Electromyographic (EMG) activity versus bite force was studied during a gradually increased isometric contraction up to maximal effort for patients with painful masseter muscles and referents. The masseter muscle, the anterior temporal muscle and the descending part of the trapezius muscle were chosen for the recordings. Bite force was registered with a bite force sensor placed between the firs...

The myotonic response of the masseter muscles following various doses of suxamethonium was measured using a unique myotonometer in 50 apparently healthy patients, the majority of whom showed a myotonic response which lasted less than 100 s. A maximum increase in masseter tone was found to be greater than 1 kg in five patients, and 12 patients developed a maximum tone of greater than 500 g. An i...

Masseter muscle hypertrophy is a rare condition characterized by unilateral or bilateral enlargement of the masseter muscle affecting both males and females following puberty. It usually manifests in late adolescence or early adulthood. Its etiology remains unknown. Masseter muscle hypertrophy produces facial asymmetry and familiarity with this condition is important to rule out other pathologi...

Jaw reflexes and masseter electromyograms were studied in five patients with mesencephalic and 11 patients with pontine lesions, vascular or tumorous in nature. In the former group jaw reflexes were abnormal, being delayed or absent, whereas masseter electromyograms were normal. In the latter group, both jaw reflexes and masseter EMG, showing denervation, were abnormal in six and both normal in...

The aim of this study was to investigate how the thickness of the masseter muscle relates to the maxillofacial morphology, including the thickness of alveolar process in the mandibular incisor region, and the thickness of the mandibular symphysis. The subjects consisted of 80 adult male volunteers (mean age: 23 years 8 months). The relationship between masseter muscle thickness and the maxillof...

Although disorders of the stomatognathic system are common, the mechanisms involved are unknown. Our objective was to study the changes in the masseter muscles after unilateral exodontia. Molar extraction was performed on Wistar rats (left side), and the animals were sacrificed after either 14 or 26 days. The masseter muscle was processed for histological analysis, conventional and in situ zymo...

OBJECTIVES To report a case and discuss the mechanism of hemimasticatory spasm. DESIGN Case report. PATIENT A 37-year-old woman had a 3-year history of involuntary spasms of the right masseter muscle in association with localized scleroderma and facial hemiatrophy. Electrophysiological studies revealed a normal blink reflex. However, the masseter reflex and silent period were absent on the ...

In this study, botulinum neurotoxin type A (BoTx/A) was injected into the temporalis and masseter muscles of growing rats to induce masticatory hypoactivity. Sixty, 30-day-old, male Long-Evans rats were randomly divided into four groups. BoTx/A was bilaterally injected in the masseter muscles in group I, in the temporalis muscles in group II, and into both the masseter and the temporalis muscle...

Background: To increase the effectiveness of orthodontic treatment in children with various degrees of dental enamel caries resistance using a personified orthodontic treatment. Materials and Methods: The present study included 108 adults (6-16 years old) with the first class of occlusion who referred for the Department of Pediatric Dent...