Color stability of polymer‐infiltrated‐ceramics compared with lithium disilicate ceramics and composite

OBJECTIVE: To investigate the color stability of hybrid ceramics and to compare it to composite and lithium disilicate ceramics. MATERIALS AND METHODS: One hundred eighty samples were fabricated and processed with a semiautomatic grinding and polishing device (final step: 1200 grit). After thermocycling, samples were immersed in a staining solution (five subgroups: water, red wine, curry, black tea, cola) for 4 weeks. A spectroradiometer was used to determine the color of the samples in CIE L*a*b*. Color measurements were performed before staining (baseline, initial color), after thermocycling, after 2 and 4 week storage in staining solution and each after a two stage repolishing approach. Discoloration of specimens was calculated by means of DeltaE00 compared to baseline values. RESULTS: All factors (material, staining solution, aging stage) were significantly associated with the extent of discolorations (P < .001). Maximum color changes occurred after 28 days staining (EN: DeltaE00 = 4.5 +/- 4.0; GB: DeltaE00 = 5.0 +/- 4.5; LS: DeltaE00 = 3.0 +/- 2.3) clearly exceeding the 50:50 threshold for acceptable color deviations. Due to repolishing, discoloration of LS samples was almost completely eliminated (DeltaE00 = 0.4 +/- 0.3) and significantly reduced for the other two materials (EN: DeltaE00 = 1.0 +/- 0.9; GB: DeltaE00 = 0.9 +/- 0.4; P = .428). CONCLUSION: Discoloration of hybrid ceramics ranged in-between lithium disilicate and composites, however more comparable to composites. Repolishing could reduce discolorations substantially. CLINICAL RELEVANCE: This study should help dental practitioners to estimate the color stability of common dental materials and the effect of polishing in removal of discolorations.