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Biomedical subjects

J D Rugh

Publications and source records attributed to J D Rugh.

At least 19 recordsLinked to original sources
PubMed1992

Electromyographic activity of the jaw-closing muscles in patients with osseointegrated implant fixed partial dentures.

The control of postural and synergistic jaw reflexes involves interrelated sensory input from receptors in the jaw muscles, temporomandibular joint, periodontal ligament, and mucosa. This investigation was done to determine whether a decrease in intraoral sensory afferent discharge significantly altered the onset of the jaw-unloading reflex. The subject population consisted of three groups with 10 subjects in each group. Group 1 had maxillary and mandibular natural teeth and group 2 consisted of edentulous subjects with complete dentures. Group 3 consisted of edentulous subjects with maxillary complete dentures and mandibular complete implant-supported prostheses. The unloading reflex was initiated with a muscle-unloading device and recorded with a storage oscilloscope. A one-way analysis of variance found no significant differences in the unloading-reflex latency for the masseter or temporal muscles among the three experimental groups (p less than 0.05).

Dental Implantation, Endosseous↗
PubMed1991

Behavioral therapy for temporomandibular disorders.

Temporomandibular disorders are varied in terms of etiology, pathophysiology, chronicity, and the disability they involve. The majority of adults in the Western world have some minor symptoms of these disorders, but only about 5% need treatment. Reversible therapies, including medication, physical therapy, behavioral therapy, and bite appliances, are popular today because of the lack of knowledge concerning the natural course of the disorders and the long-term effects of nonreversible treatments. Review articles and published guidelines generally support the use and efficacy of behavioral therapies for temporomandibular disorders. However, because these results are based on studies with methodical weaknesses, the recommendations must be viewed with caution, and further study must be conducted.

Behavior Therapy↗
PubMed1991

Tryptophan supplementation for nocturnal bruxism: report of negative results.

This experiment was designed to study the effect of L-tryptophan on nocturnal bruxism. Portable EMG recorders were used to monitor unilateral masseter muscle activity during sleep in eight patients identified as nocturnal bruxists. Following an initial baseline period, the patients were given, in a randomized double-blind study, either tryptophan (50 mg/kg of body weight) or a placebo for 8 days followed by an additional 8 days of reverse medication. Dietary patterns and food intake were monitored throughout the experimental period. No significant treatment differences in bruxing levels were found, suggesting that L-tryptophan supplementation in the absence of dietary manipulation is ineffective in the treatment of nocturnal bruxism.

Adult↗
PubMed1990

Psychophysiological responsivity on a laboratory stress task: methodological implications for a stress-muscle hyperactivity pain model.

A stress-muscle hyperactivity-pain (SMP) model has been proposed to explain the etiology of certain musculoskeletal pain disorders. According to this model, subjects should show physiological arousal during periods of stress relative to periods of rest. In a test of this prediction, 31 subjects performed a reaction time task that has been used in previous laboratory studies. Multiple psychophysiological variables were monitored during initial and final 10-minute baselines, during performance on nine 2-minute reaction time tasks, and during 36-second rest intervals following each of the 2-minute tasks, Results showed small but statistically significant differences generally supporting the SMP model when masseter EMG was averaged over time periods of 12 seconds to 2 minutes, but not when masseter EMG was averaged over 10- to 18-minute blocks. These results demonstrated the importance of carefully selecting time intervals for analysis. Additional analyses that compared TMD with symptom-free subjects revealed small differences in EMG that supported the SMP model. Analyses of EMG over shorter time intervals also showed, however, that masseter EMG increased during the 36-second rest interval following performance on a 2-minute stress task; this result suggested that a modification of the SMP model may be necessary.

Adult↗
PubMed1990

The effects of psychological stress on electromyographic activity and negative affect in ambulatory tension-type headache patients.

Fourteen female dental hygiene students (seven with episodic tension-type headache and seven who rarely or never experienced headache) wore an ambulatory electromyographic recorder and completed hourly subjective ratings of pain and negative affective states for six days while they carried out their normal daily activities. Three of the days were designated as high stress days by virtue of the fact that the students were required to take a major course examination or undergo a clinical evaluation on that day. The remaining three days were designated as low stress days by virtue of the fact that no unusual demands were made on the students, and they simply attended lectures as usual. All students showed significantly greater levels of electromyographic activity on the high stress days compared to the low stress days, but there was not a statistically significant difference between the headache and control groups. Headache group subjects reported significantly higher levels of pain compared to the control group, but their pain ratings did not differ between high and low stress days. Subjective ratings of negative affective states (anxiety, anger, sadness, and frustration) were significantly greater on high stress days compared to low stress days. Headache group subjects also exhibited a tendency to report higher levels of negative affective states than did control group subjects, but only in the case of frustration was the .05 level of statistical significance achieved.

Adolescent↗
PubMed1990

Hysteresis in jaw positioning following lateral stretches.

The purpose of this study was to examine hysteresis of the masticatory system following brief, voluntary lateral positioning of the mandible. Hysteresis was studied in ten healthy subjects, as a function of both time and distance that the mandible was held laterally off the midline. So that the effects of distance of lateral stretch on hysteresis could be studied, subjects positioned their jaws to the left or right of the midline distances of 2, 4, 6, 8, and 10 mm for ten s. So that the effects of time could be studied, the distance of lateral stretch was held a constant 8 mm for durations of two, four, six, 12, 16, and 20 s. Following each voluntary lateral stretch, subjects relaxed the muscles using EMG biofeedback and allowed the mandible to reposition itself passively. Hysteresis was defined as the difference in the mandibular resting position between pre- and post-stretch recordings. Mean hysteresis effects ranged from 0.7 mm to 1.8 mm. Hysteresis effects were found to increase with both distance and time; after eight s, however, no additional effect of time was noted.

Adult↗
PubMed1990

Comparing learning logs and note summaries in a dental research methods course.

This paper reports a study that examines how two types of writing influenced dental students' performance in critical thinking and recall in a graduate research methods course. Forty-five students in this five-week, lecture-based course were stratified by dental specialty and randomly assigned to one of two groups. The treatment group kept learning logs, expressing personal understanding of lecture material; a second group wrote note summaries, entailing the reorganization of key lecture points. Each student was asked to write for a ten-minute interval during each class meeting. Mean scores for the log writers were higher on a post-course essay measure of critical analysis; note summarizers performed better on recall; while in the direction predicted, differences did not reach statistical significance. Note summarizers' attitude toward future use of their activity in other classrooms was more positive and they complied more highly with their activity than did the log writers. This preference for the note summary method suggests that students may find the structured nature of the summary more useful when being introduced to a dental concept.

Education, Dental, Graduate↗
PubMed1989

Effect of experimental stress on masseter and temporalis muscle activity in human subjects with temporomandibular disorders.

Temporomandibular (TM) disorders have an uncertain aetiology. The purpose of this study was to replicate and extend the work of Yemm (1969) (Archs oral Biol. 14, 873-878, 1437-1439; Br. dent. J. 127, 508-510), who reported a lack of habituation to experimentally induced stress in subjects with TM disorders. In this study, 20 TM disorder patients and 20 controls, matched for age and sex, performed a timed psychomotor task while bilateral masseter and anterior temporalis electromyographic (EMG) activity, finger temperature and skin admittance were monitored. These data were sampled, stored every 4s and averaged by an Apple II Plus/ISAAC interface. A significant trials effect for finger temperature (F[4/152] = 34.99, p less than 0.001) and skin admittance (F[4/152] = 41.90, p less than 0.001) was found, suggesting that the independent variable (stress) had been successfully manipulated. A significant trials by groups effect was found for right temporalis EMG activity (F[3/144] = 3.94, p less than 0.05); the left temporalis showed a similar, but not significant, trend. The masseter muscles did not show differences or trends between groups. No significant differences were found in resting EMG levels or in the initial magnitude of EMG responses during baseline. These results provide support for the hypothesis that TM disorder and control groups respond differently to stress in terms of habituation to stressful stimuli.

Adolescent↗
PubMed1989

Effects of canine versus molar occlusal splint guidance on nocturnal bruxism and craniomandibular symptomatology.

The use of interocclusal orthopedic appliances is the most common method for managing nocturnal bruxism and associated craniomandibular symptoms. Yet there is no consensus on the mechanism of action or best design for optimal clinical results. Posterior disocclusion through canine or anterior guidance is believed to be a key feature. The purpose of this study was to compare a canine versus molar guidance appliance in eight chronic bruxist patients. The appliances were used for 10 to 14 nights. The two appliances provided nearly equivalent effects on nocturnal bruxism in seven of eight subjects. Clinical examination and subjective pain ratings did not differ with the two guidance patterns. These results question the common assumption that canine guidance is a critical design feature for the management of nocturnal bruxism and associated craniomandibular symptoms.

Adult↗
PubMed1989

Design and construction of a pressure algometer.

A handheld pressure algometer is described for the measurement of pain-pressure thresholds. This instrument has a range of measurement of 0 to 16 N/cm2 and can be modified by changing contact points or springs. Technical specifications, a schematic diagram, application examples, and information concerning construction material availability are provided.

Equipment Design↗
PubMed1988

Destructive bruxism: sleep stage relationship.

Despite apparent similar amounts of bruxism, two groups that had been evaluated polysomnographically differed dramatically in symptomatology. Patients with severe symptoms were referred to as the destructive bruxism group and were compared with (a) a group with sleep disturbance complaints who had bruxism and (b) a group of insomniac depressed patients chosen without regard to bruxism. It was hypothesized that not only the presence of bruxism during sleep but its pattern and sleep stage relationship were factors affecting clinical symptoms. The results indicated that the sleep stage relationship was an important factor. Patients with severe symptoms attributed to nocturnal bruxism were likely to have more bruxism in REM sleep than the other groups. These results if replicated prospectively would help explain some of the discrepancies in the literature concerning sleep stage relationship of bruxism, as well as help explain differences in symptomatology of bruxism patients.

Adult↗
PubMed1988

Nocturnal bruxism and temporomandibular disorders.

This chapter has discussed the important aspects of nocturnal bruxism and its relation to disorders of the masticatory system and headaches. Bruxism is believed to be a stress-related sleep disorder, occurring in both men and women, in children, and in adults. In most patients, bruxism results only in minor tooth wear; however, it can become extremely severe with damage occurring in essentially every part of the masticatory apparatus. Nocturnal bruxism should not be overlooked as an etiologic factor in muscular headaches. Short-term acute therapy may involve physical therapy, nocturnal electromyographic biofeedback, and medication to relieve anxiety and improve sleep. Long-term management usually includes some form of stress reduction, change in lifestyle, and an occlusal splint or nightguard to protect the teeth and masticatory system.

Adolescent↗
PubMed1987

Psychological components of pain.

Patients with complex orofacial pain conditions often do not respond as expected to dental care. This article discusses the many psychoanalytic factors that are involved in the pain experience of these patients.

Facial Pain↗
PubMed1986

Nocturnal electromyographic evaluation of masseter muscle activity in the complete denture patient.

Nocturnal oral activity was evaluated in 12 complete denture wearers by means of EMG measurements of the masseter muscle. Patients who had worn dentures for at least 6 months were selected. EMG levels were compared when subjects slept with and without the dentures in the mouth. Three subjects appeared to have reduced EMG values when sleeping with the dentures. However, no overall group trends or significant differences were obtained. High variability in nightly EMG values could not be explained by a post hoc analysis of patient oral symptoms or denture characteristics. Efforts should be directed at improved methodology to study the specific mechanism of the effect of denture wearing on nocturnal muscle activity levels. Additional knowledge is needed on the occurrence and effects of parafunctional habits in the edentulous patients.

Adult↗