Color in Zirconia‐Based Restorations and Related Factors: A Literature Review

Abstract

Zirconia ceramic is a popular trend in esthetic and restorative dentistry. Computer-aided design/computer-aided manufacturing (CAD/CAM) systems have been well developed to fabricate zirconia frameworks and restorations with acceptable mechanical properties. Zirconia ceramics have excellent optical characteristics; however, achieving optimal esthetic outcomes with zirconia-based restorations is still challenging due to multiple effective factors on the final color. These factors are different layers of a zirconia-based restoration and its underlying structures including: dental substrate, cement, zirconia coping, veneering ceramic, and glaze. Moreover, the laboratory procedure of these restorations' fabrication is another effective factor on the resultant color. Unpredictable esthetic results may be obtained without estimation of the role of each factor and its effect on the final color. This review discussed the color aspect of zirconia-based restorations according to these factors and based on the literature. In the past decade, investigators have been concerned with the shade reproduction with zirconia-based restorations; however, there are no sufficient clinical guidelines on how to reproduce the appearance of natural teeth with these restorations. Zirconia-based restorations have presented a new chance for accomplishing optimum esthetics. Nonetheless further investigations are needed on these restorations to establish clinical guidelines on esthetics.

Color Aspect of Monolithic Zirconia Restorations: A Review of the Literature

“…That said, the restoration thickness is initiated by clinicians through tooth/abutment preparation. Zirconia thickness affects translucency, color, and masking ability . Zirconia thickness plays a critical role in zirconia translucency.…”

“…Another effect of zirconia thickness is color masking ability. Masking ability is critical when translucent ceramics along with dark/discolored backgrounds are used . A 1‐mm‐thick zirconia ceramic has been advised for acceptable masking ability (∆E < 5.5), while for achieving ideal masking ability, the zirconia thickness should be increased to 1.6 mm (∆E < 2.6) .…”

Bioactive Glass Coated Zirconia for Dental Implants: a review

“…Zirconia with better optical, aesthetic, mechanical and biological qualifications, is a hopeful substitute to traditional Ti implant system for oral recovery [61][62][63][64], and is produced by the oxidation of zirconium [25,27,[65][66][67]. Zirconium, which is a transition metal [56,68] with greywhite color [69][70][71][72][73], can be used to make zirconia implant. Segments of the metal implant can be uncovered by recession of gingiva and the loss of apical bone, which this can disclose a discolored overlying gingiva [74][75][76][77].…”

Effect of screw access hole design on the fracture resistance of implant‐supported zirconia‐based restorations

“…Moreover, zirconia‐based crowns manifest lower fracture rates than metal ceramic crowns regardless of framework design . A proper balance of strength, precision, translucency and color enables to use zirconia‐based restorations in different clinical situations …”

“…5 A proper balance of strength, precision, translucency and color enables to use zirconia-based restorations in different clinical situations. 6,7 Two types of implant-supported zirconia-based restoration are available based on the retention system including screw-and cementretained restorations. 8 Screw-retained restorations have the advantage of easier retrieval but the disadvantages of the possibility of nonpassive fit on implants and screw loosening.…”