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STATEMENT OF THE PROBLEM: Sealing ability is one of the most important factors for successful endodontic treatment. Some studies have shown that the powder to liquid ratio can influence the properties of dental materials. Subsequently, this may happen for those used for sealing in endodontics. PURPOSE: The purpose of this research was to assess the microleakage of calcium-enriched mixture (CEM) cement apical plug in different powder to liquid ratio. MATERIALS AND METHOD: Ninety-six extracted human single root and single canal teeth were decoronated. Working length was determined using ≠15 k-file. Canal preparation was performed using step back method. Samples were divided into 3 groups randomly. CEM cement was placed into the canal with 1.13, 2.27 and 3.40 powder to liquid ratio in the group 1, 2 and 3, respectively. After complete setting of CEM cement, the micro leakage value was evaluated using fluid filtration method. Data were analyzed using ANOVA and Scheffe tests. RESULTS: The bubble movement in three groups showed a statistically significant difference (p< 0.001). Minimum and maximum bubble movements were observed in the group with powder to liquid ratios of 3.40 and 1.13 respectively. CONCLUSION: Increased CEM Cement powder to liquid ratio will increase the sealing ability of this material as apical plug. Considering the conditions of this study, the powder to liquid ratio of 3:40 provided the best sealing ability.
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INTRODUCTION: Multiple methods for evaluating microleakage have been introduced over the years, but there has been no agreement as to which technique will give more accurate results. The aim of this study was to compare the accuracy and results of fluid filtration and marginal adaptation methods for mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement apical plugs. METHODS AND MATERIALS: A total of 250 single-rooted human teeth were collected. The teeth were decoronated, the root canals were prepared and open apex condition was stimulated by passing #1 to 4 Peeso Reamer drills from apical foramen. Five teeth were selected as the positive and negative controls and the rest of the samples were randomly allocated to two groups of MTA and CEM cement plugs. In each group, apical plug was placed into the canal. After the apical plugs were completely set, microleakage and marginal adaptation of the samples were evaluated using fluid filtration method and scanning electron microscopy (SEM), respectively. The obtained results were analyzed by independent-samples t test. RESULTS: Gap between plug and dentin walls and air bubbles displacement was higher in MTA group compared to the CEM cement group, though this difference between MTA group and CEM cement group was not statistically significant. Conclusion: According to the obtained results, it seems that there is a direct relationship between the two methods of microleakage assessment.
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INTRODUCTION: The aim of this study was to compare the marginal adaptation of mineral trioxide aggregate (MTA) and calcium-enriched mixture(CEM) cement apical plugs in open apex teeth in dry, blood- and saliva-contaminated canals. METHODS AND MATERIALS: A total of 120 human extracted single-rooted teeth were used. The teeth were decoronated and canals were cleaned and shaped up to #80 K-Files. After simulating open apex condition, samples were randomly divided into two groups (Group 1: MTA plug and group 2 CEM cement plug) and each group was then further divided into 3 subgroups (dry canal, blood- and saliva-contaminated canals). MTA and CEM cement apical plugs were placed into the canal. After full setting of apical plug, immediate marginal adaptation of the samples was assessed by electronic microscope. The data were analyzed using the two-way analysis of variance. RESULTS: There was no statistically difference between the average marginal gap in MTA and CEM cement groups in three different conditions. The average gap in dry canal was significantly lower than canal contaminated with blood and saliva. CONCLUSION: It seems that marginal adaptations of MTA and CEM apical plug was not significantly different in various conditions and the two materials can be used successfully in this method.
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INTRODUCTION: Microleakage is of the causes of endodontic treatment failure. The aim of this in vitro study, was to compare the microleakage of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement apical plugs in three environments. METHODS AND MATERIALS: A total of 130 human extracted single rooted teeth were collected. After decoronation, preparation of the root canal space and simulation of open apices, 5 teeth were selected as positive and negative control groups and the rest of the samples were randomly divided into two groups (MTA plug and CEM cement plug) and each group was divided into 3 subgroups (dry, contaminated with saliva and contaminated with blood). In each group apical plug was placed into the canal. After full setting of the apical plug, microleakage of the samples were evaluated using fluid filtration method and the data were analyzed using two-way analysis of variance. RESULTS: In dry and saliva contaminated environments, the leakage of MTA samples were 40.906±2.081 and 39.608±2.081, respectively which was significantly more than that of CEM cement samples (26.977±2.081 and 27.000±2.081, respectively). However, in blood-contaminated environments, the amount of leakage in MTA group (21.640±2.081) was significantly lower than CEM cement group (44.358±2.081). CONCLUSION: According to the results of this study, in dry and saliva-contaminated conditions CEM cement provides significantly better seal in comparison to MTA.
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BACKGROUND: Sexually transmitted infections (STIs) are a diverse group of infections caused by widely differing microorganisms (viruses, protozoa, bacteria, yeasts, ectoparasites and even a nematode), with transmission from person to person by sexual contact as its common characteristic. In all societies, sexually transmitted infections rank among the most common infectious diseases. These patients are at risk for hepatitis B virus infection, but have been relatively neglected in terms of hepatitis B virus vaccination. OBJECTIVES: In this study, compliance with hepatitis B vaccination among adult males with sexually diseases was examined. PATIENTS AND METHODS: In this survey, 114 males, referred to an infectious diseases clinic, were asked to complete a questionnaire evaluating their knowledge of hepatitis B vaccine, and were interviewed to assess their reasons for refusal or acceptance. Finally, SPSS (version 16) was used to perform the statistical analyses. Variables were analyzed with Chi-square tests. RESULTS: The results of this study indicated that the overall hepatitis B vaccine acceptance rate was acceptably high. Among all, 53.5% correctly identified that a vaccine to prevent hepatitis B virus infection had been available, 15% had a negative opinion, and 31.5% were neutral. The rations of all three doses of vaccination were 69.3%. CONCLUSIONS: Among the respondents, 87% were currently married, 86.8% were currently employed, 17.5% have addiction, 34.2 % used condom, and 36.8% correctly identified hepatitis B as a sexually transmitted infection.
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OBJECTIVE: Although computer technologies are now widely used in medicine, little is known about its use among medical students in Iran. The aim of this study was to determine the competence and access to computer and internet among the medical students. METHODS: In this descriptive study, medical students of Shahid Sadoughi University of Medical Science, Yazd, Iran from the fifth years were asked to answer a questionnaire during a time-tabled lecture slot. The chi-square test was used to compare the frequency of computer and internet use between the two genders, and the level of statistical significance for all test was set at 0.05. RESULTS: All the students have a personal computer and internet access. There were no statistically significant differences between men and women for the computer and internet access, use wireless device to access internet, having laptop and e-mail address and the difficulties encountered using internet. The main reason for less utilization of internet was slow speed of data transfer. CONCLUSIONS: Because of the wide range of computer skills and internet information among medical students in our institution, a single computer and internet course for all students would not be useful nor would it be accepted.