This study aimed to understand the impact of COVID-19 distress on psychological status, features of central sensitization and facial pain severity in people with temporomandibular disorders (TMDs). In this prospective cohort study, 45 adults (19 chronic, 26 acute/subacute TMD) were recruited prior to the COVID-19 outbreak. Baseline assessment took place before the outbreak while a follow-up was performed immediately after the lockdown period. Multiple variables were investigated including age, gender, perceived life quality, sleep quality, anxiety and depression, coping strategies, central sensitization, pain intensity, pain-related disability and oral behaviour. COVID Stress Scales (CSS) were applied at follow-up to measure the extent of COVID-related distress. CSS were significantly higher in those with chronic TMDs compared to those with acute/subacute TMDs (p<0.05). In people with chronic TMD, the variation in anxiety and depression from baseline to follow-up was significantly correlated with scores on the CSS (r = 0.72; p = 0.002). Variations of the central sensitization inventory (r = 0.57; p = 0.020) and graded chronic pain scale (r = 0.59; p = 0.017) were significantly correlated with scores on the CSS. These initial findings indicate that people with chronic TMD were more susceptible to COVID-19 distress with deterioration of psychological status, worsening features of central sensitization and increased chronic facial pain severity. These findings reinforce the role of stress as a possible amplifier of central sensitization, anxiety, depression, chronic pain and pain-related disability in people with TMDs. Trial Registration: ClinicalTrials.gov ID: NCT03990662.

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IntroductionTemporomandibular disorders (TMDs) are principally characterised by pain in the craniomandibular area and probable limitations of jaw opening. Manual therapy, like other recommended conservative treatments included in clinical guidelines, is commonly used to treat patients with TMD to reduce pain and improve function. However, outcomes may be variable. The aim of this study is to identify predictors associated with pain reduction in patients with TMD following manual therapy by analysing a combination of patient-reported outcome measures and clinical tests. Such knowledge will support a more personalised management approach by facilitating clinical decision-making.Methods/analysisAn observational prospective design will recruit a cohort of 100 adults with a diagnosis of TMD (according to Axis I of the Diagnostic Criteria for TMD) at a Dental Hospital in Italy. Patients will be treated with four weekly sessions of manual therapy applied to craniomandibular structures. An array of predictors has been chosen based on previous research on prognostic factors for TMD and altered pain modulation in musculoskeletal disorders. Candidate predictors including demographic variables, general health variables, psychosocial features, TMD characteristics and clinical tests of the temporomandibular joint and masticatory muscles will be collected at baseline. Definition of good outcome is a clinically significant reduction of pain intensity over the last week (≥30% reduction Visual Analogue Scale) immediately following the four week intervention. Exploratory factor analysis will be applied to analyse factor loading of candidate predictors for good outcome at four weeks. Subsequently, a logistic multivariable regression model will be performed to calculate low and high risk of good outcome.Ethics and disseminationEthical approval has been obtained from the ‘Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico’ and University of Birmingham Ethics Committee. The results will be submitted for publication in a peer-reviewed journal and presented at conferences.Trial registration number NCT03990662; Pre-results.

Persistent idiopathic facial pain (PIFP) is a complex and uncertain nosographic entity, which has many aspects that need to be explored. The 21 patients selected (male 4 and female 17, mean age 40 years) were under electromyography (EMG) to determine the efficiency of the masseter muscles (MM) and the anterior temporalis muscles (TA), during activity and at rest, and under kinesiography (CMS) to identify the physiological rest position of the mandible after TENS stimulation. These patients were rehabilitated with a neuromuscular orthosis to provisionally correct the discrepancies identified. The EMG mean values of the muscles at rest were significantly above the normal (two-sample t test) for all four muscles and were normalized after the TENS session (Wilcoxon rank test). CMS showed that all 21 patients needed a mandibular advancement and 90.5% a correction in the frontal plane, obtained with orthosis. The comparison between the values of the maximal clench on natural dentition and on the orthosis showed a decrease in the asymmetry of muscular strength (-30.21% for TA and -55.81% for MM; Wilcoxon rank test) and a net increase of the strength expressed (LTA +25.37; LMM +59.40%, RMM +40.80%, RTA +30.27; Wilcoxon rank test; sign test). Preliminary results show a net decrease also in VAS pain score with a mean shift from 9.5 to 3.1. The results suggest a role for the neuromuscular component of the craniomandibular system in the pathogenesis of chronic idiopathic facial pain. All patients with PIFP should undergo the CMS-EMg examination.

Tweny patients (M: 4, F: 16, mean age 37 ± 11 years) with diagnosis of chronic daily headache (CDH), after drug withdrawal, were under electromyography, kinesiography and masticatory muscle deprogramming by TENS to identify the physiological rest position of the mandible. Our purpose was to clarify a possible role of the neuromuscular stomatognathic system. Examinations showed that 17 patients needed a neuromuscular orthosis, an occlusal device, to provisionally correct the detected discrepancies of jaw position. Of those, the 10 patients who showed an occlusal sagittal discrepancy higher than 2 mm and/or a lateral deviation higher than 0.4 mm, associated with more than three parafunctional activities, had a meaningful decrease on frequency/intensity of migraine crisis and/or of days of headache. VAS pain score during crisis decreased from 9.0 ± 0.9 to 4.9 ± 2.7; frequency of crisis were from 20.7 ± 5.2 to 9.5 ± 7.7. Baseline pain were from 5.3 ± 1.2 to 3.0 ± 1.3. Satisfying clinical results can be reached combining behavioural education and neuromuscular orthosis. This can be very helpful in patients who show significant discrepancy of jaw position that only TENS deprogramming can reveal and kinesiography can detect with such accuracy.