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영어

Purpose: This study aimed to evaluate the effect of postcuring conditions, such as variations in light intensity and curing time, on the color stability of resins used in three-dimensional (3D)-printed dental restorations. Methods: Using an liquid crystal display 3D printer, 81 specimens in the shape of a 10.0 mm×1.5 mm disk were produced according to the specified parameters. The printed specimens were postcured at various light intensities (17.76, 121.43, and 199.99 mW/cm2) and curing times (5, 10, and 20 minutes). Color was assessed using a color difference spectrophotometer (CM-3600A, Konica Minolta) based on the Lab* color space defined by the International Commission on Illumination, and the L*, a*, b*, C*, and H values and ΔE00 were analyzed. To evaluate the effect of postcuring conditions on the color changes, a twoway analysis of variance was conducted. Tukey’s post hoc test (α=0.05) was performed to assess significant differences. Results: The results showed significant differences in L*, a*, and ΔE00 values based on light exposure and curing time (p<0.001), whereas b* and C* values differed significantly (p<0.05). H values were not significantly different (p=0.231). Conclusion: This study demonstrated that light exposure and curing time significantly influenced the color stability of 3D-printed resin restorations. Thus, light exposure of Lv7 or lower and curing times of ≤10 minutes are recommended for optimal color stability.