The development of a 3D colour reproduction system of digital impressions with an intraoral scanner and a 3D printer: a preliminary study

Abstract This study aimed to develop a three-dimensional (3D) colour reproduction system to improve the aesthetic effects of dental prostheses. The system’s colour accuracy was also evaluated. Based on the concept of colour management, 96 colour patches were selected to develop colour profiles for an intraoral scanner and a 3D printer using polynomial regression. The colour differences Δ$${E}_{ab}^{\ast }$$ Eab⁎ between colour patches reproduced using different colour profiles and the original colour patches were analysed to select the best combinations of colour profiles. The 3D colour reproduction system with the best-performing (i.e. third-order polynomial regression) colour profiles was finally evaluated using tooth and gum shades. The median Δ$${E}_{ab}^{\ast }$$ Eab⁎ was 6.940 ranging from 1.504 to 32.660. In terms of tooth and gum shade, the median Δ$${E}_{ab}^{\ast }$$ Eab⁎ was 6.313, and half of the shade blocks were above the mismatch threshold (Δ$${E}_{ab}^{\ast }$$ Eab⁎ > 6.80). In conclusion, the colour management based on polynomial regression can decrease the colour difference of the 3D colour reproduction system, but not to clinically acceptable levels. Further advances are needed to improve the methods and hardware.