Fig. 1

(a) Median values and interquartile range of ΔE for the different cleaning/disinfection agents and simulated brushing period of heat-cured resin (n = 9). (b) Median values and interquartile range of ΔE for the different cleaning/disinfection agents and simulated brushing period of 3D-printed resin (n = 9). Different capital letters indicate significant differences in ΔE values between brushing times T1 and T2 (p < 0.05), while different lowercase letters indicate significant differences between cleaning solutions within the same brushing time (p < 0.05), according to the Mann–Whitney U test. DWT1: 1 year of brushing with distilled water; SST1: 1 year of brushing with disinfectant liquid soap solution; DTT1: 1 year of brushing with dentifrice; DWT2: 2 years of brushing with distilled water; SST2: 2 years of brushing with disinfectant liquid soap solution; DTT2: 2 years of brushing with dentifrice.