Color and translucency changes induced by try-in media in bleach-shade CAD/CAM ceramic discs: an in-vitro study

This study evaluated the optical influence of try-in media (distilled water, glycerin, and commercial try-in pastes) on ultrathin (0.5-mm) CAD/CAM bleach-shade ceramic discs, focusing on CIEDE2000 color difference (ΔE₀₀), translucency parameter (TP₀₀; ΔE₀₀ between white- and black-backed measurements), and device-reported shade outputs across different ceramic systems. Forty-four 0.5-mm CAD/CAM ceramic discs were fabricated from Celtra Duo (BL2-LT, BL3-LT), VITA Suprinity (0M1-HT), and VITA Enamic (0M1-HT). Each specimen was measured over standardized white and black backgrounds using distilled water, glycerin, eight commercial try-in pastes, or no medium (control). Lab* values and VITA Classic/3D-Master shade outputs were recorded with a dental spectrophotometer under D65/2° conditions; a custom jig standardized specimen positioning and probe angulation. Repeated measurements (n = 5) were analyzed using linear mixed-effects models. Clinical interpretation used ΔE₀₀ perceptibility/acceptability (≈ 0.8/1.8) and translucency thresholds (TPT₀₀=0.62; TAT₀₀=2.62). Relative to the no-media condition, both water and glycerin produced large, clinically perceptible color shifts across all ceramics (mean ΔE₀₀ ≈ 3.2–5.6; p < 0.001), while direct water–glycerin differences were smaller (≈ 0.7–1.6). Translucency responses were material dependent: Celtra groups showed minimal ΔTP₀₀ relative to glycerin (typically |ΔTP₀₀| ≤ ~0.3), Suprinity showed a modest reduction ( ≈ − 1 to − 2), and Enamic exhibited pronounced translucency loss ( ≈ − 5 to − 7), frequently exceeding translucency acceptability (|ΔTP₀₀| ≥ 2.62). Only selected Celtra BL2/BL3 conditions with translucent/light try-in pastes approached ΔE₀₀ acceptability (≤ 1.8) on white backgrounds. Device-reported shade agreement sometimes masked clinically unacceptable differences: 11% of 3D-Master “matches” and 28% of Classic “matches” still corresponded to ΔE₀₀ > 1.8, particularly over black backgrounds. Try-in media are not optically neutral for ultrathin bleach-shade ceramics. Water and glycerin both produced clinically visible color changes, and translucency effects depended strongly on ceramic microstructure, with Enamic showing clinically unacceptable masking. Clinically, shade selection should not rely on device-reported shade matches alone; verification with appropriate try-in media and evaluation over both white and dark conditions using continuous metrics (ΔE₀₀, TP₀₀/ΔTP₀₀) is recommended.