time consuming (P<0.001).Conclusion: Although there was no difference in cleanliness efficacy at the apical and middle thirds, the coronal third was more effectively cleaned with hand files. Predictably, time efficiency was a significant advantage with rotary technique.

Introduction: To compare the cleaning effectiveness of K3 and Race NiTi rotary systems with K-Flexo file instruments during the preparation of curved Canals in extracted human teeth.Materials and Methods: A total of 50 Root Canals of mandibular and maxillary molars with curvatures ranging between 25o and 35o were divided in three groups of 15 each and 5 as negative control groups. Canals were prepared using a low torque control motor in two rotary groups according to manufacturer's instructions. Conventional Step back with S.S K-files was the preparation technique in third group. The amount of debris and smear layer was quantified on the basis of a numerical evaluation scale. The data were statistically analyzed using Chi- Square and Likelihood Ratio tests.Results: In general, no significant difference in terms of amount of debris were found among three groups, only in apical zones of Race and K-Flexo file groups a significant difference was detected (P=0.041). Race rotary system left significantly less smear layer than K-Flexo file in the middle (P=0.009) and apical thirds (P=0.012), respectively. K3 significantly achieved higher scores of cleanliness than K-Flexo file in apical third only (P=0.049).No significant difference between Race and K3 rotary groups for residual debris and formed smear layer was detected.Conclusion: Obtaining higher scores of cleanliness in various regions of the Canals, crown down technique and the use of rotary Instrumentation seem to be superior to conventional hand Instrumentation with step back technique .No significant difference between K3 with three radial lands and Race with three cutting edges in terms of debris and smear layer formation was detected.

Background. This study compared apical extrusion of debris and Instrumentation time following Root Canal Instrumentation with Reciproc, Reciproc Blue, and Gentlefile (GF) rotary instruments versus the manual step-back technique. Methods. This in vitro study was conducted on 80 extracted mandibular premolars with mature apices and a Root curvature of<10º. The teeth were randomly assigned to 4 groups (n=20), standardized regarding working length, and placed in pre-weighed vials. The Root Canals were instrumented with Reciproc, Reciproc Blue, and GF systems and the manual step-back technique in the four groups. The vials containing the collected debris were then dried and weighed. The Instrumentation time was also recorded for each group. Data were analyzed with one-way ANOVA and post hoc Games-Howell test (α=0. 05). Results. Minimum apical debris extrusion was noted in Reciproc, followed by Reciproc Blue, GF, and manual technique (P<0. 05). Pairwise comparisons showed significantly lower apical extrusion of debris in the Reciproc compared with GF (P=0. 015) and manual Instrumentation (P=0. 011) groups. The Reciproc system also had the shortest Instrumentation time, followed by Reciproc Blue, GF, and manual Instrumentation (P<0. 05). Pairwise comparisons showed significant differences between all the systems (P<0. 05) except between Reciproc and Reciproc Blue (P>0. 05) in this respect. Conclusion. Although all systems caused apical extrusion of debris, manual Instrumentation caused maximum extrusion of debris. In contrast, the Reciproc system was superior to others regarding minimal apical extrusion of debris and the shortest Instrumentation time.

Background. The present in vitro study aimed to compare the effectiveness of the WaveOne and ProTaper Gold systems in removing the Enterococcus faecalis biofilm. Methods. Thirty-eight mandibular premolars were selected. The Root Canals were assigned to standard control (Canals serially enlarged with ProTaper Gold S1-S2-F1-F2, n=15) and experimental (Canals enlarged with Primary WaveOne file, n=15) groups. Following the Instrumentation procedure, the Root Canals underwent a sampling procedure, and the colonyforming unit (CFU) counts were determined. The samples were also evaluated under a fluorescent microscope to evaluate viable bacteria. The data were analyzed using independent samples t test and paired samples t test. Results. The results showed that, compared with the ProTaper group, the WaveOne group exhibited the least viable bacteria (P = 0. 004). Conclusion. It was concluded that comparison with the ProTaper Gold rotary system, the WaveOne reciprocating file is more successful in reducing intratubular viable bacteria counts.

Background and Aim: The aim of this study was to compare the effect of Mtwo rotary system and step back hand system in reduction of enterococcus faecalis bacteria from the Root Canals of human extracted teeth.Materials and Methods: In this study, 62 human extracted teeth were divided into two equal experimental groups with 23 teeth each and one control group two extra control groups with 5 teeth each as negative and positive were chosen for confirmation of the Canal reinfection too. All of the samples were prepared by K Flie No 20 and Gates Glidden No 2 and 3 before sterilization. Then the teeth were autoclaved and reinfected with enterococcus faecalis. The experimental groups were instrumented either with Mtwo system or step back system. Bacteriological samples were taken after Instrumentation to determine the amount of remaining bacteria.Results: In the group 1, fourteen samples and in the group 2, twelve samples represented complete reduction of bacteria. There was not statistically significant difference between two techniques (p>0.05)Conclusion: Both Mtwo and step back systems are the same on reduction of the bacteria from Root Canal system, up to the same apical size.

Background and Aim: Due to the deeper penetration of bacteria like Enterococcus faecalis into dentinal tubules in pulp diseases, different tapering in Root Canal therapies leads in different dentinal removal from Root Canal wall. Then, Root Canals with higher tapering will contain lower microbial microbial contents. Furthermore, together with higher prevalence of Root fractures in teeth with more tapering, the aim of this study is comparing the effect of different tapering of Hero Rotary files (6% versus 4%) in reduction of Enterococcus faecalis bacteria from the Root Canal of human extracted teeth.Materials and Methods: Seventy human extracted teeth were divided in two equal experimental (Hero 4%as group 1and Hero 6% as group 2) (n=27) and the control group (n=6).Two extra control group (positive n=5 and negative n=5) took for confirmation the Canal reinfection, too. All of the samples prepared by K file No 20 and Gates Gilden No 2 and 3 before sterilization. Then the teeth were autoclaved and were infected with Enterococcus faecalis. The experimental groups were instrumented either with Hero 4% or with Hero 6% files up to #30. Bacteriological samples were taken after Instrumentation to determine the level of remaining bacteria.Results: In the group 1 two samples and in the group 2 six samples represented complete reduction of bacteria. There was not statistically significant different between the two groups.Conclusion: Aggressive preparation with an Instrumentation technique removing substantial amounts of dentin (Hero 6%) did not reduce the intraCanal bacteria more effectively than a more conservative Instrumentation technique (Hero 4%) (P>0.05).