PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Masticatory Muscles”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed1997

[The effects of soft denture liners applied to complete dentures on masticatory functions].

The soft denture liner was applied to dentures for the edentulous patients with poor residual ridge and thin mucosa. It is useful for minimizing the soreness caused by the denture during mastication, however, its effect on masticatory functions has been rarely investigated. The purpose of this study was to determine the effect of a soft liner applied to complete dentures on masticatory functions. Five edentulous volunteers who were satisfied with their new complete dentures took part in this study. The lower dentures were lined with a soft liner. Comparison of occlusal force, masticatory performance, masseter muscular activity, and mandibular movement were made between new dentures and relined dentures. The results of applying soft materials to lower dentures obtained by comparison with complete dentures using hard acrylic resin bases were follows: 1. Occlusal forces were significantly larger (p < 0.01). 2. Masticatory performance in chewing peanuts increased slightly. The number of strokes and time for masticating a peanut decreased significantly (p < 0.01). 3. Masticatory muscles functioned more rhythmically and mandibular movements became smoother. 4. Integrated EMGs per stroke of all patients was similar.

Aged↗
PubMed2001

Histological study of rat masseter muscle following experimental occlusal alteration.

It has been suggested that occlusal interference results in masticatory muscle dysfunction. In our previous study, occlusal interference reduced the rat masseter energy level during masticatory movements. The purpose of this study was to investigate the histological alterations of rat masseter muscles following experimental occlusal alteration with unilateral bite-raising. A total of eight male adult Wistar rats were equally divided into control and experimental groups. The experimental rats wore bite-raising splints on the unilateral upper molar. However, 4 weeks after the operation, the anterior deep masseter muscles were removed and then stained for succinic acid dehydrogenase (SDH), haematoxylin eosin (HE) and myofibrillar ATPase. Most of the muscle fibres in experimental rats remained intact, although partial histological changes were observed, such as extended connective tissue, appearance of inflammatory cells in the muscle fibres and existence of muscle fibres with central nuclei and central cores. Moreover, the fibre area-fibre frequency histograms of experimental muscle indicated a broad pattern than that of controls. These results indicated that occlusal interference caused histological changes in masseter muscles and that this may be related to the fact that the masseter energy level was reduced during masticatory movements in unilateral bite-raised rats.

Animals↗
PubMed1991

Sleep-induced masticatory myoclonus: a rare parasomnia associated with insomnia.

Tonic and rhythmic activity of the masticatory muscles accompanied by a loud and grating or clicking sound characterizes bruxism, a well-recognized parasomnia. We describe a 63-year-old man who complained of insomnia due to repeated tongue nibbling during sleep. Nocturnal polysomnographic recordings showed brief (50-100-ms) myoclonic jerks of myloioideus and masseter muscles occurring during phase 1 of sleep and leading to troublesome tongue nibbling with arousal of the patient. Hypnograms showed reduction of phase 2 and absent phases 3-4 and REM. Different pharmacological treatments including clomipramine, benzodiazepines, and carbamazepine were ineffective. A purposive interdental plate was placed to prevent jaw closings during sleep: masticatory myoclonus still persisted, but it did not provoke arousals; insomnia disappeared and night hypnograms improved.

Cerebral Cortex↗
PubMed1999

Mechanical advantage of area of origin for the external pterygoid muscle in two murid rodents, Apodemus speciosus and Clethrionomys rufocanus.

The actions of masticatory muscles in relation to transverse grinding, associated with forward masticatory movement of the mandible, were investigated by using a mechanical model in the two murid rodents, the Japanese field mouse (Apodemus speciosus: subfamily Murinae) and the gray red-backed vole (Clethrionomys rufocanus: subfamily Arvicolinae). Furthermore, statics of the masticatory system on a sagittal plane while chewing is taking place were also analyzed in these rodents. The inward grinding movements of hemimandibles are generated by the posterior temporalis and internal and external pterygoids in both species. In addition to these muscles, the anterior temporalis also moves the hemimandibles lingually in Apodemus speciosus. The area of origin of the external pterygoid seems more advantageous for transverse grinding in A. speciosus than in Clethrionomys rufocanus. On the basis of the static analysis, the anterodorsal area of origin of the external pterygoid to the upper second and third molars in Clethrionomys rufocanus appears to be an adaptive character to prevent the jaw joints from dislocation during occlusion at a posterior point on the elongated row of cheek teeth.

Animals↗
PubMed1989

The physiology of splint therapy: a literature review.

The clinician must frequently make treatment decisions with limited knowledge of the appropriateness and consequences of the different options. Patients have specific expectations: that the treatment they receive is the usual one, that they have been informed of the alternatives and the consequences, and most importantly that the treatment has a reasonable chance of success. In TMJ therapy, as with most treatments, the patient's improvement is closely connected to a proper diagnosis based on sound physiologic principles. This investigation will review four basic splint types and discuss their success in the resolution of various temporomandibular disorders. Since the position of the condyle-disc-fossa, the occlusal contact pattern and the masticatory muscle dynamics are interrelated, this study will focus on the physiologic changes splints may cause with modification of this tooth, joint and muscle relationship. Hopefully, selection of a specific splint design appropriate to the patient's disorder will be facilitated by better understanding of its physiologic and therapeutic effects.

Bruxism↗
PubMed2000

Successful aging--the case for prosthetic therapy.

Reduced chewing ability in community-dwelling older people is linked to the presence of removable dentures and having fewer than 20 natural teeth present. Compensation is provided by chewing longer and swallowing larger food particles. Replacement of posterior tooth loss by fixed or removable prostheses increases the activity of the masticatory muscles, and reduces chewing time and the number of chewing strokes until swallowing. In residents of nursing homes and long-term care facilities undernutrition is prevalent because of general medical problems, reduced appetite, and poor quality of life. Poor oral health and xerostomia are often present and may have a negative effect on masticatory function and nutrition, precipitating avoidance of difficult-to-chew foods. There is no evidence that the provision of prosthetic therapies can markedly improve dietary intakes; however, it might improve oral comfort and quality of life and avoid enteral alimentation.

Aged↗
PubMed1986

Headache and dysfunction of the masticatory system in adolescents.

An epidemiologic group of 285 17-year-old adolescents was studied with the aid of a questionnaire for frequency and intensity of headache and for symptoms of dysfunction of the masticatory system. They were also subjected to a functional examination of the masticatory system. Recurrent headaches occurred significantly more often among the girls (18%) than the boys (6%). Girls also reported significantly more intense headaches than boys. Fatigue in the jaws and difficulties in chewing were commoner in those with frequent and more intensive headaches. Tenderness to palpation of the masticatory muscles and impaired mandibular mobility were significantly commoner findings among those with recurrent headaches and those with more intense headaches. Tooth-grinding and clenching were related to frequency but not to intensity of headache. The investigation showed a significant relationship between frequency and intensity of headaches and signs and symptoms of dysfunction of the masticatory system.

Adolescent↗
PubMed1995

Long-term effects of orthognathic surgery on the temporomandibular joint: comparison of rigid and nonrigid fixation methods.

Sixty-six patients were examined between 2 and 9.5 years after bilateral sagittal split mandibular ramus osteotomy. Thirty-two patients had nonrigid fixation consisting of superior border wires and intermaxillary fixation, while 34 patients had rigid plate fixation of the osteotomy sites with immediate function. There were no demonstrable long-term differences between the two groups with respect to mandibular vertical opening, crepitance, and temporomandibular joint pain. Masticatory muscle pain and temporomandibular joint clicking improved with rigid fixation and worsened with nonrigid fixation.

Adult↗
PubMed1984

A critical evaluation of orthopedic interocclusal appliance therapy: effectiveness for specific symptoms.

This paper reviews the effectiveness of occlusal splints on specific symptoms that are often associated with TM disorders. The research has shown the clicking TMJ is sometimes helped but not cured by the traditional stabilization interocclusal appliance and that TMJ clicking is the least responsive to treatment. Questions have been raised about the need to specifically treat the clicking joint; more research on this issue is necessary. Painful TMJs have been shown to respond to occlusal appliance therapy, but questions still exist about the effectiveness of interocclusal appliances for this symptom. There is little scientific proof available about the ability of splints to effectively slow down or reverse degenerative TMJ changes that are evident on radiographs. Masticatory muscle pain is by far the symptom that has the best experimental evidence to support occlusal splints as a highly effective method of treatment. These changes are probably mediated via an alteration in the patient's muscle activity patterns. Those patients with more severe symptoms are less likely to be helped with splints as a sole treatment modality. The effect of occlusal appliances in muscle trismus has been discussed but not effectively evaluated in the literature. Occlusal splints have been shown to have a distinct influence on improving mandibular muscle coordination. Inter-occlusal splints are a commonly used method of controlling attrition and adverse tooth loading, and few questions have been raised in the literature about this therapeutic application.

Bruxism↗
PubMed1991

Corticobulbar and corticospinal projections to neck muscle motoneurons in man. A functional study with magnetic and electric transcranial brain stimulation.

The cortical projections to neck muscle motoneurons were studied in normal subjects by electrical and magnetic transcranial brain stimulation. After magnetic stimulation with a large coil, motor evoked potentials were present in about 20% of relaxed and 100% of contracting neck muscles. The latency of these responses was short: about 7 ms in the sternomastoid and splenius and 9 ms in the trapezius muscles. Subtraction of the M-wave latency after stimulation of the accessory nerve at the skull base resulted in a central latency of about 4.5 ms. We suggest that rapid cortical projections connect with neck muscle motoneurons mono or disynaptically. The latency difference between the responses after electrical and magnetic stimulation was smaller in neck than in limb muscles but similar to that seen in masticatory muscles. A small magnetic coil was used to study the pattern of functional lateralization of cortical projections to neck muscle motoneurons; the projections for the sternomastoid and splenius are bilateral but predominantly contralateral, whereas those for the trapezius are exclusively contralateral.

Adult↗
PubMed1998

Effect of anterior repositioning splints on the electromyographic activities of masseter and anterior temporalis muscles.

The effect of anterior repositioning (AR) splint therapy on masticatory muscle activity was investigated in seventeen patients with internal derangement; disk displacement with reduction in particular. Integrated electromyography (EMG) recordings from the masseter and anterior temporalis muscles were analyzed quantitatively during maximal biting in intercuspal position before and after eight week treatment period, EMG recordings were taken for each subject prior to the beginning of clinical therapy and final EMG recordings were made without AR splint to provide a standard for comparison. The results of the investigation revealed the following: 1. AR splint therapy did not cause any significant modification of the EMG activity in the recorded muscles during maximal biting in intercuspal position; 2. Before and after treatment the EMG activity from the masseter muscle was less than from the temporal muscle; 3. AR splint therapy resulted in reduction of the pain (88.2%) and jaw joint sounds (64.7%) and mean vertical opening which was 42.17 mm before treatment increased to 45.06 mm.

Adult↗
PubMed1997

Anatomical study of arrangement and attachment of the medial pterygoid muscle in Japanese men.

We precisely examined the origin, attachment, manner and insertion of the medial pterygoid muscle to clarify the relationship between muscle morphology and mastication movement. The muscular bundle attachment of the medial pterygoid muscle at the origin could be divided into three types; 1) the muscle was attached to the inner surface of the medial pterygoid plate with a strong tendon, 2) to the posterior maxilla wall with a strong tendon, and 3) directly to the periosteum of the inner surface of the lateral plate without a tendon. Provided that the muscular bundles had a firmly tendinous attachment under strong and significant force during their functioning, significant force would be applied to the medial pterygoid muscle in two directions. Observations of the intersection with the medial pterygoid muscle in the posterior wall of the maxillary bone at the origin revealed intersecting fibers or tendon fusion in all 55 specimens. Since there are different muscular bundle groups within the medial pterygoid muscle, we expect to elucidate more of masticatory function by observing other masticatory muscles as well as the medial pterygoid muscle.

Adult↗
PubMed1995

Hemimasticatory spasm in hemifacial atrophy: diagnostic and therapeutic aspects in two patients.

We report two cases of hemimasticatory spasm in association with progressive hemifacial atrophy. On the basis of neurophysiological and magnetic resonance imaging assessments, a peripheral irritation of the trigeminal nerve--probably due to entrapment of the motor branches in the infratemporal fossa--is suggested as the cause of the involuntary movement. Local injections of botulinum toxin type A into the masticatory muscles proved to be a successful treatment in both patients.

Adult↗
PubMedDate not supplied

Fiber type-specific autoantibodies in a dog with eosinophilic myositis.

Serum from a 2-year-old male Belgian sheepdog with eosinophilic myositis, which particularly affects the masticatory muscles, was tested for the presence of muscle-specific autoantibodies. Control type 2 temporalis muscle fibers were selectively stained following incubation with the patient's serum and staphylococcal protein A conjugated to horseradish peroxidase (SPA-HRPO). Likewise, type 2 fibers in the patient's temporalis muscle were selectively stained with SPA-HRPO. The same staining procedures applied to limb muscle did not result in fiber staining. Proteins isolated from the temporalis and triceps brachii muscles of a normal dog were separated under denaturing conditions by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The separated proteins were transferred onto nitrocellulose paper and incubated with either sera from the patient, normal dogs, or neuromuscular disease controls. Subsequent incubation with peroxidase-conjugated goat anti-dog IgG demonstrated antibodies to at least four proteins of the temporalis muscle (myosin heavy chain and three unidentified proteins) when incubated with the patient's serum but not with the controls. Under all conditions, antibodies to the proteins of the triceps brachii were not detected. These findings establish the presence of autoantibodies to specific temporalis muscle proteins that may initiate the myonecrosis and inflammatory response as well as limit the distribution of the response.

Animals↗
PubMed2002

The epidemiology of self-reported TMJ sounds and pain in young adults in Israel.

OBJECTIVES: We investigated the prevalence of self-reported temporomandibular joint sounds (TMJS), masticatory muscle pain (MMP), and their interrelation in a young adult population. METHODS: A large sample (n = 20,869) of young soldiers aged 18-21 years who attended dental clinics were asked about their experience of TMJ sounds and pain. RESULTS: The overall prevalence of TMJS was 8.4 percent (8.9% in females and 8.2% in males) and for masticatory pain was 4.0 percent for both males and females (P < .001 under chi-square test). Twenty-five percent of patients reporting positive TMJS also reported positive MMP compared to 2 percent in the negative TMJS group (P < .001). Fifty-three percent of patients reporting positive MMP also reported positive TMJS, compared to 6.5 percent in the negative MMP group (P < .001). CONCLUSIONS: The low prevalence of TMJ sounds and pain found in these study might be attributed to the different cultural and social environment, as well as to the uniformity in age of the study group.

Adolescent↗
PubMed1982

Jaw movement-related activity and reflexly induced changes in the lateral pterygoid muscle of the monkey Macaca fascicularis.

The muscle was exposed in 12 lightly anaesthetized monkeys so that electromyographic recordings could be made from the superior and inferior heads. The separately recorded activity in each head was initially examined in relation to activity recorded simultaneously in other jaw muscles or to jaw movements produced actively by the animals or passively induced by the experimenter. Subsequently, the reflex effects of stimuli applied to various oral-facial sites were examined. In general, the superior head was active in association with jaw-closing muscle activity and related movements produced by the animal whereas the inferior head was mainly active in jaw-opening. Both heads increased their activity with passively-induced jaw-opening movements, especially if the jaw-opening was combined with a horizontal deviation of the mandible. Both heads showed reflexly-induced excitation and silent periods as a result of stimuli applied to oral-facial sites, the most effective sites being palatal, lingual, labial and buccal mucosa and the teeth, stimulation of which, as well as stimuli applied to mandibular joint and cutaneous afferents, could also reflexly induce silent periods in both heads. The various effects may be related to mechanisms for protection and stabilization of the mandibular joint and masticatory muscles.

Animals↗
PubMed1984

[Mechanisms of adaptation and compensation in the rat head after alteration of the arterial system].

The craniofacial growth of the Wistar rat was examined after ligature of the arteria carotis communis dextra. The adaption and compensation processes on the vascular system, skull, brain, masticatory muscle and temporomandibular joint were studied with morphological and functional investigations. The stability regions on the systems of the head were described on growth conditions.

Adaptation, Physiological↗