In order to determine the effect of root canal sealer on microleakage of obturated root canals by lateral condensation technique (LCT)-with and without tug-back (TB), seventy extracted single root canal teeth were examined. After preparation of root canal with step-back technique, teeth were divided to six groups as follows: 5 teeth as positive control group that obturated by LCT with gutta-perch without sealer. 5 teeth as negative control group in which entire root surfaces and apical foramen coated with nail varnish, and four experimental groups (each group consisted of 15 teeth). Group I ZOE with TB, group II ZOE without TB, group III Roth sealer with TB, and group IV Roth sealer without TB. Then the teeth were immerssed in Pelikan ink for 72 hours and weparated in two peices through vertical long axis. Stereomicroscope observation showed that TB groups (I & III) have statistically less microleakage than non TB groups (II & IV) (P<0.0001). There were no significant differences between two TB groups. Results also showed no relationship between root canal sealer and apical leakage with and without TB in both type of sealers.

Purpose: Many different factors are considered as effective factor that cause and have effect on endurance of low back pain. Life style is one of these factors consisted of subsets that are related to life pattern. The relation between these factors and low back pain is not well studied thus the present study by purpose of studying coping with stress as a basic factor in relation with components of low back pain have been done. Methods: from Social Welfare and Rehabilitation Sciences University of Tehran and Ferdowsi University of Mashhad of Iran 68 college students have participated in the study. All participants completed two questionnaires of Nordic musculoskeletal and Cassidi and Long problem-solving style. Analysis of data was conducted by SPSS v21 and Spearman correlation tests. Results: The results show that there is a positive correlation between age, education level and duration of low back pain with an efficient problem-solving style. On the other hand there is a negative correlation between inefficient problem-solving style and education level. In addition, results illustrate that there is a positive correlation between work absence and inefficient problem-solving style (p<0. 05). Conclusion: According to the results coping with stress style is an efficient factor in duration of low back pain and work absence. However, the effectiveness of this factor as a basic factor for the appearance of low back pain has not been shown in a proper manner.

Introduction: The reported 12 months prevalence of low back pain in nurses ranges from 43% to 76%. In most researches physical factors were only a part of high prevalence of low back pain in nurses. This study was conducted to determine the association between occupational stress and low back pain in nurses.Materials and Methods: In this case-control study, 80 nurses as case group and 80 nurses as control group were selected via convenience sampling. Case group were defined as those subjects who had experienced low back pain in the last 12 months. Control group were defined as those subjects who had not experienced low back pain in the last 12 months. A questionnaire was used for data collection which consisted of 3 sections: demographic information, history of low back pain and occupational stress. Data was analyzed using paired T, Mann-Whitney, and Chi-square tests, correlation coefficient and one way ANOVA.Results: Results indicated that, there was an association between low back pain and occupational stress (p<0/01).Also an association existed between low back pain and working hours per month (p<0/05). Statistical tests showed no significant difference between the two groups in terms of age, gender, marital status, number of childbirth, number of pregnancy, smoking, sport, work shift, number of years spent in the hospital (nursing experience).Conclusion: Results indicated that occupational stress in case group was more than control group. Since there was not any significant difference between other factors and low back pain, it can be concluded that there is an association between low back pain and occupational stress.

Background: The most frequently used test for evaluation of fetal health is the Non Stress Test (NST). Unfortunately it has a high incidence of false positive results. The combination of vibroacoustic stimulation with the NTS has been shown to reduce non reactive results.Methods: A tests assessment method was chosen with a simple randomized sampling. 40 pregnant women with non reactive NST in the first 20 minutes who received VAS in one of Tehran University's Hospitals were compared with BPP scores. A vibroacoustic stimulation was applied for a 3 seconds on the maternal abdomen and fallowed within 10 minutes. Data collection tools were NST, sonography instruments, NST result paper, tooth brusher, watch, demographic questioner and check list. Data analysis was made by descriptive static and by using the Fisher's Exact Test (with level of significant at p<0/05). All statistical analysis were performed using an spss/win.Results: After VAS, 70% of non reactive tracing became reactive. All cases with fetal reactivity response after a VAS had a subsequent BPP score of 8 (negative predictive value of 100%). False positivity of VAS was lower than NST.Conclusion: VAS offers benefits, by decreasing the incidence of non reactive test and reducing test time. VAS lowers the rate of false positive NST. VAS is safe and allows more efficient of prenatal services. This test could be used as a rapid antepartum test to predict fetal well-being.

Introduction: The final objective of root canal therapy is to create a complete seal along the length of the root canal system from the coronal opening to the apical termination and to accomplish the best adaptation from obturation material with canal walls. The tug-back of the master cone is recommended to provide apical seal. The purpose of this study was to determine the influence of tug-back on the quality of the apical seal. Materials & Methods: In this experimental in vitro study, seventy single canal teeth were selected. The crowns were removed; the canals were prepared using a step-back instrumentation technique. Patency of the apical foramen was maintained and the teeth were divided into 2 experimental groups of 32. In the first group obtruration was achieved by tug-back in master cone and in the second group without tug-back using lateral condensation technique. Six teeth were used as control group, out of which three served as negative and three as positive controls. The teeth were placed in 100% humidity and 37°c for three days. The roots of the teeth were coated with two layers of nail varnish and one layer of stick wax except for the 2mm of apical end. Teeth were immersed in methylenblue 2% solution for one week and finally the teeth were sectioned vertically. The depth of maximum dye penetration for each tooth was recorded by two evaluators with stereomicroscope. All results were submitted for statistical analysis using Student’s t-test. Results: The mean linear dye penetration for experimental group with tug-back in master cone was 6.918±2.140 mm while this was 8.110±1.929mm in the group without tug-back. This difference was statistically significant (P=0.02).  Conclusion: The results of this study showed that the tug-back in master cone provided a significantly better apical seal.