Journal of Oral & Facial Pain and Headache, 01/2022

Aims: To systematically review the scientific literature for evidence concerning the clinical use of botulinum toxin (BTX) for the management of various temporomandibular disorders (TMDs). Methods: A comprehensive literature search was conducted in the Medline, Web of Science, and Cochrane Library databases to find randomized clinical trials (RCT) published between 2000 and the end of April 2021 investigating the use of BTX to treat TMDs. The selected articles were reviewed and tabulated according to the PICO (patients/problem/population, intervention, comparison, outcome) format. Results: A total of 24 RCTs were selected. Nine articles used BTX injections to treat myofascial pain, 4 to treat temporomandibular joint (TMJ) articular TMDs, 8 for the management of bruxism, and 3 to treat masseter hypertrophy. A total of 411 patients were treated by injection of BTX. Wide variability was found in the methods of injection and in the doses injected. Many trials concluded superiority of BTX injections over placebo for reducing TMD pain levels and improving maximum mouth opening; however, this was not universal. Conclusion: There is good scientific evidence to support the use of BTX injections for treatment of masseter hypertrophy and equivocal evidence for myogenous TMDs, but very little for TMJ articular disorders. Studies with improved methodologic design are needed to gain better insight into the utility and effectiveness of BTX injections for treating both myogenous and TMJ articular TMDs and to establish suitable protocols for treating different TMDs. Keywords: botulinum toxin, bruxism, myofascial, pain, temporomandibular disorders, temporomandibular joint

Aims: To evaluate About Face, a pain management program aimed at increasing quality of life in adults living with persistent facial pain through psychology- and physiotherapy-based skill development. Methods: A total of 90 patients attended a six-session program with a 1-month follow-up between 2015 and 2019. Patients filled out self-reported outcome measures preprogram, postprogram, and at a 1-month follow-up visit. Results: There was a significant reduction in pain catastrophizing and a significant increase in engagement in meaningful activity, as well as a reduction in pain-related interference. Conclusion: This evaluation adds to the small amount of existing literature on interventions aimed at increasing quality of life in patients living with persistent facial pain and provides suggestions for future research. Keywords: persistent facial pain, pain management programme, psychology, physiotherapy, quality of life

Aims: To investigate how trait anxiety and stress jointly affect the sensory and jaw motor responses to a tonic orofacial nociceptive stimulus. Methods: Orthodontic separators were placed between the first molars in 45 adults with low (n = 14), intermediate (n = 17), and high (n = 14) trait anxiety. Tooth pain, occlusal discomfort, tooth clenching (as a jaw motor behavior), and situational stress were measured three times a day for 5 days using visual analog scales. Mixed-effects regression models were used to evaluate the sensory and motor outcome measures. Results: Pain, discomfort, and frequency of tooth-clenching trajectories were affected by trait anxiety (P = .007, P < .001, and P = .055, respectively) and stress (P < .001, P < .001, and P = .044, respectively). Individuals with high anxiety reported their highest pain (17.7 ± 2.9 mm) and discomfort (35.2 ± 4.1 mm) 24 hours earlier than those with low anxiety (pain: 15.9 ± 2.6 mm, discomfort: 28.8 ± 3.7 mm). Tooth clenching decreased progressively in response to the stimulus (P < .001). Conclusion: A tonic orofacial nociceptive stimulus triggers an avoidance jaw motor behavior. Both trait anxiety and situational stress heighten the sensory response to such a stimulus, but weakly affect the motor response to it. Keywords: anxiety, bruxism, masticatory muscles, occlusion, pain, sensory thresholds

Aims: To evaluate the short-term effects of a standardized first-line noninvasive approach (FL-A) including counseling and self-management strategies on pain, masticatory muscle tenderness, and awake bruxism in women with chronic temporomandibular disorder myalgia (mTMD) and to test whether patients' trait anxiety predicted their response to treatment. Methods: FL-A was administered to 14 women with chronic mTMD (mean age ± SD = 33.8 ± 11.1 years; 8 with Graded Chronic Pain Scale [GCPS] grade I and 6 with grade II). Its effects on facial pain, masticatory muscle tenderness, and spontaneous awake bruxism episodes were evaluated using questionnaires, surface electromyography, and quantitative sensory testing. General linear models were used to test FL-A efficacy after 1 (T1) and 2 (T2) months. Results: FL-A reduced pain (from baseline [T0] to T2, P = .010), the frequency of awake bruxism episodes (T0 to T1, P = .024), and their intensity by about 30% (T0 to T1, P < .001). Pressure pain thresholds at the masticatory muscle locations increased significantly from T0 to T2 (P < .001). Patients' trait anxiety decreased significantly from T0 to T2 (P = .030). Trait anxiety measured at baseline was not correlated with relative changes in pain (T0 to T2, P = .248). Conclusion: In the short term, FL-A reduces facial pain, masticatory muscle tenderness, and awake bruxism in women with chronic mTMD with low disability. A conservative management strategy should be prioritized for the initial management of these patients. Keywords: bruxism, facial pain, masseter, temporalis, temporomandibular disorders

Aims: To provide an analysis of the different therapeutic peripheral nerve blocks (PNBs), as well as their limitations and the related evidence base for their use in chronic orofacial pain (OFP) conditions, excluding migraine and other headache conditions. Methods/results: The evidence base for therapeutic PNBs for chronic OFP is poor and highlights the need for improved research in this area. The diagnostic criteria and interventional PNB definitions and techniques varied between studies. In addition, the placebo effect of a peripheral injection and its resultant bias was rarely considered. Most of the PNB interventions for temporomandibular disorders were for arthrogenous disorders (arthritis and disc entrapment with pain). However, there is emerging evidence for the use of onabotulinum toxin (BTX-A) in trigeminal neuralgia, with four prospective randomized controlled trials (pRCTs), and for postherpetic neuralgia. However, despite high-level evidence for BTX-A in posttraumatic neuropathic pain outside the trigeminal system, there is no evidence for its use for PTNP within the trigeminal system. Conclusion: There may be emerging evidence for treating trigeminal neuralgia with BTX-A injections; however, there is a need for future clinical studies of therapeutic PNBs in orofacial pain conditions. Keywords: reversible peripheral nerve block, therapeutic nerve block, therapeutic nerve injections, trigeminal nerve block, trigeminal nerve injections

Aims: To assess differences in catastrophizing and kinesiophobia in relation to areas of pain and somatic symptoms among participants with temporomandibular disorders (TMDs) and controls. Methods: In total, 401 participants (333 women, 68 men, mean age: 45.8 years) in the TMJ Impact Project were examined in accordance with the Diagnostic Criteria for TMD, including clinical examination (Axis I) and psychosocial assessment (Axis II) augmented with imaging of the temporomandibular joint (TMJ). Of these, 218 participants had a painful TMD pain diagnosis, 63 had a nonpainful TMD diagnosis, and 111 had no TMD. Nine participants had missing data. Participants completed the Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, Areas of Pain figure, and the Patient Health Questionnaire-15 for assessing somatic symptoms. Results: Compared to controls, participants with TMD pain showed higher levels of catastrophizing (P = .017), kinesiophobia (P < .001), areas of pain (P < .001), and somatic symptoms (P < .001). Participants with nonpainful TMD showed a higher level of kinesiophobia (P < .001) than controls. There was a positive correlation between catastrophizing and kinesiophobia for participants with TMD pain (r = 0.33, P < .001) and nonpainful TMD (r = 0.42, P < .001). Discussion: The results suggest more fear of movement, as well as an association between catastrophizing and fear of movement, in participants with TMD pain and in participants with nonpainful TMD compared to controls. Assessment and management of fear of movement as well as catastrophizing may be useful as part of individualized treatment strategies for patients with TMD. Keywords: catastrophization, facial pain, kinesiophobia, somatic symptoms, temporomandibular joint disorders

Aims: To investigate the predictive power of depression and anxiety for conditioned pain modulation (CPM) and to examine the relationships of CPM at 40°C and CPM at 47°C with age, disease-related pain, pain duration, and psychosocial factors in burning mouth syndrome (BMS). Methods: A total of 22 patients with BMS and 22 healthy female controls participated in this study. Temporal summation was used as the test stimulus for CPM, and subsequent exposure either to a nonpainful (40°C) or a painful (47°C) Peltier thermode was used as the conditioning stimulus. CPM was calculated as the difference in pain perception following the conditioning stimulus. Psychosocial factors were examined using the Profile of Mood States (POMS) and the State-Trait Anxiety Inventory (STAI). Results: State anxiety and tension-anxiety scores were significantly higher for patients with BMS than for control participants. Multiple regression analyses showed that CPM47°C was affected by vigor, fatigue, confusion, and trait anxiety (adjusted R² = 0.685, F = 5.147, P = .098). The corresponding analysis for CPM40°C showed that the model was not predictive for the following variables: disease-related pain, pain duration, or components of the POMS or STAI. A significant positive correlation was found between CPM47°C and trait anxiety, suggesting that trait anxiety negatively affected the endogenous pain modulation system. Conclusion: Increases in trait anxiety reduced the CPM effect. These findings suggest that CPM impairments and increases in trait anxiety are involved in the development of BMS. Keywords: anxiety, burning mouth syndrome, conditioned pain modulation, depression, state-trait anxiety inventory