Chewing Performance Calculator: An interactive clinical method for quantifying masticatory performance

Abstract

Statement of problem: There is a need to quantitatively differentiate between impaired and normal mastication by using straightforward and reliable methods because currently available methods are expensive, complex, and time-consuming.

Purpose: The purpose of this clinical study was to assess the reliability, validity, and clinical utility of a new Web-based software program designed to calculate masticatory performance, the Chewing Performance Calculator (CPC) measuring masticatory performance (MP), by analyzing the area of mixed bicolored chewing gum.

Material and methods: One hundred and ten participants were consecutively recruited from the School of Dentistry of the University of Salamanca. MP was determined by using 2-colored chewing gum that was masticated for a total of 20 strokes. The masticated gum was then flattened between 2 transparent glass tiles, generating a 1-mm-thick specimen that was scanned to calculate the percentage of area where the 2 colors were mixed. The area was calculated by using a photo-editing software program as described by Schimmel et al (standard method). In addition, all the images were analyzed by using the CPC Web application, which took as input the image of the masticated bolus enclosed in a custom plastic platen that allowed 3 parts of the image to be selected interactively: the platen, the bolus background, and the mixed color fraction of the bolus. The application then computed MP as a percentage. Additionally, an oral examination was carried out to record the number of occlusal units. These data were used to assess the validity of CPC by using the Pearson correlation coefficient. Construct validity was assessed by using ANOVA by comparing the MP scores obtained for masticated gums, classified upon inspection as being poorly, moderately, or highly mixed. The time spent evaluating the specimens with GSM and CPC methods was also recorded and used to indicate the usefulness of the procedure.

Results: The MP was found to range between 5.2% and 100% (95% CI: 80.8-88.8) with the GSM and between 9.2% and 96.4% (95% CI: 60.0-67.6) with the CPC. The time needed to calculate MP by using the GSM was significantly higher (235.2 versus 260.5 seconds) than that with the CPC (42.3 to 48.6 seconds). Both methods were significantly intercorrelated (r=0.65; P<.001) and correlated with the number of occlusal units (r=0.54 for CPC and r=0.40 for GSM). The correlation coefficient of MP calculated by using CPC (r=0.54; P<.001) was greater than that calculated by using GSM (r=0.40; P<.001). Moreover, both methods showed adequate construct validity because the values calculated for MP significantly increased as the mixing of the masticated gums also increased, subjectively classified as poor, moderate, and high.

Conclusions: The CPC software program allowed MP to be determined in a valid and easy-to-use manner by using 2-colored chewing gum.