Masking performance of structural‐color composites as luting agents for high‐translucency zirconia‐reinforced lithium silicate veneers
Alaa Al‐Haddad, Mikel Alrabadi, Rawan Abu Zaghlan, Omar Al‐karadsheh, Mahmoud K. AL‐OmiriAbstract
Purpose
To evaluate the aging‐related masking performance of structural‐color composites used as luting agents for ultrathin, high‐translucency (HT) zirconia‐reinforced lithium silicate (ZLS) veneers, comparing a dedicated blocker against its universal counterpart, conventional light‐cure veneer cements, and preheated composites.
Materials and Methods
ZLS discs (VITA Suprinity 0M1‐HT; 10 × 0.50 mm 2 ; n = 35; n = 5 per group) were luted to standardized zirconia substrates. Luting media included RelyX Veneer (Translucent, A3, WO), Omnichroma Universal, Omnichroma Blocker, Filtek Z250 XT B1, and Vittra APS E‐Bleach. Specimens were aged by thermocycling (10,000 cycles, 5–55°C) followed by coffee immersion (7 days, 37°C). Color was measured over white and black backgrounds at baseline and post‐aging using a spectrophotometer. Outcomes included CIEDE2000 color difference (Δ E 00 ), whiteness index change (ΔWI D ), and translucency parameter change (ΔTP 00 ). Data were analyzed using one‐way ANOVA with Holm‐adjusted pairwise comparisons ( α = 0.05). Results were interpreted against established perceptibility and acceptability thresholds (PT 00 = 0.8, AT 00 = 1.8; whiteness perceptibility threshold = 0.72, whiteness acceptability threshold = 2.62; TPT 00 = 0.62, TAT 00 = 2.62).
Results
Luting medium significantly affected all optical outcomes ( p < 0.001). For the primary endpoint (Δ E 00 over black background), Omnichroma Universal showed the smallest change (0.27 ± 0.10), whereas Vittra APS E‐Bleach showed the largest (4.38 ± 0.34), exceeding the acceptability threshold in all specimens. Omnichroma Blocker (0.57 ± 0.15) did not differ significantly from Omnichroma Universal after Holm adjustment for the primary endpoint. Filtek Z250 XT B1 (1.30 ± 0.22) exceeded the perceptibility threshold in all specimens. For whiteness change, Vittra APS E‐Bleach exceeded the acceptability threshold in all specimens (ΔWI D = 6.51 ± 1.29), whereas Omnichroma groups showed negative ΔWI D values (−0.80 ± 0.36 and −0.73 ± 0.52). Translucency changes remained below clinically detectable thresholds across all groups.
Conclusions
For ultrathin, HT ZLS veneers, aging‐related optical stability was highly luting material‐specific. Omnichroma Blocker did not provide superior aging‐related masking stability compared with Omnichroma Universal for the primary dark‐background endpoint. Vittra APS E‐Bleach showed color and whiteness changes that exceeded acceptability thresholds under the tested aging conditions, whereas translucency changes remained limited across all luting media.