KUSUMOTO Tetsuji Osaka Dental University, Faculty of Dentistry, Assistant, 歯学部, 助手 (70186394)
TOSA Junichi Osaka Dental University, Faculty of Dentistry, Assistant, 歯学部, 助手 (50148459)
SARATANI Keiji Osaka Dental University, Faculty of Dentistry, Lecturer, 歯学部, 講師 (60170817)
TANAKA Masahiro Osaka Dental University, Faculty of Dentistry, Lecturer, 歯学部, 講師 (60163573)
This study was made to investigate the influence of food texture on the chewing motion. Using a kinesiograph (Model K6, Myo-tronics Co.), the jaw movement of mandible was recorded three-dimensionally from the beginning of mastication to the swallowing in 20 normal subjects. As test food, cheese, kamaboko, takuan, bontan-ame and surume were used. On each food, the hardness, the cohesiveness, the gumminess, the stickiness, the adhesiveness and fracturability were quantified by a texturometer (Zenken Co.).
The food texture strongly related to the masticatory function was not only the hardness, but also the gumminess, expressed the required force which ground food to the extent of one's swallowable condition. As the gumminess increased, the time of the occluding phase decreased and the number of chewing strokes increased. The time of the opening phase was increased according as the increase of the stickiness and the adhesiveness. On the contrary, the time of the closing phase was increased
by the presence of the fracturability.
In further study, we investigated the effect of texture change on jaw movement during gum chewing. The textures of chewed gum (Green gum, LOTTE Co.), the hardness, the cohesiveness, the gumminess, the stickiness and the adhesiveness, were quantified by a texturometer for 10, 20, 30, 60, 90, 120, 180, 240, 300 and 600 sec in 8 normal subjects and 2 patients with craniomandibular disorders (CMD). Using a kinesiograph, the jaw movement of mandible was recorded three-dimensionally during 10 min. habitual gum chewing. Multiple regression analysis was applied for investigating the effects of the change of gum texture on chewing motion (criterion variables : chewing movement parameters, explanatory variables : texture factors).
In normal subjects, the closing and the occluding phases were observed high correlations with the hardness and the cohesiveness. On the other hand, the opening phase and the cycle time were not observed correlations with any texture. In CMD patients, all parameters of chewing movement were observed high correlations with texture factors.