Masseter Muscle In Patients Research Articles

A clinical and electromyographic study of the long‐term effects of an occlusal splint on the temporal and masseter muscles in patients with functional disorders and nocturnal bruxism

The postural activity of the temporal and masseter muscles in thirty-one patients with signs and symptoms of functional disorders were studied: before, during and after 3-6 months of occlusal splint therapy. The fluctuating signs and symptoms, as well as the postural activity of the temporal and masseter muscles were significantly reduced after treatment. Further, the coefficients of correlation within pairs of postural activity of the right and left muscles increased significantly. After cessation of the splint therapy the signs and symptoms recurred to the pre-treatment level within 1-4 weeks in about 80% of the patients. The results indicate that an occlusal splint can eliminate or diminish signs and symptoms of functional disorders and re-establish symmetric and reduced postural activity in the temporal and masseter muscles, which can facilitate procedures, such as functional analysis and occlusal adjustment.

Influence of vertical dimension on masseter muscle electromyographic activity in patients with mandibular dysfunction

Occlusal splints were adjusted to different vertical heights and used to single out the influence of vertical dimension of occlusion in increments on BT-EMG activity of the masseter muscle in patients with mandibular dysfunction. The vertical dimension of least EMG activity was determined for each of 60 patients, who were randomly divided into three groups according to the vertical dimension at which the occlusal splint was adjusted: group No. 1, 1 mm from occlusal vertical dimension; group No. 2, mean vertical dimension, 4.25 mm; group No. 3, mean vertical dimension, 8.25 mm. Results showed a significant reduction of masseter BT-EMG activity (series A and B) at the end of the 3-week treatment period for patients in group Nos. 2 and 3 in comparison with group No. 1. Furthermore, the short-term use of occlusal splints with a vertical height that exceeded the so-called physiologic interocclusal distance did not result in an increase in masseter BT-EMG activity. This study suggests that an increase of vertical dimension of occlusion to or near the vertical dimension of least EMG activity by means of occlusal splints can be an effective way to obtain a reduction in masseteric muscle activity.

Histochemical study of the masseter muscle in patients with vertical maxillary excess

This study was designed to examine the morphologic properties of the masseter muscle in individuals with vertical maxillary excess (VME). The deep surface of the anterior aspect of the superficial masseter was biopsied in nine patients at the time of corrective surgery. Individual muscle fibers were classified as slow-twitch-oxidative (SO), fast-twitch-oxidative-glycolytic (FOG), or fast-twitch-glycolytic (FG) based on staining characteristics using a battery of histochemical procedures. Most patients had normal tissue, although there were considerable differences in size and distribution of the three fiber types. Generally, SO fibers were the largest and most prevalent type of fiber. Two individuals, however, demonstrated evidence of muscle pathology that primarily affected the FG fiber population. Histochemical evidence of muscle pathology has not previously been reported in patients with VME, and the pattern of SO dominance observed in these patients may be different from the distribution that would be seen in the masseter of a person free of craniofacial deformities.

Electromyographic study on masseter muscle in patients with progressive muscle dystrophy

Electromyographic study on masseter muscle in patients with progressive muscle dystrophy

The silent period in the masseter muscle of patients with TMJ dysfunction

The silent period (SP) following a jaw jerk elicited during sustained contraction in the masseter muscles has been studied in two groups of subjects, one with and one without, acute and distinct symptoms of TMJ dysfunction. The subjects with acute TMJ dysfunction symptoms showed significantly shorter latency and longer duration of the silent period and the period of their depressed activity (DA) was also significantly longer than in the group without TMJ dysfunction. The duration of the SP of both muscles was symmetrical in about 60% of subjects in each group. This study validates that the duration of the silent period may be a useful diagnostic tool of clinical interest.

Anatomical considerations on monosynaptic reflex arcs.

Anatomical considerations on monosynaptic reflex arcs.