Dynamic effects of food consistency on chewing motions.

The purpose of the study was to find evidence of how different types of food consistency affect chewing motions, especially the forward, downward and sidewise extents of motion of the lower jaw. Nineteen individuals with intact tooth sequence, aged from 20 to 37 years, were asked to chew three types of food of different consistency (banana, bread, carrot). The motions of the lower jaw were recorded by ELITE system, i.e. the measurement instrument that by stereo-photo-grametric procedures calculates space co-ordinates of markers on faces of the study subjects. The system enables continuous recording of lower jaw motions in three dimensions, without any possibility of the study subjects' influencing the operation of the instrument, which significantly decreases the possibility of error. Study results have shown that in all 19 subjects a greater food consistency increases the extent of chewing motion. In each individual study subject different average values were found for equal shifts of lower jaw when chewing the same type of food. Although varying from subject to subject, the chewing cycle depends to a great extent on food consistency. By increasing the consistency of a bite, the extent of lower jaw motion has increased in every single study subject.