Thresholds, Firing Rates, and Order of Recruitment of Anterior Temporalis Muscle Single-Motor Units During Experimental Masseter Muscle Pain.

Aims: To test the hypothesis that, in comparison with control, experimental noxious stimulation of the right masseter muscle would result in significant changes in the firing rates, thresholds, and recruitment orders of single-motor units (SMUs) of the nonpainful, synergistic right anterior temporalis muscle during goal-directed isometric biting task performance.

Methods: Twenty healthy volunteers received an infusion of hypertonic saline (HS; 5% sodium chloride) into the right masseter to produce pain intensity of 40 to 60 on a 100-mm visual analog scale (VAS). Isotonic saline (IS) infusion was a control.

Injectable porcine bone demineralized and digested extracellular matrix-PEGDA hydrogel blend for bone regeneration.

Extracellular matrix (ECM) has a major role in the structural support and cellular processes of organs and tissues. Proteins extracted from the ECM have been used to fabricate different scaffolds for tissue engineering applications. The aims of the present study were to extract, characterize and fabricate a new class of hydrogel with proteins isolated from pig bone ECM and combine them with a synthetic polymer so it could be used to promote bone regeneration.

Reorganization of Masseter and Temporalis Muscle Single Motor Unit Activity During Experimental Masseter Muscle Pain.

Aims: To test the hypothesis that experimental noxious stimulation of the right masseter muscle results in a reorganization of motor unit activity within the right temporalis and right masseter muscles during jaw closing tasks.

Methods: A total of 20 healthy participants received hypertonic saline (5% sodium chloride) infusion into the right masseter muscle, and pain intensity was maintained at 40-60/100 mm on a visual analog scale. Standardized isometric biting tasks were performed with an intraoral force transducer while single motor units (SMUs) were recorded from the right masseter and temporalis muscles.

Experimental noxious stimulation of the right masseter muscle does not affect bilateral masseter and temporalis muscle activity and force parameters during standardised isometric biting tasks.

Aim: To determine if the electromyographic (EMG) activity of the left and right masseter and anterior temporalis muscles is altered by experimental right masseter muscle noxious stimulation during goal-directed isometric biting tasks in asymptomatic humans.

Methods: Isometric biting tasks (slow and fast ramp biting tasks, 2-step biting task) were performed on an intraoral force transducer in 18 participants during the following blocks: baseline block, hypertonic saline infusion into the right masseter muscle (painful block) and isotonic saline infusion into the right masseter (control block). Bipolar surface electrodes recorded EMG activity from the bilateral masseter and anterior temporalis muscles.