title: Reliability of masticatory efficiency with beads and correlation with the muscle activity.
abstract: BACKGROUND
  the use of the colorimetric method with beads to evaluate mastigatory efficiency may be promising, however no report is found about its reliability.
  
  
  OBJECTIVE
  to investigate the reliability of the beads to test masticatory efficiency and its correlation with the electromyographic activities of the anterior temporal and masseter muscles.
  
  
  METHODS
  participants of this study were nineteen young adults, nine males and ten females, aged eighteen to twenty-eight years, with full dentition, Angle class I, with no history of temporomandibular disorder, neurological or cognitive deficit, previous or current tumors or traumas in the head and neck region, and orthodontic treatment or orofacial myofunctional therapy. The masticatory efficiency test was performed using beads, fuchsine-containing granules, in the following conditions: habitual chewing, right and left unilateral chewing, for 20 seconds. Electromyographic recordings were obtained simultaneously. Also, the maximal clenching was registered. The amount of fuchsin released upon chewing was measured using a Beckman DU-7 UV-Visible Spectrophotometer (Beckman Inc., Palo Alto, CA, USA).
  
  
  RESULTS
  high reliability was observed for the masticatory efficiency test (r = 0.86, p < 0.01) and correlation with the electromyographic activities (r = 0.76, p < 0.01). Also, positive and significant correlations were observed when the conditions were separately analyzed.
  
  
  CONCLUSIONS
  the masticatory efficiency test performed with beads proved to be a reliable method and positively correlated to the electromyographic activities of the anterior temporal and masseter muscles.
authors.affiliation: Departamento de Oftalmologia, Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo. cfelicio@fmrp.usp.br
authors.forename: Cláudia Maria de
authors.initials: CM
authors.lastname: Felício
authors.forename: Gisele Aparecida do
authors.initials: GA
authors.lastname: Couto
authors.forename: Cláudia Lúcia Pimenta
authors.initials: CL
authors.lastname: Ferreira
authors.forename: Wilson
authors.initials: W
authors.lastname: Mestriner Junior
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D008410:Masticatory Muscles / Q000502:physiology*; D015203:Reproducibility of Results; D013703:Temporal Muscle / Q000502:physiology; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis; D055815:Young Adult