The Effect of Ceramic Type and Background Color on Shade Reproducibility of All‐Ceramic Restorations

• Published in: Journal of prosthodontics 2020-07, Vol.29 (6), p.511-517
• Main Authors: Al Hamad, Khaled Q., Obaidat, Ismaeel I., Baba, Nadim Z.
• Format: Article
• Language: English
• Subjects: Ceramics; Color; Composite materials; Dark background; Dental restorative materials; Dentistry; light background; Lithium; lithium disilicate; Reproducibility; Shade; Statistical analysis; translucency; Zirconia
• ISSN: 1059-941X; 1532-849X
• DOI: 10.1111/jopr.13005

Purpose To investigate the effects of background color on shade reproduction using CAD/CAM zirconia and lithium disilicate ceramics. Materials and Methods A plastic tooth was prepared for an all‐ceramic crown and scanned. Tooth‐shaped light background dies were manufactured. Full‐contour crowns were milled from translucent zirconia (ZT) and low translucency lithium disilicates (E [LT]). Copings from opaque zirconia (Z) and medium opacity lithium disilicate (E[MO]) ceramics were milled and layered with veneering porcelain to full contour. Metal copings were used to produce a dark background. Specimens were divided into 8 groups with 3 variables: background color, ceramic type, and translucency. Crowns were cemented using composite resin cement. Color was measured with a spectrophotometer. Color difference (∆E) was calculated using the CIEDE2000 formula between the specimens and the target shade, A1. Statistical analysis was performed using a nested design 3‐way ANOVA and Tukey multiple comparisons. Results The closest ∆E to target shade was produced by E (LT) (2.13 ± 0.19) on the dark background. This increased significantly to 2.90 ± 0.19 on the light background (p = 0.03). The e.max (MO) groups significantly increased (p = 0.001) to 4.40 ± 0.22 and 4.47 ± 0.4, (p = 1.00) for the dark and light backgrounds, respectively. ∆E for the zirconia groups were higher and ranged from 4.85 ± 0.48 to 5.60 ± 0.48 in the ZT groups (p = 0.04) and 6.5 ± 0.82 to 7.75 ± 0.53 (p = 0.001) for Z groups from dark to light backgrounds. There was an overall lack of chromaticity between the specimens and the target shade A1 Conclusions Ceramic color was affected by ceramic type, background, and translucency. Lithium disilicate appeared to be better than zirconia in shade reproduction. Less‐opaque materials matched the target shade better, while opaque materials and low translucencies were more suitable for dark backgrounds.