ABSTRACT
The purpose of the present study was to determine the effect of 17% Ethylene, di-amine, tetra-acetic acid [EDTA], 6% phosphoric acid and Erbium: Yttrium, Aluminum, Garnet [Er:YAG] Laser in removing the smear layer by scanning electron microscopy. In this study, 80 single-rooted human teeth were selected. Instrumentation was done by use of hand files and step-back technique up to file #40 at apical and file #80 at coronal area. During instrumentation, 1ml of 5.25% sodium hypochlorite [NaOCl] was used as irrigation between each file. The teeth were randomly divided into four groups with different methods of smear removal.17% Ethylene, di-amine, tetra-acetic acid was used in group 1, 6% Phosphoric acid in group 2, Erbium: Yttrium, Aluminum, Garnet laser in group 3, and no intervention in group 4 [as control]. Roots were then longitudinally sectioned and prepared for scanning electron micrograph in cervical, middle and apical areas. Data were analyzed by Kruskal-Walis, Mann-Whitney, Friedman and Wilcoxson tests [P<0.05]. The results showed a significant difference in smear layer removal between three methods in favor of the EDTA [P<0.001] and Phosphoric groups [P<0.001] with no significant difference between them [P=0.49]. Although Er:YAG laser showed some limited ability to remove the smear layer, the effectiveness was not significantly different from the control group [P=0.157]. Based on the findings of this study, EDTA and Phosphoric acid were effective methods to remove smear layer from the root canal walls but Er:YAG laser showed less efficacy compared to the other experimental groups
Subject(s)
Humans , Therapeutic Irrigation , Endodontics , Lasers, Solid-State , Microscopy, Electron, Scanning , Edetic Acid , Phosphoric AcidsABSTRACT
Various methods have been used for the treatment of dentine hypersensitivity such as dentifrices, sealants and different types of lasers. The aim of this study was to evaluate the effect of Neodimium:Yttrium-Aluminium-Garnet [Nd:YAG] laser in association with graphite on the dentin morphologic changes. In this experimental in vitro study, 16 freshly extracted third molars were selected. 5 specimens with the dimensions of 2×2×1 mm from root trunk were prepared. Specimens were randomly divided into five groups: group 1 [control, no laser irradiation]. Group 2, 3 irradiated by Nd:YAG laser 0.5 and 1W, output power respectively. Group 4, 5 smeared with graphite and then irradiated by Nd: YAG laser 0.5 and 1W output power. Samples were prepared for scanning electron microscopy. Number and diameter of dentinal tubules were determined in different groups and analyzed with the Kruskal-wallis and Mann-Whitney tests [SPSS 16]. The number of tubules had significant difference between all groups [P<0.001], except group 1 in comparison with group 2 [P> 0.05], and group 3 in comparison with group 4 [P> 0.05]. Micro-cracks and rupture of melted dentin materials were seen in group 4 and 5. According to the findings of this study, smearing with graphite on dentin surface increase the absorption of Nd:YAG laser energy and reduced the diameter and number of open dentinal tubules
Subject(s)
Humans , Graphite , Lasers, Solid-State , Microscopy, Electron, Scanning , Dentin SensitivityABSTRACT
Complete root canal seal is one of the most important aims of root canal treatment. The aim of this study was to compare the sealing ability of three resin-based sealers [AH26, AH Plus Jet and TG Adseal] against microbial microleakage. In this in vitro study, 87 single-rooted extracted human teeth were decoronated maintaining a root length of 15 mm. Apical preparation and coronal flaring of the root canals were carried out up to #40 and #80 K-files, respectively, using the step-back technique. After cleaning and shaping, the teeth were randomly divided to 5 groups: Three experimental groups of 25 teeth, a positive control group of 3 teeth and a negative control group of 9 teeth. The experimental groups were obturated with gutta-percha and AH26 sealer, gutta-percha and AH Plus Jet sealer, and gutta-percha and TG Adseal sealer. The samples were evaluated daily for 90 days and the time of culture contamination with Enterococcus faecalis was registered in each case. The results were statistically analyzed by Kaplan-Meier, Chi-square and Mann-Whitney tests. All the samples in the positive control group were infected after 24 hours. None of the negative control samples were infected after 90 days. Time of contamination between experimental groups showed no significant differences [p value = 0.611]. TG Adseal can be recommended for root canal therapy due to its sealability which is comparable to AH26 and AH Plus Jet root canal sealers and its appropriate cost
ABSTRACT
Sealing ability is an important factor for a root-end filling material in endodontic surgeries. This in vitro study aimed to compare the sealing ability of mineral trioxide aggregate [MTA] and a new endodontic cement named calcium enriched mixture [CEM] cement as root-end filling materials. The experiments were carried out in dry, saliva or blood contaminated root-end cavities of hundred single-rooted extracted human teeth. After decoronation, the root canals were cleaned, shaped, obturated, and stored in 100% humidity for 5 days. Removing the apical 2-3mm of each root, a 3mm deep root-end cavity was ultrasonically prepared. Samples were randomly divided into 2 test groups of 45 roots/experimental material, and one subgroup [n=15] for each environmental condition as follows; a] dried before placing the filling material, b] filled after contamination with saliva, and c] filled after contamination with blood. Ten roots were used as positive/negative controls. Samples were placed in an incubator at 37°C for a day and immersed in methylene blue dye under reduced pressure environment for 48hours. Roots were sectioned longitudinally and examined under stereomicroscope by an independent observer. Using Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction, the results demonstrated significantly less leakage for the CEM cement in saliva contaminated condition when compared to MTA [P<0.001]. It can be concluded that the sealing ability of CEM cement was superior to MTA in saliva contaminated condition
ABSTRACT
The human teeth have different anatomical variations and treatment of each tooth is under the influence of its configuration. The root canal anatomy, not only in various teeth, but also in one tooth might be different. The important point is to understand the canal anatomy that is essential for root canal therapy. In various studies, different results have been reported from different regions of the world, additionally a number of studies have shown different trends in shape and number of roots and canals among different races. Since there is a lack of information about canal configuration in the city of Isfahan, therefore this study was done to determine the frequency of canal configuration in maxillary first and second molars This study was descriptive, that was done on 160 extracted maxillary first and second molars, which were collected from clinics and private offices in the city of Isfahan. Pulp tissue was removed and canal system was stained with Indian ink, the teeth were decalcified with 10% nitric acid, dehydrated and cleared with methyl salicylate. Maxillary first molars were additionally cut in cross sections in three points of the root and canal configuration of teeth were evaluated. The examination of root canal systems of teeth was based on Weine classification. The majority of maxillary first and second molars had three separate roots. A variety of canal types were found in mesiobuccal [MB] roots of first and second molars. More than half of the MB roots of first molars [61%] had two canals, whereas MB roots of second molars mostly had type I canals [76.38%] in the clearing method. The palatal and distobuccal canals mainly had type I canal configuration. In the sectional method more than half the MB roots of first molars had two canals [78.47%]. In other countries many researches have been done using different methods about internal anatomy of teeth and the results are different from this study. It appears that the differences are caused by genetic factors and methods used. Also results of this study were different in types I and IV in MB roots in the two methods, this difference is probably due to better access and visibility to canal in the sectional method