Colour perception screening and shade-matching performance among undergraduate dental students: an exploratory observational study

Abstract

Background: Visual shade selection remains widely used in restorative and prosthetic dentistry and is influenced by interobserver variability, illumination conditions, and individual visual factors. However, the relationship between colour perception screening findings and shade-matching performance in undergraduate dental students remains insufficiently explored. Objective: To assess colour perception screening findings and shade-matching performance among undergraduate dental students using the Ishihara test and practical shade-selection tasks. Methods: An exploratory cross-sectional study was conducted including 80 fourth- and fifth-year dental students enroled in the prosthodontics course at the University of Barcelona during the 2017–2018 academic year. Colour perception was screened using the Ishihara 24-plate test. Shade-matching performance was evaluated through two practical tasks: pairing corresponding tabs from two Chromascop shade guides and selecting the reference shade of a ceramic crown. Incorrect responses, shade-selection discrepancies, and completion time were recorded. Statistical analysis included descriptive statistics and bivariate tests selected according to the type of variable and expected cell frequencies. Results: Eighty students participated in the study (33.75% male, 66.25% female). Ishihara screening findings compatible with colour vision deficiency were observed in 2.5% of participants, while isolated incorrect plate responses were observed in a larger proportion of students. Shade-matching discrepancies were frequent in both practical tasks. Self-reported ophthalmological conditions were associated with a higher number of shade-selection discrepancies (p < 0.05). Longer completion times tended to be associated with more discrepancies, although this association was not statistically significant. No significant differences were observed according to sex. Conclusions: Within the limitations of this exploratory study, shade-matching discrepancies were common among undergraduate dental students and were not limited to participants with Ishihara screening findings compatible with colour vision deficiency. These findings support the relevance of structured training in colour science and shade selection during prosthodontic education. Further studies using standardized perceptual and instrumental reference methods are needed.