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

Use of Botulinum Toxin in Orofacial Clinical Practice

Introduction: Botulinum neurotoxin (BoNT) is a potent biological toxin and powerful therapeutic tool for a growing number of clinical orofacial applications. BoNT relaxes striated muscle by inhibiting acetylcholine’s release from presynaptic nerve terminals, blocking the neuromuscular junction. It also has an antinociceptive effect on sensory nerve endings, where BoNT and acetylcholine are transported axonally to the central nervous system. In dentistry, controlled clinical trials have demonstrated BoNT’s efficiency in pathologies such as bruxism, facial paralysis, temporomandibular joint (TMJ) disorders, neuropathic pain, sialorrhea, dystonia and more. Aim: This study’s aim was to conduct a systematic literature review to assess the most recent high-level clinical evidence for BoNT’s efficacy and for various protocols (the toxin used, dilution, dosage and infiltration sites) used in several orofacial pathologies. Materials and methods: We systematically searched the MedLine database for research papers published from 2014 to 2019 with randomly allocated studies on humans. The search included the following pathologies: bruxism, dislocation of the TMJ, orofacial dystonia, myofascial pain, salivary gland disease, orofacial spasm, facial paralysis, sialorrhea, Frey syndrome and trigeminal neuralgia. Results: We found 228 articles, of which only 20 met the inclusion criteria: bruxism (four articles), orofacial dystonia (two articles), myofascial pain (one article), salivary gland disease (one article), orofacial spasm (two articles), facial paralysis (three articles), sialorrhea (four articles) or trigeminal neuralgia (three articles). Discussion: The clinical trials assessed showed variations in the dosage, application sites and musculature treated. Thus, applying BoNT can reduce symptoms related to motor muscular activity in the studied pathologies efficiently enough to satisfy patients. We did not identify the onset of any important side effects in the literature reviewed. We conclude that treatment with BoNT seems a safe and effective treatment for the reviewed pathologies.

Pain Predictors in a Population of Temporomandibular Disorders Patients

The aim of the present study was to assess the potential role of some biological, psychological, and social factors to predict the presence of painful temporomandibular disorders (TMDs) in a TMD-patient population. The study sample consisted of 109 consecutive adult patients (81.7% females; mean age 33.2 ± 14.7 years) who were split into two groups based on Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) diagnoses: painful TMD and non-painful TMD. The presence of pain was adopted as the depended variable to be identified by the following independent variables (i.e., predictors): age, gender, bruxism, tooth wear, chewing gum, nail biting, perceived stress level, chronic pain-related impairment (GCPS), depression (DEP), and somatization (SOM). Single-variable logistic regression analysis showed a significant relationship between TMD pain and DEP with an odds ratio of 2.9. Building up a multiple variable model did not contribute to increase the predictive value of a TMD pain model related to the presence of depression. Findings from the present study supported the existence of a relationship between pain and depression in painful TMD patients. In the future, study designs should be improved by the adoption of the best available assessment approaches for each factor.

[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.

Bruxism, temporomandibular dysfunction and cervical impairments in females - Results from an observational study

PURPOSE

Bruxism is highly prevalent and defined as abnormal habitual mouth activity including clenching of the teeth and increased jaw muscle activity. The association between bruxism and temporomandibular dysfunction (TMD) is debated, in particular the association between cervical spine impairments, bruxism, and TMD. Hence the purpose of this study was to identify the relationship between bruxism, TMD, and cervical spine impairments.

METHODS

This observational study categorized 55 female volunteers suitable for evaluation to a bruxism (n = 33) or non-bruxism group (n = 22) based on comprehensive screening using questionnaires and visual observation of the mouth by 2 independent dentists. Following this, both groups were evaluated for TMD, severity and location of head/neck pain, neck disability index (NDI), cervical spine impairments, and tissue mechanosensitivity. Regression analysis was used to evaluate the relationship between bruxism, TMD severity, and cervical impairments.

RESULTS

Coefficients of pain and bruxism were significantly associated with NDI scores (0.43, p < 0.001; 3.24, p = 0.01) with large and medium sized effects. As a consequence, both severity of TMD and bruxism status are independently associated with cervical impairments. Having TMD is an independent predictor for head/neck pain and cervical impairments. Pain associated with movement tests and tissue mechanosensitivity was found to be an important factor in bruxism.

CONCLUSION

Clinicians need to be aware that signs of cervical movement impairment are not likely to be associated with bruxism, rather they should focus on improving orofacial function and tissue mechanosensitivity.

Interventions to reduce bruxism in children and adolescents: a systematic scoping review and critical reflection

The aim of the present study was to perform a critical reflection about intervention options for bruxism reduction in children and adolescents. Search was conducted based on the PICO-structured question: "What are the intervention options to reduce bruxism in children/adolescents?". No language, year, or study design restrictions were imposed. Studies reporting interventions to reduce bruxism in children (< 10) and adolescents (10 to 19 years old) were included. Reviews and letters to editors were not included. From 2723 records, 17 papers were included. Included studies were primarily randomized clinical trials performed in Brazil (35.3%) and using different criteria for the diagnosis of bruxism. Reduction in self-reported bruxism and headaches associated with bruxism were observed in studies that used medications (hydroxyzine/trazodone/flurazepam), occlusal splints, orthodontic interventions, and psychological and physical therapy interventions. Reduction in Rhythmic Masticatory Muscle Activity was observed with the use of the occlusal splint and in orthodontic interventions. Alternative treatments (medicinal extracts such as Melissa officinalis-L) have shown inconclusive results.Conclusions: Several intervention options are available to inhibit or reduce bruxism activity. The respective indication, contraindications, and side effects of each treatment option must be assessed individually and carefully, taking into account that bruxism is not considered a disorder in otherwise healthy individuals.What is known• Biological and psychological factors have been strongly correlated to the development of bruxism• Bruxism prevalence ranging from 6 to 50% in childrenWhat is new• Reduction in self-reported bruxism and headaches associated with bruxism were observed in studies that used medication (Hydroxyzine/ Trazodone/ Flurazepam), occlusal splints, orthodontic interventions, psychological, and physical therapy interventions• A reduction in Rhythmic Masticatory Muscle Activity was observed with the use of the occlusal splint and orthodontic interventions. Alternative treatments (medicinal extracts such as Melissa officinalis L) show inconclusive results in respect of the reduction in bruxism.

Associations between sleep bruxism and (peri-)implant complications: lessons learned from a clinical study

Objective

To report and discuss the lessons learned from the conduct of a clinical study on the associations between sleep bruxism and (peri-)implant complications, the protocol of which has been pre-published.

Materials and methods

A single-center, double-blind, prospective cohort study with a 2 year follow-up was performed in the Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands. Eleven adult participants were included, where an inclusion of 98 was planned. Sleep bruxism was assessed by multiple single-channel electromyographic (EMG) recordings. Main outcomes were biological and technical complications. Results of the study are presented alongside with comments on encountered difficulties.

Results

Insufficient participant recruitment and failed EMG recordings were encountered. The small sample size did not allow answering the study’s main aim, and was mainly attributed to the study’s protocol complexity. EMG recording failures were attributed to insufficient quality of the EMG signal and detachments of the electrode.

Discussion

The lessons learned from the conduct of this study can be used to design successful future clinical studies.

Conclusions

Adequate participant recruitment, effective EMG recordings, and a careful selection of predictor variables are important ingredients for the successful conduct of a longitudinal clinical study on the association between sleep bruxism and (peri-)implant complications.

A polysomnographic study on the relationship between sleep bruxism intensity and sleep quality

Objective: To evaluate the correlation between the Bruxism Episodes Index (BEI) that determines the number of bruxism episodes per hour of sleep and sleep quality as measured by the Pittsburgh Sleep Quality Index (PSQI).Methods: Seventy-seven participants (56 women and 21 men) in which probable sleep bruxism was diagnosed using guidelines of the American Academy of Sleep Medicine underwent video-polysomnography. Sleep quality was measured using PSQI.Results: The analysis showed the lack of a statistically significant correlation between the BEI and PSQI scores (p = 0.55). Analysis also showed that the study group (bruxers) and control group (non-bruxers) did not differ significantly in terms of PSQI scores (p = 0.88).Conclusion: The intensity of bruxism seems not to affect the quality of sleep. However, the topic of the relationship between sleep quality and the occurrence of sleep bruxism requires further research, taking into account co-occurring sleep disorders and sleep architecture.

Recording of bruxism events in sleeping humans at home with a smart instrumented splint

Objective: The aim of this paper is to report quantitative and qualitative characteristics of bruxism events recorded in sleeping humans with a new smart ambulatory system specifically designed to measure dental clenching and grinding forces. The device is wireless and rechargeable, which enables its use over extended periods.Methods: Thirty recordings were obtained from volunteer subjects who wore the device at home during 10 consecutive nights (Clinicaltrials.gov N° NCT03363204).Results: The recordings showed that the system was able to successfully monitor bruxism during 10 consecutive nights, allowing a quantitative (number, duration, intensity, distribution during the night), as well as a qualitative characterization of the bruxism events (clenching vs. grinding).Discussion: This system could offer new perspectives in the field of bruxism, either as a research tool for clinical studies or as a medical device for the ambulatory home-based monitoring of bruxism.

A Further Introduction to Dental Sleep Medicine

Dental sleep medicine traditionally focuses on sleep-related breathing disorders, such as snoring and obstructive sleep apnea. However, everyday practice shows that also other sleep disorders touch on dentistry, including sleep-related orofacial pain, xerostomia, hypersalivation, gastroesophageal reflux disease and bruxism. A new definition, which covers all the diagnostic and treatment aspects of these disorders, has therefore been formulated for dental sleep medicine. This article describes why this development started and sketches the current state of affairs regarding the discipline of dental sleep medicine. The different dental sleep disorders are also described briefly, with special focus on the more remarkable associations between them.

Determination of Inflammatory Markers, Hormonal Disturbances, and Sleepiness Associated with Sleep Bruxism Among Adults

PURPOSE

Sleep bruxism (SB) is characterized by repetitive phasic, tonic, or mixed masticatory muscle activity during sleep with multifactorial etiology. Previous studies have shown that the complex origin of SB can be related to the psychological features of the affected individual, consumption of caffeine and alcohol, smoking, obstructive sleep apnea, diabetes, increased body mass index, hypertension, thyroid diseases, and probable genetic vulnerability. This study aimed to investigate the inflammatory markers, hormonal disturbances, and sleepiness associated with SB, which have a potential effect on the total cardiovascular (CV) risk among relatively young and healthy patients.

PATIENTS AND METHODS

A total of 74 individuals with probable SB were subjected to single-night polysomnography, followed by blood panel and 24-h urinary excretion tests. The level of daytime sleepiness was assessed in the participants using the Epworth Sleepiness Scale.

RESULTS

SB was found in 78.4% of participants. The bruxism episode index (BEI) positively correlated with the concentrations of 17-hydroxycorticosteroids, C-reactive protein, and fibrinogen in the collected urine samples. A positive correlation was also found between phasic BEI and glucose concentration 2 h after the consumption of glucose solution. Sleep bruxers showed significantly increased sleepiness compared to nonbruxers (p = 0.02). The scores on sleepiness were positively correlated with mixed BEI, minimal oxygen saturation, and mean heart rate.

CONCLUSION

The results of this study revealed that participants with SB had metabolic and hormonal disturbances, probably due to stress and sympathetic activity. Moreover, it was found that young sleep bruxers potentially have a high CV risk due to the increased level of inflammatory and stress markers.

Single nucleotide polymorphisms in dopamine receptor D2 are associated with bruxism and its circadian phenotypes in children

Objective: To evaluate the association of bruxism phenotypes with single nucleotide polymorphisms in FKBP5, DRD2, ANKK1, and COMT.Methods: Clinical oral examination was performed to diagnose bruxism phenotypes in 150 children. DNA was collected from saliva. Logistic univariate regression, Chi-square, and Fisher's exact tests were performed (p < 0.05).Results: Bruxism was associated with DRD2 (p = 0.02). Tooth grinding while awake was associated with ANKK1 (p < 0.001), and tooth grinding while asleep was associated with DRD2 in the additive (p = 0.030) and dominant (p = 0.008) model. Tooth clenching while awake was associated with ANKK1 in the additive (p = 0.005) and dominant (p = 0.008) models, whereas tooth clenching while asleep was associated with ANKK1 (p < 0.001) and with COMT in the additive (p = 0.001) and dominant (p = 0.003) models.Discussion: Polymorphisms in DRD2, ANKK1, and COMT are associated with bruxism phenotypes.

Intelligent Occlusion Stabilization Splint with Stress-Sensor System for Bruxism Diagnosis and Treatment

Bruxism is a masticatory muscle activity characterized by high prevalence, widespread complications, and serious consequences but without specific guidelines for its diagnosis and treatment. Although occlusal force-based biofeedback therapy is proven to be safe, effective, and with few side effects in improving bruxism, its mechanism and key technologies remain unclear. The purpose of this study was to research a real-time, quantitative, intelligent, and precise force-based biofeedback detection device based on artificial intelligence (AI) algorithms for the diagnosis and treatment of bruxism. Stress sensors were integrated and embedded into a resin-based occlusion stabilization splint by using a layering technique (sandwich method). The sensor system mainly consisted of a pressure signal acquisition module, a main control module, and a server terminal. A machine learning algorithm was leveraged for occlusal force data processing and parameter configuration. This study implemented a sensor prototype system from scratch to fully evaluate each component of the intelligent splint. Experiment results showed reasonable parameter metrics for the sensors system and demonstrated the feasibility of the proposed scheme for bruxism treatment. The intelligent occlusion stabilization splint with a stress sensor system is a promising approach to bruxism diagnosis and treatment.

The Relationship between Sleep Bruxism Intensity and Renalase Concentration-An Enzyme Involved in Hypertension Development

Background and objectives: Renalase, a novel amine oxidase, is involved in the development of hypertension. Sleep bruxism (SB) is a sleep-related behavior characterized by rhythmic or non-rhythmic activity of the masticatory muscles, which leads to the mechanical wear of teeth, pain in the masticatory muscles, and disturbed sleep. Recent studies indicate that SB plays a role in increased blood pressure. Therefore, this study aimed to determine the relationship between sleep bruxism intensity and renalase concentration, which may help in the future to elucidate the pathogenesis of hypertension and other cardiovascular disorders. Material and methods: SB was evaluated in 87 adult patients using single-night diagnostic polysomnography with video and audio recordings, and the episodes of bruxism were scored according to the standards of the American Academy of Sleep Medicine. The levels of serum renalase were measured in the patients using enzyme-linked immunosorbent assay kits. Results: SB (Bruxism Episode Index (BEI) ≥2) was diagnosed in 54% (n = 47) of the studied population, and the mean concentration of renalase was found to be decreased in the hypertensive group compared with the normotensive group (133.33 ± 160.71 vs 219.23 ± 220.58, p = 0.047). In addition, a linear negative correlation was observed between the renalase concentration and the body mass index (BMI) in the SB group (r = 0.38, p < 0.05) but not in controls. Thus, higher BEI and higher BMI were identified as factors independently associated with the lower concentration of renalase, but only in the group of patients which had a blood renalase concentration of >212.5 ng/mL. Conclusion: There exists an association between renalase concentration and SB intensity, and further studies are needed to clarify the role of renalase in the pathogenesis of hypertension and other cardiovascular disorders.

The effect of botulinum toxin injections on bruxism: A systematic review

OBJECTIVE

To systematize evidence on the efficacy of botulinum toxin type A (BTA) in the treatment of bruxism measured through bite force or electromyography (EMG) at the masseter muscle.

METHOD

Identification of relevant articles through databases PubMed, Web of Science, SCOPUS, Ovid and EBSCO and manual search were performed for sources from review articles. Studies scoring less than 3 on the Jadad Scale were excluded.

RESULTS

Four articles were included after an exclusion of 333 articles. 3 articles measured EMG and 1 bite force. 1 article did not record a significant drop of activity, 1 article recorded reduction midway and at final endpoint. 2 articles recorded initial reduction, but a non significant difference at later follow up.

CONCLUSION

The available research is inconclusive and does not show enough evidence that bruxism can be treated with BTA injections. However, promising results have been shown in individual studies and further research in this area is needed.

Are vocalists prone to temporomandibular disorders?

BACKGROUND

As vocalists demand high physical strains of the masticatory system, singing is frequently mentioned as a risk factor for temporomandibular disorders (TMDs).

OBJECTIVES

This study investigated whether vocalists report a higher prevalence of two types of TMDs (viz., TMD pain and temporomandibular joint sounds) compared with instrumentalists who do not load their masticatory system while performing. In addition, we examined which risk indicators are associated with the presence of these TMDs among musicians.

METHODS

A total of 1470 musicians from 50 different music ensembles completed a questionnaire. Of these musicians, 306 were vocalists (mean age ± SD 37.5 ± 17.7 years; 63.9% female) and 209 musicians enrolled the control group (mean age ± SD 42.7 ± 18.0 years; 40.7% female).

RESULTS

The prevalence of self-reported TMD pain among vocalists was 21.9%, as compared to 12.0% in the control group. 20.0% of the vocalists reported TMJ sounds versus 15.1% of the controls. The multiple regression models indicated that being a vocalist was not a risk indicator for the presence of self-reported TMD pain nor for self-reported TMJ sounds. Instead, it appeared that the report of TMD pain among musicians was positively associated with female gender, next to the level of physical workload, depicted as frequency of oral behaviours and the hours of daily practice. Musicians' report of TMJ sounds was associated with oral behaviours.

CONCLUSION

This study shows that singing is not associated with the reports of TMD pain and TMJ sounds, after adjusting for potentially confounding variables included in the models.

Changes in heart rate related to rhythmic masticatory muscle activities and limb movements in patients with sleep bruxism

Most sleep bruxism (SB) episodes are accompanied by an increase in sympathetic tone and heart rate (HR). To characterise heart rate (HR) changes in relation to rhythmic masticatory muscle activities (RMMAs) in SB patients, polysomnographic recordings were performed on 10 SB patients and 11 normal controls. The duration of movement events, amplitude and duration of HR increases, and time to reach HR peak associated with RMMAs and limb movements (LMs) were determined, and the relationships of the parameters of HR increases with types of movements and RMMAs were analysed. All of the parameters of HR increases associated with three types of movements (RMMAs, RMMAs + LMs and LMs) and masseter activities (phasic, tonic and mixed) were significantly different (two-way ANOVA, P < .001 for all) in both SB patients and controls. The duration of RMMAs/LMs was positively correlated with the parameters (SB patients: R²  = .24-.85, P < .0001; controls: R²  = .23-.68, P < .0001). The amplitude of HR increases was also positively correlated with respiration changes in the SB patients (R²  = .3258, P < .0001) and controls (R²  = .09469, P < .05). The proportions of phasic RMMAs associated with awakenings, microarousals and no cortical arousals were significantly different and so were the proportions of tonic and mixed RMMAs (Friedman's tests, P < .05-.001). The HR increases associated with RMMAs may be intrinsic to the cortical arousal response and autonomic activation, and differences in HR increases associated with different types of movements and RMMAs might be related to the changes in respiration and differences in cortical arousal levels.

Clinical behavior of second-generation zirconia monolithic posterior restorations: Two-year results of a prospective study with Ex vivo analyses including patients with clinical signs of bruxism

OBJECTIVES

This study aimed to investigate (1) clinical outcomes of second-generation zirconia restorations, including patients with bruxism clinical signs, and (2) the material wear process.

METHODS

A total of 95 posterior monolithic zirconia tooth-elements in 45 patients were evaluated, 85 on implants and 10 on natural teeth, and 20.3% of restorations being fixed partial dentures (FPDs). Occlusal contact point areas were determined and half of those areas were left unglazed and just polished. Restorations were clinically evaluated following criteria of the World Dental Federation and antagonistic teeth were examined at each evaluation time. Wear ex vivo analyses using SEM and 3D laser profilometry were performed at baseline and after 6 months, 1 year, and 2 years respectively, temporarily removing the prostheses.

RESULTS

The Kaplan-Meier survival rate of restorations was 93.3% (100% for FPDs) and the success rate was 81.8%, with 4 abutment debondings, 3 tooth-supported crown debondings (provisional cement use), 1 restoration fracture, 1 minor chipping, 1 core fracture, 1 root fracture, and 2 implant losses. 80% of catastrophic failures occurred in patients with clinical signs of bruxism (61.7% of patients). Complications were also observed on antagonistic teeth (3 catastrophic failures). Clinical evaluation of the restorations showed good results from the aesthetic, functional, and biological perspective. Zirconia wear was inferior to 15 μm, while glaze wear was observed on all occlusal contact areas after 1 year.

CONCLUSIONS

Monolithic zirconia FPDs are promising but the failure rate of single-unit restorations was not as high as expected in this sample including patients with bruxism clinical signs.

CLINICAL SIGNIFICANCE

Within study limitations, FPDs showed excellent short-term results but further research is needed for single-unit restorations considering samples, which do not exclude bruxers. The weak link is the restoration support or the antagonist tooth, one hypothesis being that zirconia stiffness and lack of resilience do not promote occlusal stress damping.

Myorelaxant Effect of Transdermal Cannabidiol Application in Patients with TMD: A Randomized, Double-Blind Trial

(1) Background: The healing properties of cannabidiol (CBD) have been known for centuries. In this study, we aimed to evaluate the efficiency of the myorelaxant effect of CBD after the transdermal application in patients with myofascial pain. (2) Methods: The Polish version of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD Ia and Ib) was used. A total of 60 patients were enrolled in the study and were randomly divided into two groups: Group1 and Group2. The average age in Group1 was 23.2 years (SD) = 1.6 years) and in Group2, it was 22.6 years (SD = 1.86). This was a parallel and double-blind trial. Group1 received CBD formulation, whereas Group2 received placebo formulation for topical use. The masseter muscle activity was measured on days 0 and 14, with surface electromyography (sEMG) (Neurobit Optima 4, Neurobit System, Gdynia, Poland). Pain intensity in VAS (Visual Analogue Scale) was measured on days 0 and 14. (3) Results: in Group1, the sEMG masseter activity significantly decreased (11% in the right and 12.6% in the left masseter muscles). In Group2, the sEMG masseter activity was recorded as 0.23% in the right and 3.3% in the left masseter muscles. Pain intensity in VAS scale was significantly decreased in Group1: 70.2% compared to Group2: 9.81% reduction. Patients were asked to apply formulation twice a day for a period of 14 days. (4) Conclusion: The application of CBD formulation over masseter muscle reduced the activity of masseter muscles and improved the condition of masticatory muscles in patients with myofascial pain.

Analysis of the sleep period and the amount of habitual snoring in individuals with sleep bruxism

Background

The literature does not report any association between habitual snoring and sleep bruxism, but these situations can be a reason for frequent complaints of individuals, impairing the quality of life. This study was performed to investigate the sleep period and amount of habitual snoring in individuals with sleep bruxism observing expiratory, inspiratory, and mixed snoring.

Material and Methods

A total of 90 individuals were screened and divided into the following groups: with sleep bruxism (n=45) and those without sleep bruxism (n=45). Single night sleep polysomnography was performed to diagnose sleep bruxism, quantify habitual snoring and sleep period. The results were tabulated and submitted to a Multivariate analysis of variance (MANOVA) to compare the means of the two independent groups, considering the affected diagnosis of sleep bruxism, snoring (independent variables) and age as covariate. For the post hoc, was used correcting for multiple comparisons (Bonferroni test, P <.05).

Results

There was statistically significant difference among the groups ( p =.001) in the sleep period, in that individuals with sleep bruxism slept for a longer duration (with sleep bruxism group: 460 minutes and without sleep bruxism group: 401 minutes). There were no statistically significant differences among the groups for the number of inspiratory, expiratory and mixed snores, but was observed greater amount of snoring in the with sleep bruxism group.

Conclusions

The main finding of this study is that individuals with sleep bruxism slept longer than the control group. It may also be suggested that individuals with sleep bruxism tended to increase the amount of habitual snoring during sleep.

Key words:Bruxism, adult, sleep disordered breathing, polysomnography.

Psychosocial Predictors of Bruxism

OBJECTIVES

The study aimed to investigate the psychosocial predictors of bruxism. The association of various psychosocial factors such as alexithymia, emotional processing, state and trait anxiety, and stress with awake bruxism was analysed.

METHODS

The study involved 52 volunteers diagnosed with awake bruxism. The toolkit that was used included the Toronto Alexithymia Scale (TAS-20), the Emotional Processing Scale (EPS), the Cohen Perceived Stress Scale (PSS-10), and the State- and Trait-Anxiety Inventory (STAI), with independent individual psychological diagnoses being made for every patient. The results were statistically analysed using IBM SPSS Statistics 24.

RESULTS

The obtained data clearly show that psychological traits-both permanent dispositions (e.g., state anxiety and alexithymia) and temporary states (e.g., trait anxiety, emotional processing deficits, and psychological stress)-are significant determinants of awake bruxism. The percentage of explained variance indicates the presence of other factors as well.

CONCLUSIONS

Psychosocial factors such as state anxiety and trait anxiety, alexithymia, and perceived stress are as important as somatic causes in the occurrence and maintenance of awake bruxism. The profile of the obtained data suggests the possibility of preventing or minimizing the symptoms of awake bruxism through properly constructed psychoprophylactic interactions.

The Relationship between Sleep Bruxism and Obstructive Sleep Apnea Based on Polysomnographic Findings

Obstructive sleep apnea (OSA) is the most common sleep disorder. Sleep bruxism (SB) is a masticatory muscle activity during sleep that commonly co-occurs with OSA. The presented study aimed to assess this relationship and to identify factors affecting this co-occurrence. Adult patients (n = 110) were evaluated for OSA and SB in a sleep laboratory using polysomnography. The episodes of bruxism and respiratory events were scored according to the standards of the American Academy of Sleep Medicine. The prevalence of OSA and SB was found to be 86.37% and 50%, respectively. The bruxism episode index (BEI) was increased in the group with mild and moderate OSA (apnea–hypopnea index (AHI) <30) compared to that in the group with severe OSA (AHI ≥ 30) (5.50 ± 4.58 vs. 1.62 ± 1.28, p < 0.05). A positive correlation between AHI and BEI was observed in the group with AHI < 30. Regression analysis indicated that higher AHI, male gender, and diabetes were independent predictors for the increased BEI in group with AHI < 30. The relationship between OSA and SB depends on the degree of severity of OSA. OSA is correlated with SB in mild and moderate cases of OSA in the group of patients with increased risk of OSA.

Botulinum Toxin Type A in Dental Medicine

Botulinum toxins (BoNTs) are a product of the bacteria Clostridium botulinum. By entering nerve endings, they cleave and inactivate SNARE proteins, which are essential for neurotransmitter release. Prevention of acetylcholine release at the neuromuscular junction causes long-lasting and potentially fatal flaccid paralysis-a major feature of botulism. However, an intramuscular injection of minute amounts of BoNTs, primarily type A (BoNT-A), has useful long-lasting muscle relaxation effects on spastic motor disorders. This characteristic of BoNT-A is widely used in neurology and cosmetics. Over the last few decades, it has been demonstrated that the functions of BoNT-A are not limited to muscle-relaxing or autonomic cholinergic effects but that it can act as an analgesic agent as well. More recently, it was revealed that this antinociceptive effect starts after entering the sensory nerve endings, where these agents are axonally transported to the central nervous system, suggesting that at least part of their analgesic effect might be of central origin. Because of its antinociceptive effect, BoNT-A is currently approved for treatment of chronic migraine; nonetheless, case reports and preclinical and clinical experiments indicating its benefit in numerous potential painful conditions have increased. In the field of dentistry, the US Food and Drug Administration approved BoNT-A for the treatment of sialorrhea only. Legal status of the use of BoNT-A in other countries is less known. However, there are controlled clinical trials suggesting its efficacy in other conditions, such as bruxism, temporomandibular disorders, and trigeminal neuropathic pain. Thereby, using criteria of the American Academy of Neurology, we critically reviewed the uses of BoNTs in oral medicine and found it effective for trigeminal neuralgia (category A) and probably effective in temporomandibular disorders and bruxism.

Diagnosis and management of bruxism: Evaluation of clinical practices in France

Objective: The Evaluation of Clinical Practice (ECP) conducted with a sample of French general dental practitioners aimed to measure the methods used to diagnose and manage bruxism.Methods: The ECP was performed using a declarative online questionnaire-based anonymous survey (SurveyMonkey) of 1388 practitioners. Twenty-two questions were grouped in 5 categories: (1) Sociodemographic characteristics (Q1-6); (2) Knowledge of the prevalence and definition of bruxism (Q7-9); (3) Diagnostic approach (Q10-11) and management (Q12-Q13); (4) The use of occlusal splints (Q14-21); (5) Oral rehabilitation (Q22).Results: The answers obtained (233; 16.8%) revealed a wide disparity and insufficient diagnosis (e.g. only 41% looked for sleep disorders, 22.3% for consumption of stimulants, 3% for upper airway obstruction) and management of bruxism (e.g. only 21.9% of participants proposed cognitive-behavioral therapy).Discussion: The discrepancies detected, such as the use of inappropriate splints (30 to 70%), emphasize the need for more prompt research-to-practice transfer of new knowledge.

Consensus-based clinical guidelines for ambulatory electromyography and contingent electrical stimulation in sleep bruxism

As yet, there are still no evidence‐based clinical diagnostic and management guidelines for ambulatory single‐channel EMG devices, like the BUTLER^® GrindCare^® (GrindCare), that are used in patients with sleep bruxism. Therefore, a consensus meeting was organised with GrindCare developers, researchers, and academic and non‐academic clinicians experienced with the use of ambulatory EMG devices. The aim of the meeting was to discuss and develop recommendations for clinical guidelines for GrindCare usage, based on the existing clinical and research experience of the consensus meeting's participants. As an important outcome of the consensus meeting, clinical guidelines were proposed in which an initial 2‐week baseline phase with the device in its inactive (non‐stimulus) mode for habituation and assessment of the number of jaw‐muscle activities is followed by a 4‐week active phase with contingent electrical stimuli suppressing the jaw‐muscle activities. As to avoid the commonly reported reduction in sensitivity to the stimuli, a 2‐week inactive phase is subsequently installed, followed by a repetition of active and inactive phases until a lasting reduction in the number of jaw‐muscle activities and/or associated complaints has been achieved. This proposal has the characteristics of a single‐patient clinical trial. From a research point of view, adoption of this approach by large numbers of GrindCare users creates a great opportunity to recruit relatively large numbers of study participants that follow the same protocol.

Temporomandibular disorders: improving outcomes using a multidisciplinary approach

Patients with temporomandibular disorders (TMD) can become very complex. This article aims to highlight the importance of the multimodal and multidisciplinary approach in this type of patients to improve clinical outcomes. At present we have innumerable techniques and tools to approach this type of patients from a biopsychosocial model where active and adaptive type treatments are fundamental. There are various health professions that have competence in the treatment of TMD, however, although in the most complex cases should be treated simultaneously, still too many patients receive unique treatments and only from one point of view. This review exposes the treatments available from a clinical-scientific perspective and also emphasizes the importance of working in specialized units with those professionals who have competencies on the different conditions that may occur.

Evaluation of the effectiveness of infrared light-emitting diode photobiomodulation in children with sleep bruxism: Study protocol for randomized clinical trial

BACKGROUND

Sleep bruxism is a masticatory muscle activity characterized as rhythmic (phasic) or nonrhythmic (tonic). In children and adolescents, etiological factors, such as breathing pattern and sleep quality, have recently been addressed in studies investigating sleep bruxism. New therapies for adults, such as botulinum toxin, have been investigated, but such techniques are not applicable for individuals in the growth and development phase.

METHODS

The participants will be 76 children, which will be randomly allocated to a control group, that is group 1, absence of bruxism; group 2, children with bruxism treated with infrared light-emitting diode (LED); and group 3, bruxism treated with occlusal splint. All participants will be submitted to a clinical evaluation to evaluate muscle activity and salivary biomarkers, before and after treatments. Muscle activity will be verified by electromyography of muscles mastication, masseter and temporal, and salivary biomarkers observed will be cortisol and dopamine levels.

DISCUSSION

Photobiomodulation therapy has piqued the interest of researchers, as this noninvasive method has demonstrated positive results in problems related to muscle tissues. This document describes the protocol for a proposed study to evaluate morphological and psychosocial aspects in children and adolescents with awake bruxism and their responses to photobiomodulation therapy with infrared LED. CLINICAL TRIALS:.

Association between bruxism and temporomandibular disorders in children: A systematic review and meta-analysis

BACKGROUND

Bruxism in children and its relation to the development of temporomandibular disorders (TMD) has not been clearly determined yet.

AIM

The objective of this systematic review was to evaluate the possible association between bruxism and TMD in children.

DESIGN

Seven databases were searched, and 497 articles were assessed. Methodological quality was assessed through Newcastle-Ottawa Scale. The meta-analysis was performed with the articles in which extraction of data was possible and the summary effect measure through odds ratio (OR) and respective 95% confidence intervals (CIs). Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was used to assess the certainty of evidence.

RESULTS

Ten cross-sectional studies were included in the systematic review. Of these, 8 showed a statistically significant association between bruxism and TMD. Seven studies however presented a high risk of bias. The meta-analysis was performed with 3 articles and obtained an OR of 2.97 (95% CI ranging from 1.72-5.15), indicating that children with bruxism are 2.97 times more likely to present TMD, with very low level of certainty defined by GRADE.

CONCLUSIONS

Although the studies showed high risk of bias, the qualitative analysis of individual studies showed that the children with bruxism have greater chance of developing TMD.

Relationship between Sleep Bruxism, Perceived Stress, and Coping Strategies

Sleep bruxism (SB) is a common phenomenon defined as a masticatory muscle activity during sleep. Untreated severe SB can have significant dental and orofacial consequences. SB has often been linked with stress and maladaptive coping strategies. Therefore, in this study, a potential correlation between SB, perceived stress and coping strategies was evaluated. A total of 60 adults were enrolled into this study. Participants underwent a detailed intra- and extraoral exam focused on detecting bruxism symptoms. Additionally, the overnight Bruxism Index was recorded using the Bruxoff device. A total of 35 participants with symptoms of bruxism were assigned to the study group, whereas 25 asymptomatic participants were assigned to the control group. The Perceived Stress Scale (PSS-10) was used for stress assessment and Brief-COPE for coping strategies. Results showed that the higher the PSS-10 score, the higher the Bruxism Index was in the study group. Positive coping strategies were chosen most frequently in the control group, while maladaptive ones were chosen in the study group. It can be concluded that there is a relationship between perceived stress and sleep bruxism. Moreover, the type of coping strategies used by participants may have an impact on sleep bruxism, but the relationship should be further investigated.

Correlation between Sleep Bruxism, Stress, and Depression-A Polysomnographic Study

Background and objectives: Sleep bruxism is a common phenomenon that can affect approximately 13% of adult population. It is estimated that bruxism can be caused by three types of factors: biological, psychological, and exogenous. There are many scientific reports about the coexistence of bruxism, stress, and psychoemotional disorders. The aim of this study is to evaluate the possible correlation between occurrence of sleep bruxism and perceived stress and depressive symptoms. Material and methods: The material of this study consisted of 77 patients of Clinic of Prosthetic Dentistry operating at the Department of Prosthetic Dentistry, Wroclaw Medical University, Poland in which after using guidelines of the American Academy of Sleep Medicine probable sleep bruxism was fund. Patients then underwent video-polysomnography. Exposure to perceived stress was evaluated with Perceived Stress Scale-10 (PSS-10). Occurrence of depressive symptoms was evaluated with Beck’s Depression Inventory (BDI). Results: The analysis showed lack of statistically significant correlation between Bruxism Episodes Index (BEI) and Perceived Stress Scale–10 and Beck’s Depression Inventory scores (p = 0.64, p = 0.65; respectively), also when comparing study group (bruxers) and control group (non-bruxers) (p = 0.88, p = 0.77; respectively). Conclusion: Intensity of sleep bruxism was not statistically significantly correlated with self-reported perceived stress and depression. This issue requires further research.

Polysomnographic scoring of sleep bruxism events is accurate even in the absence of video recording but unreliable with EMG-only setups

PURPOSE

To determine the accuracy of scoring masticatory muscle activity (MMA) events in seven different polysomnography (PSG) setups.

METHODS

Nineteen volunteers (13 females, 6 males, age 31.1 ± 12.9 years, 12 self-proclaimed bruxers) attended one-night PSG recording, supplemented with audio, video, and a separate frontal electroencephalography electrode set (FES). The same examiner scored the MMA events with seven different setups, with varying number of channels available: (1) one, (2) two, and (3) four EMG channels, (4) PSG without audio or video (PSG-N), (5) home PSG with FES and audio (FES-A), (6) PSG with audio (PSG-A), and (7) PSG with audio and video (PSG-AV). A subset (n = 10) of recordings was scored twice to determine intra-scorer reliability. MMA indices and accuracy of scoring the events in different setups were compared against PSG-AV.

RESULTS

The intra-class correlation coefficient (ICC) between PSG-AV and PSG-A was high (0.940, p < 0.001) as well as for FES-A (0.927, p < 0.001), whereas for PSG-N, it was lower (0.835, p < 0.001); for setups with only EMG channels, coefficients were very low (ICC < 0.100 for all). Intra-examiner reliability was high (ICC > 0.939 for all setups), with the exception of PSG-N (ICC = 0.764, p = 0.002). When comparing against the MMA events scored in PSG-AV, the sensitivity of MMA event recognition for PSG-A was 78.5% and specificity 95.5%, which were substantially higher than sensitivity (52.0%) and specificity (87.2%) of PSG-N.

CONCLUSIONS

MMA event scoring accuracy with PSG-A or FES-A is almost comparable to PSG-AV. Since precise event recognition is essential for accurate MMA scoring, it is evident that one cannot rely exclusively on EMG.

Investigation of the relationship between sleep disorders and xerostomia

OBJECTIVES

To investigate the relationship between sleep disorders, morning hyposalivation, and subjective feeling of dry mouth.

MATERIALS AND METHODS

A cross-sectional, observational, clinical study was carried out in a homogenous population sample which consists of Greek male soldiers without any medical history. After the application of oral modified Schirmer test, the sample was divided into a study group (n = 63) (MST < 25 mm/3 min) and a control group (n = 110) (MST ≥ 25 mm/3 min). In order to assess daytime sleepiness, risk of obstructive sleep apnea (OSA), sleep quality, sleep bruxism (SB), and subjective feeling of dry mouth, all the participants filled in the following scales in Greek version: Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), Berlin Questionnaire (BQ), a SB questionnaire, and Xerostomia Inventory (XI) respectively. In every subgroup that came of ESS, PSQI, BQ, and SB questionnaire scoring, subjective feeling of dry mouth was evaluated, based on XI values.

RESULTS

Statistically significant difference (p < 0.001) through PSQI scores was found between the study and control group. In contrast, a statistically significant difference was not obtained for the scores of ESS (p = 0.293), BQ (p = 0.089), and SB questionnaire (p = 0.730). XI scores introduced statistically significant difference between the subgroups of PSQI (p < 0.001), BQ (p = 0.001), SB questionnaire (p = 0.004)  and statistically weak between the subgroups of ESS (p = 0.049).

CONCLUSIONS

This is the first research study so far suggesting that patients with morning hyposalivation exhibit poor sleep quality using an objective method. The present results have, also, shown that subjective feeling of dry mouth is related to excessive daytime sleepiness, poor sleep quality, high risk of obstructive sleep apnea, and sleep bruxism, but larger-scale studies are still needed.

CLINICAL RELEVANCE

These findings should keep dentists aware of a possible association between xerostomia and sleep disorders and support larger-scale studies.

The prevalence of posterior crossbite, deep bite, and sleep or awake bruxism in temporomandibular disorder (TMD) patients compared to a non-TMD population: A retrospective study

Objective: To assess the prevalence of posterior crossbite and/or deep bite among patients diagnosed with temporomandibular disorders (TMD) compared to a non-TMD population.Methods: Four hundred ninety-four patients were enrolled: 345 with TMD according to the diagnostic criteria for TMD and 149 without TMD (control group). The chi-square test was used for statistical analysis.Results: A statistically significant association was found between sleep and awake bruxism and painful TMDs (p < .001 for both), but not with disc displacement. There was no association between posterior crossbite and/or deep bite with either painful TMD or disc displacement.Conclusion: Within the study limitations, sleep bruxism and awake bruxism may be related to pain in the TMD, and the severity of a deep overbite and presence of a unilateral or bilateral posterior crossbite should not be considered risk factors or as having any effect on the pain associated with TMD and/or disc displacement.

Presence of oral habits and their association with the trait of anxiety in pediatric patients with possible sleep bruxism

BACKGROUND

Bruxism is a repetitive masticatory muscle activity with a multifactorial etiology , that can be associated to emotional factors.

AIM

The aim of the study is to identify the presence of oral habits (OHs) and their association with the trait of anxiety (State-Trait Anxiety Inventory for Children [STAI-C]) in pediatric patients with possible sleep bruxism (PSB).

METHODS

Children between 3 and 12 years of age with PSB reported by their parents with complete deciduous or mixed dentition were included in the present study. Sociodemographic data (SD) as well as those on OHs such as only natural (ON), artificial breastfeeding (OA) or both (NA), finger sucking (FS), pacifier use (PC), and biting nails (BN) or objects (OB) were obtained through an interview with the parents/guardians answered the Brazilian version of the STAI-C questionnaire.

STATISTICAL ANALYSIS USED

SD and OH as well as STAI-C findings were descriptively evaluated, while the associations between OH and STAI-C with PSB were evaluated using the Chi-square test (P < 0.05).

RESULTS

The final sample was 52 children (6.62 ± 1.8 years). Of these, 51.9% were males, 82.7% reported not living in social risk areas, and 21.2% were only children. Considering the OH, patients participated in ON (26.9%), OA (9.6%), and both (63.5%); 13.5% had an FS habit and 46.2% had related PC use; and 80.8% were reported to have OB biting behaviors, while 53.8% participated in BN. The STAI-C was present in 25 (48.1%) patients with PSB and was not associated with the presence of OH.

CONCLUSION

There is no association between STAI-C and OH in pediatric patients with PSB.

Knowledge of parents/caregivers about the sleep bruxism of their children from all five Brazilian regions: A multicenter study

BACKGROUND

Sleep bruxism (SB) is a masticatory muscle activity that affects children. Parents' knowledge is important for its identification and report to dentists.

AIM

To investigate parents' knowledge about SB among their children.

DESIGN

A cross-sectional study included 1325 parents of children from dental clinics of seven institutions from all regions of Brazil. Parents answered questions about child's sleep, knowledge about SB and its occurrence among children and parents. SB definition given by parents was dichotomized as "correct"/"incorrect", based on the American Academy of Sleep Medicine definition. Descriptive, bivariate and multivariate analyses were performed (P < 0.05).

RESULTS

Most parents (57.3%) did not know what SB is and 88.9% would like to receive more information. SB prevalence among parents was 15.4% and 24.0% among children. Between parents who correctly defined SB, its prevalence increased to 27.5% among parents and 40.6% among children. Parents whose children had/have SB, who would like to receive more information about SB and were from the North, Central-West, Southeast, and South regions were more likely to define SB correctly (P > 0.05).

CONCLUSION

There is a lack of knowledge of parents about SB. SB among children, parents' interest in receiving more information and their location were factors associated to their knowledge.

Knowledge of parents/caregivers about bruxism in children treated at the pediatric dentistry clinic

Objective

To evaluate the knowledge on bruxism among parents/caregivers of children treated at the pediatric dentistry clinic.

Methods

A cross-sectional study was conducted with 103 parents/caregivers that filled out a questionnaire based on the criteria of the American Association of Sleep Medicine during the dental care offered to their children. The questionnaire addressed demographic issues of the child and caregiver, issues related to child's sleep characteristics (duration, quality and whether he/she sleeps alone) and questions about bruxism (knowledge of the parafunctional habit, bruxism in the caregiver and the child, search for treatment, causes and consequences of bruxism, and whether the caregivers wanted more information on the subject). Pearson's χ2 test and Fisher's exact test were performed (α = 5%).

Results

Sixty-seven percent reported knowing what bruxism is and 52.4% correctly described the parafunctional habit. Regarding the cause, 74.8% were unable to say and 16.5% associated the habit to an emotional factor. The prevalence of bruxism was 25.2% and 16.5% in the children and caregivers, respectively. Among the caregivers of children with bruxism, only 2.9% had sought some type of help. Child's sex, child's sleep and the search for help were significantly associated with bruxism (p = 0.034, 0.013 and < 0.001, respectively).

Conclusion

The knowledge among caregivers about bruxism is still insufficient, especially with regard to the etiology of the parafunctional habit. The lack of knowledge impedes caregivers from seeking help, and thus contributes to the worsening consequences of bruxism in adulthood.

The Bruxoff Device as a Screening Method for Sleep Bruxism in Dental Practice

Sleep bruxism (SB) is a masticatory muscle activity during sleep and a common phenomenon. Severe SB can have a serious impact on the success of dental treatment. Reliable methods of screening and diagnosing patients with SB are crucial. Therefore, in this study, a Bruxoff device as a potential screening and diagnostic method for sleep bruxism was evaluated. A total of 60 adults participated in this study: 35 patients with symptoms of bruxism (study group) and 25 asymptomatic patients (control group). Data were recorded using Bruxoff. All symptomatic patients participating in the study turned out to be bruxers, while not all asymptomatic patients turned out to be non-bruxers according to the Bruxoff device. Bruxoff is a simple screening device that can be safely used to evaluate masseter muscle activity during sleep. Since the device does not have a built-in microphone and/or video camera and, therefore, cannot record grinding sounds, the objective capabilities of Bruxoff as a single diagnostic device for sleep bruxism are limited.

Prevalence of Function-Dependent Temporomandibular Joint and Masticatory Muscle Pain, and Predictors of Temporomandibular Disorders among Patients with Lyme Disease

The aim was to determine the occurrence of temporomandibular disorders (TMDs) in patients with Lyme disease (LD), and to estimate the contribution of factors that may identify TMD among LD patients. In seventy-six (N = 76) adult patients with LD (mean age 57.6 ± 14.6 years) and 54 healthy non-Lyme volunteers with a mean age of 56.4 ± 13.5 years, possible function (i.e., non-pain) diagnoses were established using the Research Diagnostic Criteria of Temporomandibular Disorders (RDC/TMD). Pain diagnoses were established by means of the function-dependent dynamic and static tests. The two groups did not significantly differ in the frequency of disc displacements diagnoses and function-dependent pain diagnoses. LD showed a significantly higher frequency (p < 0.001) of osteoarthrosis than the control group. For the prediction of pain diagnoses in LD patients, the single regression analyses pointed out an association with age, sleep bruxism (SB), and awake bruxism (AB). Two predictors (i.e., SB (p = 0.002) and AB (p = 0.017)) were statistically significant in the final multiple variable model. The frequency of TMD in patients with LD based on function-dependent tests was not significantly different from that in the control group. This investigation suggests that the contribution of bruxism to the differentiation between patients with Lyme and TMD is high.

Evaluation of Biofeedback Usefulness in Masticatory Muscle Activity Management-A Systematic Review

Temporomandibular disorders (TMD) have multifactorial and complex etiology. Regardless of their etiology, all those conditions may result in centrally mediated chronic muscle pain, myalgia, myofascial pain, myofibrotic contracture, myosistis, myospasm, headache and a variety of neck, shoulder, upper back and lower back pain. Biofeedback (BF) is one of methods that has been used for more than 50 years in rehabilitation to facilitate normal movement patterns after injuries. Some studies suggest that biofeedback may be an effective treatment option for patients with different muscle disorders. The aim of this study was to evaluate the efficiency of biofeedback in masticatory muscle activity management in the light of current medical literature. The authors followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines for this systematic review. The authors searched the MEDLINE, Scopus, Web of Science, CINAHL databases to identify relevant publications. Finally 10 papers were included. Most of the selected studies showed a significant correlation between biofeedback usage and reduction of masticatory muscle activity. By analyzing qualified studies, it can be concluded that biofeedback can be an effective tool in masticatory muscle activity management.

Oro-facial pain experience among symphony orchestra musicians in Finland is associated with reported stress, sleep bruxism and disrupted sleep-Independent of the instrument group

BACKGROUND

To evaluate whether oro-facial pain experience was related to the type of musical instrument and to learn more about the roles of sleep and sleep-related issues in the pain among professional musicians.

OBJECTIVES

A standard questionnaire was sent to all Finnish symphony orchestras (n = 19), with altogether 1005 professional musicians and other personnel.

METHODS

The questionnaire covered descriptive data, instrument group, items on perceived quality of sleep, possible sleep bruxism, stress experience and oro-facial pain experience during the past 30 days.

RESULTS

In the present study, which included the musicians only, the response rate was 58.7% (n = 488). All orchestras participated in the study, and there was no significant difference in the response rate between the orchestras. The mean age of men (52.3%) was 47.7 (SD 10.3) and of women (47.7%) was 43.4 (SD 9.8) years (P < 0.001). Overall, current pain in the oro-facial area was reported by 28.9%, frequent bruxism by 12.1% and frequent stress by 20.8%. According to Somers' d, there were statistically significant but moderate correlations between overall pain reports in the oro-facial area and disrupted sleep (d = 0.127, P = 0.001), sleep bruxism (d = 0.241, P < 0.001) and stress experiences (d = 0.193, P < 0.001). Logistic regression revealed, independent of the instrument group (string, woodwind, brass wind, percussion), that current oro-facial pain experience was significantly associated with disrupted sleep (P = 0.001), frequent sleep bruxism (P < 0.001) and frequent stress (P = 0.002) experiences.

CONCLUSIONS

Among symphony orchestra musicians, oro-facial pain experience seems to be related to perceptions of stress, sleep bruxism and disrupted sleep rather than the instrument group.

Evaluation of Relationship Between Sleep Bruxism and Headache Impact Test-6 (HIT-6) Scores: A Polysomnographic Study

Sleep bruxism (SB) is a masticatory muscle activity during sleep characterized by teeth clenching or grinding and/or bracing or thrusting of the mandible. Morning headache is considered as a common symptom of SB; however, the relationship between SB and headache and its impact on patient's life is not clear. Therefore, the present study aimed to assess the relationship between SB using polysomnography with video/audio recording and Headache Impact Test-6 (HIT-6) scores. SB was evaluated in respondents by single-night diagnostic polysomnography with video/audio recording. The study found that Bruxism Episode Index was similar in the group with significant impact of headache on patient's life (HIT-6 score ≥ 50) and in group with little or no impact (HIT-6 score < 50). A statistically significant positive correlation was observed between bruxism associated with arousal and HIT-6 score (r = 0.51, p < 0.05) and between mixed bruxism and HIT-6 score (r = 0.58, p < 0.05) in the subgroup with phasic bruxism. The results indicated the relationship between SB and impact of severity of headache on the patient's life measured by HIT-6 is only modest. It was also found that the impact of severity of headache measured by HIT-6 is altered only in those with phasic bruxism and is associated with arousal. Further research should elucidate the factors influencing the relationship between SB and headache.

Trial Registration: Clinical Trials NCT03083405, WMU1/2017, https://clinicaltrials.gov/ct2/show/NCT03083405