Subjective vs. Objective Matching of Tooth Colour- A Comparative Study

Methods: Ninety students (45 second year and 45 fourth year) undergraduate dental students from the University of Sheffield, were selected to undertake a subjective comparison of tooth shade. Each student was individually asked to compare 6 anonymised shade tabs (2M2, 3R2.5, 4M1, 5M3, 1M2, 3M3) taken from the Vita 3D Master Colour Guide, against an identical but reduced guide. All subjective shade determinations were made in a single location using a Color-i-Dent II P® lighting system centered by a ring fluorescence lamp (correlated colour temperature 5500 K). The same six shade tabs were then objectively evaluated 45 times by a single trained operator using the X-rite ShadeVision system. The numbers of correct/incorrect shade tab comparisons were recorded for each student year and the X-rite system. A One-way Analysis of Variance and independent T-test were carried out (p<0.05).

Results: The fourth year generally performed better than the second year students. Both student years performed significantly better than the X-rite system (p<0.05) with all tabs except 4M1.

Conclusions: As expected the more experienced fourth year students showed a greater degree of accuracy in shade determination than the second year students. Surprisingly, however, the subjective shade determination was overall superior to that of the objective shade determination.