Search results for "Computer-aided"
showing 10 items of 416 documents
An automated image analysis methodology for classifying megakaryocytes in chronic myeloproliferative disorders
2008
This work describes an automatic method for discrimination in microphotographs between normal and pathological human megakaryocytes and between two kinds of disorders of these cells. A segmentation procedure has been developed, mainly based on mathematical morphology and wavelet transform, to isolate the cells. The features of each megakaryocyte (e.g. area, perimeter and tortuosity of the cell and its nucleus, and shape complexity via elliptic Fourier transform) are used by a regression tree procedure applied twice: the first time to find the set of normal megakaryocytes and the second to distinguish between the pathologies. The output of our classifier has been compared to the interpretati…
The double cone: a mechanical paradox or a geometrical constraint?
2011
In the framework of the Italian National Plan ‘Lauree Scientifiche’ (PLS) in collaboration with secondary schools, we have investigated the mechanical paradox of the double cone. We have calculated the geometric condition for obtaining an upward movement. Based on this result, we have built a mechanical model with a double cone made of aluminum and a couple of wooden rails.
A prospective evaluation of zirconia anterior partial fixed dental prostheses: Clinical results after seven years.
2014
Abstract Statement of problem Because of the high mechanical strength of zirconium dioxide, the metal in fixed partial prostheses can now be replaced. However, the material is susceptible to aging or hydrothermal degradation and to chipping of the feldspathic veneer. Purpose The purpose of this prospective study was to evaluate the survival (without failure) and success (survival without any complication or failure) rate and clinical efficacy of anterior zirconia partial fixed dental prostheses. Material and methods Twenty-seven anterior partial fixed dental prostheses of 3 to 6 units were fabricated. All participants were examined after 1 month and 6 months, then annually for 7 years. Resu…
Comparative fracture behavior of monolithic and veneered zirconia posterior fixed dental prostheses
2017
The purpose of this study was to evaluate and to compare the fracture load and the fracture pattern of monolithic and veneered zirconia posterior fixed dental prostheses (FDPs). Twenty standardized steel dies were prepared to receive posterior 3-unit FDPs. Specimens were randomly divided into 2 groups (n=10): (1) Lava Zirconia, and (2) Lava Plus. All FDPs were cemented using glass ionomer cement and subjected to thermal and mechanical cycling at 5-55ºC with a 30-s dwell time for 120,000 masticatory cycles. All specimens were subjected to a three-point bending test until fracture. Data were statistically analyzed using Student's t test, paired t-test and Weibull statistics (α=0.05). No diffe…
Effect of Thermomechanical and Static Loading on the Load to Fracture of Metal‐Ceramic, Monolithic and Veneered Zirconia Posterior Fixed Partial Dent…
2018
PURPOSE To evaluate the influence of static (not preloaded) and thermomechanical loading on the load to fracture of metal-ceramic, monolithic and veneered zirconia computer-aided design/computer-aided manufacturing (CAD/CAM) posterior fixed partial dentures (FPDs). MATERIALS AND METHODS One hundred standardized specimens with 2 abutments screwed onto a platform were prepared from stainless steel to receive a posterior 3-unit FPD with an intermediate pontic. Specimens were randomly divided into 5 groups (n = 20): Metal-ceramic (control group), Lava Zirconia system, Vita In-Ceram YZ, IPS e.max ZirCAD, and Lava Plus. Half of the specimens of each group (n = 10) underwent no preloading, and the…
Computer-aided system for morphometric mandibular index computation (Using dental panoramic radiographs)
2012
Objective: We propose and validate a computer—aided system to measure three different mandibular indexes: cortical width, panoramic mandibular index and, mandibular alveolar bone resorption index. Study Design: Repeatability and reproducibility of the measurements are analyzed and compared to the manual estimation of the same indexes. Results: The proposed computerized system exhibits superior repeatability and reproducibility rates compared to standard manual methods. Moreover, the time required to perform the measurements using the proposed method is negligible compared to perform the measurements manually. Conclusions: We have proposed a very user friendly computerized method to measure …
A facially driven complete-mouth rehabilitation with ultrathin CAD-CAM composite resin veneers for a patient with severe tooth wear: A minimally inva…
2020
Abstract The development of technologies that include face scanning and dental software has improved workflows in dentistry. Digital files make it possible to create a 3-dimensional virtual image of the patient that helps the clinician plan treatment and make decisions, reducing uncertainty and improving communication. This report describes the complete-mouth rehabilitation of a patient with severe tooth wear. The treatment adopted a minimal intervention approach, applying adhesive veneers in areas where the tooth structure was affected and used a computer-aided design and computer-aided manufacturing (CAD-CAM) workflow to prepare nanoceramic composite resin materials with a high filler loa…
Examining the Quality of Evolution Frameworks and Metamodeling Paradigms of Information Systems Development Methodologies
2011
Information systems development methodologies and associated CASE tools have been considered cornerstones for building quality into an information system. The construction and evaluation of methodologies are usually carried out by evaluation frameworks and metamodels, both considered as meta-methodologies. This chapter investigates and reviews representative metamodels and evaluation frameworks for assessing the capability of methodologies to contribute to high-quality outcomes. It presents a summary of their quality features, strengths, and weaknesses. The chapter ultimately leads to a comparison and discussion of the functional and formal quality properties that traditional meta-methodolo…
Conformation constraints for efficient viscoelastic fluid simulation
2017
The simulation of high viscoelasticity poses important computational challenges. One is the difficulty to robustly measure strain and its derivatives in a medium without permanent structure. Another is the high stiffness of the governing differential equations. Solutions that tackle these challenges exist, but they are computationally slow. We propose a constraint-based model of viscoelasticity that enables efficient simulation of highly viscous and viscoelastic phenomena. Our model reformulates, in a constraint-based fashion, a constitutive model of viscoelasticity for polymeric fluids, which defines simple governing equations for a conformation tensor. The model can represent a diverse pa…
Generation of Bessel beam arrays through Dammann gratings.
2012
In this work we apply the Dammann grating concept to generate an equal-intensity square array of Bessel quasi-free diffraction beams that diverge from a common center. We generate a binary phase mask that combines the axicon phase with the phase of a Dammann grating. The procedure can be extended to include vortex spiral phases that generate an array of optical pipes. Experimental results are provided by means of a twisted nematic liquid crystal display operating as a binary π phase spatial light modulator.