title: Study of the kinematic variables of unilateral and habitual mastication of healthy individuals.
abstract: OBJECTIVE
  To describe and compare the temporal-spatial kinematic variables of mandibular movement during deliberate unilateral and habitual mastication in healthy young-adult individuals.
  
  
  METHODS
  The study sample was composed of eight male healthy volunteers aged 19 to 24 years. The kinematic data were obtained using a motion analysis system - Qualisys Track Manager (QTM) ProReflex MCU. Recordings were performed during deliberate unilateral mastication (UM) and habitual mastication (HM) of firm-consistency gummy candy. The following variables were analyzed: (1) masticatory sequence: duration, number of masticatory cycles, and chewing rate; (2) masticatory cycle: duration, vertical and medial-lateral mandibular range of motion in relation to the skull, and maximum velocity during the opening and closing phases. Data of the variables were compared during UM and HM by the paired t test, and the effect sizes ('d' Cohen) were calculated.
  
  
  RESULTS
  Regarding the variables of the masticatory sequence, smaller chewing rate was observed for UM compared with that for HM (1.19±0.21Hz and 1.29±0.16Hz, respectively, p=0.004, d=0.53). Smaller values of maximum velocity during the opening (MU=67.4 mm/s and MH=80.02, p=0.053, d=0.80) and closing (MU=71.77±9.35mm/s and MH=3.51±7mm/s, p=0.014, d=0.79) phases of the masticatory cycle were observed in deliberate unilateral mastication compared with those in habitual mastication.
  
  
  CONCLUSIONS
  Kinematic variables associated with the sequence and cycle of mastication are influenced by the chewing pattern adopted - deliberate unilateral or habitual.
authors.affiliation: Universidade Federal de Santa Maria - UFSM - Santa Maria (RS), Brasil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Pasinato
authors.affiliation: Universidade de Brasília - UnB - Brasília (DF), Brasil.
authors.forename: Andréia Gussi de
authors.initials: AG
authors.lastname: Oliveira
authors.affiliation: Universidade de Brasília - UnB - Brasília (DF), Brasil.
authors.forename: Clarissa C
authors.initials: CC
authors.lastname: Santos-Couto-Paz
authors.affiliation: Universidade de Brasília - UnB - Brasília (DF), Brasil.
authors.forename: Jorge Luis Lopes
authors.initials: JL
authors.lastname: Zeredo
authors.affiliation: Universidade Federal de Santa Maria - UFSM - Santa Maria (RS), Brasil.
authors.forename: Geovana de Paula
authors.initials: GP
authors.lastname: Bolzan
authors.affiliation: Universidade de Brasília - UnB - Brasília (DF), Brasil.
authors.forename: Sergio Bruzadelli
authors.initials: SB
authors.lastname: Macedo
authors.affiliation: Universidade Federal de Santa Maria - UFSM - Santa Maria (RS), Brasil.
authors.forename: Eliane C R
authors.initials: EC
authors.lastname: Corrêa
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D008297:Male; D008334:Mandible / Q000502:physiology*; D008409:Mastication / Q000502:physiology*; D008410:Masticatory Muscles / Q000502:physiology; D009068:Movement; D013284:Stomatognathic System / Q000502:physiology*; D055815:Young Adult