title: Chewing cycle kinematics of subjects with deepbite malocclusion.
abstract: BACKGROUND
  The notion that chewing cycle shape and cycle dynamics differ between subjects with and without malocclusion is largely based on qualitative studies that combined various types of malocclusion. The purpose of this prospective study was to determine whether chewing cycle kinematics of untreated young adults with deepbite malocclusion differ from those with normal occlusion.
  
  
  METHODS
  Twenty-three deepbite subjects (>50% overbite) and 24 controls with normal occlusion chewed gum (right side only) while their jaw movements were recorded at 100 Hz by using an optoelectric jaw tracking system.
  
  
  RESULTS
  Differences in cycle duration between deepbite and control subjects were small and not significant (P >.05). The deepbite subjects showed significantly (P <.05) less maximum inferior excursion (7.7 vs 9.0 mm) and significantly greater maximum posterior excursion (5.1 vs 4.0 mm) than subjects with normal occlusion. In addition, the deepbite subjects had significantly smaller maximum vertical velocities than subjects with normal occlusion (49.2 vs 60.8 mm per second). Deepbite subjects also showed significantly (P <.05) less cycle-to-cycle variability in maximum velocities and excursions to the balancing side but significantly (P <.05) greater variability in cycle duration and maximum posterior excursions.
  
  
  CONCLUSIONS
  A deepbite malocclusion alters the shape of chewing cycles and the consistency of chewing cycle kinematics.
authors.affiliation: Baylor College of Dentistry, Dallas, Tex, USA. phbuschang@bcd.tamhsc.edu
authors.forename: Peter H
authors.initials: PH
authors.lastname: Buschang
authors.forename: Gaylord S
authors.initials: GS
authors.lastname: Throckmorton
authors.forename: Dawn
authors.initials: D
authors.lastname: Austin
authors.forename: Ana M
authors.initials: AM
authors.lastname: Wintergerst
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D002638:Chewing Gum; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007568:Jaw / Q000502:physiology*; D008297:Male; D008310:Malocclusion / Q000503:physiopathology*; D008334:Mandible / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D012737:Sex Factors; D013997:Time Factors
chemical_list: D002638:Chewing Gum