Abstract
In the present study, we developed a novel color
scale for visual assessment, conforming to
theoretical color changes of a gum, to evaluate
m a s t i c a t o r y p e r f o r m a n c e ; m o r e o v e r , w e
investigated the reliability and validity of this
evaluation method using the color scale. Ten
participants (aged 26–30 years) with natural
dentition chewed the gum at several chewing
strokes. Changes in color were measured using a
c o l o r i m e t e r , a n d t h e n , l i n e a r r e g r e s s i o n
expressions that represented changes in gum
color were derived. The color scale was developed
using these regression expressions. Thirty-two
chewed gums were evaluated using colorimeter
and were assessed three times using the color
scale by six dentists aged 25–27 (mean, 25.8)
years, six preclinical dental students aged 21–23
(mean, 22.2) years, and six elderly individuals
aged 68–84 (mean, 74.0) years. The intrarater and
interrater reliability of evaluations was assessed
using intraclass correlation coefficients. Validity
of the method compared with a colorimeter was
assessed using Spearman’s rank correlation
coefficient. All intraclass correlation coefficients
were > 0.90, and Spearman’s rank-correlation
coefficients were > 0.95 in all groups. These
results indicated that the evaluation method of the
color-changeable chewing gum using the newly
developed color scale is reliable and valid.
