The effect of ceramic thickness and resin cement shades on the color matching of ceramic veneers in discolored teeth

The objective of this study was to analyze the effects of ceramic material thickness and resin cement shade on the color matching of ceramic veneers at the gray tooth structures. Seventy-two artificial maxillary right central incisor teeth (C2 shade) were prepared according to veneer tooth preparation in practice. Ceramic materials (LT, A2 shade, IPS e.max Press) were selected to fabricate the 0.50- and 0.75-mm thick veneers at the body region. The ceramic veneer specimens were bonded to the artificial teeth by the 6 shades of resin cements (Variolink Veneer: shades of HV+3, LV-2, LV-3; and RelyX(TM) Veneer: shades of WO, TR, A3). A clinical spectrophotometer (Crystaleye, Olympus) was used to measure the color parameters. The color differences (Delta E values) of ceramic veneers and A2 shade tab (Vitapan Classical, Vita) and C* (ab) values were calculated. The results of three-way ANOVA indicated that the Delta E values of ceramic veneer and A2 shade tab were significantly different in the thickness of ceramic materials, shades of resin cements, and measuring regions (p < 0.001). There were significant differences in 0.50-mm-thick ceramic veneers that exhibited higher Delta E values compared with veneers that were 0.75-mm thick. Tukey's HSD test showed that the average Delta E values in body region were significantly smaller than that in cervical and incisal regions. The color matching of ceramic veneers was significantly influenced not only by the ceramic thickness and the resin cement shades but also the tooth regions.