Papers by Keyword: Ceramic Prosthesis

Abstract: Several CAD/CAM systems are available to dental prosthesis laboratories that can be used to make all-ceramic copings and frameworks. In Brazil, the use of these systems presents low demand, due principally the high blocks ceramics cost used for theses systems. The ceramic blocks are imported. To increase the dental ceramic CAD/CAM applications is necessary develop and produce the ceramics blocks in Brazil. The purpose of the present work is to compare the mechanical properties of blocks of zirconium developed in the Brazil (ProtMat® Co) and imported (VITA). It was determined the mechanical and physics properties of the two types of blocks of zirconium stabilized with ytria. The blocks have been sinterized at 1530 °C and their mechanical and physics properties were measured. The x-ray diffraction analysis showed only tetragonal phase, which improve the blocks toughness. The Vickers hardness and fracture toughness were 1300HV and 9 MPam^1/2, respectively. High bending fracture resistance was obtained for both materials with average values of 910MPa. The Weibull modulus was m=10 for Brazilian and imported blocks. It was not observed an important difference among the microstructures and mechanical properties of the analyzed zirconium blocks.

Abstract: Intraoral adjustment of ceramic prostheses involving cutting process is a central procedure in restorative dentistry because the quality of ceramic prostheses depends on the cutting process. In this paper, an artificial neural network (ANN) model was developed for the first time to forecast the dynamic forces in dental cutting process as functions of clinical operational parameters. The predicted force values were compared with the measured values in in vitro dental cutting of porcelain prostheses obtained using a novel two-degrees-of-freedom computer-assisted testing apparatus with a high-speed dental handpiece and diamond burs. The results indicate that there existed nonlinear relationships between the cutting forces and clinical operational parameters. It is found that the ANN-forecasted forces were in good agreement with the experiment-measured values. This indicates that the established ANN model can provide insights into the force-related process assessment and forecast for clinical dental cutting of ceramic prostheses.