title: Ultrasonographic features of the masseter muscle in female patients with temporomandibular disorder associated with myofascial pain.
abstract: OBJECTIVE
  The purpose of the present study was to examine ultrasonographic appearances in female patients with temporomandibular disorder (TMD) associated with myofascial pain in comparison with healthy volunteers.
  
  
  METHODS
  The thickness of the masseter muscle in 25 female patients with TMD was measured at rest and at maximum contraction using ultrasonography. The visibility and width of the internal echogenic bands of the masseter muscle were also assessed and the muscle appearance was classified as 1 of 3 types: type I, characterized by the clear visibility of the fine bands; type II, thickening and weakened echo-intensity of the bands; type III, disappearance or reduction in number of the bands.
  
  
  RESULTS
  There were significant differences in the thickness at rest and the increase ratio by contraction between the patient and control groups. The distribution of muscle types showed a significant difference between the 2 groups.
  
  
  CONCLUSIONS
  The ultrasonographic features of the masseter muscle in TMD patients with myofascial pain were clarified and they might be related to muscle edema.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Aichi-Gakuin University School of Dentistry, Nagoya, Japan. yoshiko@dpc.aichi-gakuin.ac.jp
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Ariji
authors.forename: Shigemitsu
authors.initials: S
authors.lastname: Sakuma
authors.forename: Masahiro
authors.initials: M
authors.lastname: Izumi
authors.forename: Jun
authors.initials: J
authors.lastname: Sasaki
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kurita
authors.forename: Nobumi
authors.initials: N
authors.lastname: Ogi
authors.forename: Minori
authors.initials: M
authors.lastname: Nojiri
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Takenaka
authors.forename: Seiji
authors.initials: S
authors.lastname: Katsuse
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Ariji
mesh_terms: D000293:Adolescent; D000328:Adult; D001732:Bite Force; D016022:Case-Control Studies; D004487:Edema; D004576:Electromyography; D005260:Female; D006801:Humans; D008406:Masseter Muscle / Q000000981:diagnostic imaging*; D015588:Observer Variation; D018709:Statistics, Nonparametric; D013706:Temporomandibular Joint Dysfunction Syndrome / Q000000981:diagnostic imaging*; D014463:Ultrasonography