Frontal-plane lateral border movements and chewing cycle characteristics

We studied the dental contact section of the chewing cycle, the most import ant section in terms of function (as it governs the effectiveness of food t rituration). Specifically, we determined closing phase dental contact dista nce and lateral path inclination in a sample of healthy subjects, and inves tigated possible relationships between these variables and Ahlgren chewing cycle type. The chewing cycle was characterized in 63 healthy subjects by f rontal plane kinesiography. In all cases kinesiographs were obtained for bo th right- and left-side chewing, with chewing gum as bolus. In all cases we determined closing phase dental contact distance, lateral path inclination and Ahlgren chewing cycle type. Most subjects (84%) showed 'normal' chewin g cycles (Ahlgren types I-IV); inverted, contralateral and irregular cycles (types V-VII) were infrequent. Mean dental contact distance was 0.9 mm for right-side chewing and 1.2 mm for left-side chewing. Mean lateral path inc lination was 35 degrees for right-side chewing and 37 degrees for left-side chewing. Normal chewing cycles are generally bilateral, whereas abnormal c hewing cycles are never bilateral. Border movement distance does not differ in any consistent way between 'chopping' and 'grinding' chewing cycle type s. Closing phase dental contact. distance showed a significant positive cor relation with lateral path inclination.