Effect of tongue position on masseter and temporalis electromyographic activity during swallowing and maximal voluntary clenching: a cross-sectional study.

The purpose of this study was to measure and compare the tonic electromyographic (EMG) activity of the temporalis and masseter muscles following placement of the tongue either on the palate or in the floor of the mouth during swallowing and maximal voluntary clenching (MVC). Thirty healthy dental students with natural dentition and bilateral molar support, between the ages of 18 and 22, with no prior history of oro-facial injury, or current or past pain in the jaw, mouth or tongue participated in the study. Tonic masseter and temporalis EMG activities were recorded using surface electrodes. Subjects were instructed to passively place the tongue either on the anterior hard palate or in the floor of the mouth during swallowing and MVC. At each tongue position, the resulting EMG was recorded. During swallowing, no significant difference in EMG activity was found either for the masseter (P-value = 0.1592) or the temporalis (P-value = 0.0546) muscles, regardless of the tongue position. During MVC, there was a statistically significant difference for both the masseter (P-value = 0.0016) and the temporalis (P-value = 0.0277) muscles with lower levels recorded with the tongue in the floor of the mouth. This study found that in normal, pain-free subjects, placing the tongue in the floor of the mouth significantly reduces masticatory muscle activity during MVC. Thus, it may be considered as a possible therapeutic option to decrease masticatory muscle activity; however, further research is needed in patients with oro-facial pain.

The effect of tongue position and resulting vertical dimension on masticatory muscle activity. A cross-sectional study.

The purpose of this study was to: (a) compare the tonic electromyographic (EMG) activity of the temporalis and masseter muscles between two tongue positions, (b) compare the vertical dimension (VD) resulting from each tongue position and (c) determine the influence of the VD on the tonic EMG activity for each tongue position. Thirty-three healthy dental students with natural dentition and bilateral molar support, between the ages of 18 and 22 years, with no prior history of oro-facial injury, or current or past pain in the jaw, mouth, or tongue participated in the study. Tonic masseteric and temporalis EMG activities were recorded using surface electrodes. Subjects were instructed to passively place the tongue either on the anterior hard palate or in the floor of the mouth. At each tongue position, the resulting EMG and VD were recorded. No significant difference in EMG activity was found for either the masseter (P-value = 0·5376) or temporalis muscle (P-value = 0·7410), between the two tongue positions. However, there was a significant difference in the VD resulting from the two different tongue positions, being greater with the tongue placed in the floor of the mouth. There was no statistically significant correlation between VD and EMG activity for both tongue positions. In spite of the lack of difference in the effect of both tongue positions on the masseteric and temporalis EMG activity, an increment of the VD was registered for the floor of mouth-tongue position. However, VD was not correlated with EMG activity for both tongue positions.

Quality difference in craniofacial pain of cardiac vs. dental origin.

Craniofacial pain, whether odontogenic or caused by cardiac ischemia, is commonly referred to the same locations, posing a diagnostic challenge. We hypothesized that the validity of pain characteristics would be high in assessment of differential diagnosis. Pain quality, intensity, and gender characteristics were assessed for referred craniofacial pain from dental (n = 359) vs. cardiac (n = 115) origin. The pain descriptors "pressure" and "burning" were statistically associated with pain from cardiac origin, while "throbbing" and "aching" indicated an odontogenic cause. No gender differences were found. These data should now be added to those craniofacial pain characteristics already known to point to acute cardiac disease rather than dental pathology, i.e., pain provocation/aggravation by physical activity, pain relief at rest, and bilateralism. To initiate prompt and appropriate treatment, dental and medical clinicians as well as the public should be alert to those clinical characteristics of craniofacial pain of cardiac origin.

Supplemental corticosteroids for dental patients with adrenal insufficiency: reconsideration of the problem.

BACKGROUND: Dental patients with primary or secondary adrenal insufficiency, or AI, may be at risk of experiencing adrenal crisis during or after invasive procedures. Since the mid-1950s, supplemental steroids in rather large doses have been recommended for patients with AI to prevent adrenal crisis. METHODS: To evaluate the need for supplemental steroids in these patients, the authors searched the literature from 1966 to 2000 using MEDLINE and textbooks for information that addressed AI and adrenal crisis in dentistry. Reference lists of relevant publications and review articles also were examined for information about the topic. RESULTS: The review identified only four reports of purported adrenal crisis in dentistry. Factors associated with the risk of adrenal crisis included the magnitude of surgery, the use of general anesthetics, the health status and stability of the patient, and the degree of pain control. CONCLUSIONS: The limited number of reported cases strongly suggests that adrenal crisis is a rare event in dentistry, especially for patients with secondary AI, and most routine dental procedures can be performed without glucocorticoid supplementation. CLINICAL IMPLICATIONS: The authors identify risk conditions for adrenal crisis and suggest new guidelines to prevent this problem in dental patients with AI.

Prevalence of infective endocarditis in patients with systemic lupus erythematosus.

BACKGROUND: Compared with the general population, patients with systemic lupus erythematosus, or SLE, have an increased prevalence of functionally impaired cardiac valves due to the presence of Libman-Sacks lesions. These lesions may place patients with SLE at risk of developing infective endocarditis, or IE. METHODS: The authors performed a retrospective chart review to determine the association between SLE with valvulopathy and IE. They reviewed the records of 361 patients from two health care facilities who had the diagnostic code of SLE. RESULTS: Of the 275 records that met the 1982 revised American Rheumatism Association criteria for SLE, 51 (18.5 percent) were for patients who had a clinically detectable heart murmur that resulted in echocardiography being performed. Nine (3.3 percent) of the 275 patients had a clinically significant valvular abnormality, three (1.1 percent) had a potentially significant valvular abnormality, and one (0.4 percent) had a history of IE that was diagnosed two years before her diagnosis of SLE was made. CONCLUSIONS: The findings suggest that 18.5 percent of this cohort of patients with SLE had a clinically detectable heart murmur that would require further investigation to determine its significance. Furthermore, between 3.3 and 4.4 percent of the study population had cardiac valve abnormalities that potentially required antibiotic prophylaxis before certain dental procedures. However, the authors identified no cases that demonstrated an association between IE and diagnosed SLE. CLINICAL IMPLICATIONS: Dentists should query their patients with SLE about their cardiac status and consult with the patient's physician if the cardiac status is unknown. Patients with confirmed valvular abnormalities should receive antibiotic prophylaxis for designated bacteremia-producing dental procedures.

Nonodontogenic toothache.

Toothache is a common complaint in the dental office. Most toothaches have their origin in the pulpal tissues or periodontal structures. These odontogenic pains are managed well and predictably by dental therapies. Nonodontogenic toothaches are often difficult to identify and can challenge the diagnostic ability of the clinician. The most important step toward proper management of toothache is to consider that the pain may not be of dental origin. Signs and symptoms suggestive of nonodontogenic toothache are as follows: 1. Inadequate local dental cause for the pain. 2. Stimulating, burning, nonpulsatile toothaches. 3. Constant, unremitting, nonvariable toothaches. 4. Persistent, recurrent toothaches over months or years. 5. Spontaneous multiple toothaches. 6. Local anesthetic blocking of the suspected tooth does not eliminate the pain. 7. Failure to respond to reasonable dental therapy of the tooth.

Need and Demand for Oral Medicine Services in 1996. A report prepared by the Subcommittee on Need and Demand for Oral Medicine Services, a subcommittee of the Specialty Recognition Committee, American Academy of Oral Medicine.

The need and demand for oral medicine services in the United States and Canada was determined by a prospective survey of American Academy of Oral Medicine practitioners who attended the Academy's 1996 annual meeting. Of the 50 surveys returned from 149 eligible registrants, it was determined that, on the average, oral medicine practitioner respondents practiced 2.3 days per week and treated 8.7 patients per day; this amounts to more than 40,000 patient-care visits per year. Almost 90% of patients were treated because of medically compromising conditions, oral mucocutaneous disease, or chronic orofacial pain. Most of the care (52%) was provided in non-university settings. Most treatment involved the comprehensive evaluation of complex oral problems (36.7%), the prescription of medications (24.2%), or comprehensive dental treatment (21.8%) for patients with severe and life-threatening medical conditions. These results suggest that oral medicine services are needed and that demand for these services is high.

The influence of deep (odontogenic) pain intensity, quality, and duration on the incidence and characteristics of referred orofacial pain.

This study examined the effects of the intensity, quality, and duration of odotogenic pain on the incidence, pattern, and clinical characteristics of pain referral in the orofacial region. Four hundred consecutive patients reporting with posterior toothache to the dental emergency clinic were included. Patients completed a standardized clinical questionnaire consisting of a numerical rating scale for pain intensity and chose verbal descriptors from a list of adjectives describing the quality of their pain. In addition, patients indicated sites to which pain referred by drawing on a mannequin* of the head and neck. Pain intensity was found to significantly affect the presence of referred pain (P < .005). However, neither duration nor quality of pain influenced the incidence of referred pain. Finally, pain referral occurred in vertical laminations as indicated on mannequin drawings, but these were not found to be diagnostic because of extensive horizontal overlap. The association of intensity and referral is attributed to central nervous system hyperexitability causing expansion of receptive fields and spread and referral of pain.

Salivary cortisol response to dental treatment of varying stress.

The physiologic stress of various dental procedures (dental examination, dental prophylaxis, restoration, root canal therapy, and tooth extraction) was measured in 50 nonsmoking healthy men between the ages of 18 and 55 years (mean 34.6 years, range 21 to 53 years) with a salivary cortisol assay. Expectorated saliva was collected at four time points: 10 minutes before the start of the procedure, 15 minutes after the patient was seated, at the end of the procedure, and 1 hour after the completion of the procedure. Of the 196 samples included for analysis, mean cortisol values ranged from 0.1 to 3.8 micrograms/dl with a recovery of 100% +/- 8.4%. The mean cortisol value for the extraction group (1.09 +/- 0.42 microgram/dl) was significantly different (p < 0.05) from the mean values of the examination (0.46 +/- 0.10 microgram/dl), prophylaxis (0.64 +/- 0.64 microgram/dl), root canal (0.49 +/- 0.07 microgram/dl), and restorative (0.60 +/- 0.04 microgram/dl) groups as determined by the Duncan's multiple range test. Cortisol levels decreased from the initial reading to the end of the procedure by about 15% for patients undergoing an examination, root canal, and restorative procedure. Cortisol levels at the end of the procedure were elevated in the prophylaxis (55%) and extraction (148%) groups compared with the baseline cortisol recording. A minority of patients in the prophylaxis group had elevated cortisol levels throughout dental treatment, whereas cortisol levels were elevated during treatment in 80% of patients undergoing extraction. These data suggest that the adrenal stress response associated with tooth extraction(s) is greater than that associated with other routine dental procedures.

Comparison of psychologic and physiologic functioning between patients with masticatory muscle pain and matched controls.

This study explored the physiologic and psychologic distinctions between masticatory muscle pain patients and age and sex-matched normal controls. Subjects completed several standardized psychologic tests. They then underwent a laboratory stress profile evaluation to obtain physiologic measures (EMG, heart rate, systolic and diastolic blood pressure) under conditions of rest, mental stress, and relaxation. The pain patients reported greater anxiety, especially cognitive symptoms, and feelings of muscle tension than did the controls. Under stress, pain patients had higher heart rates and systolic blood pressure than the controls. Electromyogram activity in the masseter regions was not significantly different between the pain and control group. The results are discussed in terms of the likely mechanisms that might account for the observed differences between masticatory pain patients and normal subjects.

Stretch-based relaxation and the reduction of EMG activity among masticatory muscle pain patients.

This study explored the efficacy of stretch-based relaxation procedures for the reduction of muscle activity in the masseter regions of subjects diagnosed with masticatory muscle pain disorders. Thirty-four subjects with elevated masseter activity were assigned randomly to either a postural relaxation/rest experimental group or a stretch-based relaxation experimental group. Following a psychosocial stressor and application of the relaxation procedure, persons in the stretch-based group showed greater reductions in EMG activity than did those in the postural group for the right masseter region (t = 1.94, P less than .04) and the left masseter region (t = 2.07, P less than .03). The results are discussed in terms of the implications of these findings for further research concerning the etiology and treatment of masticatory muscle pain.

Therapeutic considerations in special patients.

Careful attention to patients' histories and their medical problems and consultation with their physicians should provide sound bases for selection of drugs. Antibiotic prophylaxis for patients with cardiovascular disorders is described for American Heart Association standards, but for other indications sound judgment based on the principles of antibiotic prophylaxis must be the rule. Patients with end-stage renal disease and severe liver impairment may be at risk with certain drugs. The most critical time for consideration of use of drugs during pregnancy is the first trimester. However, careful selection of drugs for use during the balance of the term can reduce the risk of harm to the mother and fetus.

The effect of nitrous oxide and age on psychological and psychomotor performance.

Healthy older and younger males were compared on several psychomotor and cognitive measures before, during, and after N(2)O inhalation. Age did not appear to be a significant factor in determining response to N(2)O though on several measures younger subjects are superior to older under all conditions. N(2)O had a significant effect only on reaction time and facial recognition tasks. The relation of these findings to previous work is discussed.

Effect of age on the digit blood flow response to sedative concentrations of nitrous oxide.

Twenty healthy male subjects [11 young, x̄ = 25.4 ± 0.8 (SEM) years old; 9 elderly, x̄ = 64.5 ± 0.7 years] volunteered for a study designed to investigate the effect of age on several cardiovascular parameters to inhaled N(2)O-O(2). The protocol was designed to mimic the administration of N(2)O-O(2) for sedation in the dental office, although no dental treatment was performed. Clinical criteria were used to judge the appropriate sedative level for each subject; no attempt was made to establish doseresponse relationships. Digit blood flow was measured by strain-gauge plethysmography, and heart rate, arterial blood pressure, respiratory rate, and skin temperature were monitored and recorded. N(2)O and CO(2) levels were monitored in end-tidal gas samples by gas chromatography; machine gauge readings were calibrated against known gas mixtures by the same technique.Under the conditions of this experiment both healthy young and healthy elderly subjects experienced a marked (200-300%) increase in digit blood flow during N(2)O inhalation, compared to that during air and 100% O(2) inhalation. There was no significant difference in the degree of flow increase between young and elderly subjects. Also, there were no significant differences in the response of these healthy young and healthy elderly subjects to sedative concentrations of N(2)O with regard to heart rate, arterial blood pressure, respiratory rate, skin temperature, or mean end-tidal CO(2) levels. The data indicate that N(2)O, in the concentrations routinely administered in the dental office for sedation, does not have a differential effect on the measured parameters in healthy elderly and healthy young males.

The effects of nitrous oxide administration in the healthy elderly: N2O elimination and alveolar CO2.

Healthy young and elderly males were administered sedative concentrations of nitrous oxide/oxygen (N(2)O/O(2)) under a protocol designed to mimic that used in a dental operatory. Samples of end-tidal expired gas were taken at the end of 30-minutes inhalation of, and periodically for 70 minutes after withdrawal from, nitrous oxide/oxygen. Samples were analyzed to monitor the decline of alveolar nitrous oxide levels and any changes in alveolar carbon dioxide levels, to determine if there were any age-related differences. The fall in alveolar N(2)O following cessation of administration was rapid, and in a double-exponental manner as was expected. No age-related difference in N(2)O decline was observed. Alveolar carbon dioxide (CO(2)) levels were lower and more variable in the elderly group. Both groups exhibited elevated CO(2) levels at the end of the N(2)O period, and an unexplained rise in CO(2) at approximately 30 min post N(2)O.