title: Impact of sleep bruxism on masseter and temporalis muscles and bite force.
abstract: OBJECTIVE
  This study aimed to analyze the impact of sleep bruxism (SB) on electromyography (EMG) activity and the thickness of the masseter and temporal and maximal molar bite force.
  
  
  METHODS
  Ninety individuals, aged between 18 and 45 years, were selected and divided into two groups: Group I (case group, 45 individuals with SB) and Group II (control group, 45 individuals without SB). A diagnosis of SB was made from polysomnography.
  
  
  RESULTS
  The data obtained from EMG and the muscle thickness and the maximal molar bite force were tabulated (SPSS 21.0), normalized, and subjected to statistical analysis (p ≤ 0.05). Comparisons between the groups showed significant differences regarding the habitual chewing of hard food for the left temporalis muscle (p = 0.04) and the chewing of soft food for the right masseter muscle (p = 0.04), but no significant differences for the measurements of muscle thickness and maximal molar bite force.
  
  
  CONCLUSIONS
  The present data suggest that SB negatively altered the masticatory muscles' functions. Based on the results of this research, it can be concluded that individuals with SB showed decreased EMG activity in the masticatory muscles.
authors.affiliation: a Department of Restorative Dentistry, Ribeirão Preto School of Dentistry , University of São Paulo , São Paulo , Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Palinkas
authors.affiliation: a Department of Restorative Dentistry, Ribeirão Preto School of Dentistry , University of São Paulo , São Paulo , Brazil.
authors.forename: César
authors.initials: C
authors.lastname: Bataglion
authors.affiliation: b Department of Dentistry , Federal University of Santa Catarina , Florianopolis , Brazil.|c Department of Dentistry , University of Alberta , Edmonton , Canada.
authors.forename: Graziela
authors.initials: G
authors.lastname: de Luca Canto
authors.affiliation: d Department of Morphology, Physiology and Basic Pathology, Ribeirão Preto School of Dentistry , University of São Paulo , São Paulo , Brazil.
authors.forename: Nicolau
authors.initials: N
authors.lastname: Machado Camolezi
authors.affiliation: d Department of Morphology, Physiology and Basic Pathology, Ribeirão Preto School of Dentistry , University of São Paulo , São Paulo , Brazil.
authors.forename: Guilherme Teixeira
authors.initials: GT
authors.lastname: Theodoro
authors.affiliation: d Department of Morphology, Physiology and Basic Pathology, Ribeirão Preto School of Dentistry , University of São Paulo , São Paulo , Brazil.
authors.forename: Selma
authors.initials: S
authors.lastname: Siéssere
authors.affiliation: d Department of Morphology, Physiology and Basic Pathology, Ribeirão Preto School of Dentistry , University of São Paulo , São Paulo , Brazil.
authors.forename: Marisa
authors.initials: M
authors.lastname: Semprini
authors.affiliation: d Department of Morphology, Physiology and Basic Pathology, Ribeirão Preto School of Dentistry , University of São Paulo , São Paulo , Brazil.
authors.forename: Simone Cecilio Hallak
authors.initials: SC
authors.lastname: Regalo
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001732:Bite Force; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000503:physiopathology*; D008409:Mastication / Q000502:physiology; D008875:Middle Aged; D017286:Polysomnography; D020186:Sleep Bruxism / Q000175:diagnosis* / Q000503:physiopathology*; D013703:Temporal Muscle / Q000503:physiopathology*; D014463:Ultrasonography; D055815:Young Adult
keywords: Bite force; Electromyography; Masticatory muscles; Sleep bruxism; Ultrasonography