title: Effect of experimental chewing on masticatory muscle pain onset.
abstract: OBJECTIVE
  To evaluate the effect of a chewing exercise on pain intensity and pressure-pain threshold in patients with myofascial pain.
  
  
  METHODS
  Twenty-nine consecutive women diagnosed with myofascial pain (MFP) according to the Research Diagnostic Criteria comprised the experimental group and 15 healthy age-matched female were used as controls. Subjects were asked to chew a gum stick for 9 min and to stay at rest for another 9 min afterwards. Pain intensity was rated on a visual analog scale (VAS) every 3 min. At 0, 9 and 18 min, the pressure-pain threshold (PPT) was measured bilaterally on the masseter and the anterior, medium, and posterior temporalis muscles.
  
  
  RESULTS
  Patients with myofascial pain reported increase (76%) and no change (24%) on the pain intensity measured with the VAS. A reduction of the PPT at all muscular sites after the exercise and a non-significant recovery after rest were also observed.
  
  
  CONCLUSIONS
  The following conclusions can be drawn: 1. there are at least two subtypes of patients with myofascial pain that respond differently to experimental chewing; 2. the chewing protocol had an adequate discriminative ability in distinguishing patients with myofascial pain from healthy controls.
authors: Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. pcconti@fob.usp.br
authors: Paulo César Rodrigues
authors: PC
authors: Conti
authors: Rafael dos Santos
authors: Rdos S
authors: Silva
authors: Carlos dos Reis Pereira de
authors: Cdos R
authors: Araujo
authors: Leylha Maria N
authors: LM
authors: Rosseti
authors: Shigueharu
authors: S
authors: Yassuda
authors: Renato Oliveira Ferreira
authors: RO
authors: da Silva
authors: Luiz Fernando
authors: LF
authors: Pegoraro
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D005157:Facial Pain / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008409:Mastication / Q000502:physiology*; D008410:Masticatory Muscles / Q000503:physiopathology*; D008875:Middle Aged; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D010173:Palpation; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult