In vitro comparison of instrumental and visual tooth shade determination under different illuminants.
BACKGROUND
While a considerable body of literature deals with the comparison between visual and instrumental tooth color determination, in most of these studies either the number of color specimens or the number of examiners is too small to allow for a general statement about such a subjective method as visual color determination. Furthermore, perceptual aspects like perceptible or acceptable color differences are often not considered.


OBJECTIVE
The purpose of this study was to investigate the precision of a spectrophotometer in tooth shade determination compared with visual color matching using a shade guide in vitro. Moreover, the influence of different illuminants as well as of sex and professional experience of the examiners on visual color matching was analyzed.


METHODS
Fifty examiners (13 men, 37 women; without dyschromatopsia), grouped by professional experience, determined the shades of 10 prosthetic teeth with the Vitapan classical shade guide under 4 illuminants (daylight, halogen, fluorescent [5000 K], fluorescent [nonspecific ceiling light]) and with a spectrophotometer (Shadepilot). Reproducibility (precision) of color determination was characterized by the average of the highest percentages of interexaminer agreement for each specimen. Additionally, color differences (ΔE) were calculated based on CIELab values.


RESULTS
The mean reproducibility of the spectrophotometer was 92.2%, while for visual examination it was 43.7%. The corresponding differences in CIELab color space amounted to ΔEinstr=2.6 and ΔEvis=5.2. Illuminants and professional experience showed a significant influence, while sex did not.


CONCLUSIONS
While the spectrophotometer provided higher reproducibility, considering the color differences, the results obtained by visual inspection were still satisfactory. The differences due to type of illuminant, degree of experience, and sex of the examiners are of little practical relevance.
Resident, Department of Prosthetic Dentistry and Biomaterials, University of Münster, Münster, Germany. Electronic address: elke.kroeger@ukmuenster.de.
Elke
E
Kröger
Private practice, Unna, Germany.
Stefanie
S
Matz
Doctoral student, Department of Prosthetic Dentistry and Biomaterials, University of Münster, Münster, Germany.
Markus
M
Dekiff
Resident, Department of Prosthetic Dentistry and Biomaterials, University of Münster, Münster, Germany.
Bao Long
BL
Tran
Professor and Director, Department of Prosthetic Dentistry and Biomaterials, University of Münster, Münster, Germany.
Ludger
L
Figgener
Head, Division of Technology and Materials, Department of Prosthetic Dentistry and Biomaterials, University of Münster, Münster, Germany.
Dieter
D
Dirksen
D003116:Color; D003124:Colorimetry; D005260:Female; D006801:Humans; D008297:Male; D017797:Prosthesis Coloring; D015203:Reproducibility of Results; D013053:Spectrophotometry; D014070:Tooth