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영어

Purpose: This study aimed to quantitatively evaluate the effect of ultraviolet (UV) exposure time on the dimensional accuracy of dental models fabricated using a masked stereolithography apparatus (MSLA) printer. Methods: Hollow square specimens (10 mm outer width, 1 mm wall thickness) were designed and printed using an MSLA 3D printer. The UV-light intensity was fixed at 80%, and the exposure times were set to 2, 3, 4, and 5 seconds (n=12 per group). Following standard post-processing, the width and length of each specimen were measured using a digital Vernier caliper (n=24). One-way ANOVA and Tukey’s honestly significant difference post-hoc test were conducted to analyze intergroup differences (α=0.05). Results: Significant dimensional increases were observed with longer UV exposure times (p<0.001). The 2-second exposure group (10.122±0.037 mm) demonstrated the closest dimensions to the designed 10 mm, whereas the 5-second group exhibited the largest expansion (10.379±0.036 mm). The width and length were not significantly different in all groups (p>0.05). Conclusion: The UV exposure time is a critical parameter that affects the dimensional accuracy of MSLA 3D-printed dental models. Excessive exposure leads to over-polymerization and volumetric expansion. Therefore, regulated exposure-time is crucial for a precise clinical fit in dental prosthesis fabrication.