957 resultados para Computerized tomography


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Pós-graduação em Odontologia - FOAR

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Da a conocer el sistema que regula al archivo computarizado de direcciones ADDRESS, el cual controla la distribucion de documentos y publicaciones producidos por el sistema de la CEPAL desde mediados de 1979, sus procedimientos para el manejo de dicho archivo y las posibilidades que brinda a sus usuarios.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Color vision consists of the discrimination of objects based on their spectral composition. Among primates, the majority of Platyrrhini monkeys are estimated to have polymorphic and sex-linked dichromacy. The objective of this study was to compare the results produced by different equipment and software for the assessment of tri- and dichromatic conditions in one male and two female Cebus apella. Three experiments were programmed. In Experiment 1, verifying the trichromatic condition of one female subject and dichromatic condition of the remainder of the subjects was possible using an adapted version of the Cambridge Colour Test. Experiment 2 confirmed the results of Experiment 1 using a different array of stimuli of the same test. Experiment 3, which produced results similar to Experiment 2, consisted of a test developed for a standard computer system using stimuli with color properties similar to the ones used in the previous experiment. Favorable conditions for the assessment of color vision in Platyrrhini can be built with low-cost equipment and software. Once data have been gathered with additional subjects and new stimulus arrangements have been tested and confirmed, the procedure can be used for the evaluation of other Platyrrhini species for which behavioral color discrimination data are currently lacking.

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The search for new instruments to promote an appropriate cervical preparation has led to the development of new rotary instruments such as TripleGates. However, to the best of the authors' knowledge, there is no study evaluating TripleGates effect on the “risk zone” of mandibular molars. Objectives: The aim of this study was to evaluate the effects of a crown-down sequence of Gates-Glidden and TripleGates burs on the remaining cervical dentin thickness and the total amount of dentin removed from the root canals during the instrumentation by using cone beam computed tomography. The number of separated instruments was also evaluated. Material and Methods: Mesial roots of 40 mandibular first molars were divided into 2 equal groups: crown-down sequence of Gates-Glidden (#3, #2, #1) and TripleGates burs. Cervical dentin thickness and canal area were measured before and after instrumentation by using cone beam computed tomography and image analysis software. Student’s t-test was used to determine significant differences at p<0.05. Results: No significant differences (p>0.05) were observed between the instruments, regarding the root canal area and dentin wall thickness. Conclusion: Both tested instruments used for cervical preparation were safe to be used in the mesial root canal of mandibular molars.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Objective: To compare dental plaster model (DPM) and cone-beam computed tomography (CBCT) in the measurement of the dental arches, and investigate whether CBCT image artifacts compromise the reliability of such measurements.Materials and Methods: Twenty patients were divided into two groups based on the presence or absence of metallic restorations in the posterior teeth. Both dental arches of the patients were scanned with the CBCT unit i-CAT, and DPMs were obtained. Two examiners obtained eight arch measurements on the CBCT images and DPMs and repeated this procedure 15 days later. The arch measurements of each patient group were compared separately by the Wilcoxon rank sum (Mann-Whitney U) test, with a significance level of 5% (alpha = .05). Intraclass correlation measured the level of intraobserver agreement.Results: Patients with healthy teeth showed no significant difference between all DPM and CBCT arch measurements (P > .05). Patients with metallic restoration showed significant difference between DPM and CBCT for the majority of the arch measurements (P > .05). The two examiners showed excellent intraobserver agreement for both measuring methods with intraclass correlation coefficient higher than 0.95.Conclusion: CBCT provided the same accuracy as DPM in the measurement of the dental arches, and was negatively influenced by the presence of image artifacts.

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This case report describes the interdisciplinary treatment of a 19-year-old Brazilian man with a Class I malocclusion, a hyperdivergent profile, an anterior open bite, and signs of temporomandibular joint internal derangement. The treatment plan included evaluation with a temporomandibular joint specialist and a rheumatologist, orthodontic appliances, and maxillomandibular surgical advancement with counterclockwise rotation. Cone-beam computed tomography images were taken before and after surgery at different times and superimposed at the cranial base to assess the changes after orthognathic surgery and to monitor quantitatively the internal derangement of the temporomandibular joints and surgical relapse. Our protocol can improve the orthodontist's understanding of surgical instability, demonstrate the clinical value of cone-beam computed tomography analysis beyond the multiplanar reconstruction, and guide patient management for the best outcome possible.

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PURPOSE: To report a case of idiopathic macular hole, with vitreoretinal traction confirmed by optical coherence tomography that was successfully treated by a single intravitreous perfluoropropane (C3F8) gas bubble injection.METHODS: Case report. A 65-year-old patient with idiopathic macular hole (stage 2, one eye) received an intravitreous gas injection and was prospectively followed with optical coherence tomography.RESULTS: A complete posterior vitreous detachment was achieved within 6 weeks after gas injection. Visual acuity improved from 20/80 to 20/25 by 10 months of followup. Optical coherence tomography disclosed vitreoretinal traction release and macular hole closure. No complications were related to the procedure.CONCLUSION: This simple procedure can assist a complete posterior vitreous detachment with relief of the hyaloid-foveolar traction, facilitating macular hole closure. (C) 2001 by Elsevier Science Inc. All rights reserved.

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Horizontal root fractures (HRF) usually affect the anterior teeth as a result of trauma, and generally heal spontaneously, depending on the vitality of the pulp. Diagnosis based on clinical findings, sensitivity tests, and radiographic examination is important to determine the presence of a root fracture and to prevent a root fracture from passing unnoticed. Cone-beam computed tomography (CBCT) has been used successfully for diagnosis and prognosis imaging of root fractures and has proved to be superior to other radiographic methods. This study reports two cases of dental trauma caused by a collision and a sports accident. The patients suffered horizontal root fractures in the maxillary left central incisor and in the mandibular left central incisor. The diagnosis of root fracture was confirmed by cone-beam computed tomography (CBCT) images, which also demonstrated spontaneous healing of the fracture line. The repair occurred by interposition of connective tissue in the former case and by interposition of bone and connective tissue in the latter case. The final diagnoses of both cases were based on CBCT images, indicating the importance of a CBCT examination to reach a firm diagnosis and to follow the healing process of root fracture cases, avoiding unnecessary radical endodontic treatment.

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Contrast enhancement enables the verification of several pathological conditions that lead to vascular changes and/or breakdown of the blood-brain barrier. Examples of diseases that cause these disorders are: neoplastic diseases, vascular communications, active inflammation and cerebral ischemia. Several contrast enhancements located peripherically to cerebral lobes, in the topography of brain sulci and gyri, were identified on tomographic scan of twelve healthy cats that had their health confirmed through history, general and neurologic physical examination and polymerase chain reaction for feline leukemia (FeLV) and immunodeficiency (FIV) virus. This study aims to describe the tomographic contrast enhancement findings, which showed an identical appearance to the pia mater and arachnoid enhancement, also called leptomeninges. This finding is generally considered related to leptomeningeal diseases such as meningitis and neoplastic disease. However, in dogs, the leptomeningeal enhancement has already been described in healthy animals. This finding has a great importance in the interpretation of tomographic images of these animals since, so far, in the presence of these enhancements, meningeal disorders were suggested. Thus, the verification of other tomographic findings and the combination with other diagnostic methods are of great importance for the diagnosis of leptomeningeal disease.

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The imaging is essential to aid the diagnosis of horses that have performance decrease associated with any pain or clinical signs related to the vertebral column. Radiography is the first imaging examination performed in these cases, particularly for disorders affecting the cervical region. However, this technique has limitations when the study of subtle changes due to the overlapping of adjacent structures. Computed tomography is a new diagnostic method in Brazil for the study of bone disorders in horses, but it is of great diagnostic value associate with the radiographic examination in order to provide an accurate assessment of the study area, owing to superiority in image quality when compared to conventional radiography. The aim of this study is increase and update knowledge of diagnostic imaging available to investigate cervical disorders in horses.

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The incidence of encephalic tumors in dogs and cats has increased in recent years due to the constant advancement of methods of specialist Diagnostic Imaging: Magnetic Resonance Imaging (MRI) and Computed Tomography (CT), used in small animals. These tools, which were distant in the past, are now becoming increasingly important as an additional aid to the identification of tumor processes in the Central Nervous System. The objective, of the present study, was describe imaging findings obtained in 32 cases of encephalic tumors, through techniques of CT and MR imaging procedures during the years 2004 to 2011. Were diagnosed 19/32 by MRI and 13/32 by CT, being the most affected breed Boxer (9/32), the mean age was 10 years.