Impact of the resin cement opacity on the final color of conservative ceramic restorations and on its ability to mask substrates of different saturations

Abstract

Objective

To analyze the impact of the translucency/opacity of two commercial brands of resin cements and different translucency of lithium disilicate on the masking ability of saturated substrates.

Methods

120 samples (n = 5) were prepared using 0.5 mm lithium disilicate (IPS e.max CAD) in three translucencies (HT, MT, LT). These were cemented onto A1 and A4 resin substrates using two brands of resin cements: Allcem Veneer (FGM) in Trans (T) and Opaque White (OW), and Variolink Esthetic LC (Ivoclar Vivadent) in Neutral (N) and Light+ (L+), with a thickness of 100 µm. Color analysis was performed using reflectance measurements with a CM-3700d spectrophotometer (Konica Minolta). The Relative Translucency Parameter (RTP) and the Color Difference (∆E00) were calculated using the CIEDE2000 formula, with Perceptibility Threshold (PT) of ∆E00 = 0.8 and Acceptability Threshold (AT) of ∆E00 = 1.8. Statistical analyses were conducted using three-way ANOVA followed by Tukey's tests (α=0.05).

Results

For ∆E00 between substrates saturation (A1 VS A4), the isolated fixed factors and their interaction were statistically significant (p < .001) and showed ∆E00 > 1.8 for all groups. ∆E00 between resin cements colors of the same brand reveals significant factors (p < .001) but a non-significant statistical interaction (p = 0.072). The RTP of the resin cement were N(47.64) > T(47.47) > Ow(42.02)>L+ (23.39). For restorative set RTP, a non-significant interaction (p > 0.05) and groups cemented with L+ reveal lower RTP values than those cemented with OW.

Significance

The ceramic translucency, the resin cement brand and color were influential on ability to mask substrates of different saturations. The opaquest resin cement contributes to reduce the influence of the ceramic on restoration final color. Resin cement brand and color influences restoration esthetics.