Effect of upper thoracic manipulation on mouth opening and electromyographic activity of masticatory muscles in women with temporomandibular disorder: a randomized clinical trial.
OBJECTIVE
The purpose of this study was to assess the effect of upper thoracic manipulation on vertical mouth opening (VMO) and electromyographic activity of the masticatory muscles in women with temporomandibular disorder (TMD).


METHODS
A randomized, controlled, blinded study involving 32 women (mean age of 24.78 ± 5.41 years) diagnosed with TMD was performed. Subjects were randomly allocated to an experimental group (n = 16) or a sham manipulation (placebo) group (n = 16). A single session of manipulation was administered to the T1 vertebral area. Electromyography was used to determine activity of masticatory muscles with the mandible at rest and during isometric contraction. Vertical mouth opening was measured using a ruler. Measurements were made before manipulation, immediately after manipulation, and at the short-term follow-up (2 to 4 days after manipulation).


RESULTS
No significant differences were found in any of the comparisons of mandibular VMO or electromyographic activity of the masticatory muscles at rest or during isometric contraction of mandibular elevator muscles (P > .05). Regarding isometric contraction of the mandibular depressors, an immediate increase in muscle activity was found in the suprahyoid (P = .014) and left masseter (P = .005) muscles.


CONCLUSIONS
In the present study, no significant differences were found regarding VMO between the experimental and placebo groups or among the different evaluations times in each group. Moreover, Cohen d test revealed no clinical effect of the technique. Therefore, based upon the findings of this study, manipulation administered to the T1 vertebral area appears to have no effect on VMO and electromyographic activity of the masticatory muscles in women with TMD.
Master's Student, Laboratory of Therapeutic Resources, Postgraduate Program in Physical Therapy, Methodist University of Piracicaba, Piracicaba, SP, Brazil.
Amanda Carine
AC
Packer
Doctoral Student, Laboratory of Therapeutic Resources, Postgraduate Program in Science of Human Movement, Methodist University of Piracicaba, Piracicaba, SP, Brazil.
Paulo Fernandes
PF
Pires
Doctoral Student, Laboratory of Physiotherapeutic Resources, Postgraduate Program in Rehabilitation and Functional Performance, University of São Paulo, Ribeirão Preto, SP, Brazil. Electronic address: dibaifilho@gmail.com.
Almir Vieira
AV
Dibai-Filho
Professor, Laboratory of Therapeutic Resources, Postgraduate Program in Science of Human Movement, Methodist University of Piracicaba, Piracicaba, SP, Brazil.
Delaine
D
Rodrigues-Bigaton
D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008410:Masticatory Muscles / Q000503:physiopathology*; D009055:Mouth / Q000503:physiopathology*; D026201:Musculoskeletal Manipulations / Q000379:methods*; D009209:Myofascial Pain Syndromes / Q000503:physiopathology / Q000628:therapy*; D016037:Single-Blind Method; D013705:Temporomandibular Joint Disorders / Q000503:physiopathology / Q000628:therapy*; D013904:Thoracic Vertebrae; D055815:Young Adult
Electromyography; Manipulation, Spinal; Muscle, Skeletal; Range of Motion, Articular; Temporomandibular Joint Disorders