Résumé
Background: although it is one of the most toxic nonradioactive elements, mercury is widely used in dental amalgam. Mercury is a toxic element which can damage various organs such as central nervous system, renal, respiratory and hematologic systems. The adverse health impacts associated to exposure to some common sources of electromagnetic fields including laptop computers, mobile phones, MRI and mobile phone jammers have been evaluated by our laboratory in our previous investigations. In this study, we aimed to evaluate the effect of X ray exposure on microleakage of amalgam restoration
Materials and Methods: standardized class V cavities were prepared on the buccal surfaces of 46 non-carious freshly extracted human premolars. The teeth were randomly divided into experimental and control groups. Experimental group were exposed to X-ray using an intraoral radiography machine at 60 kVp, 0.1 s, 7 mA with 2.5 mm Al total filtration. The absorbed dose was 245.0 +/- 0.5 microGy. All specimens were placed in 2 % basic fuchsin solution for 24 hours. Then the specimens were sectioned and microleakage was assessed according to dye penetration using a stereomicroscope. Statistical analysis was performed with the Mann-Whitney U-test
Results: microleakage was significantly higher in the X-ray exposed teeth compared to those of the non-irradiated samples
Conclusion: the results of the present study suggest that X-ray exposure increased microleakage of amalgam restorations
Résumé
The international study of asthma and allergies in childhood [ISAAC] is used to define the prevalence and severity of asthma in different regions. In this study we followed the performance of the ISAAC video and written questionnaires [VQ and WQ] to classify asthma in 13-14 yr-old schoolchildren. The present study was carried out on 3540 schoolchildren 13 to 14-yrs-old using the VQ and WQ. The students were also asked to answer a separate question if they had ever been clinically diagnosed as asthmatic. The Kappa index was used to find degree of agreement between VQ and WQ regarding asthma symptoms. The sensitivity, specificity and Youden's index of both questionnaires were also determined. The most frequent asthma symptom was wheeze after exercise in both VQ [15%] and WQ [23%]. Correlations between positive responses to the corresponding questions in the VQ and WQ were significant [P<0.001]. The sensitivity of both questionnaires to the question of asthma diagnosis by physician ranged between 0.16 and 0.68. Except for wheeze limiting speech and current wheeze, the WQ had higher value of Youden's index [0.25 - 0.46]. The specificity of questions in VQ for asthma diagnosis by physician was ranged between 0.84 and 0.99. Both WQ and VQ had low sensitivity, but WQ showed higher value of Youden's index and the VQ exhibited good specificity. Therefore, one may consider the WQ for prevalence and VQ for relative risk studies