Although air abrasion and silica coating were the most effective surface treatment methods, CO(2) and Er:YAG laser irradiation alone or Nd:YAG laser irradiation after air abrasion may be used as an alternative treatment method to increase the bond strength between resin cement and Y-TZP material.

Statement of problem-It remains unclear which shade guide system is most representative of the shades found in the human dentition.Purpose-The purpose of this study was to determine and to compare the coverage errors (CEs) of 3 different shades in a selected population.Material and methods-The coverage errors of the following shade guide systems were evaluated to determine which shade guide system is most effective in producing the best visual shade match: (1) Vita Lumin, (2) Chromascop, (3) Vitapan 3D Master, and (4) a combination of the 3 shade guide systems. The spectral reflectance values of the central one ninth (1-mm diameter) of each shade tab (without a backing) were measured with a spectroradiometer and an external light source at wavelengths from 380 nm to 780 nm at 2-nm intervals. All spectral reflectance measurements were made using 0-degree observer and 45-degree illumination and then converted to CIE values. The color values of 359 anterior teeth were measured with the same protocol. The CEs for each of the 359 anterior teeth for each shade guide system, and with all 3 shade guide systems, were determined and averaged. Repeated measure ANOVA was used to evaluate the mean minimum CEs withinsubject (shade guide system) and between-subject (age) difference as well as the interaction between these variables (α=.05). Then, a post hoc multiple comparison was performed using the TukeyKramer test.Results-A significant difference (P<.001) was found among the mean minimum CEs of the 3 shade guide systems and their combination, but not between age groups (P=.384). An interaction was found between shade guide systems and age (P<.001). The Tukey-Kramer test revealed that the mean minimum CEs for Vita Lumin (5.39 ΔE) and Chromoscop (5.28 ΔE) shade guide systems were not significantly different from each other. However, the combination of all 3 shade guide systems (3.69 ΔE) and Vitapan 3D Master (3.93 ΔE) were significantly different from the Vita Lumin and Chromoscop shade guide system. The rankings of the shade guide systems within each age group were similar between the age groups. Clinical ImplicationsThe Vitapan 3D Master shade guide system provides a high potential for a good visual shade match compared to the Vita Lumin or Chromascop shade guide systems. The use of the Vita 3D Master shade guide system alone is as effective as using a combination of Vitapan 3D Master, Vita Lumin, and Chromascop shade guide systems.In restorative dentistry, the clinician commonly encounters the challenge of replicating the color of natural teeth. The goal of an esthetic restoration is to achieve morphological, optical, and biological beauty which results in social acceptance. 1,2 Clinically, the color replication process for dental porcelain consists of shade selection followed by the shade duplication phase. Shade selection can be made using either visual assessment or instrumental color analysis. 3 Although the most popular and traditional method of shade selection in dentistry is through the use of visual select...

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For patient satisfaction, restoration of missing teeth and tooth tissues with biocompatible materials that are resistant to occlusal forces also require attention to esthetics. 1,2 Esthetic restorations should be able to mimic the natural color depth of teeth, luminous transmittance, and anatomic structures. 2 In recent years, monolithic zirconia crowns have been developed. 3 Monolithic zirconias, which are produced with computer-aided design and computer-aided manufacturing (CAD-CAM) systems, consist of atoms interpenetrating without any organic binder and also have high dimensional stability. 3,4 Because they have a natural appearance, they do not need to be veneered with feldspathic ceramics, and natural tooth color can be obtained by characterization. 5 Therefore, chipping of the veneer porcelain is not a factor. 3,6,7 Monolithic zirconias have high biocompatibility and a nonporous structure, 8 and their abrasion resistance is close to that of natural teeth. 9 They cause significantly lower abrasion in antagonist teeth than veneered zirconia crowns. 10,11 In addition, they can be used in situations with insufficient interocclusal clearance, even at an occlusal thickness of 0.5 mm because of their high resistance to fracture. 12