Interepisode Sleep Bruxism Intervals and Myofascial Face Pain

A case-control study on the effect of rhythmic masticatory muscle activity (RMMA) clusters on sleep fragmentation and severity of orofacial muscle pain in sleep bruxism

Rhythmic masticatory muscle activity (RMMA) is a periodic muscle activity that characterises sleep bruxism (SB) events. These can occur as a single event, in pairs, or in clusters. Since RMMA episodes often occur in clusters and the relevance of this occurrence is unknown, we conducted a study to investigate the effect of RMMA clusters on sleep fragmentation and the severity of orofacial muscle pain. This study involved a secondary analysis using data from 184 adult subjects with orofacial muscle pain who underwent definitive polysomnography (PSG) for sleep bruxism diagnosis. Self-reported orofacial muscle pain (OFMP) was assessed using the numeric rating scale, and additional evaluation of side-to-side equivalence (symmetry) was described using a binary system. Among the 184 participants, 60.8% (n = 112) did not exhibit clusters and among the 72 participants with clusters, 36.1% (n = 26) and 63.9% (n = 46) were in the high and low RMMA frequency groups, respectively. The high SB group had significantly three times more phasic RMMA events than the noncluster group. A total of 89.67% (n = 165) of subjects reported orofacial muscle pain. While there was no difference in the severity of OFMP among groups, a significant decrease in symmetry between the severity of temporal muscle pain on the left and right sides was noted in the cluster group compared with the noncluster group. Clustering of RMMA events is associated with sleep fragmentation. The asymmetry of temporal muscle pain is related to the presence of RMMA clusters in sleep bruxism.

Effects on general pain perception and dental pulp sensibility in probable sleep bruxism subjects by experimentally induced pain in a pilot study

In this pilot study, the general pain perception and the dental pulp sensibility of probable sleep bruxism (SB) subjects were compared with that of non-SB subjects. The cold pressor test (CPT), electric pulp test (EPT), and thermal pulp test with CO₂ snow were executed by one trained dentist (blind to SB diagnosis). A one-factorial multivariate analysis of variance (MANOVA) with SB diagnosis as independent variable and standardized measures regarding pain perception and evaluation was performed. One-hundred-and-five participants (53 SB and 52 non-SB subjects) were included. The one-factorial MANOVA revealed a significant difference between SB and non-SB subjects (p = 0.01) concerning pain perception variables. Post-hoc univariate analyses of variance (ANOVA) showed statistically significant lower general pain tolerance (p = 0.02), higher general subjective sensibility of the teeth (p < 0.01), and a statistical trend for higher subjective dental pain intensity (p = 0.07) in SB subjects. In most of the standardized variables, probable SB subjects seem to react and feel similar to non-SB subjects. However, as probable SB subjects subjectively perceive their teeth to be more sensitive and tend to rate their subjective dental pain intensity more intensely after CO₂ testing, data might point to a somatosensory amplification.

Temporomandibular Disorders Within the Context of Sleep Disorders

This paper provided an overview of the knowledge on the relationship between temporomandibular disorders (TMDs) and the main sleep conditions and disorders of dental interest, namely, sleep bruxism (SB), sleep apnea, and gastroesophageal reflux disease (GERD). It emerged that although the topic of SB as a possible detrimental factor for the stomatognathic structures has been the most studied, evidence is growing that SB, obstructive sleep apnea, and GERD, all belong to a circle of mutually interacting sleep disorders and conditions that, in turn, may be associated with TMDs. The pathophysiology of the cause-and-effect relationships, if existing, has to be elucidated yet.

Ecological Momentary Assessment of Masseter Muscle Activity in Patients with Bruxism

According to the International Bruxism Consensus, bruxism refers to the activity of the masticatory muscles reflecting contraction disorders, regardless of whether it is during sleep (SB) or an awake (AB) state. The objective of the present study was to evaluate the activity of the masseter muscle by surface electromyographic (sEMG) recordings. This study was performed on 20 participants with self-reported “possible bruxism” (study group) and 20 participants with no self-reported bruxism (control group); all participants underwent an evaluation of the masseter muscle activity using the dia-BRUXO device, which provides numerical parameters regarding sEMG (the total duration and the type of bruxism specific events, the effort made by the masticatory muscles during the recording period, and the personal bruxism index of each participant). Participants from the study group presented more clenching events during AB, three times more frequent than the control group (p = 0.002, Mann−Whitney U test); for SB, the frequency of clenching and grinding events was comparable within the study group, being more frequent than for the control group; the mean value of the effort index was higher for AB (1.177%) than SB (0.470%) and the same for the duration index, with a mean value of 2.788% for AB and 1.054% for SB. All participants from the control group presented reduced values for all acquired parameters. Overall, the personal bruxism index in AB was approximately four times higher for the study group (2.251%) compared to the control group (0.585%) (p < 0.005, Mann−Whitney U test). Similar values were obtained for SB. All participants with “possible bruxism” from the study group presented a higher activity of the masseter muscle, which is specific for bruxism, thus being defined as “definite bruxism”.

Biomechanical Modelling for Tooth Survival Studies: Mechanical Properties, Loads and Boundary Conditions-A Narrative Review

Recent biomechanical studies have focused on studying the response of teeth before and after different treatments under functional and parafunctional loads. These studies often involve experimental and/or finite element analysis (FEA). Current loading and boundary conditions may not entirely represent the real condition of the tooth in clinical situations. The importance of homogenizing both sample characterization and boundary conditions definition for future dental biomechanical studies is highlighted. The mechanical properties of dental structural tissues are presented, along with the effect of functional and parafunctional loads and other environmental and biological parameters that may influence tooth survival. A range of values for Young's modulus, Poisson ratio, compressive strength, threshold stress intensity factor and fracture toughness are provided for enamel and dentin; as well as Young's modulus and Poisson ratio for the PDL, trabecular and cortical bone. Angles, loading magnitude and frequency are provided for functional and parafunctional loads. The environmental and physiological conditions (age, gender, tooth, humidity, etc.), that may influence tooth survival are also discussed. Oversimplifications of biomechanical models could end up in results that divert from the natural behavior of teeth. Experimental validation models with close-to-reality boundary conditions should be developed to compare the validity of simplified models.

Managements of sleep bruxism in adult: A systematic review

This systematic review aimed to update the management of sleep bruxism (SB) in adults, as diagnosed using polysomnography (PSG) and/or electromyography (EMG). Management methods covered were oral appliance therapy (OAT) with stabilization splints, cognitive-behavioral therapy (CBT), biofeedback therapy (BFT), and pharmacological therapy. A comprehensive search was conducted on MEDLINE, Cochrane Library, and Web of Science up to October 1st, 2021. Reference list searches and hand searches were also performed by an external organization. Two reviewers for each therapy independently performed article selection, data extraction, and risk of bias assessment. The reviewers resolved any disagreements concerning the assortment of the articles by discussion. Finally, 11, 3, 14, and 22 articles were selected for each therapy. The results suggested that OAT tended to reduce the number of SB events, although there was no significant difference compared to other types of splints, that the potential benefits of CBT were not well supported, and that BFT, rabeprazole, clonazepam, clonidine, and botulinum toxin type A injection showed significant reductions in specific SB parameters, although several side effects were reported. It can be concluded that more methodologically rigorous randomized large-sample long-term follow-up clinical trials are needed to clarify the efficacy and safety of management for SB.

Customized Appliance Device for Force Detection in Bruxism Individuals: An Observational Study

Objective

This study aims to test a customised device for detecting contact-related sleep bruxism in adult patients and to show the efficacy of an established biofeedback method incorporated within the device.

Methods

Four volunteers, three of whom suffered from bruxism and one did not, underwent four tests to assess bruxism-related force detection during sleep with concurrent electromyographic recording and to compare SB activity with and without biofeedback stimuli.

Results

The device detected sleep bruxism in bruxer individuals, whilst no activity emerged in the control individual. A correlation between EMG and device signals for bruxism-related events emerged. Moreover, bruxism activity showed a significant decrease on the nights when the biofeedback treatment was applied.

Conclusion

The force-based device can detect appliance-contacting SB events as reliably as EMG recording. Finally, biofeedback stimuli allowed achieving a reduction in the severity and frequency of SB events.

Implications of Obstructive Sleep-related Breathing Disorder in Dentistry: Focus on Snoring and Obstructive Sleep Apnea

Obstructive sleep-related breathing disorder (SRBD) is an umbrella term that encompasses various types of upper airway dysfunctions during sleep characterized by increased respiratory effort secondary to snoring and/or increased upper airway resistance and pharyngeal collapse. Obstructive sleep apnea (OSA) is a representative SRBD that involves a significant decrease in or cessation of airflow despite the presence of respiratory effort. While snoring is considered a normal condition, it can cause serious noise disturbance to sleep partners and is considered a predictor of OSA. Snoring and OSA are highly correlated with obesity. SRBDs can lead to cardiovascular disease, hypertension, decreased quality of life, decreased work efficiency, daytime sleepiness, decreased neurocognitive activity, and psychological impairments. In dentistry, research on sleep problems has focused on temporomandibular disorder (TMD)/orofacial pain. The relationship between OSA and TMD/orofacial pain has been reported, but it is not clear whether it is a simple correlation or a causal relationship. Therefore, we aimed to review the causes of SRBDs including snoring and OSA and to review and infer the relationship between these SRBDs and TMD/orofacial pain. The effects of snoring and OSA extend beyond sleep disturbances and are worthy of future research, especially with regard to TMD.

Painful and non-painful symptoms evoked by experimental bracing and thrusting of the mandible in healthy individuals

BACKGROUND

Bruxism may involve bracing and thrusting of the mandible, in addition to clenching or grinding of the teeth. It is unclear how bracing and thrusting may contribute to potential musculoskeletal symptoms associated with bruxism.

OBJECTIVE

To examine the effect of experimental bracing and thrusting of the mandible on the development of musculoskeletal symptoms in healthy volunteers.

METHODS

Thirty healthy volunteers performed six trials of 5 min of repeated bracing and thrusting of the mandible. Bracing involved forcefully maintaining maximum protruded position (5 s with 1 s rest in between), whereas thrusting involved forcefully moving the mandible in a forward direction and back (1 Hz). The participants rated pain, unpleasantness, soreness, fatigue, tension, stiffness, stress and headache on 10-cm visual analogue scales (VAS) before, immediately and 24 h after the tasks. Pain drawings were obtained and maximum voluntary protrusive force (MVPF) was determined before and after the tasks. The outcome parameters for each task were compared between the time points.

RESULTS

There was a significant increase in the VAS scores (2-4/10) of pain, unpleasantness, soreness, fatigue, tension, stiffness and stress immediately following the tasks compared to baseline and 24 h after the tasks (p < .008). Pain was frequently reported in masseter muscles. MVPF values were significantly higher immediately (p < .001) and 24 h after thrusting (p < .001) and bracing (p = .012) tasks compared to the baseline.

CONCLUSIONS

Experimental bracing and thrusting of the mandible evoked transient, mild-to-moderate levels of muscle pain, fatigue, tension and stiffness and increased unpleasantness and stress scores in healthy volunteers.

Orofacial musculoskeletal pain: An evidence-based bio-psycho-social matrix model

Pain is a multidimensional experience comprising sensory-discriminative, affective-motivational, and cognitive-evaluative dimensions. Clinical and research findings have demonstrated a complex interplay between social burdens, individual coping strategies, mood states, psychological disorders, sleep disturbances, masticatory muscle tone, and orofacial musculoskeletal pain. Accordingly, current classification systems for orofacial pain require psychosocial assessments to be an integral part of the multidimensional diagnostic process. Here, we review evidence on how psychosocial and biological factors may generate and perpetuate musculoskeletal orofacial pain. Specifically, we discuss studies investigating a putative causal relationship between stress, bruxism, and pain in the masticatory system. We present findings that attribute brain structures various roles in modulating pain perception and pain-related behavior. We also examine studies investigating how the nervous and immune system on cellular and molecular levels may account for orofacial nociceptive signaling. Furthermore, we review evidence pointing towards associations between orofacial musculoskeletal pain and neuroendocrine imbalances, sleep disturbances, and alterations of the circadian timing system. We conclude with several proposals that may help to alleviate orofacial pain in the future.

Signal acquisition and analysis of ambulatory electromyographic recordings for the assessment of sleep bruxism: A scoping review

Background

Ambulatory electromyographic (EMG) devices are increasingly being used in sleep bruxism studies. EMG signal acquisition, analysis and scoring methods vary between studies. This may impact comparability of studies and the assessment of sleep bruxism in patients.

Objectives

(a) To provide an overview of EMG signal acquisition and analysis methods of recordings from limited‐channel ambulatory EMG devices for the assessment of sleep bruxism; and (b) to provide an overview of outcome measures used in sleep bruxism literature utilising such devices.

Method

A scoping review of the literature was performed. Online databases PubMed and Semantics Scholar were searched for studies published in English until 7 October 2020. Data on five categories were extracted: recording hardware, recording logistics, signal acquisition, signal analysis and sleep bruxism outcomes.

Results

Seventy‐eight studies were included, published between 1977 and 2020. Recording hardware was generally well described. Reports of participant instructions in device handling and of dealing with failed recordings were often lacking. Basic elements of signal acquisition, for example amplifications factors, impedance and bandpass settings, and signal analysis, for example rectification, signal processing and additional filtering, were underreported. Extensive variability was found for thresholds used to characterise sleep bruxism events. Sleep bruxism outcomes varied, but typically represented frequency, duration and/or intensity of masticatory muscle activity (MMA).

Conclusion

Adequate and standardised reporting of recording procedures is highly recommended. In future studies utilising ambulatory EMG devices, the focus may need to shift from the concept of scoring sleep bruxism events to that of scoring the whole spectrum of MMA.

Is dopaminergic medication dose associated with self-reported bruxism in Parkinson's disease? A cross-sectional, questionnaire-based study

OBJECTIVES

It is not clear whether dopaminergic medication influences bruxism behaviour in patients with Parkinson's disease (PD). Therefore, the aims are to investigate (i) the prevalence of possible (i.e., self-reported) bruxism (sleep and awake) in PD patients, and (ii) whether the use of dopaminergic medication and other factors (viz., demographic characteristics, PD-related factors, and possible consequences of bruxism) are associated with possible bruxism (sleep or awake).

MATERIALS AND METHODS

This study concerns a secondary analysis of an earlier published study. Three hundred ninety-five PD patients (67.9 ± 8.6 years of age; 58.7% males) were included. The levodopa equivalent daily dosage (LEDD) was used as a measure of the dopaminergic medication level. Subsequently, a logistic regression analysis was performed for the dependent variables 'awake bruxism' and 'sleep bruxism', with the following predictors: gender, age, LEDD, time since PD diagnosis, temporomandibular disorder (TMD) pain, jaw locks, and tooth wear.

RESULTS

The prevalence of possible awake and sleep bruxism was 46.0% and 24.3%, respectively. Awake bruxism was associated with sleep bruxism (OR = 8.52; 95% CI 3.56-20.40), TMD pain (OR = 4.51; 95% CI 2.31-8.79), and tooth wear (OR = 1.87; 95% CI 1.02-3.43). Sleep bruxism was associated with tooth wear (OR = 12.49; 95% CI 4.97-31.38) and awake bruxism (OR = 9.48; 95% CI 4.24-21.19). Dopaminergic medication dose was not associated with awake bruxism (OR = 1.0; 95% CI 0.99-1.00) or sleep bruxism (OR = 1.0; 95% CI 0.99-1.00).

CONCLUSION

Bruxism is a common condition in PD patients, but is not associated with the dopaminergic medication dose.

CLINICAL RELEVANCE

(Oral) health care providers should be alerted about the possibility of sleep and awake bruxism activity in PD patients, along with this activity's possible negative health outcomes (viz., TMD pain, tooth wear).

Identifying predictive factors for sleep bruxism severity using clinical and polysomnographic parameters: a principal component analysis

STUDY OBJECTIVES

The aim was to identify predictive factors for sleep bruxism (SB) severity among polysomnographic parameters, salivary cortisol levels, temporomandibular disorders, age, and sex.

METHODS

Young adults (19-30 years) were screened for self-/roommate reports of teeth grinding/clenching during sleep associated with clinical signs of tooth wear. Individuals positive for both conditions were administered a polysomnographic exam to provide a definite diagnosis of SB (n = 28). Healthy participants without SB signs/symptoms were also included (n = 15). The Research Diagnostic Criteria for Temporomandibular Disorders was applied to determine functional, muscular, and articular domains of the Temporomandibular Index. Cortisol awakening levels were measured in saliva. Principal component analysis was used to extract the latent components emerging from polysomnographic results, and 2 regression models were adjusted to predict the number and duration of bruxism episodes.

RESULTS

Principal component analysis resulted in 4 components-C1: %N1, total sleep time, sleep efficiency, arousals/microarousals; C2: %N2, %N3; C3: periodic limb movements and apneas; C4: %REM and REM latency. The number of SB episodes/h was predicted by increasing muscular scores and C2 (decrease in %N2 and increase in %N3) (adjusted R² = 45%; P =.001). The total time of SB episodes was predicted by decreased articular and increased functional scores, age, and female sex (adjusted R² = 36%; P = 0.010). Salivary cortisol levels were not associated with SB severity and did not differ between groups.

CONCLUSIONS

The findings showed that SB severity was predicted by muscular and functional scores, female sex, and distinct polysomnographic patterns, contributing to the deeper knowledge of the underlying pathophysiology of SB severity; additionally, the findings can help to formulate health approaches that are specific to the patient and will better assist in treating this condition.

Immediate Effect of Masticatory Muscle Activity with Transcutaneous Electrical Nerve Stimulation in Muscle Pain of Temporomandibular Disorders Patients

Transcutaneous electrical nerve stimulation (TENS) is a non-invasive treatment modality for acute and chronic pain. However, little information for muscle activity is available on the immediate effects of TENS in masticatory muscle pain related to temporomandibular disorders (TMDs). The present study aimed to evaluate the immediate effects of TENS treatment on TMD-related muscle pain. Thirty-six patients with TMD-related muscle pain and 39 healthy subjects served as TMD and control groups, respectively. For objective evaluations, maximum mouth opening, and maximum bite force were measured before and after TENS. The pain intensity was assessed according to a 100-mm visual analog scale (VAS). TENS was applied to painful muscles for 20 min with frequencies of 100–200 Hz. The treatment outcome was evaluated using Global Rating of Change (GRC) scales. In the TMD group, VAS values significantly decreased after TENS. Although there was significant increase in the maximum mouth opening after TENS for only TMD group, the maximum bite force of both groups was significantly greater after TENS. According to GRC scales, one patient with TMD-related muscle pain expressed negative feelings after TENS. Conclusively, TENS treatment might quickly relieve pain in masticatory muscles and improve masticatory functions in patients with TMD-related muscle pain.

Correlations between Sleep Bruxism and Temporomandibular Disorders

The aim of this study was to identify correlations between sleep bruxism (SB) and temporomandibular disorders (TMD) as diagnosed by means of the research diagnostic criteria for temporomandibular disorders (RDC/TMD). Sleep bruxism was diagnosed on the basis of I) validated questionnaires, II) clinical symptoms, and III) electromyographic/electrocardiographic data. A total of 110 subjects were included in the study. Fifty-eight patients were identified as bruxers and 52 as nonbruxers. A psychosocial assessment was also performed. An RDC/TMD group-I diagnosis (myofascial pain) was made for 10 out of 58 bruxers, whereas none of the nonbruxers received a diagnosis of this type. No significant differences were found between bruxers and nonbruxers with regard to RDC/TMD group-II (disc displacement) and group-III (arthralgia, arthritis, arthrosis) diagnoses. Somatization was significantly more common among bruxers than nonbruxers. Multivariate logistic regression analysis revealed that somatization was the only factor significantly correlated with the diagnosis of myofascial pain. The results of this study indicate a correlation between myofascial pain, as diagnosed using the RDC/TMD, and somatization. It seems that somatization is a stronger predictor of an RDC/TMD diagnosis of myofascial pain than sleep bruxism is.

[Study on the correlation between the mandibular masticatory muscle movement and sleep tooth wear]

OBJECTIVE

To investigate the correlation between the clinical diagnostic criteria of sleep bruxism and the frequency of mandibular movements during sleep.

METHODS

Video polysomnography was used to record 20 healthy adults with at least one of the following clinical symptoms and signs: 1) report of frequent tooth grinding; 2) tooth wear and dentin exposure with at least three occlusal surfaces; 3) masticatory muscle symptoms in the morning; 4) masseter muscle hypertrophy. The rhythmic masticatory muscle activity (RMMA) and isolated tonic activity were scored to compare the correlations with clinical symptoms and signs. Finally, the incidence of temporomandibular disorders (TMD) was investigated in patients with isolated tonic and RMMA subjects.

RESULTS

Among the 20 subjects, RMMA events were observed (5.8±3.1) times·h⁻¹ and isolated tonic episodes were observed (2.1±0.9) times·h⁻¹. The frequency of RMMA events was significantly greater in the patients with acoustic molars than in those without (P<0.05). Similarly, the frequency of RMMA events was significantly greater in the patients with tooth attrition than in those without (P<0.05). However, no difference was observed between the occurrence of RMMA and the symptoms of masticatory muscles or masseter hypertrophy in the morning. The incidence of TMD was significantly higher in the patients with RMMA than in the isolated tonic patients.

CONCLUSIONS

The clinical symptoms and signs often used to diagnose sleep bruxism are different clinical and physiological mandibular movements during sleep. RMMA during sleep can reflect the occurrence of tooth attrition and the high risk of TMD.

Experience with bruxism in the everyday oral implantology practice in the Netherlands: a qualitative study

Objective

To explore how bruxism is dealt with by accredited oral implantologists within daily clinical practice.

Materials and methods

Nine semi-structured interviews of oral implantologists practicing in non-academic clinical practices in the Netherlands were performed, and thematic analysis was conducted using a framework-based approach.

Results

Oral implant treatments in bruxing patients were a generally well-accepted practice. Complications were often expected, with most being of minor impact. Contradictive attitudes emerged on the topic of bruxism being an etiologic factor for peri-implant bone loss and loss of osseointegration. Views on the ideal treatment plan varied, though the importance of the superstructure’s occlusion and articulation features was repeatedly pointed at. Similarly, views on protective splints varied, regarding their necessity and material choice. Bruxism was diagnosed mainly by clinical examination, alongside with patient anamnesis and clinician’s intuition. There was little attention for awake bruxism.

Discussion

Bruxism was generally not considered a contraindication for implantological treatments by accredited oral implantologists. Views on the interaction between bruxism and bone loss/loss of osseointegration varied, as did views on the ideal treatment plan.

Conclusions

There is a need for better understanding of the extent to which, and under which circumstances, sleep and/or awake bruxism can be seen as causal factors for the occurrence of oral implant complications.

International consensus on the assessment of bruxism: Report of a work in progress

In 2013, consensus was obtained on a definition of bruxism as repetitive masticatory muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible and specified as either sleep bruxism or awake bruxism. In addition, a grading system was proposed to determine the likelihood that a certain assessment of bruxism actually yields a valid outcome. This study discusses the need for an updated consensus and has the following aims: (i) to further clarify the 2013 definition and to develop separate definitions for sleep and awake bruxism; (ii) to determine whether bruxism is a disorder rather than a behaviour that can be a risk factor for certain clinical conditions; (iii) to re-examine the 2013 grading system; and (iv) to develop a research agenda. It was concluded that: (i) sleep and awake bruxism are masticatory muscle activities that occur during sleep (characterised as rhythmic or non-rhythmic) and wakefulness (characterised by repetitive or sustained tooth contact and/or by bracing or thrusting of the mandible), respectively; (ii) in otherwise healthy individuals, bruxism should not be considered as a disorder, but rather as a behaviour that can be a risk (and/or protective) factor for certain clinical consequences; (iii) both non-instrumental approaches (notably self-report) and instrumental approaches (notably electromyography) can be employed to assess bruxism; and (iv) standard cut-off points for establishing the presence or absence of bruxism should not be used in otherwise healthy individuals; rather, bruxism-related masticatory muscle activities should be assessed in the behaviour's continuum.

Sleep and Orofacial Pain

Sleep and pain share a bidirectional relationship. Therefore, it is important for practitioners managing patients experiencing either sleep and/or pain issues to recognize and understand this complex association from a neurobiological perspective involving neuroanatomic and neurochemical processes. Accounting for the influence of pain on the various aspects of sleep and understanding its impact on various orofacial pain disorders assists in developing a prudent management approach. Screening for sleep disorders benefits practitioners in identifying these individuals. Instituting evidence-based multidisciplinary management strategies using both behavioral and pharmacologic strategies enhances the delivery of appropriate care.

Evaluation of muscle activity, bite force and salivary cortisol in children with bruxism before and after low level laser applied to acupoints: study protocol for a randomised controlled trial

BACKGROUND

Bruxism is a repetitive activity that causes tooth wear, audible sounds, and discomfort. Preventive measures have been studied for conditions that can exert a negative influence on physiological development in children. Low-level laser therapy administered over acupoints is an effective, painless, low-cost treatment option that has achieved good results. Thus, the aim of the proposed study is to evaluate changes in muscle activity, bite force and salivary cortisol in children with bruxism after the application of low-level laser to accupoints.

METHODS

The children will be randomly allocated to four groups of 19 individuals: G1 - low-level laser; G2 - occlusal splint; G3 - placebo laser; and G4 - control (without bruxism). The BTS TMJOINT electromyography will be used to determine muscle activity and a digital gnathodynamometer will be used to measure bite force. Salivary cortisol will be analysed at baseline as well as one and six months after treatment. Two-way ANOVA will be employed and complemented by Tukey's test.

DISCUSSION

Bruxism is a repetitive activity of the masticatory muscles that can have negative consequences if not treated, such as tooth wear, noises, discomfort and anxiety. Thus, control and treatment measures should be taken. Although low-level laser therapy over acupoints has been indicated for children, the effects of this treatment modality have not yet been studied.

TRIAL REGISTRATION

NCT02757261 on 8 April 2016. This study protocol received a grant from the Brazilian fostering agency São Paulo Research Foundation (FAPESP: #2015/24731-0).