Chronic, progressive limitation of mouth opening.
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Calcinosis↗
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Results for “Temporal Muscle”
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Traumatic myositis ossificans in masticatory muscles.
3 cases of traumatic myositis ossificans circumscripta, located within the masticatory muscles are presented. Two of the lesions involved the masseter muscle, and exceptionally, 1 involved the temporalis muscle. Three pathognomonic histological zones, permitting the differential diagnosis of myositis ossificans from sarcomatous lesions, are described, and treatment incorporating ideally early surgical intervention with wide excisional biopsy of the lesion is stressed.
Adolescent↗
Midface soft tissue reconstruction with the facio-cervico-pectoral flap.
The reconstruction of large soft tissue defects in the orbital and maxillomalar region is a difficult task. A good functional and aesthetic result has to be achieved. The cervicopectoral rotation flap has many advantages; it is easy, rapid and safe to harvest, compatible with cervical dissection and radiotherapy. It is an anatomical unit, with skin properties similar to the rest of the facial skin. This is our pedicle flap of choice for large soft tissue defects in the midface, specially in elderly patients. We use it in association with the temporalis myofascial flap in cases of orbital exenteration. In large defects, the alternatives to these flaps are microsurgical free flaps or other pedicled flaps. These flaps require more complex techniques, are time consuming surgically, have greater morbidity and equal or worse functional and aesthetic results. In this paper we present our experience. Twenty-two patients with large soft tissue defects in the maxillomalar and orbital regions have had reconstructions with these flaps (facio-cervico-pectoral rotation flap and temporalis myofascial flap) in the last 8 years.
Adolescent↗
Effects of TMJ anesthesia and jaw gape on jaw-stretch reflexes in humans.
OBJECTIVE: To study the roles of afferent sensory inputs in the temporomandibular joint (TMJ) and of muscle length in the modulation of the jaw-stretch reflex in humans. METHODS: Reflexes were evoked in both the masseter and temporalis muscles under standardized conditions in 11 young women. The study was performed in two sessions; experimental conditions were jaw gape and injection of local anesthetics. For jaw gape, 4, 14, and 24 mm were used in random order. One milliliter TMJ injections (carbocaine, 10 mg/ml, versus isotonic saline, 0.9%) were given in a randomized, double blind manner. When a participant received carbocaine during the first session, isotonic saline was injected during the second one. A total of 480 reflexes were evoked in every participant. RESULTS: No significant differences were found between carbocaine and isotonic saline. ANOVA and post hoc paired t tests did show, however, a significant effect of jaw gape for the left masseter and anterior temporalis muscles, with the 14 mm gape having the highest amplitude. CONCLUSIONS: Blocking the afferent sensory input (including the mechanoreceptors) from the TMJ seems to have no influence on the sensitivity of the human jaw-stretch reflex. Instead, muscle spindles are the most likely receptors to be responsible for the reflex modulation that was observed in the present study.
Adult↗
Electromyographic evaluation of masseter and anterior temporalis muscles in patients with temporomandibular disorders following interocclusal appliance treatment.
The purpose of this study is to evaluate the interocclusal appliance efficiency in patients with temporomandibular disorder (TMD), by using computerized electromyographic (EMG) evaluation in the rest position of the mandible. Twenty-two patients (male and female) with TMD symptoms, between 18 and 53 years of age, were examined. EMG evaluations were performed before the treatment and during the 90th, 120th and 150th day of using the interocclusal appliance therapy. In the 90th and 120th day, inserting canine guidance and group function disclusion, respectively, changed interocclusal appliance. The results showed that group function disclusion caused shorter EMG activity in the mandible rest position for the anterior temporalis muscle.
Adolescent↗
Masseter and temporalis muscle EMG levels and bite force in migraineurs.
The purpose of this study was to compare absolute and proportional electromyography (EMG) levels in the masseter and temporalis muscles during performance of a variety of oral functions for migraineurs and age- and sex-matched controls. Both groups consisted of nine women and one man, with a mean age of 43 years (range, 29 to 51 years). Absolute resting EMG levels and those levels during swallowing and speech were not significantly different between the groups, but the levels of the group with migraine were significantly higher during maximum voluntary effort contractions on the anterior teeth and on the posterior teeth for both muscles. When expressed as a percentage of those levels obtained at maximal posterior contraction (ie, proportional levels), no difference in functional activity was demonstrated between groups. It was concluded that the two groups studied had similar levels of EMG activity in the masseter and temporalis muscles during the normal oral functions investigated, but that the group with migraine had higher levels of absolute EMG activity during anterior and posterior maximum voluntary contractions. Furthermore, the group with migraine demonstrated higher levels of anterior and posterior bite force, although not correlated with EMG levels.
Adult↗
Effect of parafunctional clenching on temporomandibular disorder pain and proprioceptive awareness.
This study tested the hypothesis that parafunctional clenching increases pain, can lead to a diagnosis of temporomandibular disorder (TMD) pain, and can produce reductions in proprioceptive awareness. Twenty individuals participated in EMG biofeedback training sessions on the left and right temporalis and masseter muscles. No subjects had TMD prior to training. Subjects were randomly assigned to either a Decrease group, who were instructed to maintain EMG activity below 2 microV during training, or an increase group, who were instructed to maintain EMG activity above 10 microV. To test the impact of parafunctional clenching on proprioceptive awareness, all subjects were instructed to barely touch their teeth together while EMG activity was recorded pre- and post-training. Three subjects assigned to the Increase group and no subjects assigned to the Decrease group were diagnosed with TMD pain following training. Self-reported pain post-training was significantly higher for the Increase group. Parafunctional clenching did not affect performance in the proprioceptive test.
Adult↗
Asymmetry of masticatory muscle activity during the closing phase of mastication.
The purpose of this study was to investigate the asymmetry of masticatory muscle activity between working and nonworking sides in the closing phase during mastication. Fifty adult subjects displaying normal oral function and occlusion participated in this study. Electromyographic (EMG) activity of the anterior temporalis and the superficial masseter muscle were recorded during mastication, simultaneously with motion data of the mandible. EMG activities of elevator muscles and their Asymmetry Index (AI) were analyzed depending on the vertical deviation of the lower incisal point with a two mm gap from the intercuspal position (ICP). EMG activities of both the anterior temporalis and the masseter on the working side were significantly greater than those on the nonworking side. Masseter muscles tended to show greater AI than the anterior temporalis muscles. Thus, asymmetry of the elevator muscles during mastication was a common finding in normal subjects. The normal range of variability of EMG activity and AI was confirmed in each section.
Adult↗
Relationship between the number of occlusal contacts and masticatory muscle activity in healthy young adults.
The electromyographic (EMG) potentials of left and right masseter and temporalis anterior muscles were recorded in 23 healthy young adults during: 1. a 3-second maximum voluntary clench (MVC) on cotton rolls positioned on the posterior teeth (standardized recording); and 2. a 3-second MVC in intercuspal position. EMG potentials recorded in intercuspal position were standardized as a percentage of the mean potentials of the standardized recording, and the EMG muscle activity was calculated. The number of occlusal contacts in intercuspal position was assessed by using eight microm thick shim stocks. Two groups of subjects with either 1. Less than ten occlusal contacts (11 subjects with "few contacts"); or 2. At least ten occlusal contacts (12 subjects with "many contacts") were selected. The MVC muscle activity in the "few contacts" group was significantly lower than that recorded in the "many contacts" group (p<0.005). In conclusion, the number of occlusal contacts and masticatory muscular function are significantly related, at least in young adults with a sound stomatognathic apparatus.
Adult↗
Botulinum toxin for the treatment of temporomandibular joint disk disfigurement: clinical experience.
Type A botulinum toxin was used for the treatment of symptoms of 26 patients (40 joints) with temporomandibular joint disk disfigurement. In all patients, 0.5 ml (12.5 U) was injected into the lateral pterygoid muscle. The temporalis, medial pterygoid, and masseter muscles were injected if severe tenderness was noted. The data were compared using the Wilcoxon signed rank test and the McNemar test. With the exception of clicking of the right joint, all mean outcome measures showed a significant difference between the preinjection and postinjection assessments. There was a significant difference between the preinjection and postinjection pain scores of the right joint (P=0.0019) and the left joint (P=0.000). Postinjection values of the mouth opening (P=0.002), subjective functional dysfunction (P=0.065), and clicking of the left joint (P=0.001) also showed a statistically significant difference from the preinjection values. In addition, the severity and frequency of headache were reduced after botulinum toxin-A injection into the lateral pterygoid muscle.
Adult↗
Effects of biofeedback training on tonic masticatory neck reflex: a case report.
Biofeedback training to reduce muscle tension lowered not only the spontaneous activity but also the tonic neck reflex in the jaw closing muscles. Tolperisone-HCl, which may inhibit the gamma system, inhibited the tonic masticatory neck reflex, but did not reduce the patient's spontaneous activity of the jaw closing muscles in this case. Biofeedback training may be considered to reduce the gamma as well as alpha motor systems.
Biofeedback, Psychology↗
The silent period in the masseter and anterior temporalis muscles in young adult subjects unaware of mandibular dysfunction symptoms.
In fourteen individuals unaware of mandibular dysfunction symptoms, latency and duration of the silent period in the masseter and anterior temporalis muscles at tooth tapping and jaw jerk were reasonably reproducible after 5 weeks and 5 months. Although the subjects felt no discomfort in the stomatognathic system, in some of them mild to moderate muscle tenderness, TMJ sound and occlusal disharmony were found at clinical examination. The relationship between these symptoms and the silent period was analysed. Muscle tenderness was the only factor to affect the silent period. The subjects with muscle soreness had a shorter duration of the silent period than the subjects without such symptoms.
Adult↗
A preliminary electromyographic study of bite force and jaw-closing muscle fatigue in human subjects with advanced tooth wear.
The maximum bite force was recorded in five experimental volunteers with advanced tooth wear and five control volunteers who showed no abnormal wear. All subjects were then asked to maintain a force of 50% of the maximum for as long as possible while surface electromyograms from the masseter and temporalis muscles were recorded. The bite force and endurance time were found to be slightly increased in the experimental group, but no conclusions could be drawn regarding the state of fatigue. Two significant problems with regard to fatigue studies of the jaw-closing muscles emerged from the study, namely the use of the canine position for recording of the force, and the thickness of the force meter.
Adult↗
Functional stress modification after high condylectomy surgery.
Surgical removal of the head of the condyles inevitably leads to radical redistribution of loads applied to the mandible. The nature of this redistribution can have important implications on the surgical approach and subsequent reconstructive procedures. The purpose of this investigation was to visualize photoelastically the functionally delivered stresses after high condylectomy surgery. Three identical models of a dentate human mandible were constructed from a photoelastic material. One mandible simulated a unilateral and the other simulated a bilateral high condylectomy. The third mandible had both condyles intact and served as basis for comparisons. Silicone implants were placed on the sectioned condylar heads. The condyles, with the silicone implants, were fitted into simulated fossae and the mandibles were loaded unilaterally and bilaterally. The resulting stresses were observed and photographed in the field of a circular polariscope. Substantial differences in load-generated stresses were observed as a result of both unilateral and bilateral condylectomies, compared to the normal case. The most severe stress conditions occurred with the unilateral condylectomy, where stresses associated with torsion were most evident.
Humans↗
Predictability of jaw muscle pains from surface electromyograms.
In seven (88%) of eight healthy subjects, weak to moderate pains were elicited in the masseter muscles through the isometric contractions of maximum voluntary teeth clenching. Integrated surface electromyograms of the right and left masseter muscles were used to quantify the absolute and relative contractile activities of the two muscles. The risk (relative probability) of inducing pain onset in the single masseter muscle generating the larger amount of isometric activity was 2.5 times the risk of eliciting pain onset in the single masseter muscle generating the lesser amount of isometric activity. However, as an aid in the diagnosis of pain onset, the method of masseteric surface electromyography had a false diagnostic ratio of 0.67.
Adult↗
Gum chewing and jaw muscle fatigue and pains.
To study possible associations between gum chewing and fatigue and pains in the jaw muscles, eight healthy adults performed prolonged idling, prolonged unilateral chewing of gum, and brief vigorous clenching of the teeth (MVC). Through surface electromyography (EMG), the authors monitored the cumulative (microV.s) as well as the average rates (microV.s-1) of contractile activities in the right and left masseter muscles. During 10 min of idling there was an absence of muscle fatigue and muscle pains when the EMG rates of the right and left masseter muscles were 2% and 3%, respectively, of those required to elicit isometric muscle pains through MVC. During 10 min of right-sided gum chewing at a rate of 1.2 Hz, the majority of subjects (75%) experienced weak jaw muscle fatigue-not jaw muscle pains-when the EMG rates of the right and left masseter muscles were 38% and 19%, respectively, of those required to elicit isometric pains through MVC. In comparison with 10 min of idling, the weak muscle fatigue of 10 min of unilateral gum chewing appeared when the total contractile activities of the right and left masseter muscles were increased by 1664% and 519%, respectively. It seemed as if prolonged unilateral gum chewing and previous pain-releasing MVC caused some sensitization of muscle nociceptors which, in turn, aggravated subsequent isometric jaw muscle pains elicited through MVC. Even though the right masseter muscle was the most frequent site of clinical fatigue and pains, the authors found no evidence supporting the theoretical foundation of the myofascial pain/dysfunction syndrome.
Adult↗
Masticatory function with mandibular implant-supported overdentures fitted with different attachment types.
Oral Rehabilitation by means of implant-retained mandibular overdentures is known to improve the oral function. The improvement may depend on the degree of retention and stability of the denture and thus on the type of attachment. In this within-patient cross-over clinical trial, we examined the hypothesis that more retention and stability of the overdenture improves the masticatory function. Eighteen patients received two permucosal implants, a new overdenture, and, successively, three different suprastructure modalities: a magnet, a ball, and a bar-clip attachment. We quantified aspects of the oral function by measuring the electromyographic activity of the jaw muscles and the jaw movement during chewing. The muscle activity was significantly lower for the unsupported new mandibular denture compared with values for the supported new denture. No significant differences in muscle activity were observed among the three attachment types. Furthermore, we did not observe significant differences in jaw muscle activity between the old unsupported denture and the new supported denture, despite significant differences in masticatory performance. Measuring muscle activity during chewing will thus not provide adequate information about masticatory function. Thus, subjects chewed more efficiently after implant treatment. No changes in cycle duration or in jaw movement parameters were observed among the various measurement moments.
Adult↗
The Gow-Gates mandibular block: regional anatomy and analgesia.
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Analgesia↗