Intraoral scanner and stereographic 3D print in dentistry—quality and accuracy of model—new laser application in clinical practice

Abstract

3D print techniques in dentistry have started to become an everyday part of clinical practice. The aim of our study was 3D objectification of stereolithography system (SLA) printed models, including surface analysis. Our investigated group consisted of 50 scans of upper dental arches of medical students obtained by 3Shape TRIOS 3® in the form of standard template library (STL) files. SLA 3D printer-built layers of an upper dental arch model were made by using liquid polymer hardened by laser beam (blue 405 nm laser). Each 3D SLA model was scanned from 56 positions and a section to check the precision of reconstruction. The model surface was evaluated with a profilometer, scanning electron microscope, and stereomicroscope. Differences between the intraoral scanned digital STL models and 3D SLA prints were very small, namely in hundredths of mm, and in many cases, they were also significant at lower levels. Stereolithography prepared fine-grained structures, the models were more homogeneous and smoother, and soft layering remains were visible if compared with plaster grainy surface structure showing sharp edges of orthorhombic crystals. The study has shown the precision of 3D SLA models along all three axes, a, b, c, in the whole model volume and also in cross-section. The advantages for dentistry are the colors: white, yellow and light brown; SLA models are stable and can be used repeatedly. In addition, a virtual database of models can save space in the dental office or lab.