Botulinum toxin type A (BoNT-A) is increasingly used in treating masticatory muscle pain disorder; however, safe doses and reinjection intervals still need to be established. The purpose of this randomized clinical trial was to evaluate the degree and duration of the impairment of masticatory muscle performance. Fifty-seven subjects were randomly divided into two groups: one of which received BoNT-A first (n = 28) while the other received saline first (n = 29), with the cross-over being in week 16, and a total follow-up period of 32 weeks. A total dose of 50 U of BoNT-A was injected in the masseter and temporal muscles bilaterally. Electromyographic (EMG) activity and bite forces were assessed. A significant reduction in EMG activity was observed up to week 18 (p ≤ 001), with total recovery at week 33. A significant reduction in maximum bite force was observed up to week 11 (p ≤ 005), with total recovery at week 25. In conclusion, when treating masticatory muscle pain disorder with 50 U of BoNT-A, a reinjection interval of 33 weeks can be considered safe since the recovery of muscle function occurs by that time.

To assess drawings of pain sites and self-reported comorbid pains as a part of the biopsychosocial profiling of tertiary care referral patients with temporomandibular disorder (TMD) pain. A total of 135 consecutive patients referred to tertiary care for TMD pain participated. Patients drew all the sites where they had pain on whole-body pain drawings. Other assessments included self-reported comorbid pains in the head and body regions, the Finnish Research Diagnostic Criteria for TMD (RDC/TMD_FIN Axis II), and additional biopsychosocial and treatment-related variables. Patients were grouped into pain drawing profiles (localized, regional, and widespread) and the associations between these profiles and the biopsychosocial variables were statistically evaluated using Bonferroni adjusted P values and with logistic regression using SAS 9.3. A total of 21% of the patients reported localized TMD pain, 20% reported regional pain (headaches and neckaches), and the majority, 59%, reported widespread pain (local/regional and multiple bodily pain sites). Patients with widespread pain profiles formed a heterogenous group in which 28.2% reported severe and 30.8% reported moderate pain-related disability. The widespread pain patients reported significantly higher levels of depression and somatization, lower levels of general health, more sleep dysfunction, decreased ability to control pain, and greater health care needs compared to patients with localized pain (P < .05). Patients with regional pain profiles reported moderate scores on psychosocial functioning compared to the patients with localized or widespread pain. The majority of tertiary care referral patients with TMD pain reported comorbid pains. Pain drawings were found a useful adjunctive tool for screening and as a part of comprehensive biopsychosocial assessment and treatment planning for patients with TMD pain.

The outcome evaluation method presented in this case study, including Axes I and II findings combined with the results of quantitative bite force and EMG measurements, provides a good tool for proper evaluation of the effect of BoNT‐A on patients with myofascial orofacial pain and changes in jaw muscle function.