• Tuotekuvaus

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

• Tuotetiedot

  • Kustantaja / Valmistaja Malmö högskola
  • ISBN 9789171044051
  • Tuotekoodi 9789171044051
  • Kirjoittajat Deyar Jallal Hadi Mahmood
  • Kieli Englanti
  • Thema-luokitus Hammaslääketiede; Proteesit
  • Ilmestymispäivä 11.04.2017
  • Vuosi 2017
  • Tuoteryhmä Ruots muu tieto
  • Tuotepääryhmä Ruotsinkieliset kirjat
  • Tuotelinja Kirjat
  • Sivumäärä 186
  • Kirjastoluokka MQWP; MKE
  • Pituus (mm) 240
  • Leveys (mm) 160
  • Korkeus (mm) 11
  • Paino (g) 376
  • Tuotemuoto Pehmeäkantinen
  • Tuotemuodon lisätiedot Haka- tai satulasidottu
  • ALV 13,5%

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