Effects of restorative materials, colors, and surface finishing on the scanning accuracy of an intraoral scanner

Background/purpose When teeth are restored using dental materials, there is potential for these restorations to influence the accuracy of intraoral scans. Such variations in accuracy could subsequently affect the precision of the derived virtual cast, the registration of the maxillo-mandibular relationship, and the fabrication of prostheses. This study aimed to assess the effect of various restorative materials, prosthesis colors, and their surface finishes on the accuracy of intraoral scans performed with a TRIOS 4 scanner. Materials and methods Using a 4 × 2 × 2 factorial experimental design, the research analyzed how metal-ceramic, zirconia, lithium disilicate, and milled PMMA; shades B1 and A4; and surface finishes (either polishing or glazing) influence the trueness and precision of scans. The trueness and precision were quantified using root mean square (RMS) values. Results Significant differences in scan accuracy were observed, contingent on material, color, and finishing, along with notable interactions between these factors. Overall, PMMA exhibited the highest trueness and zirconia demonstrated the best precision. Polished lithium disilicate and PMMA showed better trueness for the A4 shade, whereas glazed lithium disilicate and PMMA performed better for the B1 shade. Metal-ceramic restorations showed an opposite trend. Zirconia restorations showed better trueness for A4 shade than B1 shade for both polished and glazed surfaces. Conclusion Significant interactions between materials, colors, and surface treatments were observed. Although clinicians may not be able to modify existing restorations' materials, color, or surface treatment, they need to be mindful that the intricate interaction of these factors will affect the accuracy of intraoral scans.