title: Relationship between occlusal force distribution and the activity of masseter and anterior temporalis muscles in asymptomatic young adults.
abstract: Healthy subjects have a prevalent side on which they display higher-muscle activity during clenching. The relationship between symmetry of masseter muscle (MM) and anterior temporalis (TA) muscle activities and occlusion has been evaluated on the basis of physiological parameters. The aim of the present study was to investigate whether the symmetry of surface EMG (sEMG) activity in asymptomatic young adults is related to symmetry of occlusal contacts.
  
  
  METHODS
  The study population consisted of seventy-two 18-year-old subjects with no temporomandibular disorder (TMD) symptoms.
  
  
  METHODS
  All the participants underwent an sEMG recording with an 8-channel electromyograph (BioEMG III). A T-Scan III evolution 7.01 device was used to analyze the occlusal contact points.
  
  
  RESULTS
  The correlation between the activity of right (R) and left (L) TA and the percentage of occlusal contacts was assessed, but no significant differences were found between the RMM and LMM muscles. The differences in the medium values of sEMG between males and females were not statistically significant. Equilibrated muscular activity between RTA and LTA occurred when occlusal contacts reached the percentage of 65% on the left side.
  
  
  CONCLUSIONS
  The symmetry of sEMG activity in asymptomatic young adults is not related to symmetry of occlusal contacts.
authors.affiliation: Department of Dental Prosthetics, Institute of Dentistry, Jagiellonian University, 31-155 Kraków, Poland. aneta.wieczorek@uj.edu.pl
authors.forename: Aneta
authors.initials: A
authors.lastname: Wieczorek
authors.forename: Jolanta
authors.initials: J
authors.lastname: Loster
authors.forename: Bartlomiej W
authors.initials: BW
authors.lastname: Loster
mesh_terms: D000293:Adolescent; D001732:Bite Force; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D012737:Sex Factors; D013703:Temporal Muscle / Q000502:physiology*