Research routes on awake bruxism metrics: Implications of the updated bruxism definition and evaluation strategies.

BACKGROUND: With time, due to the poor knowledge on it epidemiology, the need to focus on awake bruxism as a complement of sleep studies emerged. OBJECTIVE: In line with a similar recent proposal for sleep bruxism (SB), defining clinically oriented research routes to implement knowledge on awake bruxism (AB) metrics is important for an enhanced comprehension of the full bruxism spectrum, that is better assessment and more efficient management. METHODS: We summarised current strategies for AB assessment and proposed a research route for improving its metrics. RESULTS: Most of the literature focuses on bruxism in general or SB in particular, whilst knowledge on AB is generally fragmental. Assessment can be based on non-instrumental or instrumental approaches. The former include self-report (questionnaires, oral history) and clinical examination, whilst the latter include electromyography (EMG) of jaw muscles during wakefulness as well as the technology-enhanced ecological momentary assesment (EMA). Phenotyping of different AB activities should be the target of a research task force. In the absence of available data on the frequency and intensity of wake-time bruxism-type masticatory muscle activity, any speculation about the identification of thresholds and criteria to identify bruxers is premature. Research routes in the field must focus on the improvement of data reliability and validity. CONCLUSIONS: Probing deeper into the study of AB metrics is a fundamental step to assist clinicians in preventing and managing the putative consequences at the individual level. The present manuscript proposes some possible research routes to advance current knowledge. At different levels, instrumentally based and subject-based information must be gathered in a universally accepted standardised approach.

Frequency of awake bruxism behaviour in orthodontic patients: Randomised clinical trial: Awake bruxism behaviour in orthodontic patients.

INTRODUCTION: The influence of aligners on the activity of the masticatory muscles is still controversial, especially regarding the behaviour associated with awake bruxism (AB). OBJECTIVE: To compare the frequency of AB behaviours between patients treated with aligners and fixed appliances. METHODS: The sample comprised 38 Class I patients (mean age 22.08 years), divided by simple randomisation into two groups: OA group; orthodontic aligners (n 19) and FA group; fixed appliance (n 19). The frequency of AB was investigated by the ecological momentary assessment using an online device (mentimeter), during 7 following days at different timepoints, before and after appliance placement and in the 2nd, 3rd, 4th and 6th months of orthodontic treatment. These variables were also evaluated: level of anxiety by the State-Trait Anxiety Inventory, stress by the Perceived Stress Scale, catastrophising related to pain and degree of hypervigilance by the Pain Vigilance and Awareness Questionnaire, and the presence of facial pain evaluated by the DC/TMD. RESULTS: There was no difference between groups in the frequency of AB behaviours, with mean of 53.5% for group OA and 51.3% for FA. The most frequent behaviour was slightly touching the teeth, and in FA group, there was a significant reduction in this behaviour soon after appliance placement. The groups did not differ concerning the degree of anxiety, stress, catastrophising, hypervigilance and facial pain. CONCLUSION: The orthodontic treatment performed with aligners or fixed appliances did not influence the frequency of AB during the 6 months of treatment. REGISTRY OF CLINICAL TRIALS: (REBEC): RBR-9zytwf.

The effect of orthodontic separator and short-term fixed orthodontic appliance on inflammatory mediators and somatosensory function.

BACKGROUND: Although inflammation can alter cytokines release and nerve function, it is not yet fully established if orthodontic-induced inflammation can cause significant extraoral trigeminal somatosensory alterations and release of inflammatory chemical mediators. OBJECTIVE: The primary aim of this study was to investigate the impact of orthodontic separator and short-term fixed orthodontic appliance on the extraoral trigeminal somatosensory function and concentrations of cytokines in the gingival crevicular fluid (GCF). METHODS: Twenty-two female patients were evaluated as follow: baseline, 24 hour-after elastomeric separator (-aES), 24 hour- and 1 month-after bonding brackets (-aBB) at both arches. The outcome variables were as follows: self-reported pain (Visual Analog Scale), QSTs (current perception threshold-CPT, cold detection threshold-CDT, warm detection threshold-WDT, mechanical detection threshold-MDT, mechanical suprathreshold-MST and wind-up ratio-WUR. All QSTs were performed at infra-orbital and mental nerve entry zone at patient`s dominant side. In addition, GCF samples in order to assess cytokines profile (IL-1ß,IL-8,IL-6 and TNF-α) were collected. ANOVA and Tukey's post hoc analyses were performed (a = 5%). RESULTS: Patients reported higher pain intensity 24 hour-aBB compared to baseline and 24 hour-aES (P < 0.050). Patients were less sensitive to pin-prick pain (MST) at 24 hour-aBB and 1 month-aBB compared to baseline (P < 0.006). Significant increases in IL-6 levels were observed 24 hour-aBB (P < 0.001). Multiple comparison analysis showed significant increase in IL-1ß levels (P < 0.001) and TNF-α (P < 0.001) 1 month-aBB compared to baseline. CONCLUSION: Elastomeric separators only induced mild pain and were not able to significantly increase proinflammatory cytokines level in the GCF. In addition, orthodontic fixed appliance may induce only minor somatosensory changes at extraoral trigeminal locations.