Journal of Oral & Facial Pain and Headache, 03/2007

This topical review presents an overview of orofacial manifestations associated with the more common connective tissue diseases affecting multiple organs. The orofacial manifestations associated with these autoimmune disorders include oral mucosa alterations, salivary gland pathosis, sensory neuropathies, headaches, and temporomandibular disorders. Since many of these orofacial manifestations may be painful, the practitioner managing pain patients should be familiar with them. An understanding of the orofacial manifestations associated with these systemic diseases will enable the pain practitioner to establish an appropriate diagnosis within the context of the underlying systemic disease. This will allow the practitioner the opportunity to contribute and collaborate as a member of a multidisciplinary health-care team in the management of these systemic autoimmune diseases. Keywords: connective tissue disease, headache, orofacial manifestation, temporomandibular disorders, trigeminal neuropathy

Aims: To investigate how often healthy controls and patients with myogenous masticatory pain have wake-time nonfunctional tooth contact, whether the frequency of nonfunctional tooth contact differs between genders or between weekdays and weekends, and whether it is influenced by stress levels. Methods: The study was performed on 24 subjects: 15 controls and 9 patients with myogenous facial pain. Before data collection the subjects were trained to ascertain their ability to feel correctly whether their teeth were in contact or apart. Subsequently, for 10 days the subjects were alerted by means of a radio wave-activated wrist vibrator approximately every 20 minutes (8:00 am to 10:00 pm) in order to report whether the teeth were in contact. Subjects also completed 2 stress assessment questionnaires, the Perceived Stress Scale (PSS) and the short version of the Trier Inventory for Assessment of Chronic Stress (TICS-S). Results: There was a significantly higher frequency of wake-time nonfunctional tooth contact in myogenous pain patients than in controls (median of 34.9% and range of 26.5% to 41.3% for patients; median of 8.9% and range of 2.3% to 14.3% for controls; P < .001). In both groups the frequency of nonfunctional tooth contact did not significantly differ among the various days or between the genders. The patients had significantly higher PSS scores and reported having experienced more stressful situations in the dimensions "social overload" and "overextended at work" than the controls. However, PSS and TICS-S scores were not correlated with the frequency of nonfunctional tooth contact for either group. Conclusions: Myogenous pain patients had nearly 4 times more nonfunctional tooth contact during wake time than controls. Keywords: bruxism, ecological momentary assessment, tooth clenching, tooth contact

Aims: To document the frequency of self-care in a clinical sample of patients with myofascial temporomandibular disorder (TMD) pain; report the perceived relief and control of pain for each of the self-care behaviors; and to test for associations between the frequency and efficacy of each self-care behavior and pain, depression and sleep quality, as assessed during a clinical visit, and to determine whether the frequency was associated with changes in pain intensity, depression, and sleep quality 30 days later. Methods: The sample consisted of 99 female and 27 male myofascial TMD pain patients who were participants in a multidisciplinary facial pain evaluation program. The subjects participated in a structured interview during a clinical visit and a follow-up telephone interview 30 days later. The interviews included questions about self-care, including resting, relaxation techniques, massage, hot and/or cold packs, home remedies, stretching or exercise, herbal remedies, and the use of vitamins or nutritional supplements for pain. Results: The passive self-care behaviors, such as resting when experiencing pain (66%) and relaxation techniques (62%), were the most commonly used. Patients reported that hot or cold packs (5.3, 0-to-10 scale) and massage (4.7) provided the greatest relief from pain, whereas resting (4.9), relaxation (4.8), and massage (4.8) resulted in the greatest ability to control pain. The most striking finding was that initial levels of pain or change in pain were not consistently associated with self-care use; however, psychosocial outcomes of depression and sleep quality were associated with self-care frequency and reported efficacy and improved in relation to patient-reported self-care frequency. Conclusion: Since people with chronic myofascial TMD pain engage in a range of pain self-care strategies, clinicians need to discuss self-care with patients regularly. Keywords: depression, massage, myofascial pain, relaxation, self-care, sleep

Aim: To develop and validate a questionnaire-based tool which would enable classification of idiopathic orofacial pain in the general population. Methods: A postal questionnaire-based cross-sectional survey was made of 4,200 randomly selected adults who were registered with a general medical practice in North West England. The questionnaire collected information on a number of factors: demographics (age, gender), orofacial pain (duration, descriptors, site, pattern, intensity, disability, and consultation behavior), and comorbidities (reporting of other unexplained symptoms and psychosocial factors). Subjects reporting orofacial pain were interviewed by an examiner blinded to their exposure status and classified into 1 of 3 categories: (a) dentoalveolar, (b) musculoligamentous/soft tissue, and (c) idiopathic orofacial pain. Results: A high adjusted response rate of 72% was achieved (crude response rate 60%). Of those who reported orofacial pain and were eligible for interview (n = 218), 197 (88%) were interviewed. Subjects classified by interview into the idiopathic category were more likely to report aching, nagging, and chronic pain pain at multiple sites. They were also more likely to report facial trauma and other chronic symptoms and to have consulted multiple health-care workers. Variables that most strongly predicted membership into the idiopathic category were female gender, nagging, aching pain which was worse when stressed, and topography (pain at multiple sites and unilateral pain). Conclusion: The classification criteria developed for idiopathic orofacial pain can be used as a screening tool for subjects with this condition in the general population. Keywords: classification, general population, idiopathic, orofacial pain

Aims: To test the hypothesis that local injection of the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine would significantly attenuate glutamate-evoked masseter mechanical sensitization and muscle pain in healthy young women either taking oral contraceptives (W+OC) or not taking oral contraceptives (W-OC). Methods: Experimental pain was evoked in 47 healthy female subjects (W+OC, n = 25; W-OC, n = 22) by 2 injections of glutamate (0.2 mL, 1 mol/L) into the masseter muscle. A first injection of glutamate alone was followed by a second injection, 35 minutes later, of glutamate combined with ketamine (0, 1, or 10 mmol/L). Evoked pain intensity was scored on a 10-cm electronic visual analog scale (VAS). Distribution of perceived pain was drawn on a lateral view of the face (pain drawing). Masseter muscle pressure pain thresholds (PPT) and pressure-pain tolerances (PPTOL) were determined bilaterally before and at regular time intervals after injections. Analyses of variance (ANOVA) were used to test the data. Results: There were no main effects of ketamine on any of the VAS pain parameters or on the pain drawing (ANOVAs: P > .055). Furthermore, there were no differences in PPT, PPTOL, VAS peak pain, duration, overall VAS pain, or pain drawing when W-OC were compared with W+OC (ANOVAs: P > .087). Repeated injection of glutamate alone significantly decreased PPT and PPTOL (ANOVAs: P < .001); however, this effect was not significantly attenuated by ketamine. Conclusions: Peripherally administered ketamine had no effect on glutamate-evoked masseter muscle pain and sensitization in healthy young women, which contrasts with recent observations in healthy young men. Further studies will be needed to reveal the mechanisms that underlie this apparent sex-related difference in ketamine-mediated analgesia. Keywords: glutamate, ketamine, muscle pain, orofacial pain, temporomandibular disorders, trigeminal physiology

Aims: To elucidate the neuronal mechanisms underlying chronic pain of the temporomandibular joint (TMJ), expression of phosphorylated extracellular signal-regulated kinase (pERK) in the trigeminal spinal nucleus caudalis (Vc) was studied in rats with a chronically inflamed TMJ. Methods: Complete Freund's adjuvant (CFA) was injected in the left TMJ region of rats anesthetized with pentobarbital (50 mg/kg intraperitoneally). Face temperature of the TMJ region was measured periodically after CFA injection. Two weeks after CFA injection, passive jaw movement with 4-, 6-, and 15-mm distances was carried out in inflamed and naive rats for 5, 15, and 30 minutes. pERK expression was studied in the medulla and upper cervical cord after passive jaw movement. Results: Face temperature was significantly increased 2 days after CFA injection and returned to the preoperative level 7 days later. The pERK-like immunoreactive (LI) cells were observed in the dorsal portion of the rostral Vc in inflamed rats after passive jaw movement, and a small number of pERK-LI cells were observed in naive rats after passive jaw movement. No pERK-LI cells were observed in the TMJ of inflamed rats without jaw movement. The number of pERK-LI cells increased following increases in the jaw-movement distance and duration. Conclusion: These findings suggest that the dorsal portion of the rostral Vc may be involved in mediating chronic pain following TMJ inflammation and that the intracellular ERK cascade may be involved. Keywords: chronic inflammation, extracellular signal-regulated kinase, jaw movement, temporomandibular joint, trigeminal spinal nucleus

Aims: To examine the expression of aggrecanase-1 and a tissue inhibitor of metalloproteinases (TIMP-3) in the condylar cartilage of young rats and to determine their relationship during altered dietary loading at different time points after weaning. Methods: One hundred Sprague-Dawley rats were randomly assigned to 1 of 2 groups: the soft-diet group, which served as the control group (n = 50), or the hard-diet group, which served as the experimental group (n = 50). Ten soft- and 10 hard-diet rats were killed at 6 hours, 12 hours, 24 hours, 48 hours, and 9 days after weaning (ie, after initiation of diet change for hard-diet rats). The right-side temporomandibular joints (TMJs) were prepared for immunohistochemical staining. The cartilage from the left-side mandibular condyles of all 10 animals in each group was combined for Western blot analysis. Results: Immunohistochemical analysis revealed strong staining for aggrecanase-1 localized mainly in the chondrocytes of proliferative and upper hypertrophic cartilage zones at all time points in both groups. The immunohistological expression of aggrecanase-1 was significantly higher in the hard-diet group at 12 and 24 hours than in the soft-diet group. Strong staining for TIMP-3 was mainly localized in the chondrocytes of proliferative and upper hypertrophic zones at all time points in both groups. The expression of TIMP-3 in the hard-diet group was at a significantly lower level compared to the soft-diet group at 6 hours. Western blot analysis also showed time-related differences in aggrecanase-1 and TIMP-3, but there was no significant difference between the 2 groups. Conclusion: The temporary change in aggrecanase-1 and TIMP-3 expression reflects the complex interaction of these enzymes in the physiologic range and cartilage response to altered dietary loading. Keywords: aggrecanase-1, joint loading, mandibular condylar cartilage, TIMP-3