Temporomandibular disorders and other causes of facial pain

Social impairment of individuals suffering from different types of chronic orofacial pain

Background

The daily life of patients suffering from orofacial pain is considerably impaired as compared to healthy subjects. The aim of this study was to investigate the influence of different categories of orofacial pain on the habitual life of adult individuals.

Methods

Seven hundred eighty-one individuals with orofacial pain were recruited from an initial sample of 1,058 patients. All the individuals were allocated to groups according to their diagnosis: myofascial pain (group A, 676 subjects, 525 females and 151 males; mean age ± SD = 35.2 ± 12.6), migraine (group B, 39 subjects, 29 females and 10 males; mean age ± SD 36.0 ± 10.7), and both myofascial pain and migraine (group C, 66 subjects, 56 females and 10 males, mean age ± SD = 35.6 ± 10.8). Characteristic pain intensity (CPI), disability days (DD), disability score (DS), and graded chronic pain intensity (GCPS) were calculated according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) axis II. Depression and somatization (nonspecific physical symptoms) scores were also calculated.

Results

A significant association between groups and GCPS categories was found (p < 0.0001). Post hoc tests showed a significant difference between groups A and B and between A and C, but not between B and C. In group A, the most frequent GCPS score was grade II. The most frequent GCPS score in groups B and C was grade III, indicating a moderate limiting impairment. This score was more frequent in group B (41%) than in the other groups (group A = 20.6%, group C = 34.8%). GCPS grade IV was more frequent in group C (19.7%) than in the other groups. Group C had significantly higher scores for nonspecific physical symptoms than group A (p < 0.05).

Conclusions

Myofascial pain and migraine sensibly affect the common daily life of adult individuals. The comorbidity of both conditions determines a major impairment.

Prevalence of parafunctional habits and temporomandibular dysfunction symptoms in patients attending a tertiary headache clinic

OBJECTIVE

To investigate the most prevalent forms of headache in a tertiary outpatient service, and to assess the frequency of associated parafunctional habits and temporomandibular dysfunction symptoms (TMD).

METHOD

All new patients referred to the Headache Outpatient Service in UNIMES during 2008 were prospectively assessed by the neurologist and the dental surgeon.

RESULTS

Eighty new patients were assessed; chronic migraine and episodic migraine without aura were the most prevalent conditions, accounting for 66.3% of all cases. There was significantly higher use of analgesics/days for the chronic migraine patients. The prevalence of parafunctional habits was 47.5% and the prevalence of TMD symptoms was 35%.

CONCLUSION

The high prevalence of primary headaches, parafunctional habits and TMD symptoms and the inadequate use of analgesic drugs suggest that primary healthcare units need further training in the field of headache and orofacial pain.

A fMRI evaluation of lamotrigine for the treatment of trigeminal neuropathic pain: pilot study

Using functional magnetic resonance imaging (fMRI) methods, we evaluated the effects of lamotrigine vs placebo in a double-blind 1:1 randomized trial. Six patients with neuropathic pain were recruited for the study. All subjects had baseline pain >4/10 on a visual analog scale (VAS) and allodynia to brush as inclusion criteria for the study. Patients underwent two fMRI sessions, with half of the subjects receiving placebo first and half receiving drug first (based on the blinding protocol). Lamotrigine decreased their average pain intensity level from 5.6 to 3.5 on a VAS. All subjects had brush, cold, and heat applied to the affected and mirror-unaffected sides of their face. The results show: 1) in a small cohort, lamotrigine had a significant effect on heat VAS but not on the other stimuli; and 2) contrast analysis of fMRI results for heat stimuli applied to the affected face for lamotrigine vs placebo produced an overall decrease in blood oxygen dependent level signal, suggesting a potential inhibitory effect of the drug on predominantly cortical regions (frontal, parietal, and temporal).

Focal Inflammation Causes Carbenoxolone-Sensitive Tactile Hypersensitivity in Mice

A focal and transitory inflammation induced by injection of complete Freund's adjuvant (CFA) in the submandibular skin of mice elicits pain behavior that persists for several weeks after the initial inflammation has resolved. Chronic pain, assessed as tactile hypersensitivity to stimulation with von Frey filaments, was evident from 1-7 weeks following CFA injection, although inflammation at the injection site was resolved by 3-4 weeks. In contrast, there were no changes in tactile sensitivity in the paw (un-injected site for comparison), no alterations in open field behavior and no differences in a functional observation battery evident in CFA-treated mice compared to controls (saline-injected) or to baseline (before CFA injection). Neither strain (Balb/c vs. C57BL/6) nor sex differences in baseline tactile threshold were significant in the submandibular skin. CFA-induced tactile hypersensitivity was also not a function of strain or sex. A single intraperitoneal injection of the gap junction blocker carbenoxolone (CBX) restored normal tactile thresholds in CFA-treated mice when administered at the peak of inflammation (1 week), after significant resolution of inflammation (3 weeks) or after total resolution of inflammation (4 and 5 weeks) without altering the tactile threshold of control subjects, tactile threshold in the paw or open field behavior. Thus, in this novel model of post-inflammatory pain, transitory inflammation induced persistent sex- and strain-independent behavioral hypersensitivity that was reversed by the gap junction blocker CBX, suggesting neuronal and/or glial plasticity as a major component of the chronic pain.