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PubMed1998

The reproducibility of muscle and joint tenderness detection methods and maximum mandibular movement measurement for the temporomandibular system.

The purpose of this study was (1) to evaluate the reproducibility of two masticatory muscle and joint tenderness detection methods; (2) to evaluate the reproducibility of maximum mandibular movement measurements; and (3) to investigate factors influencing examiner agreement. The tenderness assessment procedures involved application of a standard pressure for 2 seconds over four anatomically defined masticatory muscle sites, one control forehead site, and two temporomandibular joint sites on each side of the face. One technique utilized a pressure algometer (PAP), while the other technique required that a trained examiner apply pressure with the index fingertip (FPP). Seventy-two subjects (36 patients and 36 controls) were evaluated in a single-blind study design. Control subjects were matched for age, gender, and race with temporomandibular disorder subjects. Each subject was examined twice with each of the described methods in a randomized, fully balanced sequence by calibrated examiners. Tenderness levels were determined by the subject via self-report of pain upon pressure using a standard set of verbal descriptors. Maximum pain-free, active, and passive opening, and maximum active right and left lateral movements were measured using a millimeter ruler. Intraclass correlation coefficients (ICC) for the tenderness assessment methods ranged from 0.220 to 0.739 for the FPP method and from 0.391 to 0.880 for the PAP method. ICCs for mandibular movement measurement were much less variable, ranging from 0.59 to 0.68 for lateral movement and from 0.78 to 0.93 for opening movement. These results indicate good to excellent agreement between calibrated examiners for mandibular movement measurement and for tenderness assessment methods at two masseter (i.e., superficial and deep) and the anterior temporalis sites. Only fair agreement was found for the middle temporalis and lateral TMJ capsule sites using these methods.

Adult↗

PubMed2006

Occlusion, sternocleidomastoid muscle activity, and body sway: a pilot study in male astronauts.

The modifications induced by microgravity on the coordinated patterns of movement of the head, trunk, and limbs are reported on extensively. However, apparently there is little data on the masticatory muscles. In normal gravitational conditions, information from the neck and stomatognathic apparatus play a role in maintaining the body's balance and equilibrium. The current pilot study used normal gravity conditions to investigate the hypothesis of a functional coupling between occlusion and neck muscles and body postural oscillations. The immediate effect of modified occlusal surfaces on the contraction pattern of the sternocleidomastoid muscles during maximum voluntary clenching and on the oscillation of the center of foot pressure was analyzed in 11 male astronauts (aged 31-54 yrs). All subjects were healthy and free from pathologies of the neck and stomatognathic apparatus. Occlusal splints were prepared using impressions of their dental arches. The splints were modeled on the mandibular arch, had only posterior contacts, and were modified to obtain a more symmetric, standardized contraction of the masseter and temporalis muscles during teeth clenching. Surface EMG activity of the sternocleidomastoid muscles was recorded during a maximal voluntary clench with and without the splint. Sternocleidomastoid potentials were standardized as percent of the mean potentials recorded during a maximum contralateral rotation of the head, and the symmetry of the EMG waves of left- and right-side muscles was measured. Body sway was assessed with and without the splint, either with eyes open or closed. The variations of the center of foot pressure were analyzed through bivariate analysis, and the area of the 90% standard ellipse was computed. Within each visual condition (eyes open or closed), the difference between the areas of oscillation measured with and without the splint was computed. Muscular activity was more symmetric with the splint. The area of oscillation of the center of foot pressure was larger without the splint than with the splint, both with eyes open and eyes closed. The modifications, induced by the occlusal splint in the sternocleidomastoid muscles' symmetry, and center of foot pressure differential area with closed eyes, were significantly related (p < 0.05): the larger the increment in muscular symmetry, the smaller the area of oscillation with the splint as compared to without the splint. A functionally more symmetric maxillo-mandibular position resulted in a more symmetric sternocleidomastoid muscle contraction pattern and less body sway. Modifications in the contraction of the masticatory muscles may therefore affect the whole body.

Adult↗

PubMedDate not supplied

[Initial masseter muscle fatigue in maximal voluntary teeth clenching].

Fatigue of striated muscles is defined as the impossibility to generate the expected or required force during the repeated contraction. During the maximal voluntary teeth contraction in the position of central occlusion the initial fatigue in masticatory muscles during the isometric contraction occurs. If a person can clench its teeth continuously and voluntarily it has a diagnostic significance since the peripheral fatigue is that important factor in the masticatory muscles activity, which is in direct correlation with the function of the masticatory system. The aim was to compare the obtained results of the initial fatigue of masseter muscles during the maximal voluntary teeth contraction in subjects with naturally healthy intact dentition and subjects with a pair of new full dentures. The investigation comprised 20 subjects with healthy stomatognathic system of the skeletal class I by Angle. Comparison of the values of the obtained results was performed electromyographically by synchronous registration of action potentials of masseter muscles. Results of the investigation of the onset of initial fatigue of masseter muscles in the subjects with natural healthy intact dentions showed lower values, i.e., faster development of the muscular fatigue (31.5 s) compared to the subjects with a pair of new full dentures (44.5 s).

Adult↗

PubMed1995

The ultrasonic value of local muscle hypertrophy in patients with temporomandibular joint disorders.

Muscle pain and tenderness on palpation are two common symptoms in patients with temporomandibular joint disorders. Examination of the masticatory muscles is largely restricted to the use of electromyography. The technique of ultrasonography in the diagnosis of muscle hypertrophy in patients with temporomandibular joint disorders was investigated. The results of the study indicate that ultrasonography may be beneficial to locate affected muscles that do not exhibit symptoms of tenderness on palpation and thereby give hints for treatment planning.

Adult↗

PubMed1996

[Clinical picture and orthodontic treatment in a shortened interalveolar distance].

A total of 868 patients aged 25 to 68 with various types of occlusion and dentition defects were examined. 212 (24.4%) patients presented with a shortened interalveolar distance (height of occlusion). Abnormal abrasion of hard dental tissues, dentition defects in the lateral sections of dental arches, abnormal occlusion (deep or prognathic), reduced tolerance of periodontal tissues, and dysfunction of the masticatory muscles (bruxism) were found to be the pathogenetic factors leading to the development of this condition. Dysfunction of the masticatory muscles was detected in 41.5% of patients with shortened interalveolar distance and dysfunction of the temporomandibular joint in 9.9%; moreover, in many of them traumatic occlusion and disorders in the regional circulation in the periodontium of teeth exposed to overexercise were observed. Orthodontic treatment of patients with shortened interalveolar distance was carried out in two stages: the first stage consisted in functional and adaptation restructuring of the maxillodental system by repair of the height of occlusion and normalization of the mandibular position on a plastic cup which the patients wore for 3 months, and then the second stage ensued, at which they were fitted with dentures. Good results were attained in 95.7% patients.

Adult↗

PubMed2002

[A case of Satoyoshi syndrome complicating marginal gingivitis of the mandible and dislocation of the temporomandibular joint].

Satoyoshi syndrome is a very rare disorder, characterized by progressive painful intermittent muscle spasms beginning in adolescence. Universal alopecia, diarrhea, amenorrhea and bony deformities are also cardinal features of this syndrome. Skeletal abnormalities, such as joint deformity, epiphysial destruction and retarded growth, are observed in approximately half of patients. However, no bony changes have previously been reported in the region of the head. We present here a male patient with Satoyoshi syndrome. Muscle cramps began in the lower extremities when he was 13 years old, and gradually spread. At the age of 17 years, masticatory muscle cramps made it difficult to eat and speak fluently, and were considered a cause of malacia in this patient. Finally, recurrent severe cramps in the masseter muscles caused marginal gingivitis of the mandible, necessitated extraction of the teeth and caused dislocation of the temporomandibular joint. After treatment with dantrolen sodium at doses up to 150 mg/day, painful spasm decreased significantly. Since masticatory muscles can cause significant stress to the teeth and the temporomandibular joint, sufficient attention should be paid to the oral region to avoid complications in patients with Satoyoshi syndrome.

Adolescent↗

PubMed1989

[Muscle action potential and masticatory rhythm of anterior temporal and masseter muscles in children and adults].

For the investigation of the functional change of the masticatory muscles along with growth and development, electromyographic evaluation was carried out. The subjects were 6 children (5 males and 1 female) with full deciduous dentition (Hellman's dental age IIA) aged 4.5 +/- 0.2 years and 6 adults (4 males and 2 females) with full permanent dentition aged 27.7 +/- 3.8 years. EMG signals were recorded bilaterally by means of bipolar silver surface electrodes from the anterior temporal and masseter muscles when the subjects were chewing chewing gum or performing maximum clenches in intercuspal position. The cumulative power values from 62.5 to 1000 Hz in the EMG power spectrum during chewing or clenching were calculated as the muscle action potential. The ratio of the action potential of each muscle to the total action potential of four muscles were analyzed. Masticatory rhythm during chewing was analyzed by means of the time parameter (duration, interval and cycle) and their coefficients of variation. The results were as follows: 1. In children the temporal muscles predominated in chewing and clenching, whereas in adults there were three types with Temporal muscles predominating, Masseter muscles predominating and both muscles sharing equally. 2. No statistically significant differences between children and adults were observed in the duration, interval and cycle. 3. In adults the coefficients of variation of the duration, interval and cycle were smaller and the masticatory rhythm was more stable than in children.

Action Potentials↗

PubMed1990

Human jaw-opening muscle responses elicited by multiple-site electrical stimulation.

Electrical stimuli were applied to subjects' upper and/or lower gingivae around the right canines; (i) during maintained relaxation of masticatory muscles; (ii) at an active opening position; (iii) while clenching in an incisal edge-to-edge contact (IEC) position; and (iv) at the wide-open position. Reflex responses of the suprahyoid and jaw-closing muscles were obtained using surface electrodes. The electrical stimulation produced segmented reflex excitation(s) in the suprahyoid muscle and conventional reflex excitation and/or inhibition in the jaw-closing muscles when some background activity was maintained in the muscle(s). The excitatory reflex in the suprahyoid muscle responded to multiple site electrical stimulation which was delivered on both the upper and lower jaw simultaneously rather than to single site stimulation. Also, the responses depended on the intensity of the electrical stimulation. In particular, stronger intensities resulted in longer latencies. The results support the suggestions in our previous studies with mechanical stimuli, i.e. that the human jaw-opening reflex can be obtained only when some background activity is maintained in the jaw openers, perhaps due to low threshold afferent input, and that spatial summation may be effective for the reflex.

Adult↗

PubMed1995

[Muscle relaxation by transcutaneous electric nerve stimulation (TENS) in bruxism. An electromyographic study].

In recent years transcutaneous electrical neuromuscular stimulation (TENS) has become increasingly more common in the treatment of functional diseases of the masticatory muscles and currently the practitioner can choose among a variety of stimulators. In an electromyographic study of 17 adults suffering from nocturnal bruxism and of a control group consisting of 18 adults without any functional disturbances of the masticatory muscles, the effect of this kind of neuromuscular stimulation on the temporal and masseter muscle was examined. The myoelectric signals were registered before and after TENS treatment in 3 different positions of the mandible. Each person was treated 3 times with both the Myo-Monitor (Myo-Tronics, Seattle) and the TNS SM2 MF stimulator (schwa-medico, Giessen). The different effects of continuous low frequency and intermittent high frequency muscular stimulation were studied simultaneously. Muscular activity was determined by computer aided integration of the electromyographically measured raw signals. A fourier analysis of the power spectrum yielded information on the frequency behavior of the studied muscles resulting from the TENS treatment. A statistical analysis of the results led to the following significant conclusions: 1. TENS treatment decreased the values of the registered integrated signals on all test persons, however, the treatment increased the median frequency and the mean power frequency (MPF). Since this effect is contrary to muscle fatigue, these electromyographic results can be interpreted as providing objective proof of a relaxation in the treated muscles. 2. The electromyographic changes after TENS treatment were similar when using either the Myo-Monitor or the TNS SM2 MF stimulator. In addition, the 2 different types of stimulation (high or low frequency) showed the same effects. 3. Compared to the persons in the control group, there was no significant increased muscular activity in patients with nocturnal bruxism. Following TENS treatment both groups showed the same alterations in the electromyograms. The results of the study provide further evidence that TENS treatment is an adequate supportive procedure in the treatment of nocturnal bruxism.

Adult↗

PubMed1994

Study of pterygospinosus muscle in human fetuses.

The arrangement of the pterygospinosus muscle was analyzed in 5 human fetuses. The pterygospinosus muscle extends from the posterior border of the lateral lamina of the pterygoid process to Meckel's cartilage. Such an arrangement would permit its action on the joint formed by Meckel's cartilage and the incus of the middle ear. The pterygospinosus muscle is a remnant of the masticatory muscle group. The relationships of the pterygospinosus muscle with the mandibular nerve and its branches and the maxillary artery and its branches were analyzed.

Computer Simulation↗

PubMed1988

Oculo-facio-skeletal myorhythmia as a cerebral complication of systemic Whipple's disease.

A fifth case of oculomasticatory myorhythmia associated with cerebral Whipple's disease is reported. This peculiar abnormal movement has never been described in association with cerebral dysfunction other than Whipple's disease. The present case exhibited rhythmic convergence of the eyes and synchronous (1-2 Hz) contractions of the masticatory muscles and of the proximal and distal skeletal muscles. These abnormal movements occurred 13 years after the beginning of the disease. They were persistent and unchanged until the death of the patient 3 months later. No treatment was effective to suppress the involuntary movements (clonazepam, baclofen, antibiotics). Associated neurological signs included global supranuclear ophthalmoplegia, facial weakness, bilateral ptosis, absent gag reflex, and intellectual deterioration.

Brain↗

PubMedDate not supplied

[Use of the maximal physiologic load test in the evaluation of functional values of newly made complete dentures and dentures rebased by the Rehm method].

There is a constant dilemma of dental practitioners in contact with patients in whom complete dentures have lost congruent relation toward supporting mucoosseous tegmen if new dentures should be made or rebased by change of denture base. The investigators who have studied those problems have been mostly concerned with problem of material and rebasing procedures of complete dentures. The aim of the study was to determine the functional value of unrebased, rebased by Rehm and new complete dentures and compare the time of initial functional adaptation of patients to rebased and new complete dentures. The study included 72 examinees. The functional value of complete dentures was estimated by test of masticatory muscles, bioelectrical activity by test of masticatory efficacy and by test of maximal physiological load. On the basis of the study it was concluded that complete dentures rebased by Rehm were in function worthier than unrebased, and the period of initial functional adaptation was missing. In the examinees with pair of newly made complete dentures, functional tests revealed the reduction of initial values after the new dentures were delivered. During the examination interval, progressive dynamics with tendency of establishing the optimal functional value and initial functional adaptation was revealed after 21 days.

Bite Force↗

PubMed2005

In vivo cross-sectional area of human jaw muscles varies with section location and jaw position.

Muscle cross-sectional area (CSA) is used as a measure for maximum muscle force. This CSA is commonly determined at one location within the muscle and for one jaw position. The purpose of this study was to establish a method to standardize the analysis of the CSA of the masticatory muscles in vivo, and to compare the CSAs along their entire length for two different jaw positions (opened and closed). The CSAs in the planes perpendicular to the long axes of the masseter, medial, and lateral pterygoid muscles were measured in ten normal young adult subjects by magnetic resonance imaging. Our results showed large differences among the muscles and a non-uniform change in CSA after jaw-opening. The method enables the CSA measurement to be standardized in vivo, and allows for a correct comparison of CSAs in different skull morphologies.

Adult↗

PubMed1983

Microprobe analysis of human masseter muscle biopsies.

Biopsies of the human masseter muscle were made using an intraoral approach. Sections were cut in a cryostat and freeze-dried. Using the myosin ATPase method at pH 9.3 the recognized heterogeneity of the muscle with respect to type I and type II fibers was confirmed. Sections were examined in an SEM by the method of energy dispersive X-ray analysis using a computer assisted semi-quantitative method (bulk analysis-thick sections) to determine the distribution of Na, P, S, Cl and K and their relative masses. Element concentrations in descending order were K, S, P, Na and Cl. Some element ratios were compared with results in the literature for other muscle (biochemical and microprobe analysis) and found to be generally in reasonable agreement. The results form a basis for the study of a prominent and accessible masticatory muscle in altered states.

Adult↗

PubMed1981

Muscular and mandibular adaptation after lengthening, detachment, and reattachment of the masseter muscle.

This investigation was undertaken to study the skeletal and muscular adaptations in the mandible after lengthening, detachment, and reattachment of the masseter. Placing the bite-opening appliance and altering the length of the masseter, with and without surgical detachment and reattachment, resulted in a number of mascular and skeletal adaptations: First, a posterior and inferior rotation of the mandible was produced. In the experimental period, forward repositioning of the gonial angle and upward repositioning of the symphyseal region occurred. The amount of skeletal repositioning was greater in those animals in which the associated musculature was not detached. Second, if the masseter muscle was lengthened and not detached from the mandible, a gradual return of the muscle to its original length was observed. After 48 weeks, a 50% return occurred. Third, if a muscle was lengthened and then surgically detached, immediate shortening of the muscle occurred in an anterior and superior direction, with ultimate reattachment often at a length shorter than the original. Fourth, if a muscle was surgically detached and then surgically reattached without placement of a bite-opening appliance, a slight shortening of the muscle occurred. Fifth, if the bite was opened and the masseter was surgically detached and then surgically reattached, the muscle returned to its approximate original length and had a more predictable postsurgical positioning. It may be concluded that, in surgical procedures where lengthening of the masticatory muscles is mandatory, it is beneficial, if possible, to surgically detach these muscles from their insertions. In doing so, one would maintain the original orientation of the muscle and at the same time presumably impose less stress on the newly placed, surgically repositioned skeletal elements.

Adaptation, Physiological↗

PubMedDate not supplied

The effect of non-surgical management of TM disorders.

One hundred and ninety-three patients with varying occlusal discrepancies were diagnosed as having TM disorders with orofacial pain. They were divided into five groups with similar clinical symptomatology. There were 84 patients with clicking, 45 with headaches, 13 with neckaches, 39 with tenderness in the TMJ bilaterally and masticatory muscles and 12 with uncomfortable occlusal relationships. All were given an anterior deprogrammer to wear for a period of one week in order to relax the masticatory muscles and allow the jaw to return to a physiologic position. The follow-up occlusal device therapy varied according to clinical symptoms. The group with clicking wore anterior repositioning orthopedic devices to recapture the displaced articular disc, followed by a gradual return to a centric relation position. The other groups wore centric relation appliances providing even posterior cusp tip contacts and anterior guidance. All patients wore the appliances for varying periods, up to one year, with monthly adjustments. The clinical symptoms significantly decreased, and all but 4 patients who had to be treated surgically, had the malocclusion corrected at the same treatment position of the centric relation appliances that were worn for one year. The results suggest that short-term occlusal device therapy is effective as an interim method towards the correction of occlusal discrepancies, but should be followed by a final treatment that will maintain the jaw in an asymptomatic and physiologic position. Four-year re-evaluations revealed no reoccurrence of chronic symptoms after finalization treatment.

Activator Appliances↗

PubMed1982

Diameter spectra of sensory and motor fibers in nerves to jaw-closing and jaw-opening muscles in the cat.

The masseter and the mylohyoid nerves were examined using electron microscopy after unilateral destruction of the trigeminal motor nucleus by kainic acid injection in order to evaluate the distribution of sensory and motor fibers in masticatory muscle nerves. The surviving axons were counted and their diameters measured, and the results were compared with data for control nerves. The diameters of the control masseter nerves fibers were bimodally distributed with peaks at 2-5 and 7-9 micrometers. The nerve fiber diameters on the injected side, i.e., afferent fibers, also showed a bimodal distribution with peaks at 2-4 and 6-9 micrometers. On the other hand, the fiber diameter spectrum of the motor fibers, which was estimated from the loss of these fibers after kainic lesions, was unimodal within ranges of 1-16 micrometers. Consequently, the largest fibers of the masseter nerve were estimated to be motor fibers. A comparison of the distribution of diameters and conduction velocities of the afferent fibers indicates that both primary and secondary spindle afferents are mostly included in the larger diameter group with the peak at 6-9 micrometers. The diameters of fibers of the common mylohyoid nerve trunk showed a bimodal distribution, similarly to those of the masseter nerve. However, the analysis of the peripheral branches of the mylohyoid nerve revealed that the largest afferents in this nerve were of cutaneous origin, since muscle afferents of the anterior digastric and mylohyoid muscles have small diameters. These findings suggest that muscle spindles are absent or few in these two suprahyoid muscles in the cat.

Animals↗

PubMed2004

Comparison of algometry and palpation in the recognition of temporomandibular disorder pain complaints.

AIMS: To determine the construct validity of algometry and to compare it with that of palpation, and to compare tenderness of masticatory muscle sites and the temporomandibular joint (TMJ) on palpation and on algometry. METHODS: Two hundred fifty subjects, 148 with temporomandibular disorder (TMD) pain complaints, underwent a standardized blinded physical examination that included pain-intensity measures on palpation and pressure pain threshold measures on algometry of masseter muscle sites, temporalis muscle sites, and the TMJ. RESULTS: Logistic regression analysis indicated that the recognition of TMD pain complaints based on pressure algometry was comparable to that of palpation (R2 = 0.22 and R2 = 0.21, respectively). The masseter muscles were most tender to palpation and algometry, followed by the TMJs and the temporalis muscles. CONCLUSION: Construct validity of algometry in the recognition of TMD pain complaints is comparable to that of palpation, and differences in tenderness on palpation and on algometry are found between masticatory muscle sites and the TMJ.

Adult↗