Means and standard deviation of normalized electromyographic amplitude for four recording sites of the superficial masseter muscle during bites at different percentages of maximal voluntary bite force by healthy volunteers (n = 20).

<p>%: percent of maximal voluntary bite force.</p><p>^AStatistically significant difference between the Anterior and Posterior columns (p-value <0.05).</p><p>^BStatistically significant difference between the Anterior and Middle-posterior columns (p-value = 0.001).</p><p>^CStatistically significant difference between the Middle-anterior and Posterior columns (p-value = 0.01).</p><p>Means and standard deviation of normalized electromyographic amplitude for four recording sites of the superficial masseter muscle during bites at different percentages of maximal voluntary bite force by healthy volunteers (n = 20).</p

Masseter muscle electromyographic parameters at different levels of masticatory force.

<p>a) Amplitude in columns: Anterior (A), Middle-Anterior (MA), Middle-Posterior (MP) and Posterior (P). b) Values of entropy. c) Position of the center of mass in X. d) position of the center of mass in Y. The level of masticatory force is expressed as a percentage of MVBF. The differences are indicated by bars with their respective p-values.</p

Study design.

<p>RDCTMD: Research diagnostic criteria for temporomandibular disorders. MVBF: Maximal voluntary bite force. SMVBF: Submaximal voluntary bite force. HDEMGs: High density surface electromyography.</p

Show the matrix of electrodes used and the topographic maps of the amplitude of the EMG activity of the superficial masseter.

<p>(A) Matrix of 24 surface electrodes arranged in four columns: anterior (A), middle-anterior (MA), middle-posterior (MP) and posterior (P) columns. C: cantus, G: gonion. (B) Examples of topographic maps of the amplitude of the EMG activity of the superficial masseter recorded during bites at 20, 40, 60 and 80% of voluntary maximum bite force (VMBF). Maps were constructed in windows of 500 ms and with an interpolation factor of 8. Amplitude values of each map are expressed as a percentage of the maximum value of each one. ○: electrode positions. *: location of center of mass. *: location of center of mass at 20% of VMBF.</p