Chronic temporomandibular disorders are not necessarily associated with a compromised endogenous analgesic system.

AIMS: To test whether temporomandibular disorders (TMD) case-control differences in conditioned pain modulation (CPM) exist, using a mechanically evoked temporal summation (TS) model. METHODS: A series of 10 repetitive, mildly noxious, mechanical stimuli were applied to the fingers of 30 women with TMD, who had a primary diagnosis of masticatory myofascial pain, and 30 age-matched healthy women. The subjects rated the pain intensity caused by the 1st, 5th, and 10th stimuli in the series. To evaluate CPM, the same series of mechanical stimulations were applied with concomitant exposure of the other hand to a painfully cold water bath. Statistical inferences were based on t tests, chi-square tests, or analysis of variance (ANOVA), as appropriate. RESULTS: Pain ratings increased significantly with stimulus repetition (P < .01) and CPM significantly reduced TS of pain (P < .01). Of particular note, both groups showed very similar degrees of CPM, with no significant group difference. CONCLUSION: Painful TMD is not necessarily associated with a compromised ability to engage the endogenous analgesic system in an experimental setting.

Sleep disorders and their association with laboratory pain sensitivity in temporomandibular joint disorder.

STUDY OBJECTIVES: We characterized sleep disorder rates in temporomandibular joint disorder (TMD) and evaluated possible associations between sleep disorders and laboratory measures of pain sensitivity. DESIGN: Research diagnostic examinations were conducted, followed by two consecutive overnight polysomnographic studies with morning and evening assessments of pain threshold. SETTING: Orofacial pain clinic and inpatient sleep research facility. PARTICIPANTS: Fifty-three patients meeting research diagnostic criteria for myofascial TMD. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: We determined sleep disorder diagnostic rates and conducted algometric measures of pressure pain threshold on the masseter and forearm. Heat pain threshold was measured on the forearm; 75% met self-report criteria for sleep bruxism, but only 17% met PSG criteria for active sleep bruxism. Two or more sleep disorders were diagnosed in 43% of patients. Insomnia disorder (36%) and sleep apnea (28.4%) demonstrated the highest frequencies. Primary insomnia (PI) (26%) comprised the largest subcategory of insomnia. Even after controlling for multiple potential confounds, PI was associated with reduced mechanical and thermal pain thresholds at all sites (P < 0.05). Conversely, the respiratory disturbance index was associated with increased mechanical pain thresholds on the forearm (P < 0.05). CONCLUSIONS: High rates of PI and sleep apnea highlight the need to refer TMD patients complaining of sleep disturbance for polysomnographic evaluation. The association of PI and hyperalgesia at a nonorofacial site suggests that PI may be linked with central sensitivity and could play an etiologic role in idiopathic pain disorders. The association between sleep disordered breathing and hypoalgesia requires further study and may provide novel insight into the complex interactions between sleep and pain-regulatory processes.

Temporal summation of pain characterizes women but not men with temporomandibular disorders.

AIMS: To examine differences in temporal summation of mechanically evoked pain between women and men suffering from chronic pain associated with temporomandibular disorders (TMD), as well as between male TMD patients and healthy controls. METHODS: Series of 10 repetitive, mildly noxious mechanical stimuli were applied to the fingers of 27 female TMD patients, 16 male TMD patients, and 20 healthy men. The subjects rated the pain intensity caused by the 1st, 5th, and 10th stimulus in the series. Pain ratings were analyzed by 3-way repeated-measures analysis of variance. RESULTS: Pain ratings increased significantly with stimulus repetition for the female TMD patients (P < .001). Women with TMD exhibited significantly greater temporal summation of pain than TMD men (P < .001). Neither the healthy men nor the male TMD patients exhibited significant increases in pain perception with repetitive stimulation. In the female TMD patient group, perceptual pain magnitudes were higher with an interstimulus interval of 2 seconds rather than 10 seconds (P < .005). CONCLUSION: These findings suggest that central nociceptive processing upregulation is likely to contribute to TMD pain for women but is not a factor for

Trigeminal neuralgia in a patient with multiple sclerosis and chronic inflammatory demyelinating polyneuropathy.

BACKGROUND: Trigeminal neuralgia (TN) is characterized by unilateral, severe, brief, stabbing, recurrent pain in the distribution of one or more branches of the fifth cranial nerve. Symptomatic or secondary TN involves TN-like pain that develops owing to a central nervous system lesion (benign or malignant) or to multiple sclerosis (MS). CASE DESCRIPTION: The authors present a report of a unique case of a 43-year-old patient with unilateral TN, MS and concomitant chronic inflammatory demyelinating polyneuropathy. The facial pain preceded any other manifestations of the systemic disorders, and only after repeated neurological examinations were these diagnoses established. CLINICAL IMPLICATIONS: Magnetic resonance imaging of the brain and repeated neurological evaluations should be implemented in all patients with TN to rule out the presence of underlying disease. The dental practitioner should be familiar with TN to avoid unnecessary dental interventions and ensure prompt initiation of appropriate treatment.

Attitudes of advanced dental education students toward individuals with AIDS.

The number of patients with HIV/AIDS who receive dental care is increasing. This study was undertaken to gain a better understanding of the attitudes of dentists enrolled in postgraduate training toward AIDS and homosexuals. Each respondent received a 500-word patient case vignette and two scales for recording impressions of the person described in the vignette. There were four vignettes, identical except that the portrayed individual's illness was identified as either AIDS or leukemia and sexual preference as either homosexual or heterosexual. Two-way analyses of variance and t tests (p<.05) revealed a bias toward individuals with AIDS and toward homosexuals. Respondents reacted more negatively to both groups on the Social Interaction Scale as seen in total scale scores as well as to individual scale items. In addition, although overall Prejudicial Evaluation Scale scores displayed no evidence of bias, several individual scale items did. It is important to ensure that dentists' attitudes toward patients with AIDS and homosexuals are not a barrier to these patients receiving the best possible care. Therefore, dental education programs at all levels should give consideration to interventions to address provider attitudes and potential biases.

Attitudes of dental hygiene students toward individuals with AIDS.

This study was undertaken to gain a better understanding of dental hygiene students' attitudes toward AIDS and homosexuals. Each respondent received a 500-word patient case vignette and two scales for recording impressions of the person described in the vignette. There were four vignettes, identical except that the portrayed individual's illness was identified as either AIDS or leukemia, and sexual preference as either homosexual or heterosexual. No differences in overall ratings on either scale were noted based on the patient's disease status or sexual preference or the interaction between sexual preferences with disease type. Similarly, neither scale displayed significant differences on any of the individual items based on the patient's sexual preference. There were, however, significant differences for several individual items on both scales based on the patient's disease type; students responded more negatively to individuals with AIDS. It appears, therefore, that the hygiene students displayed no bias toward homosexuals and only very minimal bias toward individuals with AIDS.

Sex differences in temporal summation of pain and aftersensations following repetitive noxious mechanical stimulation.

Several studies demonstrate that women are more sensitive to experimental pain than men. In addition, women exhibit greater temporal summation of heat and mechanically evoked pain. Since temporal summation of pain is centrally mediated, its greater expression in women suggests a central nociceptive hyperexcitability relative to men. The purpose of this study was to pursue this theory, by further assessing sex differences in (1) temporal summation of mechanically evoked pain, and (2) aftersensations following repetitive noxious stimulation. Sixteen series of 10 repetitive, mildly noxious, mechanical stimuli were applied to the fingers of 25 women and 25 age-matched men. The subjects rated the pain intensity and unpleasantness caused by the first, fifth and tenth stimulus in the series, as well as their aftersensations 15 s and 1 min following the end of stimulation. Data were analyzed by three-way repeated-measures analysis of variance. Pain and unpleasantness ratings increased with repetition of stimulation (P<0.0001). Temporal summation of pain intensity and unpleasantness ratings were more pronounced in women than men (P<0.0001). In addition, significant temporal summation occurred only with 2 s interstimulus interval for men (P<0.0005) but with 2 and 5 s interstimulus interval for women (P<0.0001). Moreover, women provided greater ratings for the intensity and the unpleasantness of aftersensations (P<0.0005) and reported painful aftersensations at greater frequency (P<0.05) Greater temporal summation of pain and aftersensations in women suggests that their central processing of nociceptive input may be more easily upregulated into pathological hyperexcitability, possibly accounting for the higher prevalence of various chronic pain conditions among women.

Chronic paroxysmal hemicrania: a case report and review of the literature.

Chronic paroxysmal hemicrania (CPH) is a rare type of headache that is characterized by daily, multiple, short-lasting attacks of severe pain and associated autonomic symptoms. The pain is strictly unilateral and presents most commonly in the ocular, temporal, maxillary, and frontal areas. The excruciating, throbbing pain of CPH can be misdiagnosed as pain associated with dental pathology, especially when located in the maxillary area. Moreover, pain manifesting in the maxillary and temporal areas can be confused with temporomandibular disorders. CPH patients occasionally seek treatment in dental offices or orofacial pain centers. Accordingly, dentists should be familiar with CPH in order to avoid unnecessary, irreversible dental treatment. A case is presented to highlight many of the features of CPH.

Facial pain as first manifestation of lung cancer: a case of lung cancer-related cluster headache and a review of the literature.

Facial pain can, on rare occasions, be the presenting symptom of lung cancer. This report describes a patient with non-metastatic lung cancer, which was associated with attacks of debilitating facial pain, presenting as cluster headache. Moreover, 32 reported cases of lung cancer-related facial pain (including the present one) are reviewed, and their clinical features are summarized. The facial pain is almost always unilateral, and is most commonly localized to the ear, the jaws, and the temporal region. The pain is frequently described as severe and aching, and may be continuous or intermittent. Aggravation and expansion of the pain, digital clubbing, increased erythrocyte sedimentation rate, and hypertrophic osteopathy, may contribute to the diagnosis. Referred pain, due to invasion or compression of the vagus nerve, as well as paraneoplastic syndrome secondary to the production of circulating humoral factors by the malignant tumor cells, is implicated in the pathophysiology of facial pain associated with non-metastatic lung cancer. Radiotherapy and tumor resection with vagotomy are very effective in aborting the facial pain. Thus, lung cancer should be included in the differential diagnosis of facial pain that is atypical and/or refractory to treatment.

Evidence for up-regulated central nociceptive processing in patients with masticatory myofascial pain.

AIMS: Previous work suggests that hyperexcitability of central nociceptive neurons may play a role in the pain of temporomandibular disorders (TMD). The aim of this study was to test this theory by assessing differences, between myalgic TMD patients and pain-free controls, in temporal summation of mechanically evoked pain and aftersensations following repetitive noxious stimulation. METHODS: Sixteen series of 10 repetitive, mildly noxious mechanical stimuli were applied to the fingers of 25 female TMD patients with masticatory myofascial pain and 25 age-matched, pain-free female subjects. All subjects rated the pain intensity and unpleasantness evoked by the first, fifth, and tenth stimuli in the series and their aftersensations at 15 seconds and 1 minute following the last stimulus. Data were analyzed by 3-way repeated-measures analysis of variance. RESULTS: Pain and unpleasantness ratings increased with repetition of the stimulation (P < .0001). In addition, there was a significant trial number x group interaction for the pain intensity ratings, such that TMD patients provided higher ratings than controls for the tenth stimulus (P < .001). The increase in unpleasantness ratings with repetitive stimulation was also higher for the patient group (P < .0001). Moreover, TMD patients rated the intensity of aftersensations as higher (P < .005) and reported painful aftersensations at significantly greater frequency (P < .05). CONCLUSION: A generalized hyperexcitability of central nociceptive processing in this TMD patient group is indicated by their more pronounced temporal summation of pain and greater aftersensations following repetitive noxious digital stimulation versus controls. Such hyperexcitability may contribute to the pathophysiology of TMD pain.

Tooth erosion caused by chewing aspirin.

BACKGROUND: Although the effects of aspirin on the oral mucosa are well-documented, there is little documentation of the effects of aspirin-chewing on the enamel and dentin. CASE DESCRIPTION: The authors present two cases of patients with damage to their tooth enamel and dentin. Both patients had similiar symptoms, but had not been told that chewing aspirin could harm tooth structure. The authors identify clinical signs and symptoms and discuss ways to prevent erosion. CLINICAL IMPLICATIONS: The common factor in these cases is that aspirin was the only possible cause of the tooth erosion. Dentists should be aware of the effects of aspirin-chewing on tooth structure and advise their patients accordingly.

The use of an oral exercise device in the treatment of muscular TMD.

Forty-five patents with a primary diagnosis of muscular MD were evaluated and treated in a university based facial pain center. The patients were equally and randomly assigned to one of three treatment groups. Group 1 patients were treated with traditional therapies appropriate for the particular patent. Group two patients used similar therapies that were appropriate for the patient but also had an oral vertical exercise device integrated into their therapy. Patients in the third group were instructed in home care, educated about TMD, and instructed in the use of the oral exercise device. Results indicated that all three groups demonstrated significant overall patient clinical and subjective improvement. The three groups did not differ significantly from each other in degree of patient improvement.

Referring patients for stress-related disorders.

Stress and psychological disorders can have a profound effect on the etiology, duration, and outcome of nearly all physical conditions. They also can interfere with the dentist's diagnosis and treatment of patients, particularly those who suffer from chronic pain. Dentists should be able to identify the possibility of the presence of stress and psychological disorders in patients and to make an appropriate referral when it is indicated.

Evidence for indirect effects of pain catastrophizing on clinical pain among myofascial temporomandibular disorder participants: the mediating role of sleep disturbance.

Sleep disturbance and pain catastrophizing are important mediators of the chronic pain experience. To date, these factors have not been considered concurrently despite compelling theoretical rationale to do so. In the present study, we examined whether pain catastrophizing not only has direct effects on clinical pain and pain-related interference, but also indirect effects through its association with sleep disturbance. We evaluated this hypothesis using a cohort (n=214) of myofascial temporomandibular disorder participants using a statistical bootstrapping technique recommended for tests of indirect effects. Results suggested that pain catastrophizing was associated with greater sleep disturbance, and that a significant portion of variance in clinical pain severity and pain-related interference attributable to pain catastrophizing was mediated by sleep disturbance. Supplementary analyses revealed that the rumination component of catastrophizing seemed to be indirectly related to clinical outcomes through sleep disturbance. No evidence for indirect effects was observed for helplessness and magnification components. These results suggest that rumination about pain may contribute to clinical pain indirectly through alterations in sleep. Prospective studies are needed to examine lagged associations between these constructs. These findings have important theoretical and clinical implications. Critically, interventions that reduce pain catastrophizing may concurrently improve sleep and clinical pain.

Orofacial Pain--Part II: Assessment and management of vascular, neurovascular, idiopathic, secondary, and psychogenic causes.

Chronic orofacial pain is a common health complaint faced by health practitioners today and constitutes a challenging diagnostic problem that often requires a multidisciplinary approach to diagnosis and treatment. The previous article by the same authors in this issue discussed the major clinical characteristics and the treatment of various musculoskeletal and neuropathic orofacial pain conditions. This second article presents aspects of vascular, neurovascular, and idiopathic orofacial pain, as well as orofacial pain due to various local, distant, or systemic diseases and psychogenic orofacial pain. The emphasis in this article is on the general differential diagnosis and various therapeutic regimens of each of these conditions. An accurate diagnosis is the key to successful treatment of chronic orofacial pain. Given that for many of the entities discussed in this article no curative treatment is available, current standards of management are emphasized. A comprehensive reference section has been included for those who wish to gain further information on a particular entity.

Orofacial pain--Part I: Assessment and management of musculoskeletal and neuropathic causes.

Orofacial pain is a common complaint, affecting the lives of millions of people around the world. Chronic orofacial pain often constitutes a challenging diagnostic problem that can be complicated by psychosocial factors and typically requires multidisciplinary treatment approaches. The fundamental prerequisite for successful management of orofacial pain is an accurate diagnosis. Generating a differential diagnosis, which will ultimately lead to a definite diagnosis, requires thorough knowledge of the diagnostic range of orofacial pain. There is a vast array of orofacial pain categories including: (1) musculoskeletal, (2) neuropathic, (3) vascular, (4) neurovascular, (5) idiopathic, (6) pain caused by local, distant, or systemic pathology, and (7) psychogenic. This article presents the salient clinical features and the therapeutic approaches for the various subtypes of musculoskeletal and neuropathic pain. Musculoskeletal pain is the most prevalent orofacial pain, with temporomandibular disorders and tension-type headache being the main examples. Neuropathic pain develops secondary to neural injury and/or irritation and can be distinguished into episodic, including trigeminal neuralgia and glossopharyngeal neuralgia, as well as continuous, such as herpetic and postherpetic neuralgia, traumatic neuralgia, and Eagle's syndrome.