In-vitro Comparison of Hot Pressed and Milled Feldspar Ceramic Regarding Optical Properties and Roughness

Objectives: The purpose of this study was to evaluate differences of the optical properties and roughness between a hot pressed and a CAD/CAM feldspar ceramic after immersing in artificial saliva.
Methods: A total of 16 feldspar ceramic samples with medium translucency and a thickness of 1.5 mm were fabricated. 8 of the samples were obtained by hot pressing feldspar(Vita PM9 Zahnfabrick, Germany) and 8 of the samples by slicing CAD/CAM blocks (Vita Mark II, Vita Zahnfabrick Germany). The samples were polished and immersed in artificial saliva before baseline color measurements were carried out according to the CIELab color system. The L*, a*, b* values were obtained using a spectrophotometer (Vita Easy Shade 4.0 Vita Zahnfabrick, Germany). TP and OP parameters were calculated using their formulas. After evaluating the optical properties, the roughness of the samples was evaluated by measuring Ra and Rz parameters with a profilometer.
Results: The highest mean translucency value was obtained in the CAD/CAM feldspar group. The highest mean opalescence value was obtained in the hot pressed feldspar ceramic group. Ra and Rz did not indicate noticeable differences between the samples.
Conclusions: Based on the results of this study, there are some differences in the optical properties of the two ceramics and these have clinical implications. Both types of ceramic have an indication for polishing and the roughness values of the samples were similar.