Papers by Keyword: Dental Bridge

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Authors: Susanne S. Scherrer, Janet B. Quinn, George D. Quinn
Abstract: The dental community is using a variety of ceramic restorative materials such as porcelains (leucite or alumina based), glass-ceramics (leucite, mica, lithium disilicates), alumina-glass infiltrated, and CAD-CAM ceramics including pure alumina and zirconia (3Y-TZP) core materials. Polycrystalline ceramics such as alumina and zirconia serve as substructure materials (i.e., framework or core) upon which glassy ceramics are veneered for an improved appearance. Under masticatory loads, sudden fracture of the full-thickness restoration or of the veneering ceramic (chips) may occur. Stereomicroscope and scanning electron microscope analyses were used to perform qualitative (descriptive) fractography on clinically failed dental ceramic restorations. The most common features visible on the fracture surfaces of the glassy veneering ceramic of recovered broken parts were hackle, wake hackle, twist hackle, arrest lines, and compression curls. The observed features are indicators of the local direction of crack propagation and were used to trace the crack’s progression back to its initial starting zone (the origin). This paper presents the applicability of fractographic failure analyses for understanding fracture processes in brittle dental restorative materials and it draws conclusions as to possible design or processing inadequacies in failed restorations.
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Authors: Amel Boukhlif, Ali Merdji, Noureddine Della, Ould Chikh El Bahri, Osama Mukdadi, Rajshree Hillstrom
Abstract: The number of supporting dental implants is an important criterion for the surgical outcome of dental bridge fixation, which has considerable impact on biomechanical load transfer characteristics. Excessive stress at the bone–implant interface by masticatory loading may result in implant failure. The aim of this study was to evaluate the impact of the number of implants supporting the dental bridge on stress in neighboring tissues around the implants. Results of the study will provide useful information on appropriate surgical techniques for dental bridge fixation. In this study, osseointegrated smooth cylindrical dental implants of same diameter and length were numerically analyzed, using three-dimensional bone–implant models. The effect of the number of supporting implants on biomechanical stability of dental bridge was examined, using two, three and four supporting implants. All materials were assumed to be linearly elastic and isotropic. Masticatory load was applied in coron-apical direction on the external part of dental bridge. Finite Element (FE) analyses were run to solve for von Mises stress. Maximum von Mises stresses were located in the cervical line of cortical bone around dental implants. Peak von Mises stress values decreased with an increase in the number of implants that support the dental bridge. Results of this study demonstrate the importance of using the correct number of supporting implants to for dental bridge fixation.
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Authors: Qing Li, Ionut Ichim, Jeffery Loughran, Wei Li, Michael Swain, Jules Kieser
Abstract: Ceramics have rapidly emerged as one of the major dental biomaterials in prosthodontics due to exceptional aesthetics and outstanding biocompatibility. However, a challenging aspect remaining is its higher failure rate due to brittleness, which has to a certain extent prevented the ceramics from fully replacing metals in such major dental restorations as multi-unit bridges. This paper aims at simulating the crack initiation and propagation in dental bridge. Unlike the existing studies with prescriptions of initial cracks, the numerical model presented herein will predict the progressive damage in the bridge structure which precedes crack initiation. This will then be followed by automatic crack insertion and subsequent crack growth within a continuum to discrete framework. It is found that the numerical simulation correlates well to the clinical and laboratory observations.
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Authors: Mihai Cosmin Cotrut, Sorin Ciuca, Florin Miculescu, Vasile Iulian Antoniac, Mihai Tarcolea, Maria Diana Vrânceanu
Abstract: This paper aims to characterize two dental bridges made from Co-Cr alloy, the first one obtained by the conventional method (casting) and the second one by Selective Laser Sintering technique (SLS). The elemental composition, microstructure, hardness and corrosion behavior in artificial saliva were investigated, allowing a parallel analysis of this two samples obtained with the two methods mentioned above.
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Authors: Ján Milde, Ladislav Morovič
Abstract: Dental restorations are currently produced mainly by conventional dental technology methods. The automation of the manufacturing process can be achieved by the use of CAD/CAM technology. Basic research on the most important aspects of CAD/CAM fixed dental restorations from the viewpoint of production, information technology, and dentistry/dental technology are the subject of a current article. The aim of this article is practical using of computer aided technologies such as 3D scanning and 5-axis machining for designing and fabrication of dental restorations. It further explains the detailed process of acquiring a digital description of tooth’s shape and its subsequent modification. Attention is drawn to a detailed analysis of dental restorations’ design obtained from a digital description of a tooth in Cercon Art software. The last part of this paper concentrates on the fabrication of dental restorations, which took place at CAD/CAM dental centre in Bratislava, Slovakia. The fabrication was accomplished by 5-axis kinematic structure of machine tools.
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