Meeting Abstract

S2.11  Tuesday, Jan. 4  The mandibular instantaneous center of rotation in non-human primates and its relation to gape. TERHUNE, Claire E.*; IRIARTE-DIAZ, Jose; TAYLOR, Andrea B.; ROSS, Callum F.; Duke University; University of Chicago; Duke University; University of Chicago claire.terhune@duke.edu

Kinematic analyses of mandibular movement in humans have demonstrated that the location of the mandibular instantaneous center of rotation (ICoR) is most commonly located near the level of the occlusal plane and varies in its position during a chewing sequence. Few data are available regarding the path of the ICoR in non-human primates, and it remains unclear how the position of the ICoR varies in association with mastication and/or gape behaviors. Here we expand and elaborate upon the existing dataset for the ICR in non-human primates and evaluate the relationship of ICR position to gape. We quanitifed ICoR throughout the gape cycle in three species of non-human primates (Chlorocebus aethiops, Eulemur fulvus, Varecia variegata). Cartesian coordinates of mandibular and cranial markers were extracted from lateral videofluoroscopic movies for multiple chewing sequences, and the coordinates of the position of the ICoR were calculated in a coordinate system centered at the top of the condyle at rest. Consistent with previous analyses, the ICoR is commonly located below the mandibular condyle close to the occlusal plane, and varies considerably both superoinferiorly and anteroposteriorly throughout the chewing sequence. Significant correlations were found between ICoR position and condylar movement, and particularly between the superoinferior location of the ICoR and gape angle, but not between gape and anteroposterior ICoR position.