Premium
Influence of Accelerated Aging on the Color Stability of Dental Zirconia
Author(s) -
Volpato Cláudıa Ângela Mazıero,
Cesar Paulo Francısco,
Bottıno Marco Antônıo
Publication year - 2016
Publication title -
journal of esthetic and restorative dentistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.919
H-Index - 60
eISSN - 1708-8240
pISSN - 1496-4155
DOI - 10.1111/jerd.12239
Subject(s) - lightness , hue , cubic zirconia , materials science , tukey's range test , color difference , ceramic , accelerated aging , statistical analysis , analysis of variance , dentistry , composite material , mathematics , optics , medicine , statistics , computer science , artificial intelligence , physics , enhanced data rates for gsm evolution
Objective This study evaluated the influence of different aging times on the color stability of zirconia that is either veneered or not by ceramic. Materials and Methods Fifteen zirconia disks (3Y‐TZP) were produced (12.0 mm in diameter and 1.0 mm‐thick). Five disks (G1) did not receive veneering ceramic layer; 5 disks (G2) were veneered with 1.0 mm a ceramic layer and the other 5 disks (G3) were veneered with layer of 1.5 mm. The L*a*b* coordinates (T1) were measured with a spectrophotometer. The disks were subjected to an accelerated aging protocol for 1 hour (T2), 2 hours (T3) and 4 hours (T4). Measurements were made after each aging time. Differences in color (ΔE00), lightness (ΔL′), chroma (ΔC′), and hue (ΔH′) were calculated by CIEDE2000 color difference formula among standard‐averages, aging times and thickness tested. For ΔE 00 , one‐way ANOVA was performed for the G1 and two‐way ANOVA for G2 and G3. Repeated measures ANOVA was performed for ΔL′, ΔC′, and ΔH′. Multiple comparisons were performed using Tukey's test ( α = 0.05). Results For G1, statistical differences were found for lightness (ΔL′), chroma (ΔC′), and hue differences (ΔH′) ( p = 0.0001), highlighting the major in chroma differences (ΔC′). Discrete color differences (ΔE 00 ) were observed (0.95ΔE 00 ) especially after 4 hours of aging (T4). For G2 and G3, statistical differences for ΔL′, ΔC′, and ΔH′ were found as a function of the thickness of the ceramic coating ( p < 0.0001) and aging time ( p = 0.02). Conclusions When 3Y‐TZP was subjected to aging, discrete color differences were present. With exception of the G2, the color difference was less than 1.25ΔE 00 , demonstrating that the zirconia maintained its colorimetric properties after aging protocol. CLINICAL SIGNIFICANCE After prolonged aging, discrete color changes can occur in zirconia, particularly when it is contact with the oral environment, as is the case of abutments and monolithic crowns. Thus, clinical and laboratory care should be taken to maintain surface integrity of zirconia, minimizing aging. (J Esthet Restor Dent 28:304–312, 2016)