[Utility of color-changeable chewing gum to evaluate masticatory ability in community-dwelling elderly persons].

PURPOSE: The masticatory ability of community-dwelling elderly persons is often evaluated using subjective questionnaires. However, an objective evaluation would clearly be beneficial so that problems can be adequately addressed. The purpose of this study was to determine the utility of color-changeable chewing gum to evaluate masticatory ability in community-dwelling elderly persons. METHODS: We analyzed the reliability of the chewing gum for assessment of masticatory ability in 5 individuals who were examined on 5 occasions at 2 hour intervals. We also analyzed the validity of color-change of the chewing gum for assessment of masticatory ability by means of a four-part examination of 210 community-dwelling elderly persons. The four parts were as follows: evaluation of masticatory ability with the gum, determination of the number of residual teeth, measurement of maximum bite force, and a questionnaire in which participants were asked to assess their own masticatory ability. Color changes in the gum after chewing were measured with a color-reader and quantified with the a* color space defined by the Commission Internationale de l'Eclairage. A higher a* value indicates a higher degree of mastication. RESULTS: With respect to reliability, the coefficient of variation for the a* of the color-changeable chewing gum was 2.15-3.75%. There were no significant a* value differences between men and women in any age group. Decrease with age was significantly only in women. With respect to validity, the a* value of the color-changeable chewing gum had a significant positive correlation with the number of residual teeth and maximum bite force in both men and women. In addition, men and women who reported good masticatory ability in response to the questionnaire had significantly high a* values. CONCLUSION: We found the use of color-changeable chewing gum to be a highly reliable and valid method for evaluating masticatory ability. Our results indicate that this method could be useful for monitoring masticatory ability in the community-dwelling elderly.