Meeting Abstract

P1-223  Saturday, Jan. 4  Variability in Mammalian Chewing using Functional Data Analysis: Differences in Jaw Pitch Amplitude and Velocity throughout the Chewing Cycle MONTUELLE, SJ*; TEWKSBURY, C; WILKINSON, K; OLSON, R; WILLIAMS, SH; GERSTNER, G; University of Michigan School of Dentistry; University of Michigan School of Dentistry; University of Michigan; Ohio University; Ohio University Heritage College of Osteopathic Medicine; University of Michigan School of Dentistry montuell@umich.edu

Mammalian chewing is based on precise jaw movements that align teeth so that the food is processed until it can be swallowed. Movement modulation from one chewing cycle to the next is key to responding to changes in food properties and position, but for mammals, modulation may hinder rhythmicity. Between-cycle variability resulting from modulation is traditionally evaluated by comparing predetermined time points (e.g., phase transitions). However, chewing movements are continuous in time and thus so is their variability. We use functional data analysis to quantify variability in the amplitude and velocity of jaw pitch (opening-closing movements) continuously throughout the gape cycle during chewing in three mammalian species (pigs, raccoons, skunks). In all 3 species, both the amplitude and velocity of jaw pitch is most variable as the jaw opens and closes, whereas is is least variable during the power stroke. Stereotypy during the power stroke may minimize occlusal force unpredictability whereas variability during opening and closing may provide greater flexibility in manipulating the food bolus depending on its positioning and/or properties. In addition, skunks and raccoons appear to be more variable in jaw pitch velocity than pigs. Compared to the more permissive morphology of the pig temporomandibular joint (TMJ), the hinge-like TMJ of carnivorans may be more stable for accommodating greater modulation in jaw velocity without risking dislocation.