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München, Germany

Ender A.,University of Zurich | Bienz S.,University of Zurich | Mormann W.,University of Zurich | Mehl A.,University of Zurich | And 2 more authors.
Dental Materials | Year: 2016

Objectives To evaluate marginal adaptation, fracture load and failure types of CAD/CAM polymeric inlays. Methods Standardized prepared human molars (48) were divided into four groups (n = 12): (A) PCG (positive control group); adhesively luted glass-ceramic inlays, (B) TRX; CAD/CAM polymeric inlays luted using a self-adhesive resin cement, (C) TAC; CAD/CAM polymeric inlays luted using a conventional resin cement, and (D) NCG (negative control group); direct-filled resin-based composite restorations. All specimens were subjected to a chewing simulator. Before and after chewing fatigue, marginal adaptation was assessed at two interfaces: (1) between dental hard tissues and luting cement and (2) between luting cement and restoration. Thereafter, the specimens were loaded and the fracture loads, as well as the failure types, were determined. The data were analysed using three- and one-way ANOVA with post hoc Scheffé test, two sample Student's t-test (p < 0.05). Results Before and after chewing fatigue, marginal adaptation for interface 1 showed significantly better results for TRX and PCG than for TAC (p = 0.001-0.02) and NCG (p = 0.001-0.047). For interface 2, marginal adaptation for TAC was significantly inferior to TRX (p < 0.001) and PCG (p < 0.001). Chewing fatigue had a negative impact on the marginal adaptation of TAC and NCG. No significant differences in fracture load were found between all tested groups. Significance Self-adhesive luted polymeric CAD/CAM inlays showed similar marginal adaptation and fracture load values compared to adhesively luted glass-ceramic inlays. © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. Source


Stawarczyk B.,Munich Dental School | Beuer F.,Munich Dental School | Wimmer T.,Munich Dental School | Jahn D.,nt trading GmbH | And 3 more authors.
Journal of Biomedical Materials Research - Part B Applied Biomaterials | Year: 2013

Objectives To study the surface properties of polyetheretherketone (PEEK) and its bond strength with two veneering resins after different conditioning methods as well as fracture load of PEEK three-unit fixed dental prostheses (FDPs). Methods Two hundred and twenty five PEEK specimens were fabricated and divided into five groups: no treatment (A), etching with 98% sulfuric acid for 1 min (B), air-abrasion for 10 s with either 50 or 110 μm alumina (C and D, respectively), and silica coating using the Rocatec System (E). On 15 specimens of each conditioning method, contact angle and surface roughness were determined. The remaining 150 specimens of each conditioning method were divided into two groups for the veneering procedure with the composites Gradia (GC Europe) and Sinfony (3M ESPE). Shear bond strength (SBS) was measured and failure types were assessed. In addition, 15 FDPs were milled and the fracture load was tested. Data were analyzed using descriptive statistics, one-way ANOVA (Scheffé test), two sample Student's t-test, and Weibull statistics (p < 0.05). Results Silica-coated PEEK surfaces showed the highest wettability. The highest roughness and lowest contact angles were observed for 110 μm air-abraded and silica-coated PEEK surfaces. The highest SBS values were, however, achieved in the acid-etched group. PEEK three-unit FDPs showed a mean fracture load of 1383 N with a plastic deformation starting approximately at 1200 N. Conclusions Acid etching should be applied when PEEK is used as substructure material and composite veneering material is applied. In this combination, PEEK might be a suitable material for FDPs, especially in load-bearing areas. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 1209-1216, 2013. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company. Source


Beuer F.,Munich Dental School | Stimmelmayr M.,Josef Heilingbrunner Str. 2 | Gueth J.-F.,Munich Dental School | Edelhoff D.,Munich Dental School | Naumann M.,University of Ulm
Dental Materials | Year: 2012

Objectives: Zirconia based restorations exhibited high failure rates due to veneering-porcelain fractures. Milling to full-contour might be an alternative approach for zirconia restorations. The aim of this study was to evaluate full-contour zirconia crowns in terms of light-transmission, contact wear (restoration and antagonist) and load-bearing capacity. Powder build-up veneered zirconia substructures and CAD/CAM-veneered zirconia substructures served as controls. Methods: Four different kinds of crowns were fabricated on 12 metal dies: zirconia substructure with powder build-up porcelain (veneering technique), zirconia substructure with CAD/CAM generated veneering (sintering technique), full-contour zirconia glazed (glazed full-contour) and full-contour zirconia polished (polished full-contour). All crowns had the same dimensions. After light-transmission was measured the crowns were cemented on the corresponding metal dies. The specimens were loaded according to a special wear method in the chewing simulator (120,000 mechanical cycles, 5 kg load, 0.7 mm sliding movement, 320 thermocycles). Wear of the restoration and the antagonist were measured. All specimens were loaded until failure. One-way ANOVA and a LSD post-hoc test were used to compare data at a level of 5%. Results: Polished full-contour showed significantly higher light transmission than the other groups (p = 0.003; ANOVA). Polished full-contour exhibited significantly less contact wear at the restoration (p = 0.01; ANOVA) and higher contact wear at the antagonist (p = 0.016; ANOVA) compared to the other groups. Glazed full-contour zirconia showed similar contact wear at the antagonist compared to veneering technique (p = 0.513, post-hoc LSD). Crowns with conventional veneering showed significantly lower load-bearing capacity (p < 0.001; ANOVA). Significance: Milling zirconia to full-contour with glazed surface might be an alternative to traditionally veneered restorations. © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. Source

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