Objectives: To predict perceptual tooth yellowness with the development of an equation. Methods: An experiment where 500 participants ranked a set of 58 shade guide samples produced a large set of psychophysical yellowness data. Using this psychophysical data a yellowness equation, YIO, was developed by optimizing the data to maximize the coefficient of determination, r2. Three indexes, a new yellowness index, YIO and two existing equations (WIO and b*) were evaluated by comparing their values for the 58 shade guide tabs with the psychophysical data. Coefficient of determination (r2) and ‘% wrong decision’ were used to measure the performance of the equations. An experiment with 40 participants ranking 5 sets of 9 samples that were viewed on emissive display was used to validate the yellowness equation. The candidate equations were evaluated using the validation set of data, r2, and %WD metrics Results: The three indexes YIO, WIO, and b* strongly correlated with perceptual yellowness. However, YIO and WIO showed stronger correlations to the data than b*. Conclusions: A new yellowness index YIO has been developed which correlates to perceptual tooth yellowness.
Division: Meeting:2019 British Division Meeting (Leeds, England) Location: Leeds, England
Year: 2019 Final Presentation ID: Abstract Category|Abstract Category(s):Dental Materials 7: Color and Appearance (Esthetics)
Authors
Sullivan, Chelsea
( University of Leeds
, Leedfs
, United Kingdom
)
Westland, Stephen
( University of Leeds
, Leedfs
, United Kingdom
)
Ellwood, Roger
( Manchester University
, Manchester
, United Kingdom
)
Pan, Qianqian
( University of Leeds
, Leedfs
, United Kingdom
)
Financial Interest Disclosure: Colgate-Palmolive provides the funding and works with this PhD at the University of Leeds, for which this research was conducted.
Support Funding Agency/Grant Number: Colgate-Palmolive
SESSION INFORMATION
Poster Session
Abstracts Presented at the 2029 BSODR Meeting