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Biomedical subjects

J D Rugh

Publications and source records attributed to J D Rugh.

At least 37 records · Page 2Linked to original sources

Does chewing performance depend upon a specific masticatory pattern?

The purpose of this article is to review the literature concerning the ideal chewing pattern for best chewing performance. We conclude that at this time there is not one ideal chewing pattern which can be used clinically or in research to assess the health of the mastication apparatus nor to predict chewing performance. It is clear that human masticatory behaviour is one of the most complex human behaviours. Chewing is under the control of the central pattern generator located in the brain stem but is influenced by dental and temporomandibular joint morphology. The most important portion of the chewing cycle is the area entering and leaving the intercuspal position where gliding contacts occur. Maximal chewing capability will likely occur when the chewing pattern follows the dental anatomy unique to the individual. The chewing cycle appears to increase the lateral component of its movement when increased chewing efficiency is required. These situations include increased hardness or the size of bolus, the position of the bolus and the results of the proceeding chewing stroke. The chewing pattern for any one cycle is influenced by a number of factors, thus it is not surprising that the question of the ideal chewing pattern remains unresolved.

Dental Occlusion↗

Psychosocial predictors of high-risk patients undergoing orthognathic surgery.

The purpose of this analysis was to identify a set of predictor variables that are prospectively related to postsurgical outcomes. Specifically, psychosocial characteristics were sought to predict postsurgical outcomes. The 5 Revised Symptom Checklist-90 (SCL-90-R) scales, the neuroticism score of the Eysenck Personality Inventory (EPI), the psychosocial domain score from the Sickness Impact Profile (SIP), and 4 scales from the Oral Health Status Questionnaire (OHSQ) were used as the predictors. A total of 31 male and 86 female subjects participated in this multicenter randomized trial, which compared rigid and wire fixation. Data were collected prior to placement of orthodontic appliances, 1 to 2 weeks presurgery, and at 1 week, 8 weeks, 6 months, and 2 years after surgery. Baseline oral health was used as an indicator of postsurgical oral health functioning. A path analytic model of influences on presurgical oral health was estimated (R2 = 0.43). The results suggest that presurgical screening of demographic characteristics (age, sex, and ethnicity), oral health (the OHSQ), quality of life issues (SIP), and personality features (SCL-90-R), accounts for 23% to 39% of the variance in postsurgical oral health outcomes. The path analysis conducted suggests that a patient's age, ethnicity, gender, and elevated scores on the EPI have indirect effects on postsurgical health. As determined by a 2-stage least squares regression model, 3 variables--the patient's presurgical oral health (per the OHSQ), pre- and postsurgical Global Severity Index (GSI) score from the SCL-90-R, and the psychosocial scale score from the SIP--were found to have a statistically significant impact on postsurgical outcomes. Additionally, the GSI, SIP, and OHSQ are reliable measures in predicting oral health outcomes.

Adult↗

Effects of hypesthesia on oral behaviors of the orthognathic surgery patient.

PURPOSE: The purpose of this study was to compare orthognathic surgery patients with and without significant hypesthesia with respect to perceived problems with specific oral behaviors. PATIENTS AND METHODS: Data from 116 patients 6 months after bilateral sagittal split osteotomy (BSSO) and mandibular advancement were analyzed. Tactile sensation in the right and left mental nerve areas was determined using monofilaments and brush strokes (von Frey hairs). The right infraorbital region was used as a control. A difference of 450 mg of force between the control and test sites was considered significant hypesthesia. Patients rated their level of subjective problems with swallowing liquids or solids, smiling, spitting, kissing, speaking, eating, and drooling on a scale from 1 (none to mild) to 7 (extreme). A value of 5 or greater was considered significant impairment. RESULTS: Hypesthesia was shown in 23 patients (19.8%) with the monofilaments and in 29 patients (25.0%) using brush stroke direction. In each of these two groups, a significant correlation was observed between hypesthesia and difficulty in chewing and kissing. No correlation was observed between any of the remaining seven oral behaviors and hypesthesia. CONCLUSION: These findings suggest that only certain oral behaviors are affected by hypesthesia of the mental nerve.

Adolescent↗

Health-related quality of life following orthognathic surgery.

A randomized controlled trial was conducted to compare the effects of rigid and wire fixation on health-related quality of life following surgical mandibular advancement in patients with Class II malocclusions. Sixty-four patients randomly selected to receive rigid fixation with bicortical position screws were compared with 63 patients randomly selected to receive nonrigid fixation with inferior border wires. Quality of life was measured using the Sickness Impact Profile, a generic measure of health-related quality of life, and the Oral Health Status Questionnaire, a specific measure of oral health and function designed for use with orthognathic surgery patients. Patients were evaluated prior to application of orthodontic appliances, approximately 2 weeks before surgery, and 1 week, 8 weeks, 6 months, 1 year, and 2 years following surgery. Neither instrument revealed a statistically significant difference in quality of life between wire and rigid fixation at any time period. The health-related disability associated with Class II malocclusion is modest compared to many other medical conditions. Nonetheless, orthognathic surgery patients exhibit progressive and statistically significant improvement in health-related quality of life across a wide variety of functional domains, regardless of the fixation method used.

Adolescent↗

Effects of major Class II occlusal corrections on temporomandibular signs and symptoms.

This study explored the relationship between malocclusion and signs and symptoms of temporomandibular disorders (TMD) in 124 patients with severe Class II malocclusion, before and 2 years after bilateral sagittal split osteotomy (BSSO). Patients were evaluated with the Craniomandibular Index (CMI), the Peer Assessment Rating Index (PAR Index, to assess gross changes in the occlusion), and symptom questionnaires. The results showed a significant improvement in occlusion; PAR Index scores dropped from a mean of 18.1 before surgery to a mean of 6.1 at 2 years postsurgery (P < 0.001). The CMI and masticatory index (MI) for muscle pain indicated clinically small but statistically significant improvement (P = 0.0001) from before surgery (mean CMI = 0.14, mean MI = 0.15) to after surgery (mean CMI = 0.10, mean MI = 0.08). The number of patients with clicking upon opening decreased significantly from 33 (26.6%) to 13 (10.5%) (P = 0.001). However, the number of patients with fine crepitus increased from 5 (4.0%) before surgery to 16 (12.9%) at 2 years postsurgery (P = 0.005). Significant reductions in subjective pain and discomfort were also found 2 years after surgery. The magnitude of change in muscular pain was not related to the severity of the pretreatment malocclusion, a finding that suggests that factors other than malocclusion may be responsible for the change in TMD.

Adolescent↗

Comparing prospective and retrospective evaluations of temporomandibular disorders after orthognathic surgery.

The authors conducted a study to document agreement between prospective examinations performed by trained clinical trial examiners and retrospective surgical chart reviews in identifying signs and symptoms of temporomandibular disorders, or TMD. Only a small fraction of the signs and symptoms identified by clinical trial examiners were documented in the surgical charts. Studies relying on retrospective chart reviews may seriously underestimate signs and symptoms of TMD.

Adolescent↗

Effects of electrical stimulation to the soft palate on snoring and obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a disorder and has been associated with social and physical problems. Many treatments of OSA have been proposed with various levels of success. Seven patients with histories of snoring and OSA participated in this pilot study to evaluate the effects of electrical stimulation to the soft palate. Each patient slept with a palatal appliance that delivered a weak electrical stimulus to the soft palate on activation. A 3 milliampere stimulus in the range of 9 to 10 volts was found to be effective in terminating snoring without causing patient arousal. The effects of the stimulus on OSA were variable. The results of this study indicated that electrical stimulation of the soft palate may be effective as a treatment for snoring and OSA and warrants further investigation.

Adult↗

A comparison of questionnaire versus monofilament assessment of neurosensory deficit.

PURPOSE: Because neurosensory deficit is commonly reported by patients after orthognathic surgery, it is important to know how accurately patients can report their own sensory deficit. This analysis compares the results of objective neurosensory tests with the results of a subjective patient questionnaire. MATERIALS AND METHODS: Before and 6 months after bilateral mandibular sagittal ramus split osteotomy, 101 patients with class II facial deformities were asked to rate sensations of numbness or tingling in the area of the mental nerve. Simultaneously, they were objectively tested using monofilament neurosensory tests (light touch and brush stroke direction). RESULTS: More than 70% of patients subjectively reported neurosensory problems, but objective assessment identified neurosensory deficits in less than 60% of the patients. The sensitivity and specificity of the patients' subjective assessments were 75.3% and 52.8%, respectively, for the light touch test, and 77.9% and 59.8%, respectively, for the brush stroke test. CONCLUSIONS: It was concluded that when monofilament neurosensory testing is used as the gold standard, patients appear to overreport neurosensory problems; ie, the positive predictive value of patient reports is only 63.2%, resulting in frequent false positives.

Adolescent↗

Skeletal change at surgery as a predictor of long-term soft tissue profile change after mandibular advancement.

PURPOSE: This study examined the time course of hard and soft tissue changes after mandibular advancement surgery and the association between skeletal changes as a result of surgery and subsequent soft tissue changes. PATIENTS AND MATERIALS: Subjects were enrolled in a randomized clinical trial of rigid versus wire fixation after sagittal split ramus osteotomy, with cephalometric data obtained before orthodontics, immediately before surgery and at 8 weeks, 6 months, 1 year, and 2 years postsurgery. This early report describes changes in 20 Caucasian female subjects who had completed all phases of the study; these were not segregated by fixation method. Cephalometric changes were referenced to a cranial base coordinate system. Differences in soft and hard tissue changes among time intervals were examined using analysis of variance; the associations between immediate surgical change in chin landmarks and subsequent short- and long-term soft and hard tissue changes were examined using linear regression analysis. RESULTS: Soft and hard tissue mandibular structures were positioned anteriorly and inferiorly during surgery; the horizontal and vertical hard tissue mandibular changes were stable for 2 years after surgery (P > .30), as were the vertical soft tissue changes (P > .08). There was horizontal relapse of the lower lip and the inferior sulcus (P < .03) by 8 weeks; no horizontal relapse was detected in soft tissue chin points for up to 2 years after surgery. The time course of changes in osseous pogonion was more strongly predicted by the amount of surgical osseous chin change than were changes in soft tissue chin projection. CONCLUSIONS: Prediction of changes in soft tissue chin projection after mandibular advancement surgery is less certain as time from surgery increases and less certain than the prediction of changes in bony chin projection.

Adolescent↗

Signs of temporomandibular disorders in patients with horizontal mandibular deficiency.

This study assessed the relationship between temporomandibular disorders (TMD) and malocclusion in a group of 102 patients with horizontal mandibular deficiency who had elected mandibular advancement surgery. The prevalence of TMD as reflected by the overall Craniomandibular Index, Dysfunction index, and Muscle index scores was within the range of non TMD populations (mean Craniomandibular Index = 0.14; mean Dysfunction index = 0.12; mean Muscle index = 0.15). Forty-two percent of the patients exhibited essentially no signs of TMD, 7.8% had primarily muscle tenderness to palpation, 36.3% had joint sounds with or without temporomandibular joint tenderness, and 13.7% had combined muscle-joint signs. There were no convincing correlations among any of the cephalometric variables and Craniomandibular Index, Dysfunction index, and Muscle index scores. A subgroup of 30 of this patient population was evaluated both before and during orthodontic treatment just prior to surgery. No statistically significant changes were found in Craniomandibular Index, Dysfunction index, or Muscle index scores. Thus, a period of orthodontic treatment in these patients does not appear to increase the probability of TMD.

Adolescent↗

The effect of pain from orthodontic arch wire adjustment on masseter muscle electromyographic activity.

Pain has been shown to have an effect on muscle activity even when it does not originate in the muscle itself or in the related joint. The effect of pain from arch wire adjustment on jaw muscle activity is unclear. This study systematically evaluated the effects of orthodontic arch wire adjustment pain on masseter electromyographic (EMG) activity and on the swallowing threshold. The EMG recordings were made on 22 subjects (ages 11 to 15) under three conditions: chewing five peanuts (10 seconds), watching TV chewing gum (15 minutes), and watching TV with no gum (15 minutes). An arch wire adjustment or placebo adjustment was then made. Subjects returned after 48 hours, and the EMG measurements were made under the same conditions. After 3 weeks, subjects received arch wire or placebo treatment in a crossover design with identical recording procedures. The EMG levels while chewing peanuts decreased in 18 of 22 subjects after treatment, compared with 9 of 22 subjects after the placebo. While watching TV with gum, the EMG levels of 20 of 22 subjects decreased after treatment, compared with 9 of 22 subjects after the placebo. The number of chewing strokes before swallowing increased significantly after treatment compared with after placebo. The results suggest that orthodontic pain on teeth tend to reduce muscle activity during function.

Adolescent↗

Evaluation of a training program intended to calibrate examiners of temporomandibular disorders.

The adequacy of a training program intended to calibrate examiners of temporomandibular disorders (TMD) was evaluated. Eight examiners blindly rated 12 subjects with various TMD signs and symptoms after participating in a 5-h intense training procedure. Some examiners had earlier experience of TMD examinations, and some were newly trained. The Craniomandibular Index was used as the assessment instrument. Agreement within the whole group of examiners was low. Training tended to increase the probability of correctly registering signs. It is concluded that the program was not sufficient to create reliability among multiple examiners. More extensive training, not only to a standard but also between the different examiners, appears necessary. Revision of the examination technique is suggested, and recommendations for strengthening the calibration procedures are made.

Adult↗

Temporomandibular disorders: assessment of psychological factors.

Factors such as psychological stress, anxiety, depression, oral habits, and chronic pain behaviors have been found in subgroups of Temporomandibular Disorders (TMD) patients. This paper reviews the current status of diagnostic methods and instruments designed to identify various psychological factors. The authors offer the following general conclusions: Although the DSM-III-R has significant limitations, it is currently the most common gold standard with which other psychological instruments are compared. There are several specific assessment instruments, such as the Beck Depression Inventory and the Zung Self-Rating Depression Scale, which have been found to have acceptable sensitivity and specificity scores. In addition, certain simple screening questions may be cost-effective for the identification of psychological factors. Because of studies indicating that the dentists' recognition of psychological factors is inaccurate, a brief screening questionnaire may be useful in TMD patients. The literature does not support the routine use of the MMPI. A major conclusion of this review is that there are several psychological instruments available which have demonstrated reasonable validity through a blind comparison with a gold standard. There is need for further development and testing of brief screening instruments using clinical decision methods.

Anxiety↗

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↗

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↗

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↗

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↗