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Purpose: The aim of this study was to review the fit and assess the accuracy of tooth-supported single and multi-unit zirconia fixed dental prostheses. Background: The fit of zirconia restorations has been reported in several studies, but the accuracy of the manufacturing process is seldom discussed or used when drawing conclusions on the fit. Materials and methods: A literature search of articles published in PubMed between 2 March 2013 and 1 February 2018 was performed using clearly defined inclusion and exclusion criteria. 841 articles were found and 767 were excluded after screening the title and abstract. After full-text analysis another 60 articles were excluded which left 14 articles to be included for data extraction. Fit was the mean of distances reported in the studies and accuracy was the fit minus the pre-set spacer Results: For marginal gap of single crowns and multi-unit FDPs combined, the fit was 83 μm and the accuracy was 59 μm. The internal gap fit was 111 μm and the accuracy 61 μm. For the total gap, the fit was 101 μm, and the accuracy of the zirconia restorations was 53 μm. Conclusions: Within the limitations of the present systematic review the fit of zirconia single crowns and multi-unit FDPs may be regarded as clinically acceptable, and the accuracy of the manufacturing of zirconia is ∼60 μm for marginal, internal, and total gap. Also, digital impressions seem to be associated with a smaller gap value.

Objectives. The aim of this retrospective study was to evaluate the three-year clinical outcome for ceramic-veneered zirconia fixed dental prostheses (FDPs). Methods. All patients who were treated with ceramic-veneered zirconia FDPs, in three private practices in Sweden, during the period June 2003 to April 2007 were included. Case records from 151 patients, treated with a total of 184 zirconia FDPs (692 units), were analysed for clinical data. All complications noted in the charts were registered and compared to definitions for success and survival and statistical analysis was performed using the Kaplan-Meier method and a Cox regression model. Results. In total, 32 FDPs in 31 patients experienced some type of complication (17.4% of FDPs, 20.5% of patients). Core fractures occurred in two (1.1%) FDPs. Two (1.1%) FDPs or 0.6% of units showed adhesive veneer fractures. Cohesive veneer fractures occurred in 10 (5.4%) FDPs (1.6% of units). The three-year cumulative success and survival rates (CSR) were 82.3% and 95.2%, respectively. Conclusions. Ceramic-veneered zirconia is a promising alternative to metal-ceramic FDPs, even in the posterior area. However, the higher survival rate of metal-ceramic FDPs should be noted and both dentists and patients must be aware of the risks of complications.

The general aims of this thesis were to study CAD/CAM production processes, material aspects on cobalt-chromium (CoCr), clinical performance, and fit of tooth-, and implant-supported fixed dental prostheses (FDPs). A retrospective study of ceramic veneered CoCr FDPs was conducted to evaluate the performance of restorations made with the lost wax technique. One hundred forty-nine patients with 201 FDPs were followed for five years by data collection from patient records. To study CAD/CAM techniques, the fit of tooth-supported CNC-milled CoCr three-unit FDPs, made using conventional or digital impression techniques, was compared. Also, the fit of implant-supported CNC-milled and additively manufactured CoCr and titanium FDPs was evaluated before and after ceramic veneering. CoCr FDPs are a promising alternative to other dental alloys, presenting a low level of ceramic fractures, cement failure, caries, and other complications during the first five years in function. To evaluate their longer-term success and possible biologic adverse effects, further long-term randomized controlled studies are necessary. The digital impression technique produced FDPs with a significantly more accurate fit than conventional impressions using VPS impression material. Implant-supported frameworks can be produced in either titanium or CoCr using either CNC-milling or additive manufacturing with a fit well within the range of what is regarded as clinically acceptable. The fit of frameworks of both materials and production techniques are affected by the ceramic veneering procedure to a small extent, most likely of no clinical significance.