Clinical Evaluation of the Influence of Illumination During Visual Shade Matching

Purpose: This study evaluated the influence of ambient light and a D65 standard light source during visual shade matching for natural teeth. Materials and Methods: Sixty undergraduate students (33 female; 27 male), studying at the Dental School participated in this study. The shade of a maxillary incisor was initially determined using an intraoral spectrophotometer (Vita Easyshade Compact, VITA Zahnfabrik, Bad Säckingen, Germany) and acted as the reference values (A1 and 1M2) for the subjects. After calibration of the students, the shade of a maxillary central incisor was determined visually for three times using two shade guides, the Vita Classic (VC) and Vita 3D Master Linearguide (VL3D), with and without the aid of a standard light source (D65). The obtained results were compared to the reference value. The data were analyzed using the Mann-Whitney U-test. Results: Both the light source and the shade guide showed significant effects on the outcome (P<0.0001). The use of a D65 light source increased the probability of correct visual shade matching with both VC (50%) and VL3D (63.3%) shade guides when compared to ambient light (3.3% and 6.7% for VC and VL3D, respectively). Conclusion: Standardized lighting with a D65 light source may improve the correct choice of tooth shade by students, although errors in correct shade matching were not completely eliminated.