Impact of the ambient light illuminance conditions on the shade matching capabilities of an intraoral scanner

Purpose To compare the shade matching capabilities between an intraoral scanner (IOS) and a spectrophotometer under different ambient light illuminance conditions. Material and methods The shade of three teeth of a patient was obtained using an IOS (IOS group) (TRIOS 3; 3Shape) and a spectrophotometer (DS group) (EasyShade V; Vita Zahnfabrik) at 4 ambient illuminances: 10000-, 1000-, 500-, and 0-lx. Ten shade measurements were documented using Vita Classical and 3D-Master guides per tooth at each lighting condition. Data was analyzed using the Kruskal-Wallis and Mann Whitney U tests (alpha = .05). Results Significant shade discrepancies were obtained between the groups in different lighting conditions (P< .05). The IOS group presented significant shade discrepancies in different lighting conditions when evaluated using either shade guide, with lower variation under the 0-lx condition. However, the DS group did not present significant shade discrepancies among the different lighting conditions with either shade guide, except for the maxillary lateral incisor measured under 10 000-lx condition using the 3D-Master guide. Conclusions Lighting conditions influenced the shade matching competency of an IOS. The IOS tested obtained high variation in the different lighting conditions evaluated and provided a lower shade value than the spectrophotometer. The spectrophotometer revealed high consistency amongst the various lighting conditions evaluated. Clinical implications Ambient light illuminance conditions can impact the shade matching capabilities of IOSs. The results of this investigation suggest the use of a supplementary instrumental method for assessment of tooth shade.