Inter-measurement variation of masticatory performance test using gummy jelly.

The purpose of this study was to clarify the inter-measurement variation of the masticatory performance test. Forty healthy adults were divided into group A (10 males and 10 females), who did not chew the test food before experiment, and group B (10 males and 10 females) who chewed the test food before the experiment. Subjects were asked to chew a gummy jelly for 20 s on the habitual chewing side, and the amount of glucose extraction was measured. The test was repeated three times with an interval of 1 min in both groups (Group A: A1, A2, A3; Group B: B1, B2, B3). In both groups A and B, the difference between the measured values was compared and the reliability between measurements was investigated. In group A, the value of A1 was small, and a statistically significant difference was observed between A1 and other measured values. In group B, the three measured values were similar and no significant difference was observed among the measured values. The intraclass correlation coefficient (ICC) values for determining inter-measurement reliability in group A were 0.758 for A1-A2-A3, 0.708 for A1-A2, and 0.901 for A2-A3. The ICCs in group B were 0.924 for B1-B2-B3, 0.945 for B1-B2, and 0.926 for B2-B3. Based on these results, it can be suggested that high reliability between the measurements can be obtained if the subjects are accustomed to chewing the test food before the experiment, and that the measured values were similar whether it was performed two or three times. Consequently, one measurement was sufficient if subjects were accustomed to chewing the test food before the experiment.