Evaluation of visual and instrumental shade matching by dental students

Methods: The color of central incisors and canines of three different patients (D1-complex case, D2-intermediate case and D3–simple case) was determined by the spectrophotometer Spectro-Shade Micro (MHT - Niederhasli, Switzerland). Each student, in the 4th and 5th grades of a Dental Medicine course, selected the closest match for each tooth using the Vita classical shade guide (VITAPAN^®classical, Vita Zahnfabrik - Bad Säckingen, Germany). They also had to answer two questions: “What was the tooth that they felt more difficult for shade evaluation?” and “which factors had most influenced on shade evaluation?”.

Results: After the color evaluation by dental students (n=110), the results showed that for the central incisor of D1 the visual method of color evaluation matched the spectrophotometric method in 37.3% of the cases and for the canine that percentage was higher (52.7%). For D2, the results were 53.6% and 35.5%, and for D3, 39.1% and 45.5%, respectively. Inferential statistics analysis was performed (at a 5% significance level) in order to compare the results of color evaluation by the two methods, as a function of gender and dental students grade. No significant differences were found (Fischer’s Exact test, p>0.05) The difficulty degree in color evaluation among the three different patients was also compared and no significant differences were found (Chi-square test, p>0.05).

Conclusion: Shade evaluation with the visual shade guide was consistent with the spectrophotometric shade analysis. No statistically significant differences were detected between the two methods, as a function of gender and dental students grade. However, the perception of color match can be affected by light conditions, tooth shade guide, tooth characteristics and distance.