{"product_id":"on-core-and-bi-layered-all-ceramic-fixed-dental-prostheses-design-and-mechanical-properties-studies-on-stabilized-zirconiumdioxide","title":"On core and bi-layered all-ceramic fixed dental prostheses, design and mechanical properties : studies on stabilized zirconiumdioxide","description":"Doctoral dissertation in odontology \u003cbr\u003eLoss of teeth can affect a person’s self-esteem, social life, appearance\u003cbr\u003e and oral function. Reconstruction of a missing tooth has scientifically\u003cbr\u003e been shown to increase self-esteem and quality of life and to maintain\u003cbr\u003e oral function. For many patients a fixed dental prostheses (FDP)\u003cbr\u003e is preferred, either tooth- or implant-supported. Improvement and\u003cbr\u003e development of all-ceramic materials have made them preferable to\u003cbr\u003e other alternatives. However, despite properties of dental ceramics’\u003cbr\u003e well known biocompatibility, good chemical and mechanical,\u003cbr\u003e the materials have their weaknesses, such as brittleness and some\u003cbr\u003e difficulties with the layering porcelain. Many all-ceramic materials\u003cbr\u003e cannot withstand minor flexure; more than 0.1 - 0.3 %, will lead\u003cbr\u003e to fracture. Oxide-ceramic, specifically yttria stabilized tetragonal\u003cbr\u003e zirconia polycrystals (Y-TZP) has become the most commonly used\u003cbr\u003e all-ceramic material. This material has the potential to be used for\u003cbr\u003e larger restorations. In addition, one of many challenges is to ensure\u003cbr\u003e durable zirconia-based restorations in the oral cavity.\u003cbr\u003e In the clinical situation, crowns and bridges are supported by a\u003cbr\u003e combination of different structures with differing properties, i.e.\u003cbr\u003e bone, dentine and enamel. The complexity of the supporting tissues\u003cbr\u003e in the oral cavity creates stress patterns in the prosthetic material,\u003cbr\u003e which need to be considered when designing a dental restoration.\u003cbr\u003e The durability of all-ceramic FDPs is dependent on knowledge of\u003cbr\u003e the material and design of the FDPs. In particular the design, shape of\u003cbr\u003e the connector and the radius of curvature at the gingival embrasure\u003cbr\u003e play a significant role in the load-bearing capacity of FDPs.\u003cbr\u003e The overall aim of this thesis is to evaluate design of zirconia-based\u003cbr\u003e restorations in relation to achieving increased fracture resistance.\u003cbr\u003e Another aim is related to how the choice of material used for\u003cbr\u003e supporting tooth analogues in the test set-up and how this influences\u003cbr\u003e test results relating to fracture strength of all-ceramic FDPs.\u003cbr\u003e Study I evaluates different radii (0.60 and 0.90 mm) of curvature\u003cbr\u003e in the embrasure of the connector area and different connector\u003cbr\u003e dimensions (2 x 2, 3 x 2 and 3 x 3 mm) and their effects on the fracture resistance of 3-unit all-ceramic FPDs made of Y-TZP. The\u003cbr\u003e results show that by increasing the radius of the gingival embrasure\u003cbr\u003e from 0.6 to 0.9 mm, the fracture strength for a Y-TZP FPD with\u003cbr\u003e connector dimension 3 x 3 mm will increase by 20%.\u003cbr\u003e Study II investigated how the choice of material (aluminium,\u003cbr\u003e polymer and DuraLay) used for supporting tooth analogues and\u003cbr\u003e support complexity influence test results concerning the fracture\u003cbr\u003e strength of FDPs made of a brittle material Y-TZP. The outcome\u003cbr\u003e of the study demonstrated that Y-TZP FDPs cemented on tooth\u003cbr\u003e analogues made of aluminium, with high E-modulus showed a\u003cbr\u003e significantly higher load at fracture and a different fracture mode\u003cbr\u003e than shown in clinical situations.\u003cbr\u003e Study III evaluates how factors as different default settings for\u003cbr\u003e connector design of two different CAD\/CAM systems and different\u003cbr\u003e radii of curvature in the embrasure area of the connector will affect\u003cbr\u003e the fracture strength and the fracture mode of 3-unit, i.e. 4-unit allceramic\u003cbr\u003e FDPs made from Y-TZP and further to investigate how the\u003cbr\u003e number of pontics affect the fracture strength of Y-TZP. The results\u003cbr\u003e showed that the most crucial factor for the load-bearing capacity\u003cbr\u003e is the design of the radius of the gingival embrasures. Increasing\u003cbr\u003e the number of pontics from three to four decreases the load-bearing\u003cbr\u003e capacity nearly twice.\u003cbr\u003e Study IV investigate and compare the fracture strength and fracture\u003cbr\u003e mode in 11 groups of the currently most used multilayer all-ceramic\u003cbr\u003e systems for Y-TZP FDPs, with respect to the choice of core material,\u003cbr\u003e veneering material area, manufacturing technique (split-file, overpress,\u003cbr\u003e built-up porcelains and glass-ceramics), design of connectors\u003cbr\u003e and radius of curvature of FDP cores. The results show that the\u003cbr\u003e design of a framework is a crucial factor for the load bearing capacity\u003cbr\u003e of an all-ceramic FDP. The state-of-the-art designs are preferable,\u003cbr\u003e since the split-file designed cores call for a cross-sectional connector\u003cbr\u003e area, at least 42% larger, to have the same load bearing capacity as\u003cbr\u003e the state-of-the-art designed cores. Analyses of the fracture patterns\u003cbr\u003e demonstrated differences between the milled veneers and over-pressed\u003cbr\u003e or built-up veneers, where the milled ones showed numerically more\u003cbr\u003e veneer cracks whereas the other groups only showed complete\u003cbr\u003e connector fractures. All veneering materials\/techniques tested were\u003cbr\u003e found, with great safety margin to be sufficient for clinical use both\u003cbr\u003e anteriorly and posteriorly.","brand":"Malmö högskola","offers":[{"title":"Default Title","offer_id":31916912312409,"sku":"9789171044051","price":24.95,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0061\/0372\/8217\/files\/9789171044051_1-on-core-and-bi-layered-all-ceramic-fixed-dental-prostheses-design-and-mechanical-properties-studies-on-stabilized-zirconiumdioxide.jpg?v=1749821210","url":"https:\/\/www.suomalainen.com\/products\/on-core-and-bi-layered-all-ceramic-fixed-dental-prostheses-design-and-mechanical-properties-studies-on-stabilized-zirconiumdioxide","provider":"Suomalainen.com","version":"1.0","type":"link"}