Effects of Food Texture and Sample Thickness on Mandibular Movement and Hardness Assessment during Biting in Man

Abstract

This study was designed to investigate the relationship among jaw movements, physical characteristics of food, and sensory perception of hardness in man. Vertical movements of the mandible were recorded with an infrared tracking device in humans during biting on two test foods, carrot and cheese. Samples of standard length (2 cm) and width (2 cm) were prepared in three different thicknesses (0.5, 1.0, and 1.5 cm). Nine subjects were asked to perform two types of bite with their incisor teeth. In the first, they cut through the food, then stopped and spat out the pieces (bite alone); in the second, biting was followed by mastication and swallowing (bite+chew). The 12 conditions (thickness x3, food x2, and bite x2) were presented in a random order within each block, and blocks were repeated five times (60 trials per subject). Subjects also estimated the hardness of the samples twice for each condition on visual analogue scales (VAS) 100 mm long. The duration, vertical amplitude, and maximum vertical velocity of the mandible during biting were calculated by computer for the three phases of the movements (opening, and fast and slow closing). Multilevel statistical models were used for data analysis. The estimated hardness scores associated with the first bite of thin carrot (59.0 VAS units) was significantly greater than for cheese (16.8 VAS units). The type of bite had no significant effect on these scores, but the estimate of hardness was significantly greater for the thickest sample (+13.3 VAS units). Food type had its strongest effect on the slow-closing phase. In particular, the peak velocity that followed the fracturing of the food sample was much greater for carrot than for cheese (thin, 34.1 mm.s-1 vs. 26.6 mm.s-1), and the difference between foods increased with thickness. The amplitude of opening was significantly greater for the thickest sample than for the other two. There were no significant relationships between VAS scores and the movement parameters. These results suggest that, when humans bite food: (1) changing the thickness of food has a greater effect on movement parameters than changing from soft to hard food, (2) the parameters of biting change little if biting is followed by mastication, (3) hardness perception is dependent on the thickness of food, (4) hardness perception is not different when food is removed from the mouth than when it is chewed and swallowed, and (5) there is no relationship between any of the parameters of movement that change with food type and the perceived hardness of food.

Biomechanics of human tongue movement during bolus compression and swallowing

“…Food consistency strongly affects jaw-closing muscle activity per chewing cycle during food reduction (16,17), and increased food hardness, toughness, or resistance to trituration increases the number of chewing cycles before swallowing (18,19). The bolus volume in one bite was found to have similar effects on chewing behaviors, as most parameters-including the jaw-closing muscle activity (20,21) and duration (19)-increased with bolus volume. Blissett et al reported that changes in the physical properties of boluses, rather than changes in the bolus volume during chewing, had significant effects on tongue movement (22).…”

Influence of age on mastication: effects on eating behaviour

“…In consequence, during chewing, muscle activity is found to respond to food texture as early as the first chew (Mioche et al 2003). Several kinetic parameters of a chewing cycle also depend on the food properties such as its shape (Gibbs et al 1981), vertical dimension (Diaz-tay et al 1991Peyron et al 1997) and jaw closing angle (Agrawal et al 2000). These variations in the general shape of the chewing cycle are believed to reflect some aspects of the intra-oral events of tongue activity which enable, with cohesive food such as meat, the placement of new food surfaces onto dental arches from one cycle to another (Fig.…”

Video Evaluation for Mastication Validation inPersons with Down?s Syndrome

“…As a consequence, the test foods used during the meal were not calibrated in form and size across the different foods. However, food size influences the masticatory muscle activity in human mastication [20,21]. This may have influenced the fact that differences in MT and MC were not consistent across food types when comparing the two groups.…”