Bond strengths of the luting cement tested on the dental ceramics following surface conditioning methods varied in accordance with the ceramic types. Hydrofluoric acid gel was effective mostly on the ceramics having glassy matrix in their structures. Roughening the ceramic surfaces with air particle abrasion provided higher bond strengths for high-alumina ceramics and the values increased more significantly after silica coating/silanization.

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There are 7 categories of additive manufacturing (AM) technologies, and a wide variety of materials can be used to build a CAD 3D object. The present article reviews the main AM processes for polymers for dental applications: stereolithography (SLA), digital light processing (DLP), material jetting (MJ), and material extrusion (ME). The manufacturing process, accuracy, and precision of these methods will be reviewed, as well as their prosthodontic applications.

OBJECTIVE: This study investigated the effect of sintering temperatures on flexural strength, contrast ratio, and grain size of zirconia. MATERIALS AND METHODS: Zirconia specimens (Ceramill ZI, Amann Girrbach) were prepared in partially sintered state. Subsequently, the specimens were randomly divided into nine groups and sintered with different final sintering temperatures: 1,300°C, 1,350°C, 1,400°C, 1,450°C, 1,500°C, 1,550°C, 1,600°C, 1,650°C, or 1,700°C with 120 min holding time. Three-point flexural strength (N = 198; n = 22 per group) was measured according to ISO 6872: 2008. The contrast ratio (N = 90; n = 10 per group) was measured according to ISO 2471ISO : 2008. Grain sizes and microstructure of different groups were investigated (N = 9, n = 1 per group) with scanning electron microscope. Data were analyzed using one-way ANOVA with Scheffé test and Weibull statistics (p < 0.05). Pearson correlation coefficient was calculated between either flexural strength or contrast ratio and sintering temperatures. RESULTS: The highest flexural strength was observed in groups sintered between 1,400°C and 1,550°C. The highest Weibull moduli were obtained for zirconia sintered at 1,400°C and the lowest at 1,700°C. The contrast ratio and the grain size were higher with the higher sintering temperature. The microstructure of the specimens sintered above 1,650°C exhibited defects. Sintering temperatures showed a significant negative correlation with both the flexural strength (r = -0.313, p < 0.001) and the contrast ratio values (r = -0.96, p < 0.001). CONCLUSIONS: The results of this study showed that the increase in sintering temperature increased the contrast ratio, but led to a negative impact on the flexural strength. CLINICAL RELEVANCE: Considering the flexural strength values and Weibull moduli, the sintering temperature for the zirconia tested in this study should not exceed 1,550°C. 20]. In fact, the stability of the complete system consisting both the zirconia framework and the veneering ceramic is of clinical importance.In order to decrease the costs and at the same time overcome the chipping problem, it is possible today to produce zirconia FDPs without veneering ceramic.Such monolithic zirconia FDPs require higher translucency with superior mechanical properties especially when they are to be used in the anterior region. Framework translucency is therefore one of the primary factors with respect to aesthetic properties in the selection of dental materials [21,22]. The translucency of dental ceramic is highly dependent on light scattering [23]. When the majority of light passing through a ceramic is intensely scattered and diffusely reflected, the material would appear opaque. However, if only part of the light is scattered and most of it is diffusely transmitted, the material would appear translucent where Y B was the value with a black background, and Y w was the value with a white background. In all calculations, 0 was considered as totally transparent and 1 as

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This study evaluated the effect of chairside and laboratory types of surface conditioning methods on the adhesion of dualcure resin cement with MDP functional monomer to zirconia ceramic after thermocycling. Disk-shaped (diameter: 10 mm, thickness: 2 mm) Y-TZP ceramics (Lava™, 3M ESPE) were used (N＝40) and finished with wet 1200-grit silicon carbide abrasive paper. Specimens were randomly divided into four experimental groups according to the following surface conditioning methods (n＝10 per group): Group 1-Chairside airborne particle abrasion with 50-μm Al2O3 + Alloy Primer (Kuraray); Group 2-Airborne particle abrasion with 50-μm Al2O3 + Cesead II Opaque Primer (Kuraray); Group 3-Airborne particle abrasion with 50-μm Al2O3 + Silano-Pen + silane coupling agent (Bredent); Group 4-Laboratory tribochemical silica coating (110-μm Al2O3 + 110-μm SiOx) (Rocatec) + silane coupling agent (ESPE-Sil). Adhesive cement, Panavia F 2.0 (Kuraray), was bonded incrementally to the ceramic surfaces using polyethylene molds (diameter: 3.6 mm, height: 5 mm). All specimens were thermocycled (5 and 55℃, 6,000 cycles) and subjected to shear bond strength test (1 mm/min). Data were statistically analyzed (one-way ANOVA, α＝0.05), whereby no significant differences were found among the four groups (8.43±1.3, 8.98±3.6, 12.02±6.7, and 8.23±3.8 MPa) (p＝0.1357). Therefore, the performance of chairside conditioning methods used for zirconia was on par with the laboratory alternative tested.

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