In Vitro Evaluation of the Shading Effect of Various Zirconia Surface Stains on Porcelain Crowns

Abstract

Human teeth display various colors under natural light. Dental restorations, such as zirconia crowns, are generally used to rehabilitate the oral function of patients with tooth loss due to trauma or natural tooth falls. However, significant improvements in the color and translucency of zirconia are required to meet the clinical needs for dental restoration. In the past, a large amount of ceramic powder has been used to improve the appearance of zirconia. However, the interface between the ceramic powder and zirconia makes them prone to falling off. Therefore, the aesthetics of zirconia crowns remains a major challenge. Recently, substantial advances have been made in the field of dental materials, as special staining agents for zirconia have been introduced as alternatives to ceramic powders. Therefore, this study tested zirconia-specific staining agents that were used to produce zirconia samples with A1 and A3 colors. A dental colorimetric plate was used as the control group to assess the staining effects of the different brands of staining agents. Meanwhile, two hypotheses were proposed: that the staining effects of these special staining agents for zirconia met the criteria for clinical application and that there was no significant difference between the different staining agents for zirconia. The results showed that the coatings of different brands of staining agents were ultrathin, with a thickness of approximately 27–78 µm. In addition, the coloring effects of the zirconia staining agents were not significantly different from those of the colorimetric plates. After staining, the zirconia samples had decreased surface roughness and contact angle values, which improved surface smoothness and cleanliness. In summary, the results support the hypothesis of this study that zirconia stains can be used as an alternative to the current fabrication methods for clinical dental restorations. We sought to identify the clinical techniques that are easier to perform and to overcome the current problem of dental technicians requiring considerable dentin space for staining. It is expected that the results of this study will be useful in clinical dental restorations.

Effect of various post-curing light intensities, times, and energy levels on the color of 3D-printed resin crowns

“… 24 , 25 Specimens were post-cured by a single operator at 5, 10, or 15 min intervals. Color differences were then calculated using the following formula: 26

Figure 2 Illustration of the measurement color landmarks of the single crown (a) and a pontic (b).

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Dental Ceramics: Fabrication Methods and Aesthetic Characterization

“…the final restoration is constructed with the help of specific software. The dimension and shape information of the restoration is then sent to a milling unit in which the ceramic restoration is made [25,[68][69][70][71][72][73][74][75][76][77][78][79].…”

“…On the digital image of the prepared tooth, the digital image of the final restoration is constructed with the help of specific software. The dimension and shape information of the restoration is then sent to a milling unit in which the ceramic restoration is made [25,[68][69][70][71][72][73][74][75][76][77][78][79]. (2nd) After obtaining all the digital information, the milling step of a previously sintered/crystallized block is started under ideal conditions by the manufacturer.…”