Does masticatory muscle hyperactivity occur in individuals presenting temporomandibular disorders?|
Rodrigues-Bigaton, Delaine; Berto, Rosemary; de Oliveira, Anamaria Siriani & Bérzin, Fausto
To verify whether patients with temporomandibular disorders
(TMD) present masticatory muscle hyperactivity with the mandible
in the rest position.
Forty-six women were selected (18-33
years-old, mean age = 22.7 ± 3.52 years), 31 with TMD (experimental
group) and 15 without TMD (control group). Electromyography
(EMG) was performed in two situations: 1) with the mandible in the
rest position and 2) in maximal dental clenching. RMS (root mean
square) was used for EMG signal analysis. Data were analyzed
statistically by the Mann Whitney U-test.
groups presented increased EMG activity of the muscles evaluated
with the mandible in the rest position compared to the control. In
maximal dental clenching, no differences were observed between the
groups. Analyzing the percentage of EMG activity at rest, the control
group presented EMG activity around 1 to 6% of maximal dental
clenching and the experimental group, around 1 to 12% of the same
The experimental group presented an increase
in EMG activity at rest in the studied muscles, mainly in the anterior
portion of the temporal muscle, bilaterally. However, this increase
should not be called muscular hyperactivity, but should rather be
considered as an important sign of TMD.
temporomandibular joint dysfunction syndrome, electromyography, masticatory muscles