Assessment of the accuracy of 3d dental arch models obtained by digital methods

The introduction of digital technologies into prosthetic dentistry has led to a transition from traditional clinical and laboratory stages to fully digital treatment protocols based on digital jaw models. Assessment of the identity of digital models makes it possible to evaluate how interchangeable different scanning methods are when solving clinical tasks. A pilot study demonstrated that dental arch models obtained by intraoral and laboratory scanning show a high degree of agreement, while the detected discrepancies are localised in the distal molar region and ranged from 139 to 282 μm (mean 186.6 ± 42.5 μm).
Aim. To evaluate the identity of digital dental arch models obtained by intraoral and laboratory scanning using the method of three-dimensional virtual model superimposition.
Material and methods. At the Department of Prosthetic Dentistry of Kemerovo State Medical University, 5 volunteers with intact dentitions were examined. Each participant underwent intraoral scanning (Shining3D Aoralscan 3) and laboratory scanning of a gypsum model obtained using a one-step A-silicone impression technique. In the DentalCAD software environment (ExoCAD, EU), three-dimensional virtual models were superimposed, and the maximum shortest distance between surfaces in areas of greatest mismatch was measured.
Results. The maximum discrepancies were localised in the distal molar region and ranged from 139 to 282 μm (mean 186.6 ± 42.5 μm), while in the anterior and anterolateral segments of the dental arch, model coincidence was visually more complete. The data obtained in this pilot study may serve as a starting point for further development of technical and algorithmic solutions aimed at reducing accumulated error during full-arch scanning.
Conclusion. The pilot study showed that dental arch models obtained by intraoral and laboratory scanning generally demonstrate a high degree of agreement, with discrepancies being local in nature and maximal in the distal molar region. The obtained results allow intraoral scanning to be considered a reliable source of digital data for planning and fabrication of prosthetic restorations spanning 4–6 teeth, while maintaining caution when dealing with more extensive prosthetic constructions.

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