Comparative judgment of artificial tooth shade by subjectivity and colorimeter

Objectives: Subjective judgment in the use of a shade guide is common in the selection of the color of anterior artificial teeth for a removable partial denture, and the dentist may waver in selecting a color to match that of the extracted tooth. In this research, we considered the differences in subjective vs. colorimetric judgments in the selection of artificial tooth shades.

Methods: Shade Eye NCC (Shofu, Japan) was the colorimeter used. Two kinds of hard-resin teeth (Duradent, GC, Japan; Endura, Shofu, Japan) were used for the test. There were 4 artificial tooth colors (A2, A3, A3.5, B2). The artificial tooth was set in paraffin wax, and the shade number was investigated by colorimeter. The artificial tooth (still in wax) was shown to dentists, who were asked to choose the correct shade from the shade guide (Vita Pan Classical, Vita; and two shade guides for hard-resin teeth). The 2x2 dividing method was used for statistical analysis.

Results: The percentage of correct answers based on use of the shade guide for artificial teeth was significantly higher than that from use of the shade guide for porcelain (p < 0.05). The percentage of correct answers based on the different manufacturers' shade guides for artificial teeth was significantly higher than that for porcelain (p < 0.05). The percentage of correct answers based on colorimetric judgment was significantly lower than that from use of the shade guide for artificial teeth (p < 0.05).

Conclusions: These results suggest that the use of a shade guide for porcelain and and a colorimeter is no substitute for subjective judgment in the selection of an artificial tooth shade.