Aim: The aim of this study was to compare the effects of Ethylen glycol tetra acetic acid (EGTA) and EDTA for their smear layer removal capability using scanning electron microscopy technique.Material and Methods: A group of 28 single rooted teeth were instrumented to size 60 master file. Four teeth were also kept as control while the remaining teeth were divided into two groups. Group A: in which 12teeth were irrigated with 10 ml of 17% EGTA for 2 minutes? Group B: consisted of 12teeth irrigated with 10 ml of 17% EDTA for 2 minutes. Both groups were then irrigated with 10 ml of 5% Naocl. the control group were just irrigated with 10 ml of 5 % Naocl. All teeth in then the control group were only irrigated with 10 ml of 5% Nacl. Specimeus were then sectioned longitudinally. A scanning electrone microscope was wsed to in vetig ate the intenal surfaces of the canal.Results: EGTA chelated dentin surface more conservatively than EDTA without causing erosion.Conclusion: It seems that EGTA can be used safely to remove smear layer from the canal surfaces.

Background and purpose: Because of the importance of early diagnosis of cervical cancer and high false negative results of conventional smear method, several studies have been performed to find a more appropriate test in recent years. Fluid-based methods especially thin prep are considered to have the highest potential to reduce the false negative results and to increase the adequacy of specimens. The purpose of this study was to compare the Papanicolaou fluid-based thin layer smear with conventional pap smear in term of adequacy of specimen.Materials and methods: In this prospective study, the results of 120 thin layer smears were compared with 120 conventional pap smears. Cervix brush was used to prepare the samples of papanicolao and thin prep. The smears were interpreted using Bethesda system.Results: The number of SBL (Satisfactory but limited) in thin layer method and conventional pap smear were 11.9% and 39.2%, respectively. The number of unsatisfactory was 4.2% in the thin layer method compared with 9.2% in the conventional method. The reduction of satisfactory in thin layer method was not statistically significant (P>0.05), but the reduction of SBL (P<0.05) and increasing of satisfactory in thin prep method was statistically significant (P<0.05).Conclusion: The results demonstrated that fluid-based thin layer method may improve the adequacy of specimen and in turn lead to reduction of unsatisfactory and SBL cases.

Introduction: Recently, attention has been drawn to the influence of smear layer removal on apical seal, and the relation of root canal filling material with canal wall surface in the presence and absence of the smear layer. The purpose of this study was to evaluate the influence of the smear layer removal on the apical sealing ability of AH26 sealer.Materials and Methods: Forty extracted human anterior teeth were used in this study.All teeth were decoronated at CEJ. Root canals were prepared; and before obturation, they were randomly divided into two groups (n=17): Group A in which the smear layer was left intact, and in Group B smear layer was removed. Six roots were served as controls. After obturation, micro leakage was measured by the electrochemical method for 30 days with 3-day intervals. Data were then analyzed by using Mann-Whitney test.Results: Based on the results of this study, in the absence of the smear layer, a highly significant decrease of apical leakage was found (P<0.001).Conclusion: This study showed that the removal of the smear layer can significantly improve the apical sealing ability of AH26 sealer.

Background: The purpose of this study was to evaluate the effect of smear layer on apical seal of endodontically treated teeth.Methods: Sixty extracted single-rooted human teeth were randomly divided into two experimental groups (n=25) and two control groups (n=5). The teeth were instrumented with K-type files to size 40 and then flared. Apical patency was ensured in all teeth. 5% sodium hypochlorite and 17%Ethylenediamine tetraacetic acid was used as irrigants to remove the smear layer in the second experimental group. The experimental groups were obturated by laterally condensed gutta - percha with Roth 801 sealer. The positive control group was obturated with gutta - percha without sealer. The root surfaces were then coated with nail polish and sticky wax except for the apex in the experimental groups and positive control group. The roots were completely covered in the negative control group. The samples were then immersed in India ink for 1 week at 37°C.Results: The statistical analysis of the results showed that the apical leakage was significantly increased in obturated canals with smear layer.Conclusion: The removal of smear layer might improve the long term apical seal and success of endodontically treated teeth.

Background: Chemo mechanical debridement is an important part of endodontic treatment. Elimination of pulpal tissue, microbiota and their by-products, organic and inorganic debris removal by using instruments and intracanal irrigants are objectives of this important phase of treatment. The aim of this study was to ex-vivo evaluation of smear layer removal in conventional clinical methods, Passive Ultrasonic Irrigation, Laser Activated Irrigation.Material and Methods: 54 anterior mandibular teeth was used in this study. After preparation of samples, they were divided in to 3 groups of Conventional Irrigation +Smear layer removal, Passive Ultrasonic Irrigation, Laser Activated Irrigation. Then, the samples were cut longitudinally in mesiodistal direction for examination by SEM (1500X) for assessing smear layer removal.Results: In coronal, middle and apical one third, the best result was obtained from Conventional Irrigation + Smear layer removal group for smear layer removal.Conclusion: According to better smear layer removal in Conventional Irrigation + Smear layer, it is considered as gold standard protocol and other groups cannot be a suitable substitution for this method.

Introduction: One of the main goals of endodontic treatment is to decrease the harboring bacteria within the root canal system and dentinal tubules. This experimental study attempted to investigate the antibacterial efficacy of three root canal irrigants in the presence and absence of smear layer (SL).Methods and Materials: A total of 210 sound extracted human single-rooted teeth were prepared.After creating the SL and its removal in half of the samples, they were infected withCandida albicans (C. albicans) and Actinomyces israelii (A. israelii). A total of 180 specimen were used to assess the antimicrobial efficacy of the three irrigants in presence and absence of SL, 24 specimen were placed in the positive and negative controls, 2 samples were utilized for scanning electron microscopy (SEM) analysis and 2 were used for Gram staining. Then, they were exposed to irrigants including 2.61% sodium hypochlorite (NaOCl), 0.2% chlorhexidine gluconate (CHX) and 1% povidone-iodine (PI) for 5, 30 and 60 min. Presence/absence of test microorganisms was determined by incubation of specimens in test tubes containing brain-heart infusion (BHI) broth and then measuring the colony forming units (CFU) on BHI agar. A cumulative logistic model was used to analyze the ordinal response.Results: The 2.61% solution of NaOCl was significantly more effective than 0.2% CHX and the latter was more efficient than 1% PI for decreasing fungal and microbial infection of dentinal tubules in the presence and absence of SL.Conclusion: The presence of smear layer decreased the efficacy of antimicrobial irrigants. The minimum time required for elimination of fungal/microbial infection was 30 min.