There have been many attempts to further improve and automate cephalometric analysis in order to increase accuracy, reduce errors due to subjectivity, and to provide more efficient use of clinicians' time. The aim of this research was to evaluate an automated system for landmarking of cephalograms based on the use of an active appearance model (AAM) that contains a statistical model of shape and grey-level appearance of an object of interest and represents both shape and texture variations of the region covered by the model. Multi-resolution implementation was used, in which the AAM iterate to convergence at each level before projecting the current solution to the next level of the model. The AAM system was trained using 60 randomly selected, hand-annotated digital cephalograms of subjects between 7.2 and 25.6 years of age, and tested with a leave-five-out method that enabled testing not only of the accuracy of the AAM system but also the accuracy of each AAM. Differences between methods were examined using the non-parametric Wilcoxon signed rank test. An average accuracy of 1.68 mm was obtained, with 61 per cent of landmarks detected within 2 mm and 95 per cent of landmarks detected within 5 mm precision. A noticeable increase in overall precision and detection of low-contrast cephalometric landmarks was achieved compared with other automated systems. These results suggest that the AAM approach can adequately represent the average shape and texture variations of craniofacial structures on digital radiographs. As such it can successfully be implemented for automatic localization of cephalometric landmarks.
The discomforts deriving from the cervical part of the spine are present at great percentage of our examinees. Considering the fact that the said discomforts affect performing both professional and everyday activities, its prevention is necessary in order to avoid the consequences they carry.
The results of this study suggest that the examined interalar width and inner canthal distance cannot be considered reliable guidelines in the selection of artificial upper anterior teeth. However, they may be used as a useful additional factor combined with other methods for objective tooth selection. The final decision should be made while working on dentures fitting models with the patient's consent.
The impaction of food boluses in the esophagus is significantly higher in women, usually after 76 years of age. There is a positive correlation between the presence of oesophageal stricture and recurrence of food bolus impaction. Partial and total tooth loss is present in a high percentage but there is no correlation with the food bolus impaction. Impaction of food bolus was equally found in the upper and lower third of the oesophagus and it was usually meat. Radiographic diagnosis should precede each esophagoscopy. Esophagoscopy with rigid oesophagoscope is a reliable method for the extraction of a bolus of food from the oesophagus in elderly patients.
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