[show abstract][hide abstract] ABSTRACT: This study was performed to evaluate the effect of blood contamination on the compressive strength (CS) of Root MTA (RMTA) modified with Calcium chloride (CaCl2) and Disodium hydrogen phosphate (Na2HPO4) as setting accelerators over time.
A total of 110 cylindrical specimens of RMTA were divided into 6 experimental groups as follows: Group1, RMTA; Group 2, RMTA modified with CaCl2 (RMTA-C); Group 3, RMTA modified with Na2HPO4 (RMTA-N); Group 4, RMTA contaminated with blood; Group 5, RMTA-C contaminated with blood; Group 6, RMTA-N contaminated with blood. The CS of specimens in all groups was evaluated after 3 hr, 24 hr, and 1 wk. In the modified groups (groups 2, 3, 5, and 6) the CS of five specimens per group was also evaluated after 1 hr.
Blood contamination significantly reduced the CS of all materials at all time intervals (p < 0.05). After 3 hr, the CS of specimens in the RMTA groups (with and without blood contamination) was significantly lower than those in the RMTA-C and RMTA-N groups (p < 0.05). The CS values were not significantly different at the other time intervals. In all groups, the CS of specimens significantly increased over time (p < 0.05).
Blood contamination decreased the CS of both original and accelerated RMTA.
[show abstract][hide abstract] ABSTRACT: The aim of this study was to compare 2 kinds of anti-inflammatory medicines (ie, dexamethasone and ibuprofen) with a placebo according to their effects on the success rates of an inferior alveolar nerve block (IANB) for the endodontic treatment of mandibular molars with irreversible pulpitis.
A total of 165 patients were divided into 3 groups of 55 patients each and were given a capsule of the same color and size (ie, a placebo of lactose powder, 400 mg ibuprofen, or 0.5 mg dexamethasone). One hour after the oral administration of the capsules, all the patients received a standard IANB. In patients with a successful IANB, the teeth were examined with a cold pulp test. Patients were asked to assess their pain using the visual analog scale. Then, endodontic access cavity preparation was initiated. In case of pain during the treatment, the patients were asked to rate the pain on the visual analog scale. Success was defined as no or mild pain during treatment. The chi-square test and analysis of variance were used to compare qualitative and quantitative data among the groups.
No significant differences were found regarding the sex of the patients in the 3 groups (P > .05). The dexamethasone group showed significantly higher success rates compared with the placebo group (P = .001). There were no significant differences between the ibuprofen and placebo groups (P = .055) or the dexamethasone and ibuprofen groups (P = .34).
Premedication with dexamethasone increased the success rate of an IANB in mandibular molars with asymptomatic irreversible pulpitis.
Journal of endodontics 02/2013; 39(2):160-2. · 2.95 Impact Factor
[show abstract][hide abstract] ABSTRACT: Root canal anatomy diversity and aberrations are common especially in permanent dentition. A thorough understanding of the basic root canal anatomy and its diversities are necessary for successful endodontic treatment. Mandibular second premolars are usually single-rooted and have one root canal. Incidence of three separate root canals in this tooth is quite rare and taurodontism with three separate canals has never been reported in literature so far. The use of cone-beam computed tomography scan in this rare case greatly contributed to making a confirmatory diagnosis and successful nonsurgical endodontic management thereafter.
[show abstract][hide abstract] ABSTRACT: Thorough understanding of the anatomic and internal morphology of a root canal system is absolutely essential for the success of endodontic treatment. Since permanent maxillary first molars have shown variation in internal anatomy, morphology, this tooth has been reviewed extensively. Presence of two canals in a two-rooted maxillary first molar has rarely been reported in studies describing tooth and root canal anatomies. In this report, three cases are presented, which involve the root canal treatment of maxillary first molars with fusion of the two buccal roots.
[show abstract][hide abstract] ABSTRACT: The aim of the present in vivo study was to determine bone tissue reaction to calcium enriched mixture (CEM) and mineral trioxide aggregate (MTA) using a rat femur model.
Sixty-three rats were selected and randomly divided into three groups of 21 each [experimental groups (n=15), control (n=6)]. Implantation cavities were prepared in each femoral bone and randomly filled with the biomaterials only in the experimental groups. The animals in three groups were sacrificed 1, 4, and 8 weeks postoperatively. Histologic evaluations comprising inflammation severity and new bone formation were blindly made on H&E-stained decalcified 6-µm sections.
At 1, 4, and 8 weeks after implantation number of inflammatory cells had decreased in the CEM, MTA and control groups, respectively, with no statistically significant differences. Conversely, new bone formation had increased in all the experimental and control groups, without statistically significant differences.
The results suggest that biocompatibility of MTA, as gold standard, and CEM cement as a new endodontic biomaterial are comparable.
[show abstract][hide abstract] ABSTRACT: This survey was conducted to provide statistical data regarding publications in PubMed-indexed journals from Tabriz University of Medical Sciences Faculty of Dentistry.
The database used for this study was PubMed. The search was conducted using key words including the names of the heads of the departments. Papers published between January 1, 2005 and April 31, 2012 were considered. The retrieved abstracts were reviewed and unrelated articles were excluded. Data were transferred to Microsoft Excel software for descriptive statistical analyses.
A total of 158 papers matched the inclusion criteria, with the majority from the Department of Endodontics (49 articles). The highest proportion (48.3%) of papers was related to in vitro studies, followed by clinical trials, in vivo studies, and case reports. The number of publications showed a considerable increase over the studied period.
PubMed-indexed publications from different departments have increased steadily, suggesting that research has become an essential component in the evaluated institute.
Journal of dental research, dental clinics, dental prospects. 01/2012; 6(4):160-2.
[show abstract][hide abstract] ABSTRACT: The aim of the present study was to electrochemically evaluate corrosion resistance of RaCe and Mtwo files after repeated sterilization and preparation procedures.
A total of 450 rotary files were used. In the working groups, 72 files from each file type were distributed into 4 groups. RaCe and Mtwo files were used to prepare one root canal of the mesial root of extracted human mandibular first molars. The procedure was repeated to prepare 2 to 8 canals. The following irrigation solutions were used: group 1, RaCe files with 2.5% NaOCl; group 2, RaCe files with normal saline; group 3, Mtwo files with 2.5% NaOCl; and group 4, Mtwo files with normal saline in the manner described. In autoclave groups, 72 files from each file type were evenly distributed into 2 groups. Files were used for a cycle of sterilization without the use of files for root canal preparation. Nine new unused files from each file type were used as controls. Then the instruments were sent for corrosion assessment. Mann-Whitney U and Wilcoxon tests were used for independent and dependent groups, respectively.
Statistical analysis indicated that there were significant differences in corrosion resistance of files associated with working and autoclave groups between RaCe and Mtwo file types (p<0.001).
Corrosion resistance of #25, #30, and #35 Mtwo files is significantly higher than that in RaCe files with similar sizes.
[show abstract][hide abstract] ABSTRACT: There is some evidence that the pH at the root surface is reduced by intracoronal placement of bleaching pastes, which is known to enhance osteoclastic activity. Therefore, it is recommended that a protective barrier be used over the canal filling to prevent leakage of bleaching agents. Glass-ionomer (GI) is commonly used as a coronal barrier before nonvital bleaching. Because mineral trioxide aggregate (MTA) creates high alkalinity after mixing with water, using MTA as a protective barrier over the canal filling may not only prevent leakage of bleaching agents and microorganisms, but may prevent cervical resorption. The aim of this study was to evaluate sealing ability of white mineral trioxide aggregate (WMTA) as a coronal barrier before nonvital bleaching.
Root canals of one hundred thirty human maxillary incisors were instrumented and filled with gutta-percha without sealer. Gutta-percha was removed up to 3 mm below the cementoenamel junction (CEJ). The teeth were randomly divided into six experimental groups of 20 teeth each and two control groups of 5. In three experimental groups, WMTA was packed into the canal to the level of CEJ. In the remaining experimental groups, glass-ionomer (GI) was used as a coronal barrier. After a 24-hour incubation period, one of the following three bleaching agents was placed in the access cavity of each of the WMTA or GI groups. These three bleaching agents were 30% hydrogen peroxide, sodium perborate mixed with 30% hydrogen peroxide, and sodium perborate mixed with distilled water. The bleaching agents were replaced every 3 days for three times. In the positive controls, no coronal barrier was used. In the negative controls, all the tooth surfaces were covered by two layers of nail varnish. Microleakage was evaluated using protein leakage test. Statistical analyses were performed with the Kruskal-Wallis and Mann-Whitney tests.
The experimental groups showed minimum leakage which was not significantly more than tha in the negative controls. There was no statistically significant difference in leakage between the experimental groups (p<0.05).
This study indicated that different bleaching agents have no effect on sealing ability of WMTA.
[show abstract][hide abstract] ABSTRACT: The aim of this study was to evaluate microleakage of white mineral trioxide aggregate (WMTA) after its exposure to a range of alkaline environments during hydration.
Seventy single-rooted teeth were divided into 4 experimental and 2 control groups. All the teeth were instrumented, and their apices were resected. Root-end cavities were filled with WMTA in the experimental groups. In the control groups, root-end cavities were not filled. Root-end fillings were exposed to alkaline environments with pH values of 7.4, 8.4, 9.4, or 10.4 for 3 days. Microleakage was evaluated by bovine serum albumin. Evaluations were carried out at 24-hour intervals for 80 days. Data were analyzed by one-way analysis of variance and a post hoc Tukey test at the 0.05 level of confidence.
The number of days (mean ± standard deviation) needed for color change at pH values of 7.4, 8.4, 9.4, and 10.4 were 78.53 ± 5.68, 80.00 ± 0.00, 68.93 ± 19.00, and 34.46 ± 12.73, respectively. The time needed for leakage to occur was significantly shorter in samples stored at a pH value of 10.4 (P<0.001).
Within the limits of this study, it can be concluded that pH values greater than 9.4 may jeopardize the sealing ability of WMTA during hydration.
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to compare apical microleakage following canal obturation with lateral and thermoplasticized gutta-percha compaction techniques. Ninety extracted single-rooted maxillary teeth were used in this study. Seventy teeth were randomly divided into two groups: One group was obturated by lateral compaction technique and the other was obturated by Obtura II (thermoplasticized gutta-percha compaction technique); 5 teeth were positive controls (without obturation) and 5 teeth were negative controls (with obturation) in each group. The specimens were placed in India ink for 48 h and then divided into two halves. The amount of dye penetration was observed under a stereomicroscope at ×16 magnification and 0.1 mm accuracy. In this study, there was apical leakage in the two experimental groups but the amount of microleakage was not significant. According to the results of independent samples test, there was no significant difference between the two experimental groups.
AFRICAN JOURNAL OF BIOTECHNOLOGY 12/2010; 9:8235-8240. · 0.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: The effect of sodium hypochlorite (NaOCl) gel along with EDTA on the removal of the smear layer has not been studied; therefore, the aim of the present study was to compare the efficacy of gel and solution forms of NaOCl in removal of the smear layer from root canal walls.
A total of 40 single-rooted teeth with minimum curvature (<5 degrees) were selected and divided into two experimental groups, each containing 15 teeth and one positive control group containing 10 teeth. The canals of all the teeth were prepared with rotary RaCe instruments up to #35. In the NaOCl solution group, the root canals were flushed with 2.5% NaOCl solution during instrumentation and in NaOCl gel group, the instruments were coated with gel form of NaOCl and used inside the root canals; then saline was used for root canal irrigation. Finally, 1 mL of 17% EDTA was used to rinse inside the root canals and remained in the root canals for 2 minutes in the both experimental groups; in the saline group, only saline was used for irrigation. The amount of the smear layer was quantified according to the Torabinejad method using a scanning electron microscope. Data were analyzed by the Kruskal-Wallis and Mann-Whitney tests. All the statistical analyses were set with a significance level of alpha = 0.05.
There were no significant differences between NaOCl gel and solution forms in the coronal, middle, and apical thirds of root canals. There were significant differences between NaOCl solution and saline groups in the three parts of root canal walls and between NaOCl gel and saline in the coronal, middle, and apical thirds.
The use of NaOCl gel can be as effective as NaOCl solution along with EDTA in smear layer removal in the three parts of root canal walls.
Journal of endodontics 07/2010; 36(7):1234-7. · 2.95 Impact Factor
[show abstract][hide abstract] ABSTRACT: Recently, some studies have compared mineral trioxide aggregate (MTA) with Portland cements, concluding that the principal ingredients of Portland cements are similar to those of MTA. The purpose of the present study was to evaluate the effect of gray MTA, white MTA, and gray and white Portland cements on inflammatory cells in rats.
Fresh mixtures mixed with distilled water were placed in polyethylene tubes, which were implanted in the dorsal subcutaneous connective tissue of 60 Sprague-Dawley rats along with empty tubes as controls. Tissue specimens were collected after the rats were sacrificed after 7, 15, 30, 60, and 90 days. The specimens were fixed, stained, processed, and histologically evaluated under a light microscope. Inflammatory reactions were classified as grade 0: without inflammatory cells, grade I: sporadic infiltration of inflammatory cells, grade II: moderate infiltration (<25 cells), grade III: dense and severe infiltration (25-125 cells), and grade IV: very dense and severe infiltration (>125 cells). Data were analyzed with the nonparametric (two factor) analysis of variance and Kruskal-Wallis H-test.
All the groups showed grade III inflammation after 7 and 15 days; there was a decrease in the inflammatory process after 30, 60, and 90 days. After 90 days, gray MTA, white MTA, and control groups had grade 0 inflammatory process, but gray Portland cement and white Portland cement groups showed grade 0 to grade I inflammatory processes.
MTAs were more biocompatible; however, more studies are required.
Journal of endodontics 05/2010; 36(5):899-903. · 2.95 Impact Factor