title: Jaw-movement smoothness during empty chewing and gum chewing.
abstract: A major goal of motor coordination is the production of a smooth movement. Jerk-cost, which is an inverse measure of movement smoothness, has been evaluated during gum chewing in previous studies. However, the effect of the gum bolus is still unclear. The aims of this study were to compare the jerk-cost values of normal gum chewing with those of empty chewing. Thirteen subjects undertook, empty chewing, then chewing of gum, and then a second empty chewing. Jerk-cost was calculated from an accelerometer attached to the skin of the mentum. There was a significantly higher smoothness (i.e. lower jerk-cost, P < 0.05) during the opening and second-half closing phases in empty chewing compared with gum chewing. There were no significant differences in jerk-costs (i.e. opening or closing) between the first and the second empty-chewing sequences. These results suggest that the influence of the mechanical effects of tooth contact on jerk-cost is not restricted just to the occlusal phase of chewing, but rather the effect influences the entire opening and closing phases of chewing.
authors.affiliation: Jaw Function and Orofacial Pain Research Unit, Faculty of Dentistry, University of Sydney, NSW, Australia. minami.rpro@tmd.ac.jp
authors.forename: Ichiro
authors.initials: I
authors.lastname: Minami
authors.forename: Rahena
authors.initials: R
authors.lastname: Akhter
authors.forename: Julien
authors.initials: J
authors.lastname: Luraschi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Oogai
authors.forename: Tetsu
authors.initials: T
authors.lastname: Nemoto
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Peck
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Murray
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002638:Chewing Gum; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D008875:Middle Aged; D008954:Models, Biological; D009068:Movement; D016059:Range of Motion, Articular; D012016:Reference Values; D013704:Temporomandibular Joint / Q000502:physiology*; D013996:Time and Motion Studies
chemical_list: D002638:Chewing Gum