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Biomedical subjects

C S Stohler

Publications and source records attributed to C S Stohler.

45 records · Page 3Linked to original sources
PubMed1987

The effects of succinylcholine on mouth opening.

Mouth opening and the resistance to opening developed by the muscles of mastication were measured in 63 children anesthetized with halothane and relaxed with succinylcholine, pancuronium, or vecuronium. Measurement of mouth opening, induced by a constant test force, was made when each patient was deeply anesthetized, as judged by clinical parameters. Succinylcholine, vecuronium, or pancuronium was then administered. The mouth opening measurement was repeated immediately after the loss of limb muscle twitch response and 45 s following the loss of twitch response. For the 24 patients receiving succinylcholine, there was a significant reduction in mean mouth opening (P less than 0.0001) and a significant increase in jaw stiffness (P less than 0.0001) immediately after limb relaxation. Forty-five seconds after full limb relaxation was attained, the mean mouth opening was still reduced (P less than 0.0001) and the mean jaw stiffness was still increased (P less than 0.0003) in the succinylcholine group. Patients receiving either vecuronium or pancuronium did not show a significant change of mouth opening or jaw stiffness following limb relaxation. Three patients, who received succinylcholine, required several attempts at tracheal intubation due to increased resistance to mouth opening. Anesthesia and surgery proceeded in all patients. None of the patients developed malignant hyperthermia. In view of the fact that a reduction in mouth opening was a constant finding when succinylcholine was administered during halothane anesthesia, the assumption that isolated "masseter spasm" or jaw stiffness heralds malignant hyperthermia should be reconsidered.

Anesthesia, Inhalation↗
PubMed1986

A comparative electromyographic and kinesiographic study of deliberate and habitual mastication in man.

Twelve healthy, fully-dentate subjects participated in experiments which included the continuous recording of surface electromyography and jaw movement during habitual and deliberate right-sided or left-sided chewing of a coherent bolus. Analogue data streams were converted to digital values. Root-mean-square (r.m.s.) muscle-activity traces were computed from raw electromyographic data. The working side was defined as the side from which the mandible approached the position of occlusal stoppage when in the most cranially directed part of the chewing cycle. In any given muscle, greater mean peak r.m.s. activities were found with ipsilateral than contralateral bolus replacement (p less than 0.01, s); such differences were more pronounced for the masseter than the anterior temporal muscles. During habitual chewing, mean peak r.m.s. activities exceeded the value established by deliberate mastication with ipsilateral bolus placement in 27 of 48 muscles; this may be because of more vigorous chewing during habitual performance. No subject was strictly unilateral in their preference for bolus placement and in 6 of the 12 subjects, there was a timed side-switching of the bolus within the masticatory sequence. The results also indicated that any averaging of data based upon time-amplitude alone would be inappropriate for habitual chewing because of the call for different working sides within a particular masticatory sequence. Thus a new data format based upon numerical representation of the electromyographic activity against time was introduced.

Adult↗
PubMed1986

Excitatory response of jaw elevators associated with sudden discomfort during chewing.

Abnormalities associated with the chewing contraction of the masseteric and anterior temporal muscles were evaluated in patients who sensed pain in the area of the temporomandibular joint during mandibular movement. The patients were instructed in the use of an electronic switch to mark any event of discomfort/pain during natural chewing. Individual stimulus to response reaction-times were determined. The electromyographic pattern of the jaw elevators was quantified by root mean square (r.m.s.) peak voltage and contraction time. The statistical analysis of group data showed significantly prolonged contraction times and greater r.m.s. amplitudes for chewing cycles with, compared to cycles without, indication of pain. Also, individual data showed statistically significant differences between painful and non-painful cycles in some cases. It is concluded, that the conscious perception of nociception during the closing phase of chewing is associated with an excitatory response of jaw elevators.

Adolescent↗
PubMed1985

Non-linear amplification of electromyographic signals with particular application to human chewing.

A method is described for logarithmically-amplifying electromyographic signals so that the most commonly-occurring events within them are enhanced selectively before digital conversion. There is a need to resolve low and intermediate levels of activity during chewing, while preserving the occasional high-level responses. Besides achieving a higher resolution in subsequent digital sampling, this signal-processing technique increased the representation of low and intermediate activities in polygraphic displays. It further ensured that signals were presented to the A/D converter within the code width of the instrument.

Amplifiers, Electronic↗
PubMed1985

Short and long latency jaw-opening reflex responses elicited by mechanical stimulation in man.

Jaw-opening reflex responses elicited by tapping the chin during maximum clenching in incisal edge-to-edge contact position were studied in 10 healthy subjects. Stimuli were also delivered during weak clenching on a rubber stamp, separating the incisors by approx. 10 mm and protruding the mandible to the edge-to-edge incisor relationship. All four central incisors were stimulated simultaneously. With weak stimuli, there was a short-latency (9.5 ms) digastric response which may have had a disynaptic pathway. Taps of moderate strength produced long-latency (20 ms) responses, and sometimes a short-latency (9.5 ms) component as well. Strong (non-painful) taps produced an even longer-latency digastric response, 30 ms or more following the stimulus with less synchronization than earlier responses. Jaw-jerk reflexes occurred 8.5 ms following the tap, independently of the magnitude of the stimulus. Local anaesthesia of the upper and lower incisors abolished the digastric muscle response. Thus large periodontal afferents may be responsible for the early digastric reflex activity and smaller fibres for later effects. Temporal summation of the reflex response probably occurred when all incisors were stimulated simultaneously.

Adult↗
PubMed1985

Real-time analysis of electromyograms in clinical dentistry.

A neurophysiologic real-time data acquisition and analysis system with a versatile hardware/software combination to be applied in clinical dentistry is introduced. Its application in the clinical environment allowed the analysis of jaw reflexes and the generation of a hard copy output in approximately 3 1/2 minutes. Such a system may provide the basis for advanced diagnostics in dentistry.

Computers↗
PubMed1985

Demonstration of chewing motor disorder by recording peripheral correlates of mastication.

Chewing motor performance was examined in twenty-one patients. Twelve patients had TMJ dysfunction syndrome, eight had occlusal trauma, and one had CNS impairment. Surface electromyography and three-dimensional jaw movement was recorded. Discomfort was recorded by the patient during chewing of beefstick. Specific changes in mandibular movement were related to the presence of pain, discomfort and other symptoms of the TMJ dysfunction syndrome.

Adult↗
PubMed1985

The effect of acrylic bite plane splints and their vertical dimension on jaw muscle silent period in healthy young adults.

A significant question relative to treatment and disappearance of symptoms is raising the bite in combination with a maxillary bite plane splint in patients with TMJ muscle dysfunction. The objective of this research was to investigate the effect, if any, occlusal bite plane splints have on the latency and duration of the mention tap silent period and particularly whether the degree to which the bite is raised is of significance. Recordings were made in healthy young adults from both anterior temporal and masseteric muscles while subjects were clenching at their 70% maximum clenching effort. Placement of a splint significantly (P less than 0.05) prolonged the silent period duration (SPD). However, mean SPD values taken at two different vertical raised bites did not differ significantly (P greater than 0.05). The anterior temporal muscle SPD was less sensitive to a smaller change of vertical dimension than the masseteric SPD. Silent period latencies remained unchanged in all experimental conditions.

Acrylic Resins↗