Purpose: Recognizing canal configuration is necessary for a correct endodontic therapy; and having no information about canal configuration causes failure in therapy. Since one of the most effective factors in canal configuration is race' we decided to have a laboratory and clinical research in Isfahan. The aim is to recognize canal configuration of the mandibular first premolar and compare the clinical and laboratory results.Methods & Materials: 1- Laboratory study (Invitro): At first we selected 127 mandibular first premolar' then we disinfected them in CLONA 5.25%. We made a correct access cavity on the teeth. In order to vacate pulp tissue in chamber and canals, we placed them in H2O2 35% for 15 days. Then we placed them in HNO3 5% for 3 days to be decalcified. Then we used 70%, 90%, 100% isopropyl alchole to dehidrate the teeth. After the above processes we injected India ink in -1.8 P, in canals and sealed access cavity by Zonaline cement, we used the teeth in Metyl Salicylate to make clear. Then, we studied canal configuration. 2- Clinical study (Invivo): In this study we selected 125 mandibular first premolar treated in post graduate and under graduate departments of Isfahan University school of Dentistry. Then we studied every radiograph using a negatoscope, and the data were analysed.Results: 1-Laboratory (invitro) results: Out of 112 mandibular first premolar (researchable), 75 type I (67%),5 type II (4.5%), 13 type III (11.6%), 16 type IV (14.2%) and 3 (2.7%) were out of Weine classification. 2-Clinical (invivo) results: Out of 125 mandibular first premolar, 103 type I (82.4%),3 type II (2.24%), 12 type III (9.66%), 5 type IV (4%) and 2 (1.66%) were out of Weine classification.Conclusion: The out coming results of this study are different from other researches. Perhaps the differences are caused by some factors such as race and method. Also the clinical results are too different from laboratory results which could be due to method. The laboratory study is more exact.

Purpose: The antibacterial activity of three endodontic sealers, a Ca (OH)2 based sealer (apexit) a Zoe based sealer (Drofill) and a resin based sealer (AH26) was assessed on the growth of an anaerobic bacteria (peprostreptococcus spp.) using the Agar diffusion test (ADT). Materials and Method: Thirty brain heart diffusion agar plates were incubated with peptostreptococcus anaerobics. Each plate was divided into two separate areas. In one area, 0.1ml droplet of a given fresh sealer and in the other area a dry material of the same sealer were placed, such that each plate had two areas with the same sealer in two forms of fresh and dry (setform). There were ten plates for each of the three sealers. The plates were placed into anaerobic jars and incubated at 37oC. After varying periods, zone of inhibition of bacterial growth were observed, measured and compared by t and Paired T-test.Results: There was no statistically significant differences between the activity of AH26 and drofill in the fresh form(P>0.05). However there were significant differences between (the two sealers in set form) (P<0.05) Drofill was more antibacterials in the set form than AH26. All sealers were more active when fresh than ages.Conclusion: It is likely that the eugenol in the Dorifill and the formaldehyde in the AH26 are responsible for their greater antimicrobial activity.

Introduction: After cleaning and shaping of the root canal, to prevent recontamination and to ensure the success of root canal therapy, it is necessary to fill root canal space. Studies, so far, have not been able to identify a specific method as the best method of obturation. The present study was an attempt to introduce and compare different root canal obturation techniques.Materials and Methods: In this review, using specific key words such as root canal obturation, root canal filling materials and gutta-percha, search was run in Pubmed, Cochrane and ISI Web of Science databases for high-quality articles published from 1960 to 2013.Results: There are several methods to obturate the root canal system, designed based on the use of plastic materials, injectable materials, single cones, or compaction of gutta-percha. A brief review of each technique and its advantages and disadvantages were discussed. The reasons for choosing the cold lateral compaction technique as a frequently used and the selected technique by many dentists as well as academic centers were explained.Conclusion: Considering the advantages and disadvantages and long-term outcomes of root canal obturation techniques, it seems cold lateral compaction is the selected root canal filling technique in the majority of cases.

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.