RESUMEN
Objective: To investigate the root canal curvatures of anterior teeth in the Han nationality in Shaanxi province.Methods:392 permanent anterior teeth were examined by indirect digital radiography both from labiolingual and mesiodistal directions according to Schneider method, root canal curvatures were analyzed by electronic rule.Results:Root canals of the anterior teeth were mainly of type I. High rate of root canal curvature was found in maxillary canines (68.5%), and most of curves were in the apical third. There was a relationship between the root canal curvatures of maxillary canine and age(P=0.03). Conclusion:Root canal curvatures of maxillary canine are complicated,especially in maxillary canines. The root canal curvatures of maxillary canine decreased with aging.
RESUMEN
Objective To investigate the optimal beam tube potential for amorphous silicon/cesium iodide flat panel digital chest radiography(indirect DR). Methods(1)60 healthy adults were undergone digital posteroanterior(PA) chest radiography at 80,100,150 kV respectively.The images quality of these three were compared by 5 independent observers.Several normal anatomy parts of the chest and the overall impression of the images were evaluated;(2)PA chest exposures of the anthropomorphic chest phantom to produce a constant ESDs(entrance skin doses) and exit dose were made using tube potential at 80,100,120,150 kV.The simulated chest nodules were scored. Results The quality of the adult chest radiography and the manifestation of the simulated chest nodules were superior at the lower tube voltages.The contrast of the images were best at 80 kV,while the appearance of the images look like that of the low potential radiography. Conclusion The optimal tube potential for chest DR is considered to be 80~100 kVp,while the high KV technique is no longer suitable for digital equipment.