138 - Effect of milling and artificial aging on translucency of CAD/CAM zirconia for chairside restorations

• Published in: Dental materials Vol. 39; p. e75
• Main Authors: Tsetseli, P, Vamvakoudi, E, Mourouzis, P, Tolidis, K
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 2023
• ISSN: 0109-5641; 1879-0097
• DOI: 10.1016/j.dental.2023.08.153

This study aimed to evaluate the optical properties of highly translucent 5mol% yttria, partially stabilized monolithic zirconia, after their subjection to different milling methods and artificial ageing. A highly translucent 5mol% yttria, partially stabilized monolithic zirconia was used; Katana STML. A total of 60 specimens were categorized according to the milling method (dry- or wet-milling) and the solution used for milling (fresh distilled water or impregnated water with residues of CAD/CAM ceramic materials). The translucency and contrast ratios of all specimens were calculated after they were subjected to sintering and accelerated ageing. The material phase composition was tested before and after ageing, using X-ray diffraction analysis to evaluate T-M phase transformation. Data were statistically analyzed via three-way analysis of variance between the subject factors, the material and milling method, and the within-subject factor, ageing. The analysis of covariance model was used to analyze the changes in translucency and contrast ratio between baseline and ageing, with statistical significance set at p < 0.05. Katana STML showed the highest translucency when dry-milled, and the lowest when milled with used impregnated water. Wet-milling using impregnated water, should be avoided owing to the saturation of alumina particles. Accelerated ageing resulted in the same pattern for both materials. Dry milling of highly translucent zirconia can result in higher translucency and lower contrast ratio values.