Journal of Oral & Facial Pain and Headache, 03/2016

Aims: To evaluate whether a biobehavioral intervention would be more effective than a self-care intervention or no intervention in reducing psychosocial distress, reducing pain, and improving functioning in patients with an acute myofascial temporomandibular disorder (m-TMD). Methods: Participants (n = 435) were from community dental clinics in the Dallas-Fort Worth Metroplex who were seeking treatment for their acute TMD symptoms and were recruited between 2008 and 2013. The participants were diagnosed using the Research Diagnostic Criteria for TMD (RDC/TMD) and assigned to a biobehavioral intervention, self-care intervention, or no intervention. Three outcomes were assessed: psychosocial distress, pain, and functioning; and treatment effectiveness was assessed according to TMD diagnosis. Outcome evaluations were conducted immediately postintervention as well as at 1 and 2 years postintervention. Analyses were conducted using two-level hierarchical multilevel linear models (MLMs). Results: Contrary to expectations, patients did not respond differently to the intervention based on their TMD diagnosis. Acute m-TMD patients, especially those with other comorbid TMD diagnoses, reported the highest levels of pain and pain-related symptoms and disability. They also exhibited poorer jaw functioning, especially if they were at high risk for chronic TMD. Conclusion: This study indicates that acute m-TMD tends to result in more severe symptom presentations, particularly if diagnosed in combination with other TMD comorbidities. Additionally, patients do not appear to respond better to biobehavioral or self-care intervention on the basis of their TMD diagnosis. Keywords: acute myogenous pain, high-risk, psychosocial distress, RDC/TMD, temporomandibular disorder

Aims: To investigate the relationship between omentin-1 levels and painful temporomandibular disorders (TMD). Methods: In a case-control design, chronic painful TMD cases (n = 90) and TMD-free controls (n = 54) were selected from participants in the multisite OPPERA study (Orofacial Pain: Prospective Evaluation and Risk Assessment). Painful TMD case status was determined by examination using established Research Diagnostic Criteria for TMD (RDC/TMD). Levels of omentin-1 in stored blood plasma samples were measured by using an enzymelinked immunosorbent assay. Binary logistic regression was used to calculate the odds ratios (ORs) and 95% confidence limits (CLs) for the association between omentin-1 and painful TMD. Models were adjusted for study site, age, sex, and body mass index. Results: The unadjusted association between omentin-1 and chronic painful TMD was statistically nonsignificant (P = .072). Following adjustment for covariates, odds of TMD pain decreased 36% per standard deviation increase in circulating omentin-1 (adjusted OR = 0.64; 95% CL: 0.43, 0.96; P = .031). Conclusion: Circulating levels of omentin-1 were significantly lower in painful TMD cases than controls, suggesting that TMD pain is mediated by inflammatory pathways. Keywords: chronic pain, epidemiology, etiology, inflammation mediators, temporomandibular disorders

Aims: To analyze the methodologic quality, summarize the findings, and perform a meta-analysis of the results from randomized controlled trials that assessed the effects of physiotherapy management of temporomandibular disorders. Methods: A literature review was performed using the electronic databases PubMed, Science Direct, and EBSCO. Each article was independently assessed by two investigators using the Physiotherapy Evidence Database (PEDro), Jadad scales, and the Cochrane Risk of Bias tool. A meta-analysis was conducted by using the DerSimonian-Laird random-effects method to obtain summary estimates of the standardized mean differences (SMD) and the corresponding 95% confidence intervals (95% CI). Between-study heterogeneity was computed and publication bias was assessed. Results: Seven articles met the inclusion criteria and were used in the analysis, corresponding to nine estimates of SMD. The meta-analysis showed that for pain reduction, the summary SMD favored physiotherapy (SMD = −0.63; 95% CI: −0.95 to −0.31; number of studies = 8; I2 = 0.0%), while for active range of movement (ROM) the differences between the intervention and control groups were not statistically significant (SMD = 0.33; 95% CI: −0.07 to 0.72; number of studies = 9; I2 = 61.9%). Conclusion: Physiotherapy seems to lead to decreased pain and may improve active ROM. However, the results are not definitive and further studies and meta-analyses are needed before these results can be considered fully generalizable. Keywords: mandibular function, pain, RCT

Aims: To determine whether there is an association between temporomandibular disorders (TMD) and a history of facial/jaw injury (FJI), orthodontic treatment (OT), or third molar removal (TMR) in university students, and to evaluate the students' awareness of a possible relationship between jaw pain or other TMD symptoms, FJI, OT, and TMR, and the presence of TMD. Methods: This cross-sectional study involved 1,381 Oporto District university students. The Portuguese version of the Research Diagnostic Criteria for TMD was used for TMD diagnosis. FJI, OT, and TMR histories were evaluated by questionnaire. Univariate associations between categorical variables were tested by using chi-square tests. Multivariate logistic regression was applied to predict independent factors associated with TMD. Results: Of the 1,381 students (mean age ± standard deviation [SD]: 21.7 ± 3.9 years), 39.3% had TMD, 23.2% had a history of FJI, 44.5% had undergone OT, and 26.2% had undergone TMR. Univariate analyses showed significant associations between OT and TMD (P = .044) and between TMR and TMD (P = .003). Multivariate regression analyses using FJI, OT, TMR, OT × TMR interaction, sex, and age in the first step showed TMR (Odds Ratio [OR] = 1.30; P = .041), sex (OR = 1.59; P = .001), and age (OR = 1.04; P = .013) as significant. A positive correlation between TMD and awareness of the relationship between jaw pain or TMD symptoms and a history of FJI or OT (P .001 and P = .002, respectively) was documented. Conclusion: TMR, female sex, and older age were risk factors independently associated with TMD. The results also suggest that patients' awareness of potential risk factors for TMD should be taken into account on an individual basis. Keywords: jaw injury, orthodontic treatment, RDC/TMD Axis I, third molar removal, university students

Aims: To evaluate the transient effects of orthodontic treatment on the mechanical detection threshold (MDT) and mechanical pain threshold (MPT) of the buccal attached gingiva and the pressure pain threshold (PPT) of the buccal attached gingiva and of the teeth in two directions (perpendicular and parallel). Methods: A total of 20 patients (15 females and 5 males) aged 18 to 30 years participated in the study. Perceived pain on a 0- to 10-cm visual analog scale (VAS) and MDT, MPT, and PPT scores were evaluated at two time points at the masseter muscle, gingiva, teeth, and hand (control) prior to orthodontic treatment (T0) and 24 hours after the first archwire placement (T1). Mean values and SEMs were calculated for all continuous variables. The differences between T0 and T1 of MDT, MPT, and PPT were analyzed by means of a paired Student t test. Results: The pain intensity as assessed on the VAS was 4.2 ± 1.8 cm. No significant changes in MDT or MPT were found at the hand and buccal attached gingiva (P > .06). The PPTs at the buccal attached gingiva of teeth 21, 23, 24, and 34, at teeth 21, 23, 24, and 34 (perpendicular) and at teeth 21 and 23 (parallel) were lower (ie, more sensitive) at T1 compared with T0 (P .04). Conclusion: This study indicates for the first time that pain following insertion of an archwire causes sensitization to blunt-pressure stimuli both in the attached gingiva and in the periodontal ligament. Quantitative assessment of mechanical sensitivity may provide more insights into procedural pain and allow for better monitoring and evaluation of the effects of orthodontic treatment in the future. Keywords: f ixed appliances, orthodontics, pain, pressure pain threshold, quantitative sensory testing

Aims: To determine if pressure pain thresholds (PPTs) of masticatory and neck muscles change after the application of a mandibular advancement device (MAD) in patients with obstructive sleep apnea (OSA). Methods: A prospective study was conducted in a sample of 27 OSA patients (24 males and 3 females; mean age ± standard deviation [SD]: 54.8 ± 11.8, mean apnea-hypopnea index ± SD: 23.5 ± 13.3) and 27 age- and sex-matched healthy controls. Exclusion criteria were signs and symptoms of temporomandibular disorders (TMD), metabolic diseases, and use of antidepressants, analgesics, or anti-inflammatory drugs. A calibrated examiner evaluated PPTs of seven head and neck muscles bilaterally by using a Fischer algometer. In the OSA group, PPTs were recorded immediately before the MAD application (T0), after 15 days (T1), and after 6 months (T2) of therapy; in the control group, PPTs were recorded at the same time intervals. PPT differences at baseline and over time within each group and between OSA and control groups were analyzed by Friedman and Mann-Whitney tests. Results: There were no PPT differences between groups at baseline. In the OSA group, PPTs of temporalis and masseter muscles decreased significantly at T1 compared with T0 (P .05), but no differences were found at T2. No significant PPT differences were found in the neck muscles or over time in the control group. Conclusion: MAD application induces a decrease of PPTs of masticatory muscles at the beginning of the therapy, but a physiologic adaptation occurs by 6 months. Keywords: algometer, mandibular advancement device, masticatory muscles, obstructive sleep apnea, pressure pain threshold

Aims: To assess the influence of clenching side and location (ie, tooth) on the bite force necessary to induce pain or discomfort in patients with unilateral anterior disc displacement (ADD) of the temporomandibular joint (TMJ). Methods: A total of 17 patients with unilateral ADD diagnosed clinically and with magnetic resonance imaging were included. A bite force meter was positioned at each of four experimental positions: the mandibular first premolars and first molars, bilaterally. Subjects were instructed to clench on the bite force meter until they felt pain or discomfort in the orofacial area and to report the location of the pain. Differences in pain location (ADD side versus contralateral side) and in the bite force thresholds for eliciting pain or discomfort were assessed by means of the paired t test and Wilcoxon signed-rank test. Results: Only 18% of subjects (3 out of 17) reported pain in the TMJ with ADD during clenching at the ipsilateral molar, whereas 65% (11 out of 17) reported joint pain during clenching on the contralateral molar (P = .005). At the molars, the mean ± standard deviation bite force necessary to induce pain was 241.2 ± 135.5 N on the side with ADD and 160.9 ± 78.0 N on the contralateral side. The mean molar bite force necessary to induce pain on the side with ADD was significantly higher than that on the contralateral side (P = .002). Conclusion: Patients with unilateral ADD had fewer reports of TMJ pain and discomfort when they were molar clenching on the ipsilateral side compared to molar clenching on the contralateral side. Keywords: anterior disc displacement, bite force, preferred chewing side, temporomandibular disorders, temporomandibular joint

Aims: To determine whether there is a correlation between any psychological features and sleep bruxism (SB). Methods: A total of 36 healthy volunteers underwent an in-home evaluation with a portable device combining electromyographic (EMG) and electrocardiographic (ECG) recordings for the diagnosis of SB. They were administered questionnaires that assessed state and trait anxiety levels and coping strategies. The study hypothesis was that the SB index was significantly correlated with an individual's anxiety and coping. Correlation between SB index and psychological features was assessed and a comparison between SB prevalences in subjects with different psychological scores was carried out. Results: Correlation analysis showed that the SB index was not correlated with any of the psychological scales; however, there were some significant correlations (r values range from 0.393 to 0.458) between the SB index and specific items from the trait anxiety and coping scales. Crosstabulations of subjects with SB and with high (overmedian) or low (undermedian) scores for the various psychological measures revealed significant correlations between the prevalence of SB in higher-scoring subjects for state anxiety scores (Phi coefficient = .456; P = .006), trait anxiety scores (Phi = 0.369; P = .027), and social support coping strategy (Phi = 0.387; P = .020). Conclusion: These findings support the study hypothesis only in part and confirm the absence of a clear-cut relationship between SB and psychological features. Keywords: anxiety, bruxism, coping, personality, psychology, sleep bruxism

Aims: To conduct a systematic review to determine the efficacy of oral medications for the management of postherpetic neuralgia (PHN). Methods: Three electronic databases were searched: Cochrane Library (up to 7 July 2015), MEDLINE via PubMed (from 1950 to 7 July 2015), and Web of Science (1864 to 7 July 2015). Studies were limited to double-blind, placebocontrolled, randomized controlled trials on oral medications used to treat PHN. Risk of bias was independently assessed in duplicate. Results: A total of 256 abstracts were screened by two independent reviewers and 26 full-text articles were assessed for eligibility. A total of 11 relevant articles were selected for inclusion. These 11 articles were included in a qualitative synthesis and 8 were included in a meta-analysis; however, all the included studies had a high or unclear risk of bias and the interventions were heterogenous. In a subgroup analysis of five studies, anticonvulsants (gabapentin, pregabalin, and divalproex sodium) were found to improve short-term pain intensity (standardized mean difference [SMD] = −0.484, 95% confidence interval [CI] = −0.622 to −0.346, P .001). In a second subgroup analysis of five studies, it was found that patients taking anticonvulsants were 2.5 times as likely to have a 50% or more reduction in pain after treatment than patients taking placebo. Conclusion: This review has provided favorable but low-quality evidence to support the use of anticonvulsants for PHN. Although statistically significant effects were observed for posttreatment pain and the percent of responders, the number of studies in each subgroup analysis for anticonvulsants was small and the included studies had high or unclear risk of bias. Further high-quality methodologic studies are needed to explore the effects of orally administered anticonvulsants for PHN. Keywords: anticonvulsants, antidepressants, herpes zoster, opioids, postherpetic neuralgia

This article is a case report of a female patient in whom sour and spicy foods evoked trigeminal neuralgia (TN). An attempt to reveal the underlying pain mechanism is described and discussed. The 81-year-old woman had been suffering from classical TN since the age of 50. Attacks occurred spontaneously or in response to mechanical stimuli. In addition, sour and spicy foods also evoked TN attacks and were therefore avoided for years. Medical treatment was initially effective, but two radiofrequency ablations of the gasserian ganglion were required later on and yielded good, albeit incomplete, pain relief. Sensory examination consisted of application of a mechanical stimulus and sweet, salty, sour, and spicy solutions to the anterior part of the tongue and the mandibular mucosa on both sides. Mechanical stimuli were felt but produced no pain. When applied to the tongue, the tastes of all solutions were identified but produced no pain. When applied to the mucogingival line, none of the solutions was identified but the sour and the spicy solutions provoked TN immediately following their application. These findings suggest that in this patient, sour and spicy solutions may have evoked TN attacks by direct activation of trigeminal C-nociceptors, possibly via interactions with transient receptor potential vanilloid 1 receptors. Keywords: facial pain, gustatory, sensory-testing, trigeminal neuralgia, TRPV1 receptors