title: [A study of mandible chewing movement in patients with developmental lateral jaw deformity].
abstract: OBJECTIVE
  The purpose of the present study was to investigate effects of developmental lateral jaw deformity (DLJD) on masticatory movement.
  
  
  METHODS
  Three coordinates of mandibular movement signals were recorded in 35 young healthy adults with normal occlusion and 28 patients with DLJD by means of a Sirognathography System during gum chewing movement. Paired and unpaired t-tests were used to compare significant difference of intra-group and inter-groups in displacement and speed. P < 0.05 was chosen as significance level.
  
  
  RESULTS
  (1) The rhythm and directional sequence of chewing trajectory in both frontal and sagittal planes were normal in control group, while anomalies of rhythm and distribution (n = 9) and reversed sequencing (n = 7) were found in DLJD group. (2) The maximum magnitude of jaw retrusion and average speed were significant higher in DLJD group than those in control group (P < 0.01). The spatial displacement and average speed in horizontal plane and in chewing phase were also higher in DLJD group compared with control group (P < 0.05).
  
  
  CONCLUSIONS
  DLJD patients showed anomalies in chewing pattern as well as chewing speed and displacement in horizontal plane.
authors.affiliation: Department of Stomatology, General Hospital of PLA, Beijing 100853, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Dong
authors.forename: Tian-wen
authors.initials: TW
authors.lastname: Guo
authors.forename: Hong-chen
authors.initials: HC
authors.lastname: Liu
authors.forename: Xin-mu
authors.initials: XM
authors.lastname: Wang
authors.forename: Mei-qing
authors.initials: MQ
authors.lastname: Wang
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D007569:Jaw Abnormalities / Q000503:physiopathology*; D007574:Jaw Relation Record; D008297:Male; D008334:Mandible / Q000502:physiology*; D008409:Mastication / Q000502:physiology*; D055815:Young Adult