Effects of therapeutic exercise on masticatory function in patients with progressive muscular dystrophy.

Abstract

SUMMARY The slope of the curve relating integrated electromyographic activity of masseter muscle to biting force, the latency of the jaw-jerk reflex, and masticatory performance were estimated in patients with Duchenne type of progressive muscular dystrophy before and during therapeutic exercise of the somatognathic system. The slope and latency were slightly decreased, and masticatory performance was increased during exercise. These results suggest that therapeutic exercise of the stomatognathic system is effective in improving masticatory function in patients with progressive muscular dystrophy.Previous electromyographic study' analysing masticatory function in patients with the Duchenne type of progressive muscular dystrophy (PMD) has shown that the slope of the curve relating integrated electromyographic activity of the masseter muscles to biting force during rapid isometric contraction of the jaw (slope of the voltage/tension curve) was steeper in patients with muscular dystrophy than in healthy subjects. It was also shown that the latency of the jaw-jerk reflex was longer and the masticatory performance was considerably less in muscular dystrophy than in a healthy subject. However, there were no differences between those with and without an open-bite, which is characteristic of Duchenne type of muscular dystrophy, for all of the tests. From these findings, the authors suggested that the masticatory disturbance in patients with muscular dystrophy is due more to neuromuscular disturbances in the masticatory system rather than to malocclusion such as an open-bite. It was therefore considered that the masticatory disturbance in muscular dystrophy could not be improved by simply increasing the contact points between upper and lower teeth.Therapeutic exercise has been recommended for

The effects of isometric exercise on maximum voluntary bite forces and jaw muscle strength and endurance

“…Kawazoe et al . (1982) studied the effects of isometric exercise on the masticatory function in patients with progressive muscular dystrophy.…”

Comparison of Experimental Protocols of Physical Exercise for mdx Mice and Duchenne Muscular Dystrophy Patients

“…For masticatory muscles, two studies showed that jaw and tongue training for 24 weeks, accompanied by massage of the masseter muscle, could improve jaw performance and ease of eating [99, 100] (Table 2B). …”

Oral health considerations in muscular dystrophies

“…The indication for orthodontic treatment to improve masticatory function is difficult to determine as progressive development of the dentofacial abnormalities in MD renders prognosis unpredictable. The inability of the masticatory muscles (as well as other skeletal muscles) to relax after voluntary contraction in myotonic dystrophy patients has been reported 49 . Clinically, this will present as a rigid jaw with limitation in opening if the masseter muscle is involved.…”