title: Influence of malocclusion on the development of masticatory function and mandibular growth.
abstract: OBJECTIVE
  To verify the hypothesis that appropriate acquisition of masticatory function and normal growth of the mandible are modified by malocclusion.
  
  
  METHODS
  Eighteen Jcl:ICR mice were divided into two groups. In one group we shifted the mandible laterally using an occlusal guidance appliance, creating a posterior crossbite at 5 weeks of age. The other group served as control. After 10 weeks, three-dimensional jaw movements and muscle activities were recorded simultaneously during mastication. Microcomputed tomography scans were obtained in vivo to evaluate morphometric changes in the mandible.
  
  
  RESULTS
  (1) The jaw movement pattern in the sagittal plane showed significantly less anteroposterior excursion in the malocclusion group during the late-closing phase (power phase). (2) Electromyography showed significantly less masseter activity in the malocclusion group. (3) The condylar width and mandibular bone mineral density (BMD) were significantly reduced in the malocclusion mice compared to the normal mice.
  
  
  CONCLUSIONS
  These findings suggest that optimization of the chewing pattern and acquisition of appropriate masticatory function is impeded by malocclusion. Altered mechanical loading to the mandible may cause significant reduction of condylar width and mandibular BMD.
authors: Department of Orthodontics and Dentofacial Orthopedics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors: Aya
authors: A
authors: Nakamura
authors: Jorge L
authors: JL
authors: Zeredo
authors: Dai
authors: D
authors: Utsumi
authors: Ayumi
authors: A
authors: Fujishita
authors: Yoshiyuki
authors: Y
authors: Koga
authors: Noriaki
authors: N
authors: Yoshida
mesh_terms: D000818:Animals; D015519:Bone Density / Q000502:physiology; D004576:Electromyography; D008310:Malocclusion / Q000503:physiopathology*; D008334:Mandible / Q000254:growth & development*; D008406:Masseter Muscle / Q000502:physiology*; D008409:Mastication / Q000502:physiology*; D051379:Mice; D008813:Mice, Inbred ICR; D055114:X-Ray Microtomography