Color inconstancy of natural teeth measured under white light-emitting diode illuminants

Manuel Melgosa; Javier Ruiz-López; Changjun Li; Pedro A García; Alvaro Della Bona; María M Pérez

doi:10.1016/j.dental.2020.10.001

Color inconstancy of natural teeth measured under white light-emitting diode illuminants

Dent Mater. 2020 Dec;36(12):1680-1690. doi: 10.1016/j.dental.2020.10.001. Epub 2020 Nov 7.

Authors

Manuel Melgosa¹, Javier Ruiz-López², Changjun Li³, Pedro A García⁴, Alvaro Della Bona⁵, María M Pérez²

Affiliations

¹ Department of Optics, University of Granada, Granada 18071, Spain. Electronic address: mmelgosa@ugr.es.
² Department of Optics, University of Granada, Granada 18071, Spain.
³ School of Electronics and Information Engineering, University of Science and Technology Liaoning, Anshan 114051, China.
⁴ Department of Statistics and Operations Research, University of Granada, Granada 18071, Spain.
⁵ Post-graduate Program in Dentistry, Dental School, University of Passo Fundo, Brazil.

PMID: 33172605
DOI: 10.1016/j.dental.2020.10.001

Abstract

Objective: To evaluate color and whiteness changes of natural teeth under nine white LED illuminants recently proposed by CIE.

Methods: From spectral reflectance factors of 36 caries-free upper central incisors, corresponding colors under illuminant D65 and CIE 1931 standard colorimetric observer were computed for all tested illuminants, using the chromatic adaptation transform CAT16. Color differences (CIELAB and CIEDE2000 units) and whiteness (WI_D and WI_O indices) from teeth illuminated by CIE standard illuminants (D65 and A) and white LED illuminants were calculated. The appearance of 630 pairs of teeth under all illuminants was also evaluated.

Results: Color gamuts from 36 teeth under tested illuminants showed similar volume and shape in CIELAB color space, but their centers of gravity changed in many different directions with respect to colors under D65 or A illuminants: Considering colors under D65/A, color shifts produced by white LED illuminants were in the ranges 2.0-8.6/1.1-7.0 CIELAB units (1.4-8.2/0.6-6.8 CIEDE2000 units). Average WI_D and WI_O values for the 36 teeth under different illuminants ranged from -5.8 to +19.3 and from -7.7 to +11.1, respectively. Considering 630 pairs of teeth, average color differences (mainly lightness differences) were below 0.5 CIELAB units (0.3 CIEDE2000 units), and average whiteness differences ranged from 8.1 to 10.7 for WI_D (23.4-25.1 for WI_O).

Significance: Using CIE LED illuminants, most changes in color and whiteness for individual teeth were above typical threshold values of perceptibility and acceptability in dentistry. However, considering pairs of teeth, the average color and whiteness differences under all tested illuminants were very similar.

Keywords: CAT16; CIEDE2000; Color; White light-emitting diode; Whiteness.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Color
Color Perception*
Colorimetry*
Incisor