Relationship between head position and the muscle hardness of the masseter and trapezius muscles: a pilot study.

The purpose of this study was to examine the hardness of the masseter and trapezius muscles at various head positions and to explore the relationship of these two muscles to each other in terms of their respective levels of muscle hardness at different head positions. Twenty-two asymptomatic male subjects participated in this study. Using a hand-held hardness meter, muscle hardness was first measured in a relaxed position as a baseline.

Effect of short-term use of a centric occlusion stabilization oral appliance on sensory and pain perception thresholds in the cervically innervated area: a pilot study.

This preliminary study was done to determine the effect of short-term use of a centric occlusion stabilization oral appliance with regard to noxious and sensory perception in the upper extremities. The subjects consisted of 22 asymptomatic females, and the experiments were performed on two separate days within the same week, with the days randomly assigned as either appliance-wearing or nonappliance-wearing days. For each experimental day, cool sensation, warm sensation, cold-induced pain and heat-induced pain were measured using a computer-based quantitative testing device, and these thresholds were compared between the experimental days with or without the oral appliance.

Changes in sensory and pain perception thresholds after linear polarized near-infrared light radiation in the trigeminal region.

Linearly polarized light in the near-infrared portion of the spectrum has recently been associated with a variety of musculoskeletal disorders including temporomandibular disorders. The purpose of this study was to determine whether short-term linearly polarized near-infrared light radiation in the trigeminal region affects sensory and pain perception thresholds in the trigeminally mediated region and in the cervically mediated region of normal subjects. Thirty-five normal female volunteers participated in this study.

Muscle hardness characteristics of the masseter muscle after repetitive muscle activation: comparison to the biceps brachii muscle.

The purpose of this study was to compare hardness characteristics of the masseter muscle to those of the biceps brachii muscle during repetitive muscle movements. Seventeen asymptomatic female subjects participated in this study. Each subject, on separate days, undertook a 5-minute unilateral chewing gum task on the right side and a 5-minute flexion-extension exercise on the right hand with a 2kg dumbbell.