RESUMO
Background: Ceramics have anextended history in fixed prosthodontics of attaining optimal esthetics. Yttrium tetragonal zirconia polycrystal [Y-TZP]-based systems are a recent addition to the high-strength, all- ceramic systems used for crowns and fixed partial dentures, the highly esthetic nature of zirconia coupled with its superior physical properties and biocompatibility have resulted in restorative systems that meet optimal recent demands
Aim of the study: systematically review relevant contemporary literature regarding investigating the strength and accuracy of fit of zirconia fixed partial dentures [FPD]
Methods: A systematic review of the scientific literature from 2000 to 2017[PubMed, Embase and CENTRAL Cochrane Central Register of Controlled Trials, CINAHL, Google Scholar as well as individual Dentistry journals such as International Journal of Prosthodontics, International Journal of Periodontics and Restorative Dentistry. We followed PRISMA/STROBE guidelines. Medline s were retrieved using an algorithm comprising relevant MeSH terms
Results: The search yielded 11 studies enrolling 231 cases that met the inclusion criteria of the review. Absolute, Vertical and Horizontal margin gaps were recorded. Four of them were in- vivo studies while seven were in Vitro. The study outcome was focused on the assessment of the internal fit as well as the Marginal fit of zirconia FPDs versus the effect of various parameters of CAD / CAM and CAM systems, post-sintered and pre-sintered milling, framework configuration, veneer application and ageing. Average absolute marginal [AM] gap= 92 microns. For each system, the values were; Everest= 121, Lava= 71, Cercon = 93.5, Procera = 51, Xawex = 147, CerecInLab = 88.8
Conclusion: It was concluded that CAD/CAM have more accurate marginal and internal fit compared to CAM in fabricating zirconia frameworks. Moreover, post-sintered milling will most likely result in complex geometry and longer span FPDs. Nevertheless, the clinical implications of this difference have yet to be determined, and the pros and cons need to be taken into account first provided the hardship of post sintered milling. Veneering zirconia frameworks resulted in deterioration in fit, ageing of zirconia had no implications on the fit