COMPARATIVE EVALUATION OF THE DIMENSIONAL ACCURACY OF BRIDGE PROSTHESIS FRAMES MADE USING TRADITIONAL AND DIGITAL

Abstract

Subject. Modern digital technologies make it possible to automate the process of creating bridges to a large extent. First, digital images of the patient's dentition are obtained, then the future prosthesis is virtually modeled and manufactured using a subtractive method using milling and grinding machines or an additive method using a 3D printer. For clinical evaluation of the quality of orthopedic fixed structures made using digital methods, it is necessary to evaluate their dimensional accuracy. The aim is to conduct a comparative assessment of the dimensional accuracy of bridge prosthesis frames made using modern digital technologies and traditional casting method. Methodology. The intraoral laser scanner iTero Cadent, the 3D printer Asiga Max UV, the CAD/CAM system KaVo ARCTICA, the software DentalCAD 2.2 Valletta and the computer program MeshLab were used to study the dimensional accuracy of the bridge frames. The Kruskal-Wallis H-test and the Mann-Whitney U-test were used for statistical analysis of the data obtained. Results. All digital methods of manufacturing bridge frames are distinguishable from the traditional casting method with a significance level of p<0.05 on the basis of dimensional accuracy. The frames of bridge prostheses made by the subtractive method have a higher dimensional accuracy compared to the frames obtained using additive technologies. There were no statistical differences in the dimensional accuracy of milled titanium and zirconium bridge frames. Conclusions. Based on the data obtained, we concluded that the bridge frames made using modern digital technologies have a higher dimensional accuracy (the average value of the median distance of milled zirconium frames is 0,03067 ± 0,001234 mm, milled titanium frames are 0,03032 ± 0,002698 mm, frames made using additive technologies are 0,03686 ± 0,003068 mm) compared to the bridge frames made by the traditional casting method (the average value of the median distance 0,04342 ± 0,003722 mm), with a significance level of p<0,05 (U-Mann-Whitney criterion =0, p=,002).