The purpose of this study was to clarify the difference in mandibular movements during chewing of soft and hard foods. The mandibular movement was recorded using a Mandibular Kinesiograph (MKG-K6I) when the healthy dentate adults chewed chewing gum (soft food) on the habitual chewing side for 20 seconds. They showed that the amount of glucose eluted when chewing gummy jelly exceeded the reference value. For the 10 cycles from the 5th cycle, the masticatory movement path patterns were classified into 5 types by displaying the superimposed path and average path. The mandibular movement of the subjects showing a normal pattern chewed a peanut (hard food) on the habitual chewing side until swallowing was recording using a MKG. The pattern of masticatory movement path during chewing of peanut was classified. Next, the amount of movement and movement rhythm during chewing of soft and hard foods were calculated and compared between the foods. The pattern of masticatory movement path did not change with the difference of foods in all subjects. The amount of movement was significantly greater when chewing a peanut than when chewing a softened gum, and a significant difference was observed between the two foods. The movement rhythm tended to be longer when chewing a peanut than when chewing a softened gum, but there was no significant difference between the two. From these results, in healthy dentate adults who have a normal masticatory movement path pattern and good masticatory performance when chewing soft food, it was suggested that no change in the masticatory movement path pattern was observed even when chewing hard food, and that the amount of movement increased significantly when chewing hard food.

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The purpose of this study was to clarify the conditions for adequately testing the masticatory performance and occlusal force of adults with missing unilateral molars. Twenty females with missing molars on one side （unilateral molar loss group） and 20 females with natural dentition （control group） participated in this study. The amounts of glucose eluted when the participants chewed a gummy jelly on the habitual and non-habitual chewing sides were measured. Furthermore, using an occlusal force analysis system （Dental Prescale II, Bite Force Analyzer, GC, Tokyo, Japan）, the occlusal force on the habitual and non-habitual chewing sides during maximum clenching （lasting about 3 seconds）（hereinafter referred to as occlusal force） was measured. For the amount of glucose eluted and the occlusal force, the presence or absence of a correlation between the habitual and non-habitual chewing sides was investigated. Next, the presence or absence of a correlation between the amount of glucose eluted on the habitual chewing side and the occlusal force on the habitual chewing side and between the amount of glucose eluted on the habitual chewing side and the occlusal force on the entire dentition （both sides） were investigated. In both the unilateral molar loss group and the control group, a significant correlation was observed between the amount of glucose eluted on the habitual chewing side and the amount of glucose eluted on the non-habitual chewing side, and between the amount of glucose eluted on the habitual chewing side and the occlusal force on the habitual chewing side. In the control group, there was a significant correlation between the occlusal force on the habitual chewing side and the occlusal force on the non-habitual chewing side, and between the amount of glucose eluted on the habitual chewing side and the occlusal force on the entire dentition. However, no significant correlation was observed in the unilateral molar loss group. It was suggested that both masticatory performance and occlusal force should be analyzed on the habitual chewing side instead of the entire dentition.

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