Electromyographic Patterns and the Identification of Subtypes of Awake Bruxism

Abstract

The future of awake bruxism assessment will incorporate physiological data, possibly electromyography (EMG) of the temporal muscles. But up to now, temporal muscle contraction patterns in awake bruxism have not been characterized to demonstrate clinical utility. The present study aimed to perform surface EMG evaluations of people assessed for awake bruxism to identify possible different subtypes. A 2-year active search for people with awake bruxism in three regions of the country resulted in a total of 303 participants (223 women, 38 ± 13 years, mean and SD). Their inclusion was confirmed through non-instrumental approaches for awake bruxism: self-reported questionnaire and clinical exam, performed by three experienced and calibrated dentists (Kappa = 0.75). Also, 77 age- and sex-matched healthy controls were recruited (49 women, 36 ± 14 years). Temporalis surface EMG was performed with a portable device (Myobox; NeuroUp, Brazil). EMG signals were sent to a computer via Bluetooth 4.0 at a sampling rate of 1,000 Hz. Digital signal processing was performed using the commercial neuroUP software, transformed in RMS and then normalized for peak detection (EMG peaks/min), in a 10 min session. Cluster analysis revealed three distinct subtypes of awake bruxism: phasic, tonic, and intermediate. Individuals with a predominance of EMG peaks/min were classified as the “phasic” subtype (16.8%). Those with the highest EMG rest power were classified as the “tonic” subtype (32.3%). There was also an “intermediate” subtype (50.8%), when both variables remained low. Characterization of awake bruxism physiology is important for future establishment of instrumental assessment protocols and treatment strategies.

Effectiveness of Biofeedback in Individuals with Awake Bruxism Compared to Other Types of Treatment: A Systematic Review

“…The presence of phasic activity of the masticatory muscles affects at least 16.8% of individuals with awake bruxism, and high tonic activity can also be found in this population (32.3%) [ 35 ]. The repetitive and/or sustained activity of the masticatory muscles can result in tooth wear and softening pain [ 36 ], as well as increased muscle tension [ 37 ].…”

Predictors of Step Length from Surface Electromyography and Body Impedance Analysis Parameters

“…The amplitude, time, and frequency domains of the sEMG signals are affected by the timing and intensity of the muscle contraction [ 38 ]. The RMS value, calculated from the average power of these signals, is used as a validated parameter from sEMG data in many types of research [ 39 , 40 , 41 ]. Although the RMS value at maximal knee flexion strength tended to positively correlate with measured strength, it did not show a very high correlation in our study (R 2 = 0.1549, p < 0.001, Figure S4 ).…”

Accuracy of Surface Electromyography in the Diagnosis of Pain-Related Temporomandibular Disorders in Children with Awake Bruxism

“…Bruxism is an umbrella term for various masticatory muscle motor phenomena/behaviours of the masticatory muscles [ 1 ]. According to the current international consensus on the assessment of bruxism, awake bruxism (AB) is defined as “masticatory muscle activity during wakefulness that is characterized by repetitive or sustained tooth contact and/or by bracing or thrusting of the mandible” [ 2 ].…”

“…In this light, bruxism is seen as a risk factor that may have possible negative oral health results, such as severe pain in the masticatory muscles or temporomandibular joint (TMJ), extreme mechanical tooth wear, cracked teeth, and/or prosthodontic problems [ 2 , 3 ]. Consequently, people with AB are more likely to develop pain-related temporomandibular disorders (TMD-P) [ 1 , 3 , 4 , 5 ] due to overload of musculoskeletal structures and craniofacial pain [ 6 , 7 ], although the relationship between pain and bruxism remains unclear [ 8 , 9 , 10 ].…”

“…Both non-instrumental (especially self-reporting) and instrumental (notably electromyography-EMG) methods can be used in evaluation of bruxism, leading to three degrees of probability of correct diagnosis AB and SB, namely “possible” (positive self-report only), “probable” (positive clinical evaluation with or without positive self-report) and “definite” (positive instrumental assessment with or without positive self-report and/or positive clinical inspection) [ 2 ]. Instrumental methods, such as surface electromyography (sEMG) during wakefulness, can provide evidence of AB, although there are no protocol recommendations yet [ 1 , 24 ]. In a review of the literature, Yamaguchi et al [ 25 ] revealed that to assess AB, EMG measurements of masticatory muscle activity can be easily and accurately performed during the day using wearable EMG devices.…”