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PubMedDate not supplied

Effect of conventional TENS on pain and electromyographic activity of masticatory muscles in TMD patients.

Temporomandibular disorders (TMD) are characterized by several signs and symptoms, such as pain and changes in the electrical activity of masticatory muscles. Considering that transcutaneous electrical nerve stimulation (TENS) is a resource indicated to promote analgesia, the objective of this study was to evaluate the effect of TENS on pain and electromyographic (EMG) activity of the jaw elevator muscles in TMD patients. This study evaluated 35 female volunteers: 19 TMD patients (mean age = 23.04 +/- 3.5) and 16 normal subjects (mean age = 23.3 +/- 3.0). Transcutaneous electrical nerve stimulation (conventional mode, 150 Hz) was applied once to each group for 45 minutes. Surface electromyography (gain of 100 times and 1 kHz sampling frequency) and the visual analogue scale (VAS) were applied before and immediately after TENS application. Both VAS data and root mean square (RMS) values were analyzed using Student's t-test. The TMD group, compared to the control group, showed higher EMG activity of the jaw elevator muscles at rest. No difference was observed between the groups regarding maximum voluntary clenching (MVC). In TMD patients, TENS reduced both pain and EMG activity of the anterior portion of the temporal muscle, increasing the activity of the masseter muscles during MVC. It is possible to conclude that a single TENS application is effective in pain reduction. However, it does not act homogeneously on the features of the electric activity of the muscles evaluated.

Adult↗
PubMed1995

Distribution of the macromolecular components of masticatory muscles during differentiation of the muscle fibers in the postnatal rat.

The distribution of collagen fibers of rat masticatory muscles during the postnatal period (two weeks), was investigated by electrophoresis and immunohistochemistry. At these stages, the myosin of rat masticatory muscles displays specific electrophoretic patterns. Comparison of the myosin patterns of these muscles allows their identification. 1) Analysis by SDS-PAGE indicated that one of three weakly reactive stainable proteins with lower mobility than the heavy chain of myosin disappeared from the temporal muscle on day 13, as compared with other masticatory muscles. However, in histochemical analysis of the muscle fibers, the reaction specific for succinic dehydrogenase (SDH) activity was strong, and the fibers on day 13 could be classified into two types with respect to SDH activity. By contrast, on day 0, the fibers were classified into two types with respect to myosin ATPase activity. 2) Immunohistochemical analysis indicated that the distribution of the components of the extracellular matrix in the epimysium (type I collagen), perimysium (type I collagen, fibronectin, and laminin) and endomysium (type III collagen, fibronectin, laminin, and tenascin) was related to the metabolic capacity on days 12 to 13. The variability in the types of myosin and in proteins of the extracellular matrix might be important during the development of rat masticatory muscles.

Animals↗
PubMed1979

[Blood flow in skeletal muscle microvessels in normoxia and arterial hypoxemia (microcinematographic studies)].

Vital microfilming revealed peculiarities of blood flow in microvessels of 2-5-micron diameter under relatively resting conditions, in normoxia, as well as the microcirculatory response to hypoxia (breathing with mixture of nitrogen and 6-8% oxygen for 5 min), in intact temporal muscle of rat. The average blood flow velocity in normoxia was 1.14 +/- 0.04 mm/sec in capillaries and 2.43 +/- 0.08 mm/sec in terminal arterioles. Breathing with the hypoxic mixture decelerated blood flow in 75% of the vessels. The blood low velocity in the muscle capillaries correlated with arterial blood pressure.

Animals↗
PubMedDate not supplied

Effect of botulinum toxin A injections in the treatment of chronic tension-type headache: a double-blind, placebo-controlled trial.

In addition to vascular and supraspinal influences, contraction of craniofacial muscles or central sensitization processes following continuous nociceptive input of craniofacial muscles may play an important role in the pathogenesis of tension-type headache. Chemodenervation induced by botulinum toxin injection is successfully used to decrease muscle tension. If muscle tension is important in this type of headache, then botulinum toxin could be helpful in its treatment. We conducted a randomized, placebo-controlled study to examine the effect of 20 U botulinum toxin injected into frontal and temporal muscles in patients with chronic tension-type headache. During a baseline of 4 weeks and a posttreatment period of 8 weeks, the effect was evaluated with daily records and the West Haven-Yale Multidimensional Pain Inventory. Some improvement in affective variables were demonstrated in the botulinum group, but important outcome variables, such as pain intensity, the number of pain-free days, and consumption of analgesics, were not statistically different between the groups. Reasons for these moderate effects may include the injection sites, dose of botulinum toxin, and duration of treatment.

Adult↗
PubMed1987

Evidence that periodontal pressoreceptors provide positive feedback to jaw closing muscles during mastication.

1. Mastication was produced by stimulation of the right motor-sensory cortex of urethan-anesthetized rabbits with 15-s trains of shocks (1-ms duration) at 50 Hz. Movements of the lower jaw and jaw muscle electromyograms (EMGs) were recorded on magnetic tape for later computer analysis. 2. The stimulus site was chosen, and stimulus intensity adjusted, so that stereotyped movements were produced that included a wide swing of the mandible to the left side during jaw closure. 3. Control trials were alternated with trials in which a steel ball (2 mm diam) was thrust between the anterior molar teeth on the left side and left in place for several seconds. 4. When the obstruction was first introduced, a jaw opening reflex was sometimes evoked if the ball struck the buccal surface of the advancing mandibular molar teeth. Thereafter, when the ball was crushed between the occlusal surfaces of the teeth, no jaw opening reflex was seen. 5. Instead, the amplitude and duration of all the jaw closing EMGs increased, beginning at least 12 ms after contact with the ball. This caused a prolongation of the slow closing (SC) phase of the cycle that, coupled with a delay in the start of activity in the digastric muscle (jaw opener), prolonged the cycle by more than 60 ms. 6. During the SC phase of the obstructed trials, the medially directed grinding stroke was exaggerated because of an increase in the contraction of the contralateral zygomaticomandibular and anterior temporal muscles. 7. After collecting data, the sensory nerves to the maxillary and mandibular anterior molar teeth were cut to eliminate feedback from the periodontal pressoreceptors. Control and obstructed trials were repeated. 8. Following denervation, the obstructed cycles were of shorter duration. The mandible still moved to the right during SC in some animals, but the increase in closer muscle EMG activity was much reduced. 9. We conclude that periodontal receptors provide positive feedback to the jaw closing muscles during mastication. This is supplemented by input from other receptors, probably muscle spindles. In addition, an increase in periodontal feedback prolongs the SC phase and the early phases of the opening stroke.

Animals↗
PubMed1979

Motor nuclear representation of masticatory muscles in the rat.

Representation of the masticatory muscles within the motor trigeminal nucleus was studied in rats by the horseradish peroxidase (HRP) method and the antidromic field potential method. The motor trigeminal nucleus of the rat could be divided cytoarchitecturally into a dorsolateral and a ventromedial division. Within the dorsolateral division, the temporal muscle was represented dorsomedially, the masseter muscle dorsolaterally and laterally, and the lateral and medial pterygoid muscles ventrolaterally. Within the ventromedial division, the anterior digastric muscle was represented dorsomedially and the mylohyoid muscle ventrolaterally. Distribution of antidromic field potentials evoked by stimulation of the mylohyoid and masseteric nerves coincided with the results from the HRP investigation.

Animals↗
PubMedDate not supplied

The influence of dental status on masticatory muscle activity in elderly patients.

PURPOSE: The objective of this study was to determine whether elevator and depressor muscle activity during 5 minutes of mastication is affected by the presence of a prosthetic appliance in elderly patients. MATERIALS AND METHODS: Thirty edentulous subjects (EG) and 30 age-matched dentate subjects (DG) were studied. Surface electromyographic (EMG) recordings were obtained from the anterior temporal muscle, masseter muscle, and the submandibular group in the region of the anterior belly of the digastric muscle on the left and right sides. Muscle activity was recorded during maximal voluntary contraction (MVC) in the intercuspal position, maximal opening (Omax), and during 5 minutes of mastication. Elevator muscle activity during mastication was expressed as a percentage of maximal muscle activity in the intercuspal position (%MVC), and depressor muscle activity was expressed as a percentage of maximal opening (%Omax). The effect of 3 factors was investigated using a mixed analysis of variance design: the factor of muscle, with 6 muscles involved; the factor of time (5 minutes of mastication); and the factor of dental status, where some participants had their own natural dentition and others had complete dentures. RESULTS: The results revealed significant effects for the factors "muscle" and e" (P < .001 for the factor "muscle"; P < .001 for the factor "time"). The time by group interaction was significant (P = .046). In the EG, muscle activity gradually decreased during the 5-minute interval of mastication, while in the DG it decreased more rapidly from the first to the third minute and then increased until the fifth minute. There was also a significant effect regarding the presence of natural teeth or complete dentures (P < .034). Complete denture wearers had higher muscle activity relative to %MVC or %Omax than dentate subjects. CONCLUSIONS: Muscle activity during 5 minutes of mastication depended greatly on the presence of the prosthetic appliance, since edentulous subjects had to use higher potentials of muscle activity (%MVC or %Omax) than age-matched dentate subjects, and were unable to increase activity at the end of mastication. The difference in chewing patterns and activity between complete denture wearers and dentate subjects should be explained to patients prior to prosthetic treatment to help them adjust their expectations.

Aged↗
PubMed2000

Abnormal muscle activation characteristics associated with loss of dexterity after stroke.

The aim of this study was to characterise the abnormalities of muscle activation which underlie low dexterity after stroke. A broad definition of dexterity was adopted, where loss of dexterity refers to an inability to coordinate muscle activity in the performance of a motor task (i.e. dexterity was not confined to manual dexterity). EMG of biceps brachii and triceps brachii were monitored from 16 people after stroke and 10 neurologically normal controls as they performed a tracking task requiring coordinated elbow flexion and extension. Weakness could not interfere with performance since the task was designed to require minimal strength. Stroke subjects were assigned to a low (n=10) or high (n=6) dexterity group based on their performance. Spatiotemporal aspects of biceps and triceps EMG were analysed. Low dexterity performance after stroke was characterised by excessive biceps muscle activation (P=0.002) and decreased coupling of muscle activation to target motion (P=0.002). In this study, we could rule out weakness, slowness of muscle activation, excessive co-contraction and spasticity as causes of these abnormalities. Therefore, the loss of dexterity after stroke can be seen as a specific negative impairment which can exist independently of other motor impairments and reflects a loss of skill in generating spatial and temporal muscle activation patterns which conform with environmental demands.

Aged↗
PubMed2002

[Role of recombinant human bone morphogenetic protein 2/collagen as an onlay bone graft on adult rat calvarial bone].

OBJECTIVE: To evaluate the bone regenerative potential of recombinant human bone morphogenetic protein 2(rhBMP-2)/collagen on adult rat calvarial bone. METHODS: A tight subperiosteal pocket was produced under both sides of the temporal muscle in rats. rhBMP-2/collagen was implanted in one side and collagen alone was implanted in the other side as control. The rats were sacrificed 2, 4 and 8 weeks after operation. The specimen was harvested and examined histologically. For morphometric analysis, the thickness of the temporal bone of both sides was measured and compared. RESULTS: The rhBMP-2/collagen onlay implant resulted in active bone formation and the augmented bone was connected directly with the original bone, whereas the collagen alone resulted in neither bone nor cartilage production. The ossification process in the rhBMP-2/collagen occurred directly through bone formation, similar to intramembranous ossification. CONCLUSION: rhBMP-2/collagen is an effective material as a biological onlay implant.

Animals↗
PubMed1994

Evaluation of the reproducibility of rest activity of the anterior temporal and masseter muscles in asymptomatic and symptomatic temporomandibular subjects.

There is a general assumption that temporomandibular disorders and the pain and tenderness of mastication muscles may be caused by hyperactivity. Five asymptomatic men, five asymptomatic women, and five women with temporomandibular disorders participated in this study. Multiple examinations were performed to provide information concerning the reproducibility of the rest electromyographic signals. No significant differences between groups were noted. This study supports the contention that the mean rest activity in women with pain and dysfunction is less than or equal to that of sex-matched controls.

Adult↗
PubMed1999

Gait analysis following varus osteotomy of the femur for hip osteoarthritis.

The purpose of this study was to evaluate differences in the gait patterns of healthy and osteoarthritic hips, and changes in these patterns after intertrochanteric varus osteotomy of the femur, in relation to the strength of the muscles around the hip joint. We measured the strength ratio of hip abductor muscles, temporal and distance factors, and pelvic movement, and carried out dynamic electromyography (EMG) in 24 women who underwent unilateral varus osteotomy of the femur for hip osteoarthritis (OA), 30 non-surgically-treated women with hip OA, and 54 healthy women. The stance phase time was shorter and the strength ratio of hip abductor muscles was lower in the operated patients than these values in the other two groups, changes in pelvic obliquity and tilt were smaller, and changes in the percent maximum voluntary contraction of the gluteus medius and tensor fascia latae muscles were greater than these values in the healthy subjects. This study showed the postoperative reappearance of the simulated conditions in the hip before varus osteotomy of the femur, providing evidence that the pelvis was horizontally maintained during walking due to the decreased stance phase time and increased performance of the hip abductor muscles achieved after this procedure.

Adult↗
PubMedDate not supplied

[Oto-vestibular symptoms in patients with temporomandibular joint dysfunction. Electromyographic study].

The authors analyse the otovestibular symptoms (acoupheny, muffled hearing, vertigo, hypoacusia, otalgia) present among other symptoms of craniomandibular dysfunctions. A number of hypotheses have been advanced regarding the etiopathogenesis of these symptoms, but all stem from three theories. The first theory is based on the possibility of a mechanical transmission of force from the temporomandibular joint to the middle ear by the discomalleolar ligament. Another theory hypothesises the possible direct irritation by the condyl on the auriculotemporal nerve. The most widely credited etiopathogenetic theory, which is examined in this study, is that the hypertone of the tensor muscle of the tympanum and the tensor muscle of the velum palatinum, which are innervated like the masticatory muscles of the mandibular branch of the trigeminal nerve is the effect of these same muscles' hypertone. A group of 53 adult patients was selected to verify this theory. All patients were receiving treatment for dysfunctions of the temporomandibular articulation. Initial data were collected relating to the prevalence of each of the otovestibular symptoms studied; each patient then underwent computerised electromyographic analysis while the right and lefthand masseter and temporal muscles were resting. All tests were performed by the same operator. When analysing the results, patients were divided into two groups: one group contained those patients who had no symptoms relating to the ear, and the other contained patients with at least one symptom relating to the ear. Moreover, the group of symptomatic patients was divided into subgroups of patients with 1, 2, 3, and 4 of the symptoms studied. The mean electromyographical values for each muscle examined were then compared. The following results were obtained: 67.9% of subjects examined presented at least one otovestibular symptom; the symptom that was most frequently found was the feeling of muffled hearing (41.5%), followed by otalgia and vertigo; the prevalence of otalgia was much lower (7.5%). The most interesting finding emerged from a comparison between electromyographical values in patients suffering from otovestibular symptoms and the asymptomatic group. There was no significant difference in this series between this two groups, and the mean electromyographical value was higher in the group of asymptomatic patients.

Adult↗
PubMed1989

[Electromyographic study of masticatory muscle fatigue and recovery under voluntary contraction. 1. Comparison of spectrum parameters for the power spectral shift].

The aim of this paper was to determine the best parameter for describing the muscle fatiguing process. Three parameters of mean power frequency (MPF), median frequency (MF), and peak frequency (PF) were tested with healthy subjects. During 10 sessions at more than one week intervals, the subjects performed the same endurance test with clenching at 80% of maximal electromyographic activity. Changes in the surface electromyogram of the bilateral masseter and temporal muscles were obtained in the above three parameters. From the comparison between the three parameters, PF showed the largest scattering, and MPF indicated a clear difference calculated from the values before and after fatigue. Thus it is concluded that MPF may be the best parameter.

Electromyography↗
PubMed1995

Multiple skeletal muscle metastases from malignant pleural mesothelioma.

A 54-year-old male patient (occupational asbestos exposure over 27 years) died 2 years and 4 months after the diagnosis of malignant pleural mesothelioma of the right side, despite twice undergoing pleurectomy and radiotherapy. The autopsy revealed a locally advanced pleural mesothelioma of both sides involving the pericardium, heart, right diaphragm, liver and peritoneum. Disseminated metastases in numerous lymph nodes and a hematogenous metastatic spread into both lungs, the thyroid gland, peritoneum and skeletal musculature were found. The left temporal muscle and proximal limb skeletal muscles of the right upper arm and both thighs exhibited multiple metastases measuring up to 7 cm in diameter. Microscopically, a biphasic type of mesothelioma was detected. To our knowledge this is the first extensive case report on muscle metastases in malignant mesothelioma. Reviewing the literature, it is thought that in the presented case the long survival time of the patient and his protracted preterminal immobility could have contributed to the unusual formation of multiple skeletal muscle metastases.

Asbestos↗
PubMed2000

Application of artificial dermis graft to correct a depression after tissue resection.

The authors present 7 cases of artificial dermis implantation to correct a depression after tissue resection. Four of the seven cases resulted from resection of a malignant tumor (N = 3) and from a benign subcutaneous tumor (N = 1). The other 3 cases were the result of temporal muscle harvest to reconstruct facial palsy. In 1 patient a mild degree of bone deformity also existed. The pieces of artificial dermis employed varied from 35 x 40 to 40 x 80 mm in size. In 5 patients two sheets were implanted, and in 2 patients three sheets were implanted. In 2 patients the dermis sheets were covered by a pedicled temporal fascial flap with a free split-thickness skin graft because whole skin was resected as a result of a malignant skin tumor. There was no postoperative infection or allergic reaction in any of the patients. In all cases there was no postoperative contracture, and the implanted area was soft. An adequate or acceptable thickness of subcutaneous tissue was obtained. Artificial dermis may be a useful option as implantation material to correct a depression after tissue resection, especially for wide and comparatively shallow depressions.

Aged↗
PubMed2005

Temporal bone chondroblastoma: a review.

The objective of this paper was to review temporal bone chondroblastomas in regard to their presentation, radiographic findings, histopathology, and treatment. A case report of a 38-year-old man who presented with the left-sided hearing impairment and temporal swelling was reviewed. A CT scan revealed an osteolytic lobulated expansile mass. MRI depicted two cystic components with fluid-fluid level and enhanced solid mass. Immunohistochemical study of S-100 was performed using avidinbiotin-complex method. The tumor was totally removed, with eroded squamous bone and temporal muscle, via the left zygomatic-extended middle fossa approach. The pathology of the tumor showed that the tumor cell was spindle-shaped, along with multinucleated giant cells. These cells had oval to polygonal nuclei; some cells showed grooved nuclei. Intercelluar calcification and hemorrhagic components were also observed in the tumor. Tumor cells were strongly positive for S-100 protein. Temporal bone chondroblastomas are extremely rare osseous tumors with only 45 cases previously reported in the published literature. They may be confused with more common lesions seen in the temporal bone. Diagnostic radiology, including CT and/or MRI, as well as immunohistochemical staining with S-100 protein, may assist in making the diagnosis. Treatment is complete surgical excision with preservation of vital neurovascular structures.

Adult↗
PubMed1995

[Neurilemmoma of intra-temporal facial nerve:case report].

A case of facial nerve neurilemmoma within the temporal bone is reported. The patient is a 47-year-old female complaining of 10 years' history of left facial palsy. CT and MRI examinations showed an enlarged mass of the tympanic cavity protruding into the petrous bone, mastoid cavity and external auditory meatus. An open biopsy of the tumor at the external auditory meatus revealed neurilemmoma. The tumor was totally removed by a retroauricular approach. Five months after surgery, both the cross nerve graft using the peroneal nerve and the temporal muscle transfer, method modified by Johnson were performed for the functional recovery of facial palsy.

Cranial Nerve Neoplasms↗
PubMed1992

A comparison of jaw muscle cross-sections of long-face and normal adults.

Long-face subjects have smaller maximum molar bite forces than do normal individuals. This has been attributed both to differences in moment arms and size of the jaw muscles. In this study, a comparison was made between the mid-belly cross-sectional areas of the jaw muscles of 13 long-face and 35 normal adults by means of serial MRI scans. The subjects were selected on the basis of anterior lower face height as a percentage of anterior total face height. These and other cephalometric variables were measured from lateral radiographs. In the long-face group, the cross-sectional areas of the masseter, medial pterygoid, and anterior temporal muscles were, respectively, 30%, 22%, and 15% smaller than in the control group. By a discriminant analysis and a multivariate analysis of variance, these differences were found to be significant (p less than 0.001). The findings of this study hint that differences in the sizes of the jaw muscles of long-face and normal subjects might explain, in part, the observed differences in maximum molar bite force.

Adult↗