Investigation of color and surface roughness of permanent crown materials produced by additive and subtractive manufacturing after brush abrasion

Technological advances in dentistry have increased the variety of materials used in permanent crown production. Additive manufacturing methods offer advantages over subtractive methods in terms of reduced material loss, while restorations produced using CAD/CAM and 3D printing systems are important in terms of aesthetics, stability, and biocompatibility. However, color changes and surface damage that may occur over time can have negative effects on patient satisfaction and oral health. In this study, the color and surface roughness of permanent crown materials produced using additive and subtractive methods were evaluated after brush abrasion. VarseoSmile Crown Plus (Varseo XS, BEGO, Germany) prepared using DLP technology was used for additive manufacturing, while Tetric CAD, IPS e.max CAD, and Vita Mark II blocks were used for subtractive methods. Twenty-six samples were prepared from each material (n=13 color, n=13 surface roughness) and processed according to the manufacturer's instructions. Color measurements were performed using Vita Easyshade, and surface roughness measurements were performed using the Perthometer M2 device. Surface topographies after brushing were examined using a scanning electron microscope. The obtained data were evaluated using the Shapiro-Wilk test, Kruskal Wallis, and Mann Whitney U tests were used in the statistical analyses and the Bonferroni correction was applied. The relationships between variables were analyzed using the Spearman corelation test. According to the results, there was no significant effect of material type and brushing on color change (p>0.05). However, a statistically significant increase in surface roughness was observed after brushing (p<0.001). When surface topographies were examined, negative changes in surface properties were observed in all materials after brushing, and it was determined that materials produced by the subtractive method exhibited lower surface stability compared to additive manufacturing. Keywords: 3D Printing, CAD/CAM, Color, Surface Roughness, Brush Abrasion