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Biomedical subjects

S E Mohamed

Publications and source records attributed to S E Mohamed.

At least 19 recordsLinked to original sources
PubMed2001

The effect of four-week administration of amitriptyline on sleep bruxism. A double-blind crossover clinical study.

The purpose of this study was to evaluate the effect of a tricyclic antidepressant (amitriptyline) on nocturnal masseteric activity and duration of sleep in bruxists. Using a randomized, double blind, crossover design, ten females (mean age 39 yrs, +/- sd seven yrs) received active (amitriptyline 25 mg/night) and inactive (placebo 25 mg/night) medication, over a period of four weeks each. A portable EMG integrator recorded the nocturnal, unilateral, and cumulative myoelectrical activity (microV/min of sleep) of the masseter muscle during the fourth and eighth weeks of the study. The results showed that amitriptyline did not significantly decrease the mean EMG activity (df = 9, alpha = 0.05, paired-t = 0.892, p = 0.3964), nor did it significantly increase the duration of sleep (df = 9, alpha = 0.05, paired-t = 2.140, p = 0.061). The results of this study do not support the administration of 25 mg of amitriptyline per night over a period of four weeks for the management of sleep bruxism.

Adult↗
PubMed2001

A randomized double-blind clinical trial of the effect of chondroitin sulfate and glucosamine hydrochloride on temporomandibular joint disorders: a pilot study.

Previous studies have shown chondroitin sulfate and glucosamine hydrochloride have beneficial effects on symptoms of osteoarthritis of the knee. Our aim was to study the effect of a daily dose of 1500 mg of glucosamine hydrochloride (GH) and 1200 mg of chondroitin sulfate (CS) taken for twelve weeks on subjects diagnosed with capsulitis, disk displacement, disk dislocation, or painful osteoarthritis of the temporomandibular joint (TMJ). Forty-five subjects were enrolled in the study and were randomly assigned to either an active medication group or a placebo group. Eleven subjects were lost from the study for various reasons, resulting in fourteen subjects remaining in the active medication group and twenty subjects remaining in the placebo group. Subjects taking CS-GH had improvements in their pain as measured by one index of the McGill Pain Questionnaire, in TMJ tenderness, in TMJ sounds, and in the number of daily over-the-counter medications needed. Subjects taking the placebo medication had improvements in their pains as measured by the visual analog scale and by four indices of the McGill Pain Questionnaire. Additional studies are required to evaluate the clinical effectiveness of CS-GH and to determine the exact mechanism by which CS-GH affects the articular cartilage of synovial joints.

Adult↗
PubMed2001

The effect of amitriptyline on pain intensity and perception of stress in bruxers.

PURPOSE: The purpose of this clinical pilot study was to evaluate the effect of a tricyclic antidepressant, amitriptyline, on pain-intensity level and level of stress in bruxers. MATERIALS AND METHODS: In a randomized, double-blind, crossover experimental design, 10 subjects received active (amitriptyline 25 mg/night) and inactive (placebo 25 mg/night) medication, over a period of 4 weeks. RESULTS: The administration of amitriptyline for 4 weeks did not significantly (p >.05) reduce pain intensity. However, it significantly (p <.05) reduced the level of stress perception. CONCLUSION: The results of this limited study do not support the administration of small doses of amitriptyline over a period of 4 weeks for the management of pain resulting from sleep bruxism. However, the results support the administration of small doses of amitriptyline for the management of the perception of stress levels associated with sleep bruxism.

Amitriptyline↗
PubMed1997

A randomized double-blind clinical trial of the effect of amitriptyline on nocturnal masseteric motor activity (sleep bruxism).

Using a double-blind and randomized experimental design, ten adult subjects with sleep bruxism were administered amitriptyline (25 mg/night) and placebo (25 mg/night), each compound over a period of one week. Neither the intensities and locations of pains nor the nocturnal masseteric electromyographic activities were significantly affected by the tricyclic antidepressant. In fact, intake of amitriptyline was unpredictably associated with either an increase or a decrease in masseteric electromyographic activity (microV.s/min of sleep). On the basis of this study, small doses of amitriptyline cannot be recommended for the control of sleep bruxism and associated discomforts.

Adult↗
PubMed1997

Management of temporomandibular disorders in a restorative practice.

Various disorders related to the masticatory muscles or to the temporomandibular joints may be encountered in a restorative dental practice. Most of them can be managed by the restorative dentist whose primary interest may not lie in the area of temporomandibular disorders. The term temporomandibular disorders is used in this discussion to denote the group of diseases of the masticatory system that involves primarily the temporomandibular joints, the masticatory muscles, and the occlusion of the teeth. The learning objective of this article is to describe temporomandibular disorders encountered in general practice. Managing these disorders in the general practice of restorative dentistry is not difficult and adds to the comfort of the patient and possibly to the success of the restorations.

Diagnosis, Differential↗
PubMed1996

Masticatory tooth contact patterns: cuspid and first molar contacts during mastication of three types of food.

In ten healthy subjects, bilateral contacts between opposing cuspid and first molar teeth were recorded during one sequence of unilateral chewing of apple, peanuts, and banana. Unknown magnitudes of mechanophysical (masticatory) forces were inferred to act directly on the chewing-side cuspid teeth in 71% of all masticatory cycles and on the nonchewing-side cuspid teeth in 68% of all masticatory cycles. In addition, unknown magnitudes of mechanophysical forces were inferred to act directly on the chewing-side first molar teeth in 74% of all masticatory cycles and on the nonchewing-side first molar teeth in 86% of all masticatory cycles. During the chewing of peanuts, the total number of chewing-side cuspid contacts exceeded significantly the total number of nonchewing-side cuspid contacts, suggesting more repetitive direct mechanophysical loading of the chewing-side cuspid teeth. During the chewing of apple, the total number of nonchewing-side first molar contacts exceeded significantly the total number of chewing-side first molar contacts, suggesting more repetitive direct mechanophysical loading of the nonchewing-side first molar teeth. The variable contact patterns were, to a large extent, explained by rotational movements of the entire mandible resulting in translational movements of the hemimandible.

Adult↗
PubMed1996

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↗
PubMed1996

Bilateral masseteric contractile activity in unilateral gum chewing: differential calculus.

Twelve healthy subjects performed 10 s, 15 s, 20 s, and 25 s of right-sided and, subsequently, left-sided gum chewing. The contractile activities of the ipsilateral (chewing side) and contralateral (non-chewing side) masseter muscles, mainly the concentric contractions of the phase of jaw closing and the isometric contractions of the phase of dental occlusion, were recorded through cumulative surface electromyography (EMG). A linear function (y = ax + b) described the association between an increase in the duration (x) of unilateral gum chewing and the cumulative EMG (y) of both the ipsilateral and the contralateral masseter muscle, and because of different slopes (a) of the two straight lines a geometric function (y = aqx) described the progressively larger differences between the paired and straight lines. When differential calculus was applied to the exponential functions, it became evident that the chewing forces generated by the ipsilateral masseter muscle continually exceeded those generated by the contralateral masseter muscle, and that the positive work (force x distance) produced by the concentric contractions of the ipsilateral masseter muscle continually exceeded that produced by the concentric contractions of the contralateral masseter muscle. It was inferred that mechano-physical work plays a major role if clinical muscle fatigue develops during prolonged unilateral gum chewing.

Adult↗
PubMed1991

Temporomandibular disorder in a child.

Temporomandibular (TM) disorders among children are uncommon. Their many etiologies include interferences with the formative process, malocclusion, and muscle disharmony. Facial pain, earache, headache, difficulty with chewing, and joint noise during mandibular function are symptoms. The two year course of a TM disorder that first became symptomatic in a six month old child is described.

Facial Asymmetry↗
PubMed1985

Mandibular reference positions.

An overview is presented of the mandibular reference positions of centric occlusion, centric relation and centric relation occlusion, and the position of rest. Clinical applications of the different positions are discussed on the basis of the physiology of the mandibular locomotor system.

Dental Occlusion↗
PubMed1985

Isometric endurance of the human masseter muscle during consecutive bouts of tooth clenching.

Three human subjects performed teeth clenching at maximum voluntary contraction strength (MVC) of the mandibular elevator muscles. At intervals of 10s, ten successive bouts of MVC clenching were exercised until total exhaustion of the contracting muscles (isometric endurance). Isometric endurance time decreased exponentially from 59 to 12s. The curve of the decrease showed a monotone power function (y = x-1). Electromyographic recordings from masseter muscles suggested that fatigable motor units, possibly fast glycolytic units, dropped out during the initial stages of maintained MVC isometric activity. The silent period of the monosynaptic jaw jerk reflex was increased by about 35% following exhaustion of the masseter muscle.

Adult↗
PubMed1984

Effects of topical cooling on isometric contractions of the human masseter muscle.

Six adult males performed tooth clenching for 10 and 80 s at maximum voluntary contraction strength (MVC). Motor activity in the right and left masseter muscles was monitored by surface electromyography. Local temperatures of both cheeks were monitored by a thermocouple. MVC activity for 80 s induced pain and fatigue in both muscles; 10 s of clenching caused no muscle discomfort. Ice, subsequently applied to the right cheek for 30 min, lowered the temperature of the cheek and masseter muscle. The isometric MVC exercises were then repeated. During 10 s of isometric contraction, MVC motor activity in the cooled masseter muscle was significantly increased by 29 per cent; that of the non-cooled contralateral muscle was insignificantly reduced by 12 per cent. During 80 s of clenching, MVC motor activity in the cooled muscle was significantly increased by 30 per cent; that of the non-cooled muscle was insignificantly reduced by 4 per cent. MVC activity for 80 s by the cooled muscle caused no pain and fatigue, but the discomforts continued in the non-cooled muscle. Increased MVC alpha motor activity in the cooled masseter muscle might have resulted from motor facilitation that was mediated by cutaneous, muscular or mucosal cold receptors, or it might have been due to the absence of pain and fatigue.

Adult↗
PubMed1984

Contractile activity of the masseter muscle in experimental clenching and grinding of the teeth in man.

Six human subjects exercised maximum voluntary tooth clenching and right-sided tooth grinding to determine the onset of fatigue in the right and left masseter muscle. Static and dynamic contractile activity of the two muscles was determined by surface electromyography. Muscle fatigue appeared after about 30 s of isometric contractions (clenching), while 30 s of combined concentric and eccentric contractions (grinding) induced no fatigue. In the right muscle the contractile activity of negative work (eccentric contractions of mandibular laterotrusion) was about 50% of that of positive work (concentric contractions of mandibular mediotrusion). During clenching an increased number of contacting teeth might have facilitated the contractile activity of the two muscles. During grinding the height of the cusps of the working side teeth might have contributed to a decrease of tension production by the right masseter muscle. Non-working side tooth contacts and peripheral receptors might have facilitated the contractile activity of the left masseter muscle during tooth grinding. Static contractile activity of the mandibular elevator muscles produced high levels of isometric tension and led to masseter muscle fatigue in about 30 s. The same duration of dynamic contractile activity, resulting in low levels of tension during positive and negative work, did not induce fatigue.

Adult↗
PubMed1983

Effects of cyanoacrylates on die stone.

An evaluation was made of the effects of the application of an increasing number of coats of cyanoacrylate on die stone. The application of one coat of cyanoacrylate adhesive on the surface of trimmed and marked dies increases the surface hardness, increases the scratch resistance, will not change the dimensions of the die appreciably, and renders the margin marking more permanent. Excess resin should be removed immediately by compressed air. The use of hardener instead of water is recommended for mixing Type IV dental stone. Use of the cyanoacrylate method will aid the dentist and the technician in achieving an accurate crown fit.

Calcium Sulfate↗
PubMed1983

Tooth contact patterns and contractile activity of the elevator jaw muscles during mastication of two different types of food.

The pattern of molar and canine contacts and the contractile activity of the masseter and anterior temporal muscle were studied, through integrated electromyography, during right-sided mastication of banana and apple in ten healthy male subjects. Tooth contacts occurred on both the chewing and the non-chewing side. This study does not support the clinical concept that non-chewing side contacts are necessarily detrimental to the jaw muscles and the temporomandibular joints. The activity of the elevator jaw muscles and the tooth contact patterns suggest that the mandible tilted around a sagittal axis, and rotated around a vertical axis, during the phase of elevation of a masticatory cycle.

Adult↗
PubMed1983

The possible activity of large and small jaw muscle units in experimental tooth clenching in man.

Eight human subjects exercised maximum voluntary tooth clenching until there was complete exhaustion of the contracting jaw muscles (isometric endurance time). During the isometric muscle contractions the myoelectrical currents of the masseter and anterior temporalis muscle were sampled by bipolar surface electrodes, integrated, and cumulatively stored. The myoelectrical activity was studied at recording thresholds of 1 microV and 40 microV, i.e. all action potentials below threshold level were ignored. The observations suggested that the number of fast glycolytic and fast oxidative glycolytic motor units in the masseter muscle might have exceeded that in the anterior temporalis muscle; and/or the size of the masseter muscle units might have been larger than that of the anterior temporalis muscle units.

Action Potentials↗