Papers by Keyword: Computerized Tomography

Abstract: The management of traumatic dental caries in primary teeth has the main objective to avoid their consequences that can affect the immediate and longterm quality of life of the child. Aggressive forms of decays can develop on smooth surfaces of teeth and progress rapidly, the effect being detrimental on the dentition. The objective of this study was to compare the stress and displacement distributions in the models of two assemblies by means of the three-dimensional finite element analysis: deciduous maxillary lateral incisor - restorative filling – bone structure and deciduous mandibular lateral incisor – restorative filling – bone structure respectively. Both models were subjected to a 120 N static load applied on the upper surface. The models were built from computed-tomography scans. Two different restorative dental materials were considered. In addition, the results obtained were compared with previous research of the authors, i.e. the mechanical behavior of a deciduous restored molar and deciduous restored canine respectively. As a result of the study, it can be concluded that the biomechanical analysis of deciduous dental caries is a valuable aid in enabling the dentist to make correct and effective treatment decisions.

Abstract: The number of projection affects the reconstruction quality in computed tomography system. Larger projection number will lead to better reconstruction quality. On the other hand, less projection number can reduce the radiation dose, save time and keep the patients comfortable. The optimal number of projection compromises both the mathematical accuracy and practical requirement. The purpose of this paper is to find the relationship between the projection number and the noise properties of reconstructed cross-section. It can provide references for researchers on CT application. A micro-CT system is utilized to validate the relationship between projection number and reconstruction quality in fan beam geometry. Full-scan and short-scan method are applied to reconstruct the specimen. Compared with full-scan method, short-scan can reduce radiation dose with the same step angle, and it can achieve better results with the same projection number when the sample data is sufficient.

Abstract: Medical visualization refers to the techniques and processes used to create images of the human body for clinical purposes or medical science including the study of normal anatomy and physiology. The visualization of medical images data sets is to reconstruct 3D images with the 2D slice images so as to reveal the 3D configuration of organs through human visual system. Visual C++ are used to reconstruct 3D images using the CT slice sequence. The key algorithms and human CT 3D visualization results are given in this paper. The coordinates can be acquired by the mouse clicking in the 3D space, by which to realize the point coordinate acquisition of the 3D medicine images. The visualization of medical images can provide us with more information and means of visual interactive for simulated operations and assistant diagnosis. The technique can realize the real time interaction quantitative measurement of three-dimensional CT image.

Abstract: Delamination is one of the most concern defects in drilling of composite material. Delamination depends on the factors such as feed rate, tool geometry and wear. The mechanics of drilling composite materials has been examined along with the quality of the hole and the effect of tool design parameters. The capacity of computerized tomography (CT) showing sample cross-section in a nondestructive way made it successful in measuring the drilling-induced delamination. In the experiment, the correlation between thrust force and the measured delamination extent in use of twist drill and core drill is illustrated and compared with the known ultrasonic C-scan. It is compared with the ultrasonic technique and is demonstrated a feasible and an effective tool for the evaluation of drilling-induced delamination.