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

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 velocit...