Color stainability, fluorescence, opalescence, and surface analyses of extrinsically stained resin-matrix CAD-CAM materials after toothbrushing and thermocycling

STATEMENT OF PROBLEM: The long-term color stainability and surface analyses of extrinsically stained computer-aided designed and computer-aided manufactured (CAD-CAM) restorations remain insufficiently understood. Further evaluation is necessary to establish the synergistic effects of aging tests on the esthetic and functional outcomes of characterized dental materials. PURPOSE: The purpose of this in vitro study was to evaluate the effects of toothbrushing with 2 dentifrices and thermocycling on the color stainability and surface changes of stained CAD-CAM materials. MATERIAL AND METHODS: Specimens of VITA Mark II (VM), Lava Ultimate (LU), and VITA Enamic (VE) were stained and glazed and subjected to toothbrushing with conventional or whitening dentifrice followed by thermocycling. Color differences (ΔE00), opalescence, fluorescence, surface roughness, surface topography, and elemental characterization were assessed at baseline as the control group and after aging. Data analyses (α=.05) included 2-way ANOVA and Games-Howell tests for ΔE00 and the 3-way repeated measures ANOVA with Sidak post hoc test for opalescence, fluorescence, and surface roughness. ΔE00 values were compared with perceptibility and acceptability thresholds (PT00 and AT00). RESULTS: VE exhibited the highest ΔE00, with noticeable values for both dentifrices and significantly higher surface roughness in the whitening group (P<.05). Opalescence followed the order VE<VM<LU (P≤.001) and increased post-aging (P=.023). The fluorescence of LU significantly decreased after aging with both dentifrices (P<.05). Surface topography changes associated with aging were more pronounced in the whitening groups. Overall, the mass percentage of chemical elements on the surface of materials changed after aging. CONCLUSIONS: Aging had varying effects on the stained CAD-CAM materials. Both dentifrices significantly influenced the evaluated properties. Changes in color and surface roughness were material-dependent, with VITA Enamic exhibiting the most significant impact from aging.