## 3 Results and Discussion
Such measurements indicate the quality of the mapped surfaces, which has a significant impact on the fabrication aesthetics of, for example, dental prostheses. The evaluation of the surface structure at the microscale was carried out using an Alicona InfiniteFocus G5 (Alicona Imaging GmbH, Graz, Austria) differential focusing microscope, which is very useful in dental applications [58]. Due to the small measurement range of the device, measurements were limited only to an analysis of molar surfaces, which can be considered representative of the entire impression when analyzed on a microscale. Since the material of the test object is susceptible to damage and scratching, measurements were carried out using a noncontact system. Analysis of the surface topography was carried out using the MountainsMap (Digital Surf Headquarters, Besancon, France) software. The impression materials and resulting  
Figure 11: Comparison of scans of a plaster model created from a silicone impression obtained on an optical 3D scanner (**a**) and micro-CT (**b**). Figure 4:0 Comparison of scans of a plaster model created from a polyether material impression obtained on an optical 3D scanner (**a**) and micro-CT scanner (**b**). -plaster models were analyzed on a microscale. Example results for the silicone material and the corresponding gypsum model are shown in Figure 13, while results for the polyether material are shown in Figure 4:1 The parameters describing the surface structures of the example considered are shown in Tables 1 and 2. Comparing the results for the impression materials and gypsum models, differences in the height parameters describing the surface structure can be clearly observed. These differences are particularly evident for the polyether material and the corresponding gypsum model. The reason for this result may be that air bubbles formed on the surface of the model during the cooling process of the gypsum material. The final task of this study was an attempt to replace the gypsum materials with models made using 3D printing. In order to determine the accuracy of the reproduction, the  
Figure 4:2 Graphical representation of the surface texture for the silicone impression (**a**) and plaster model (**b**). obtained model of the jaw was measured using a 3D scanner. Figure 15 shows a comparison between the digitized model made using the incremental method and the model taken as nominal in the form of a color deviation map. \begin{table}
\begin{tabular}{l c c} \hline
**Surface Structure Parameters** & **Impression** & **Plaster Model** \\ \hline Sq (Root Mean Square Height) & 2.97 μm & 2.86 μm \\ Ssk (Skewness) & \(-\)1.12 & 0.0587 \\ Sku (Kurtosis) & 60.8 & 32.0 \\ Sp (Maximum peak height) & 50.4 μm & 331 μm \\ Sv (Maximum pit height) & 184 μm & 26 μm \\ Sz (Maximum height) & 234 μm & 357 μm \\ Sa (Arithmetical mean height) & 2.12 μm & 2.13 μm \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of the basic surface structure parameters for the silicone impression and plaster model. Figure 14: Graphical representation of the surface texture for the polyether material impression (**a**) and plaster model (**b**). The model resulting from 3D printing clearly offers a very good reproduction compared to the nominal model, with deviations from the nominal model not exceeding 0.2 mm. The results of this model obtained by reverse engineering and rapid prototyping indicate the possibility of using an alternative replacement for plaster models obtained with commonly used dental impressions.