The aim of our study was to analyze the precision of fused-deposition modeling (FDM), polyjet technology (PJ), stereolithography (SLA) and selective laser sintering (SLS) and to evaluate some interesting indications of these methods in clinical practice. Forty upper dental arches were scanned using a 3Shape Trios 3R optical scanner system and 3D models were made. An Atos II 400 optical 3D scanner was used for calculating the coordinates of points by optical triangulation, photogrammetry and fringe projection. Each model was scanned from a minimum of 56 positions to evaluate global coordinates. Surface morphology was evaluated with an Alpha Step IQ profilometer and a JSM 5510 LV scanning electron microscope. From the measurements in cross-sections it was evident that the deviation shifted by approximately 0.1 mm. The smoothest and most homogeneous sample was SLA. SLS and SLA samples showed the most similar results in comparison of perpendicular directions (homogeneity). FDM and PJ materials exhibited significantly greater roughness in the printing direction than in the perpendicular one, which is most likely caused by the technology selected and/or print parameters. Clinical applications have demonstrated unusual treatment options for patients with rare diseases.

The integration of computational intelligence and augmented reality has become increasingly prevalent in dental practices. Three-dimensional (3D) printing techniques have now become routine in orthodontics, prosthetics, and maxillofacial surgery. The objective of this study is to assess the effectiveness of stereolithography (SLA) printed models compared to traditional plaster casts over a three-year period. The experimental dataset consisted of 36 orthodontic patients, each with SLA printed models and plaster casts for both the upper and lower jaws, resulting in a total of 72 scans in the form of Standard Template Library (STL) files and 72 traditional impressions. The upper dental arch models were constructed using an SLA 3D printer, employing a blue 405 nm laser beam to solidify a liquid polymer. The classical plaster casts were prepared in a dental laboratory. The models were retained for long-term orthodontic therapy control. To evaluate the differences between the dental models, a laboratory scanner was used to generate virtual casts. The meshes obtained were adjusted and pre-aligned using the best-fit algorithm. Subsequently, registration of the models was performed using the iterative closest point (ICP) algorithm. Distances between the point clouds and meshes for each point of the printed model were calculated by determining the nearest triangle on the reference mesh (cast). Additionally, the model surfaces were assessed using a scanning electron microscope and a stereomicroscope. The results from 22 experimental datasets indicated a high level of agreement between the plaster casts and virtual surfaces, with a mean absolute difference of 0.018 mm and a standard deviation of 0.17 mm. These values were obtained by averaging 231,178 data points for each comparison. Overall, this study demonstrates the comparability and accuracy of SLA printed models in relation to traditional plaster casts, supporting their potential as reliable alternatives in dental practice.