Journal of Oral & Facial Pain and Headache, 04/2014

Aims: To carry out a systematic review to consolidate current knowledge on the potential association between sleep bruxism (SB) and sleep-disordered breathing (SDB). Methods: For this systematic review, articles were retained only if they reported studies using full ambulatory polysomnography as "the gold standard" reference test to determine SDB and the international diagnostic criteria proposed by the American Association of Sleep Medicine to determine SB. Detailed individual search strategies from MEDLINE, PubMed, Embase, the Cochrane Library, and LILACS databases were developed. The references cited in the selected articles were also checked, and a partial literature search was undertaken. The selection was completed independently by two reviewers in two phases. The methodology of selected studies was evaluated using the seven-item quality-assessment tool for experimental bruxism studies. Results: During the initial search, 333 different citations were identified across the six electronic databases. After a comprehensive evaluation of the abstracts, and the full papers when considered necessary, only one study was finally selected for the qualitative/quantitative synthesis. This study did not support the putative association between SB and SDB, since SB was not observed during or in temporal conjunction with snoring or apneic events in any of the evaluated patients. In addition, masseter activity was not observed during apneic episodes. Conclusion: There is not sufficient scientific evidence either to confirm or discredit the association between SB and SDB. Keywords: bruxism, sleep apnea, sleep bruxism, sleep-disordered breathing, systematic review

Aims: To (1) quantitatively investigate the possible long-term surgical impact of orthognathic surgery on the patients' trigeminal somatosensory functions and (2) investigate the influence of ongoing pain on the trigeminal somatosensory functions of the patients. Methods: A group of patients before orthognathic surgery (Pre-op), a group of patients 1 year after orthognathic surgery (Post-op), and a group of control participants (Control) were recruited (n = 28 in each group). A standardized quantitative sensory testing protocol was followed to record a battery of 13 parameters, which reflect both sensory loss and gain. The data were analyzed using three-way repeated measure analysis of variance with group and pain as between-subject factors and testing site as within-subject factor. Results: In the Post-op group, of the 21.4% patients who reported ongoing pain after surgery, 7.1% were diagnosed with neuropathic pain and 14.3% had musculoskeletal pain. Facial cold detection threshold (CDT) of the Post-op group was significantly lower (less sensitive) than that of the Pre-op group (P .039). Facial pressure pain threshold (PPT) of the Post-op group was significantly lower (more sensitive) than that of the Pre-op and Control groups (P .006). Masseter PPT of the Postop group was significantly lower than that of the Control group (P = .02). The facial vibration detection threshold (VDT) of the Post-op group was significantly higher (less sensitive) than that of the Pre-op and Control groups (P .014). Pain patients in the Post-op group showed significantly elevated VDT compared to patients without pain (P .001). Conclusion: The pattern of sensory alteration in orthognathic surgical patients with or without pain was characterized by sensory loss in thermal parameters and non-nociceptive mechanosensory parameters and sensory gain in nociceptive mechanosensory parameters. The elevated VDT might be a potential indicator of the impact of postoperative pain on trigeminal somatosensory functions. Keywords: musculoskeletal pain, neuropathic pain, orofacial pain, orthognathic surgery, quantitative sensory testing, somatosensory function

Aims: To investigate possible associations between the presence of craniofacial pain of cardiac origin and the location of cardiac ischemia and conventional risk factors. Methods: A total of 326 consecutive patients with confirmed myocardial ischemia (192 males, 134 females, mean age 64 years) were studied. Demographic details, health history, risk factors, prodromal symptoms, electrocardiogram (ECG) findings, and pain characteristics during the ischemic episode were assessed. The location of the ischemia according to the ECG findings was categorized as anterior, inferior, or lateral. Univariate chi-square analyses and a multivariate logistic regression model were used for data analysis. Two age subgroups ( 65 and > 65) were established when controlling for covariates. Results: Craniofacial pain of cardiac origin was significantly associated with an inferior localization of cardiac ischemia (P .001) and was more frequently reported in diabetic patients (P = .014). Thirty-eight patients (12%) did not experience chest pain during the myocardial ischemia. Nine patients (3%) experienced a prodromal angina episode without chest pain. Conclusion: The occurrence of craniofacial pain during myocardial ischemia, with or without an acute myocardial infarction, was associated with ischemia within the inferior wall. This result suggests the involvement of the vagal afferent system in the mechanisms of craniofacial pain of cardiac origin. Keywords: acute myocardial infarction, cardiac ischemia, chest pain, craniofacial pain, dental pain

Aims: To assess whether trait anxiety as a person's general disposition to be anxious is a risk factor for temporomandibular disorder (TMD) pain. Methods: A total of 320 adult TMD patients with at least one pain-related TMD diagnosis according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were included in the study. Subjects from the general population without pain-related TMD were used as controls (n = 888). All study participants completed the State-Trait Anxiety Inventory (STAI). The association between the level of trait anxiety (STAI-Trait scores) and case-control status (patients diagnosed with pain-related TMD and controls) was analyzed using logistic regression analysis. Odds ratios (OR) with 95% confidence intervals (CI) were computed. Results: The level of trait anxiety was associated with the subject status (case vs control). A one-point increase in STAI-Trait sum scores (range: 20 to 80) was related to an increase of the odds for pain-related TMD by the factor 1.04 (CI: 1.02-1.05; P .001). Severe trait anxiety (above the 90th percentile of general-population subjects) doubled the odds (OR: 2.05; CI: 1.42-2.98; P .001). Analyses adjusted for age, gender, and level of education did not change the results. Conclusion: Trait anxiety is significantly associated with diagnoses of TMD pain. Keywords: pain, risk factor, temporomandibular disorders, trait anxiety

Aims: To assess the prevalence of temporomandibular joint (TMJ) bony changes in cone beam computed tomography (CBCT) images of adult subjects without ongoing orofacial pain or complaints from the TMJ. Methods: The study included 84 TMJs from 28 men and 14 women (mean age [± SD]: 51 ± 11 years) without orofacial pain or TMJ complaints who were participants in a study of patients with obstructive sleep apnea. They were examined before any treatment with the Research Diagnostic Criteria for Temporomandibular Disorders and with CBCT (NewTom VGi; 15 × 15 cm, exposure time 18 seconds, axial thickness 0.3 mm). Osseous TMJ deviations were assessed blindly and classified. Results: Degenerative changes were noted in the CBCT images of 33 (39.3%) of the TMJs, of which 21 were classified as osteoarthritic alterations and 12 as indeterminate changes of osteoarthritis. Two TMJs were clinically classified as osteoarthrosis and 6 as disc displacement with reduction. The CBCT images of the 2 TMJs with a clinical diagnosis of osteoarthrosis showed also bony changes, but the CBCT images also revealed osteoarthritic bony changes in the 18 TMJs without any clinical diagnosis. Conclusion: CBCT images of asymptomatic adult TMJs commonly show degenerative bony alterations. Accordingly, such radiographic findings should be used with care and only as a supplement to clinical assessment. Keywords: cone beam computed tomography, imaging, Nordic Orofacial Test-Screening, osteoarthritis, osteoarthrosis, RDC/TMD, temporomandibular joint

Aims: To investigate in a representative sample of South Koreans (1) the prevalence of and associations between general pain, temporomandibular disorders (TMD), and suicide ideation (SI), and (2) whether the associations between general pain, TMD, and SI differ according to cancer history. Methods: Data were from the Fourth Korean National Health and Nutrition Examination Survey (KNHANES IV; N = 16,658). KNHANES IV participants provided reports regarding their cancer history, EQ-5D (a measure of health status from the EuroQoL Group), and TMD symptoms including clicking of one or both temporomandibular joints, pain, and mouth-opening limitation (MOL). Participants were assessed for any SI over the last 12 months, as a dependent variable. The independent variables were pain/discomfort (EQ-PD) reported by the subjects on the EQ-5D, severe TMD (tenderness or reduced jaw mobility once or more per week), and total TMD (occurrence of clicking, tenderness on palpation, or reduced jaw mobility [opening 30 mm] once or more per week). Demographic information (age and gender), socioeconomic status (income, education, occupation, and marital status), behavioral factors (smoking and binge drinking), and cancer history were evaluated as covariates. The association of TMD with SI was assessed by the prevalence ratio (PR) and 95% confidence intervals. Results: In fully adjusted models, elevated PRs for SI were observed for each pain condition (PR = 1.26 for total TMD, PR = 1.35 for severe TMD, and PR = 1.75 for EQ-PD). In the subgroup analyses by cancer history, the PRs were higher in the cancer history (+) group; the order of magnitude was severe TMD (PR = 2.20), EQ-PD (PR = 2.16), and total TMD (PR = 2.02). Conclusion: Pain conditions, including TMD pain, might aggravate SI among those with a cancer history. These findings add to a growing body of evidence indicating that TMD warrants further attention in relation to suicide. Keywords: epidemiology, pain, suicide, temporomandibular disorders

Aims: To carry out a pilot study to test the hypothesis that human herpes virus-6 (HHV-6) infection or reactivation plays a role in the pathogenesis of temporomandibular disorders (TMD) of muscular origin (ie, localized myalgia). Methods: Sixteen patients with localized myalgia participated in this pilot study. Thirty-six healthy individuals served as controls. The participants were examined clinically for the presence of the TMD according to the Research Diagnostic Criteria for TMD, and the salivary levels of HHV-6 were measured by quantitative polymerase chain reaction (qPCR). The Z test, Student t test, and Mann- Whitney U test were used as appropriate. Results: The results demonstrated that 77.8% of healthy individuals were HHV-6 positive, but a significantly lower proportion (43.8%) of the TMD patients with localized myalgia were positive for HHV-6 (P .05, Fisher exact test). The levels of HHV-6B DNA were lower in the saliva of HHV-6-positive TMD patients with localized myalgia (median: 564 genome/mL; range: 184 to 5,835 genome/mL) than in that of healthy individuals (median: 1,081 genome/mL; range: 193 to 8,807 genome/mL), but the difference was not statistically significant (P > .05, Mann-Whitney U test). Conclusion: The results of this pilot study indicate that HHV-6 infection or reactivation does not appear to play a role in the pathogenesis of TMD reflecting a localized myalgia. Keywords: chronic fatigue syndrome, herpes virus 6, myalgia, saliva, temporomandibular disorders

Aims: To assess the analgesic effect of pregabalin in orofacial models of acute inflammatory pain and of persistent pain associated with nerve injury and cancer, and so determine its effectiveness in controlling orofacial pains having different underlying mechanisms. Methods: Orofacial capsaicin and formalin tests were employed in male Wistar rats to assess the influence of pregabalin (or vehicle) pretreatment in acute pain models, and the results from these experiments were analyzed by one-way analysis of variance (ANOVA) followed by Newman Keuls post-hoc test. Pregabalin (or vehicle) treatment was also tested on the facial heat hyperalgesia that was evaluated in rats receiving injection of the inflammatory irritant carrageenan into the upper lip, as well as after constriction of the infraorbital nerve (a model of trigeminal neuropathic pain), or after inoculation of tumor cells into the facial vibrissal pad; two-way repeated measures ANOVA followed by Newman-Keuls post-hoc test was used to analyze data from these experiments. Results: Facial grooming induced by capsaicin was abolished by pretreatment with pregabalin at 10 and 30 mg/kg. However, pregabalin failed to modify the first phase of the formalin response, but reduced the second phase at both doses (10 and 30 mg/kg). In addition, treatment of rats with pregabalin reduced the heat hyperalgesia induced by carrageenan, as well as by nerve injury and facial cancer. Conclusion: Pregabalin produced a marked antinociceptive effect in rat models of facial inflammatory pain as well as in facial neuropathic and cancer pain models, suggesting that it may represent an important agent for the clinical control of orofacial pain. Keywords: cancer, inflammatory pain, infraorbital nerve constriction, pregabalin, trigeminal pain

This article describes the case of a 41-year-old woman who presented with the complaint of crepitation sound and mild pain in the left temporomandibular joint area. Panoramic radiographs taken to rule out degenerative or arthritic changes in the joints demonstrated a radiopaque mass within the left condyle. Cone beam computed tomography scans revealed an ectopic tooth located centrally within the left condyle. Thus, while considered rare, the mandibular condyle can be a possible location of an ectopic tooth.