Journal of Oral & Facial Pain and Headache, 02/2021

Aims: To test the hypothesis that, in comparison with control, experimental noxious stimulation of the right masseter muscle would result in significant changes in the firing rates, thresholds, and recruitment orders of single-motor units (SMUs) of the nonpainful, synergistic right anterior temporalis muscle during goal-directed isometric biting task performance. Methods: Twenty healthy volunteers received an infusion of hypertonic saline (HS; 5% sodium chloride) into the right masseter to produce pain intensity of 40 to 60 on a 100-mm visual analog scale (VAS). Isotonic saline (IS) infusion was a control. Standardized biting tasks were performed with an intraoral force transducer, and intramuscular electromyographic activity was recorded from the right anterior temporalis muscle. Tasks (slow and fast ramp biting tasks, two-step biting task) were performed in 3 blocks: baseline, HS infusion, and IS infusion. Across blocks, SMU thresholds and firing rates were statistically compared, and SMU recruitment sequences were qualitatively compared. Statistical significance was set at P < .05. Results: No significant differences (P > .05) were noted between HS and IS infusion blocks in thresholds or firing rates of anterior temporalis SMUs. Individual SMUs showed increases or decreases in thresholds or firing rates or changes in recruitment sequences mostly during HS compared to IS infusion. Conclusion: The reorganization of SMU activity that has been suggested to occur in both painful and nonpainful agonist jaw muscles may involve not only recruitments and de-recruitments of SMUs, but may also extend to more subtle increases and/or decreases in firing rates, thresholds, and recruitment sequences of individual SMUs in the nonpainful synergistic muscles. Keywords: electromyography, hypertonic, isometric contraction, masticatory muscles, saline solution

Aims: To determine the relationship between hormonal contraceptive (HC) use and painful symptoms, particularly those associated with headache and painful temporomandibular disorders (TMD). Methods: Data from the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) prospective cohort study were used. During the 2.5-year median follow-up period, quarterly health update (QHU) questionnaires were completed by 1,475 women aged 18 to 44 years who did not have TMD, menopause, hysterectomy, or hormone replacement therapy use at baseline. QHU questionnaires evaluated HC use, symptoms of headache and TMD, and pain of ≥ 1 day duration in 12 body regions. Participants who developed TMD symptoms were examined to classify clinical TMD. Headache symptoms were classified based on the International Classification of Headache Disorders 3 (ICHD-3). Associations between HC use and pain symptoms were analyzed using generalized estimating equations and Cox models. Results: HC use, endorsed in 33.7% of QHU questionnaires, was significantly associated with concurrent symptoms of TMD (odds ratio [OR]: 1.20, 95% CI: 1.06 to 1.35) and headache (OR: 1.26, 95% CI: 1.11 to 1.43). HC use was also significantly associated with concurrent pain of ≥ 1 day duration in the head (OR: 1.38, 95% CI: 1.16 to 1.63), face (OR: 1.44, 95% CI: 1.13 to 1.83), and legs (OR: 1.22, 95% CI: 1.01 to 1.47), but not elsewhere. Initiation of HC use was associated with increased odds of subsequent TMD symptoms (OR: 1.37, 95% CI: 1.13 to 1.66) and pain of ≥ 1 day in the head (OR: 1.37, 95% CI: 1.01 to 1.85). Discontinuing HC use was associated with lower odds of subsequent headache (OR: 0.82, 95% CI: 0.67 to 0.99). HC use was not significantly associated with subsequent onset of examiner-classified TMD. Conclusion: These findings imply that HC influences craniofacial pain, and that this pain diminishes after cessation of HC use. Keywords: contraception, facial pain, headache, hormones, pain

Aims: To report the effectiveness of temporomandibular joint (TMJ) arthrocentesis with viscosupplementation for degenerative joint disease (DJD) over a long-term (ie, 10-22 years) follow-up. Methods: A total of 103 patients aged between 30 and 91 years (13 men and 90 women; mean age 63.7 years) who received a cycle of five arthrocentesis sessions with HA viscosupplementation to manage their symptoms related to TMJ DJD during the time period from 1998 to 2010 were recalled for clinical evaluation. After the treatment cycle, clinical outcomes were assessed based on the following parameters: maximum mouth opening (MO), pain with function (PF), pain at rest (PR), and self-reported chewing efficiency (CE). Data were collected at baseline (T₀) and at successive follow-up assessments, after at least 3 months (T₁) and 1 year (T₂), as per previous publications. Patients who had received treatment at least 10 years prior were then recalled for this study (T₃: 10 to 22 years follow-up). Analysis of variance for repeated measures was performed to assess changes over time. Results: Significant improvement in all clinical parameters was achieved at T₁ and was maintained for up to 10 years (T₃), with P < .01 for each parameter. At T₃, treatment effectiveness was perceived as excellent by 56% and as good by 26.5% of subjects, while 10.7% perceived a moderate improvement, and 6.8% referred a slight improvement or did not have any improvement. Only seven individuals required additional treatments after T₂. Conclusion: These findings suggest that the symptomatic management of TMJ DJD achieved in the short or medium term with a cycle of arthrocentesis and viscosupplementation was effectively maintained in the long term. Keywords: arthrocentesis, temporomandibular disorders, temporomandibular joint

Aims: To analyze Axis I and II findings of patients diagnosed as having painful temporomandibular disorder (TMD) with headache attributed to TMD (HAattrTMD) in order to assess whether HAattrTMD is associated with a specific Axis I and II profile suggestive of the central sensitization process. Methods: This retrospective study included 220 patients with painful TMD divided into those with (n = 60) and those without (n = 160) HAattrTMD, and the patients were compared for Axis I and II results according to the Diagnostic Criteria for TMD (DC/TMD). A P value < .05 was considered statistically significant. Results: A total of 27.3% of the patients received a diagnosis of HAattrTMD. Myofascial pain with referral was significantly more common in the HAattrTMD group (P < .001), while local myalgia was significantly more common in the non-HAattrTMD group (P < .001). Characteristic pain intensity was significantly higher in the HAattrTMD group (P = .003), which also showed significantly higher levels of depression (P = .002), nonspecific physical symptoms (P = .004), graded chronic pain (P = .008), and pain catastrophizing (P = .013). Nonspecific physical symptoms were positively associated with HAattrTMD (odds ratio [OR] = 1.098, 95% CI = 1.006 to 1.200, P = .037). Local myalgia was negatively associated with HAattrTMD (OR = .295, 95% CI = 0.098 to 0.887, P = .030). Conclusions: Painful TMD patients who report headache in the temple area and are diagnosed as having local myalgia rather than myofascial pain with referral probably do not have HAattrTMD. The diagnosis of HAattrTMD may point to a central sensitization process and possible current/future chronic TMD conditions. Keywords: Axis II, DC/TMD, headache attributed to TMD, local myalgia, myofascial pain with referral

Aims: To answer the question: among observational studies, is there any association between primary headaches and bruxism in adults? Materials and methods: A systematic review of observational studies was performed. The search was performed in seven main databases and three gray literature databases. Studies in which samples were composed of adult patients were included. Primary headaches were required to be diagnosed by the International Classification of Headache Disorders. Any diagnostic method for bruxism was accepted. Risk of bias was evaluated using the Joanna Briggs Institute Critical Appraisal Tool and the Meta-Analysis of Statistics Assessment and Review Instrument (MAStARI) tool. Associations were analyzed by calculating odds ratios (OR) in Review Manager 5.3 software. The evidence certainty was screened by Grading of Recommendations Assessment, Development, and Evaluation criteria. Results: Of the 544 articles reviewed, 5 met the inclusion criteria for qualitative analysis. The included studies evaluated both awake and sleep bruxism, as well as tension-type headaches and migraines as primary headaches. Among two migraine studies, one showed an OR of 1.79 (95% CI: 0.96 to 3.33) and another 1.97 (95% CI: 1.5 to 2.55). On the other hand, among three tension-type headache studies, there was a positive association only with awake bruxism, with an OR of 5.23 (95% CI: 2.57 to 10.65). All included articles had a positive answer for more than 60% of the risk of bias questions. The evidence certainty varied between low and very low. Due to high heterogeneity among the studies, it was impossible to perform a meta-analysis. Conclusion: Patients with awake bruxism have from 5 to 17 times more chance of having tension-type headaches. Sleep bruxism did not have any association with tension-type headache, and the association with migraines is controversial. Keywords: bruxism, primary headache disorders, migraine disorders, systematic review, tension-type headache

Aims: To compare the prevalence of facial pain and headache across various regions in Sweden. Methods: This study involved a comparison of cross-sectional questionnaire studies over a period of 10 years including 128,193 individuals and assessed facial pain, pain on function, and headache. Participants included (1) all Public Dental Service patients aged 16 to 90 years in Västerbotten (n = 57,283) and Gävleborg (n = 60,900); and (2) random samples of residents in Kalmar (n = 3,560) and Skåne (n = 6,450). Facial pain and pain on function were assessed for all participants, and headache was also assessed for participants in Kalmar and Skåne. Descriptive statistics were used to estimate unadjusted prevalence estimates and demographic characteristics. Prevalence estimates were adjusted for age and sex using weighted distributions from the 2015 data in the Swedish population registry before comparisons across the regions. Results: Overall, the prevalence of facial pain and headache were significantly higher in female than in male participants (P < .01). The standardized prevalence of facial pain was 4.9% in Västerbotten, 1.4% in Gävleborg, 4.6% in Kalmar, and 7.6% in Skåne. For headache, the standardized prevalence was 18.9% in Kalmar and 21.3% in Skåne. In Skåne, individuals with facial pain had a 15-fold higher odds of headache than those without. Conclusion: In the present Swedish epidemiologic study, the prevalence of facial pain ranged from 1.4% in Gävleborg to 7.6% in Skåne. Besides different sampling frames and other population characteristics, the presence of a high number of immigrants in Skåne may account for some differences in pain prevalence across the Swedish regions. Keywords: facial pain, headache, prevalence, survey, temporomandibular disorders

Aims: To investigate the sensitivity and specificity of the TMD pain screener in a headache population. Methods: A cross-sectional study was conducted at the Danish Headache Center (DHC). Patients were included if they had primary or secondary headache, trigeminal neuralgia, or facial pain. The pain screener was compared to the outcome of a full Diagnostic Criteria for TMD (DC/TMD) examination. Results: A total of 62 headache patients were included (77% women). The sensitivity of the pain screener short version (three questions) was 85% (95% CI: 70% to 94%), and the specificity was 64% (95% CI: 41% to 83%). In the full version (six questions), the sensitivity was 83% (95% CI: 67% to 93%), and the specificity was 82% (95% CI: 60% to 95%). Conclusion: The TMD pain screener seems to be a valid tool to accurately screen for the presence of TMD to provide the most optimal treatment for headache patients. These findings should however be confirmed in a larger sample with migraine, tension-type headache, and trigeminal neuralgia. Keywords: diagnostic accuracy, migraine, orofacial pain, tension-type headache, TMD, trigeminal neuralgia