The effect of sleep position on sleep bruxism in adults with obstructive sleep apnea.

BACKGROUND: Most of the respiratory events in adults with obstructive sleep apnea (OSA) occurs in supine position. It has been reported that the contraction of masseter muscles is dependent on the occurrence of arousals rather than on the occurrence of respiratory events. OBJECTIVES: This study had two aims: (1) to compare the rhythmic masticatory muscle activity (RMMA) index in supine position (RMMA_sup) and in non-supine positions (RMMA_nsup) in adults with OSA; and (2) to determine the associations between RMMA index in both supine position and non-supine positions on the one hand, and several demographic and polysomnographic variables on the other hand. METHODS: One hundred OSA participants (36 females and 64 males; mean age = 50.3 years (SD = 10.5)) were selected randomly from among patients with a full-night polysomnographic recording. RMMA_sup index and RMMA_nsup index were compared using Mann-Whitney U-test. Multivariate linear regression analyses were used to predict RMMA index both in supine and non-supine positions based on several demographic and polysomnographic variables. RESULTS: In patients with OSA, the RMMA_sup index was significantly higher than the RMMA_nsup index (p < .001). RMMA_sup index was significantly associated with the arousal index (p = .002) and arousal index in supine position (p < .001). RMMA_nsup index was only significantly associated with the arousal index in non-supine positions (p = .004). CONCLUSION: Within the limitations of this study, RMMAs occur more frequently in supine position than in non-supine positions in patients with OSA. In both sleep positions, RMMAs are associated with arousals.

Tooth wear and bruxism: A scoping review.

OBJECTIVE: This study presents a scoping review to determine the association between tooth wear and bruxism. DATA: A protocol was developed a priori (Open Science Framework (DOI 10.17605/OSF.IO/CS7JX)). Established scoping review methods were used for screening, data extraction, and synthesis. Risk of bias was assessed using JBI tools. Direct associations between tooth wear and bruxism were assessed. SOURCES: Embase, SCOPUS, Web of Science, Cochrane, and PubMed were searched. STUDY SELECTION: Any clinical study containing tooth wear and bruxism assessment done on humans in any language was included. Animal, in-vitro studies and case reports were excluded. CONCLUSIONS: Thirty publications reporting on the association between tooth wear and bruxism were included. The majority of publications were cross-sectional studies (90%) while only three were longitudinal (10%). Eleven papers assessed definitive bruxism for analysis (instrumental tools), one paper assessed probable bruxism (clinical inspection with self-report) and eighteen assessed possible bruxism (self-report). Of the eleven papers assessing definitive bruxism, eight also reported outcomes of non-instrumental tools. Tooth wear was mostly scored using indexes. Most studies reported no or weak associations between tooth wear and bruxism, except for the studies done on cervical tooth wear. When bruxism assessment was done through self-report, more often an association was found. Studies using multivariate analyses did not find an association between tooth wear and bruxism, except the cervical wear studies. Evidence shows inconclusive results as to whether bruxism and tooth wear are related or not. Therefore, well-designed longitudinal trials are needed to address this gap in the literature. CLINICAL SIGNIFICANCE: Based on the evidence, dental clinicians should not infer bruxism activity solely on the presence of tooth wear.

Prevalence and risk factors of sleep bruxism in adults with primary snoring: a large-scale polysomnographic study.

STUDY OBJECTIVES: To determine the prevalence and risk factors of sleep bruxism (SB) in adults with primary snoring (PS). METHODS: This study included 292 adults with PS (140 males, 152 females; mean age ± SD = 42.8 ±12.2 years; mean BMI ± SD = 26.7 ± 4.7 kg/m2) without previous treatment for snoring. SB was diagnosed based on the frequency of the biomarker of SB: rhythmic masticatory muscle activity (RMMA; SB when RMMA ≥ 2 episodes/hour). Logistic regression was performed, with SB as the dependent variable and with age, sex, BMI, and sleep- and respiratory-related polysomnographic parameters as the independent variables to identify the risk factors for SB. RESULTS: The prevalence of SB was 44.6% in adults with PS. Younger age (OR = 0.965 [0.944, 0.987]) and shorter total sleep time (OR = 0.760 [0.609, 0.948]) significantly increased the risk of SB (P < 0.05). CONCLUSIONS: SB is highly prevalent in adults with PS. Younger age and shorter sleep time are significant risk factors for SB in adults with PS. CLINICAL TRIAL REGISTRATION: Registry: Netherlands Trial Register; Name: A Large Sample Polysomnographic Study on Sleep Bruxism; Identifier: NL8516.

Una Caracterización de la Arquitectura del Sueño en Adultos con Bruxismo del Sueño: Un Estudio Descriptivo Retrospectivo / Characterization of Sleep Architecture in Adults with Sleep Bruxism: A Retrospective Descriptive Study

Objetivo: Caracterizar la arquitectura del sueño en un grupo poblacional de adultos con bruxismo del sueño, en forma general y según sexo.Materiales y método: Estudio descriptivo retrospectivo, con un muestreo por intención de 33 polisomnografías que identificaban sujetos con bruxismo del sueño, según el “cut off” sugerido por Lavigne et al (25 eventos /hora), entre los años 2011-2019. Se consideraron las variables sexo, edad, peso, talla e índice de masa corporal (IMC). Se determinó la arquitectura del sueño en cuanto a duración de las etapas del sueño, micro despertares y eventos de bruxismo. Se realizó un análisis descriptivo de las variables y se compraron los resultados entre los sexos.Resultados: En el grupo poblacional 64% eran mujeres y 36% hombres. El promedio de edad fue de 32.5 años, de talla 1.65, de peso 68 kg, con un IMC promedio de 24.89 (peso normal). Los sujetos tuvieron un promedio de 387.6 horas de sueño, 270 minutos en NMOR y 10.8 en MOR, con un promedio de 50 micro despertares durante la noche y de 48.64 eventos de bruxismo por hora. Según sexo los valores en minutos fueron (p>0.05): NMOR (H: 316.2 – M:256.8); MOR (H: 105 – M:104.4); microdespertares (H :58.9 – M: 45.1); Eventos de BS/hora: (H:48.6 – M: 46.6) Los sujetos con BS durmieron, en promedio, un mayor número de minutos en decúbito lateral (196,59).Conclusión: Los sujetos con BS registran determinadas características en la arquitectura del sueño que deben considerarse. No hubo diferencia en la arquitectura del sueño según sexo. (AU)

Objective: To characterize sleep architecture in a population group of adults with sleep bruxism, in general and by sex. Materials and method: Retrospective descriptive study, with intentional sampling of 33 polysomnographies that identified subjects with sleep bruxism,according to the “cut off” suggested by Lavigne et al (25 events /hour/), between the years 2011-2019. The variables sex, age, weight, height and body mass index (BMI) were considered. Sleep architecture was determined in terms of duration of sleep stages, micro-awakenings, and bruxism events. A descriptive anlysis of the variables was carried out and the results were compared between the sexes.Results: In the population group, 64% were women and 36% men. The average age was 32.5 years, height 1.65 m, weight 68 kg, with an average BMI of 24.89 (normal weight). Subjects had an average of 387.6 minutes of sleep, 270 minutes in non-rapid eye movement (NREM) and 10.8 in rapid eye movement (REM), with an average of 50 micro-awakenings during the night and 48.64 bruxism events per hour. According to sex, the values in minutes were: NMOR (H:316.2 – M:256.8); MOR (H:105 – M:104.4); microawakenings (H:58.9 – M:45.1); BS events/hour: (H:48.6 – M: 46.6), no significant differences were found between them (p>0.05). Subjects with BS slept, on average, a greater number of minutes in the lateral decubitus position (196.59). Conclusion: Subjects with BS register certain characteristics in their sleep architecture that must be considered. There was no difference in sleeparchitecture according to sex.(AU)

Decrypting the putative interrelation between sleep bruxism, masticatory muscle pain and sleep breathing disorders: Nosology and the role of hypoxia.

This commentary on sleep medicine explores whether the potential relationship between sleep bruxism (SB), masticatory muscle pain (MMP) and sleep breathing disorders (SBDs)contributes to improving the management of co-occurring conditions.The paper is divided into 2 sections: (1) reviewing the debate on SB nosology; and (2) based on the publications from the Martynowicz & Wieckiewicz research group, exploringthe role of intermittent hypoxia as a putative mechanism endotype that may link such co-occurrence among individuals for whom characteristics are not yet clear.

Bridging semantics and medical ontology in the definition of bruxism: An argument for a holistic definition.

OBJECTIVE: The objective of this commentary is to advocate for a holistic, ontology-based definition of bruxism. The intention is to synthesise the best aspects of current definitions into a structured ontological model, thereby refining and enhancing a comprehensive understanding of the full spectrum of bruxism. MATERIALS AND METHODS: The commentary elaborates on the process of integrating these insights into a hierarchical ontology that aligns with ontological principles. SETTINGS AND SAMPLE POPULATION: Not directly applicable as this is a commentary. RESULTS/CONCLUSION: The proposed ontology-based definition of bruxism aims to clarify communication within the medical community and advance research by enabling a comprehensive ontology-based classification of bruxism. By aligning with ontological principles, this approach aspires to act as a catalyst for further research, discussion and consensus in the field.

Oral biosciences: The annual review 2023.

BACKGROUND: The Journal of Oral Biosciences is dedicated to advancing and disseminating fundamental knowledge with regard to every aspect of oral biosciences. This review features review articles in the fields of "bone regeneration," "periodontitis," "periodontal diseases," "salivary glands," "sleep bruxism," and "Sjögren's syndrome." HIGHLIGHT: This review focuses on human demineralized dentin and cementum matrices for bone regeneration, oxidized low-density lipoprotein in periodontal disease and systemic conditions, the relationship between inflammatory mediators in migraine and periodontitis, phosphoinositide signaling molecules in the salivary glands, and the pathophysiologies of sleep bruxism and Sjögren's syndrome. CONCLUSION: The review articles featured in the Journal of Oral Biosciences have broadened the knowledge of readers regarding various aspects of oral biosciences. The current editorial review discusses the findings and significance of these review articles.

Inflammatory Markers and Sleep Architecture in Sleep Bruxism-A Case-Control Study.

Background: Sleep bruxism (SB) is a common sleep-related movement behavior with a multifaceted etiology and a deficiently understood pathophysiology. A recent hypothesis suggests a link between SB and systemic inflammation. The scope of the study was to determine whether bruxers have altered sleep structure and different levels of inflammatory parameters compared to nonbruxers. Methods: A total of 83 adults underwent full-night polysomnography. The polysomnograms were evaluated using the American Academy of Sleep Medicine (AASM) guidelines. Then, the blood samples were obtained from the participants by venipuncture and the analyses were performed. The study group was divided based on bruxism episode index (BEI) into two groups: BEI ≤ 4 and BEI > 4. Results: In comparison with nonbruxers, the oxygen desaturation index (ODI) was significantly higher in severe bruxers (7.5 ± 11.08 vs. 3.33 ± 5.75, p < 0.005), as well as the arousal parameters (7.77 ± 4.68 vs. 4.03 ± 2.97, p < 0.001), and the mean oxygen desaturation (3.49 ± 0.69 vs. 3.01 ± 0.67, p < 0.05). Moreover, the differences in sleep architecture and deprivation of the deep sleep phase were observed, the non-REM sleep stage 3 was significantly shorter in severe bruxers (p < 0.03). Differences were also noted in non-REM sleep stage 1 and REM sleep phase. In the investigated group, there were no statistical differences in inflammatory cytokines levels between bruxers and nonbruxers. Conclusions: Sleep bruxism is associated with sleep structure alterations and may be associated with deep sleep phase deprivation. The inflammatory markers are not linearly correlated with the severity of sleep bruxism expressed as BEI.

Short-Term Effects of 3D-Printed Occlusal Splints and Conventional Splints on Sleep Bruxism Activity: EMG-ECG Night Recordings of a Sample of Young Adults.

(1) Background: This study aims to compare the effects of 3D-printed splints and conventional manufactured splints on sleep bruxism (SB) EMG activity. (2) Methods: Twenty-six patients (19 M, 7 F, 25.8 ± 2.6 years) were randomly allocated to a study group (3D splints) and a control group (conventional manufactured splints) and followed for a period of three months with night EMG-ECG recordings. Samples of the involved materials were analyzed for nanoindentation. The outcomes of interest considered were the overall SB index, the total amount of surface masseter muscle activity (sMMA), and general and SB-related phasic and tonic contractions. A statistical evaluation was performed with a confidence interval (CI) between 2.5% and 97.5%. (3) Results: Differences between groups with OAs were observed for general tonic contraction (p = 0.0009), while differences between recording times were observed for general phasic contractions (p = 0.002) and general tonic contractions (p = 0.00001). Differences between recording times were observed for the total amount of sMMA (p = 0.01), for general phasic contractions (p = 0.0001), and for general tonic contractions (p = 0.000009) during night recordings without OAs. (4) Conclusions: Three-dimensional splints seem to have a higher impact on SB-related electromyographic activity but not on the overall sleep bruxism index. The more regular surfaces offered by 3D splints could be related to phasic contraction stabilization.

Probable sleep and awake bruxism in adolescents: A path analysis.

BACKGROUND: Bruxism has a multifactorial etiology, including the influence of sleep characteristics and chronotypes. AIM: To identify the pathways that influence the occurrence of probable sleep bruxism (PSB) and probable awake bruxism (PAB) in adolescents. DESIGN: A total of 403 adolescents, aged 12-19 years, participated in the study. Parents/caregivers filled out a questionnaire about sociodemographic issues and the adolescent's health conditions, and the adolescents about sleep characteristics, occurrence of bruxism (based on previous study and the International Consensus of Bruxism), and chronotype (Circadian Energy Scale). Clinical examinations were performed. Statistical analysis included descriptive analysis and path analysis. RESULTS: PSB and PAB are related to each other, with moderate and positive correlation (ß = .390). Poor sleep quality and higher household income had a direct effect on both PSB (ß = -.138; ß = .123, respectively) and PAB (ß = -.155; ß = .116, respectively). Chronotype had a direct effect on PSB, in such a way that adolescents with a morningness chronotype tend to have PSB (ß = -.102). Adolescents that drool on the pillow (ß = .184) and/or have agitated sleep (ß = .104) tend to have PSB. CONCLUSION: Poor sleep quality, household income, morningness chronotype profile, drooling on the pillow, and agitated sleep influence the paths taken by PSB. PAB was influenced by the quality of sleep and family income.

Instrumental assessment of sleep bruxism: A systematic review and meta-analysis.

This systematic review and meta-analysis (MA) aimed to evaluate the diagnostic validity of portable electromyography (EMG) diagnostic devices compared to the reference standard method polysomnography (PSG) in assessing sleep bruxism. This systematic review was completed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement and was registered with PROSPERO prior to the accomplishment of the main search. Ten clinical studies on humans, assessing the diagnostic accuracy of portable instrumental approaches with respect to PSG, were included in the review. Methodological shortcomings were identified by QUADAS-2 quality assessment. The certainty of the evidence analysis was established by different levels of evidence according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. A meta-analysis of diagnostic test accuracy was performed with multiple thresholds per study applying a two-stage random effects model, using the thresholds offered by the studies and based on the number of EMG bruxism events per hour presented by the participants. Five studies were included. The MA indicated that portable EMG diagnostic devices showed a very good diagnostic capacity, although a high variability is evident in the studies with some outliers. Very low quality of evidence due to high risk of bias and high heterogeneity among included studies suggests that portable devices have shown high sensitivity and specificity when diagnosing sleep bruxism (SB) compared to polysomnography. The tests performed in the MA found an estimated optimal cut-off point of 7 events/hour of SB with acceptably high sensitivity and specificity for the EMG portable devices.

Comparative analysis of different types of occlusal splints for the management of sleep bruxism: a systematic review.

BACKGROUND: Sleep bruxism is a prevalent condition in dentistry practice, characterized by involuntary grinding or clenching of the teeth during sleep. Several therapies, including occlusal splints, have been used to manage sleep bruxism and temporomandibular disorders, including occlusal splints. This study aimed to compare the effectiveness of different occlusal splints in managing sleep bruxism. METHODS: The PICO framework encompasses the characterization of the population, intervention, comparison, and pertinent outcomes. A comprehensive and systematic literature review was conducted on PubMed, Scopus, and Google Scholar to identify grey literature. The search specifically targeted scientific studies published before September 20, 2023. The Cochrane Collaboration Risk of Bias Tool assessed the accuracy of the included Randomized Control Trials (RCTs). The modified Newcastle-Ottawa Scale assessed non-randomized studies. Data were systematically extracted, synthesized, and reported thematically. RESULTS: Out of the total of 808 articles that were evaluated, only 15 articles were found to meet the specified inclusion criteria. Adjustable splints, such as full-occlusion biofeedback splints, were more effective in reducing sleep bruxism episodes, improving patient-reported symptoms, and enhancing overall well-being. The impact of different occlusal sprints on electromyographic activity varies, and potential adverse effects should be considered individually. CONCLUSIONS: This review provides valuable insights into the effectiveness of occlusal splints in managing sleep bruxism. The results of this study indicate that occlusal splint therapy is a viable treatment approach for sleep bruxism.

Prevalence of Bruxism in Children and Adolescents with Cerebral Palsy: Systematic Review and Meta-analysis.

AIMS: To perform a systematic review and meta-analysis compiling data on the prevalence of bruxism in children and adolescents with cerebral palsy. METHODS AND RESULTS: Searches were carried out in PubMed/Medline, Web of Science, and Scopus databases to identify the articles published by February 2023. Two independent reviewers, and in duplicate, employed a two-stage process to select publications. The same two reviewers performed the data extraction. Studies were included when the following eligibility criteria were met: performed in children and/or adolescents with cerebral palsy and reporting bruxism. Potentially eligible studies were read in full and excluded that: not presented numerical data on the prevalence of bruxism; not reported how the bruxism was assessed; not reported data about the cerebral palsy; and not an observational study. The risk assessment of bias was assessed by the Newcastle- Ottawa Scale. After reading the titles and abstracts of the 358 identified articles, eight articles from 1966 to 2020 were included. The main reason for not including the studies was not to report data about bruxism (59.3%), and 44.5% were excluded for not reporting data from patients with cerebral palsy. The studies were carried out in schools, university hospitals, or centers for patients with special needs (Brazil, the United States, and Egypt). The pooled prevalence of bruxism in children and adolescents with cerebral palsy was 46% (95%CI: 0.38-0.55) after removing one study. CONCLUSION: The pooled prevalence of bruxism in children with cerebral palsy can be considered high since almost half of the studied population is affected by this condition. PROSPERO #CRD42021225781.

Classification of bruxism based on time-frequency and nonlinear features of single channel EEG.

BACKGROUND: In the classification of bruxism patients based on electroencephalogram (EEG), feature extraction is essential. The method of using multi-channel EEG fusing electrocardiogram (ECG) and Electromyography (EMG) signal features has been proved to have good performance in bruxism classification, but the classification performance based on single channel EEG signal is still understudied. We investigate the efficacy of single EEG channel in bruxism classification. METHODS: We have extracted time-domain, frequency-domain, and nonlinear features from single EEG channel to classify bruxism. Five common bipolar EEG recordings from 2 bruxism patients and 4 healthy controls during REM sleep were analyzed. The time domain (mean, standard deviation, root mean squared value), frequency domain (absolute, relative and ratios power spectral density (PSD)), and non-linear features (sample entropy) of different EEG frequency bands were analyzed from five EEG channels of each participant. Fine tree algorithm was trained and tested for classifying sleep bruxism with healthy controls using five-fold cross-validation. RESULTS: Our results demonstrate that the C4P4 EEG channel was most effective for classification of sleep bruxism that yielded 95.59% sensitivity, 98.44% specificity, 97.84% accuracy, and 94.20% positive predictive value (PPV). CONCLUSIONS: Our results illustrate the feasibility of sleep bruxism classification using single EEG channel and provides an experimental foundation for the development of a future portable automatic sleep bruxism detection system.

Prevalence and predictors of sleep bruxism in patients with obstructive sleep apnea and the effect of positive airway pressure treatment.

BACKGROUND: Sleep bruxism (SB) is often found to co-exist with obstructive sleep apnea (OSA). However, there are no data on prevalence and risk factors of SB in patients with OSA patients regarding the effect of optimal positive airway pressure (PAP). OBJECTIVE: This study aimed to study prevalence and risk factors of SB in OSA and to compare SB episodes during pre-treatment versus during optimal PAP therapy. METHODS: This investigation was a retrospective study including randomly selected patients with OSA who underwent split-night polysomnography. Data were collected from August 2021 to October 2022. Clinical demographic data and SB data were analyzed. The association between SB episodes and obstructive respiratory events were manually reviewed. If most of the SB episodes were observed within 5 s following obstructive respiratory events, SB was defined as SB associated with OSA. Comparison of SB index (SBI) was made between baseline portion of the study versus during optimal PAP. RESULTS: Among 100 patients enrolled, mean age was 50.8 ± 16.7 years and 73 subject (73%) were male. Mean respiratory disturbance index (RDI) and mean nadir oxygen saturation were 52.4 ± 33.4 and 79.3 ± 11.2% respectively. During the baseline portion of the study, 49 patients (49%) had SB and 31 patients (31%) had severe SB (SBI ≥ 4). Sleep bruxism associated with OSA was observed in 73.5% of all SB. The risk factor for SB was endorsement of nocturnal tooth grinding (odds ratio (OR) 5.69, 95%CI 1.74-18.58). Risk factors for severe bruxism were male sex (OR 4.01, 95%CI 1.02-15.88) and endorsement of nocturnal tooth grinding (OR 9.63, 95%CI 2.54-36.42). Risk factors for SB associated with OSA were non-supine RDI (OR 1.02, 95%CI 1.001-1.034) and endorsement of nocturnal tooth grinding (OR 5.4, 95%CI 1.22-23.93). In SB group, when comparison was made between baseline portion and during optimal PAP, significant reduction of SBI was observed (5.5 (3.2, 9.3) vs. 0 (0, 2.1), p < 0.001). Median difference of SBI between baseline portion and during optimal PAP was 4.4 (2.0, 8.3) (p < 0.001). CONCLUSIONS: In this group of patients with OSA, almost half was observed to have SB in which the majority were associated with OSA. Optimal PAP resulted in a significant reduction in SB episodes. In addition to endorsement of nocturnal tooth grinding, non-supine RDI was observed to be a potential risk factor for SB associated with OSA.

Association between perfectionism, personality traits and probable sleep bruxism in Spanish schoolchildren: A case-control study.

BACKGROUND: The aetiology of Sleep bruxism includes specific personality traits, related to perfectionism. AIM: To investigate the relationship between probable sleep bruxism (PSB) and personality traits in children and their parents, determining whether children with PSB and their parents are more perfectionists. DESIGN: This case-control study included 104 children aged 8-9 years, 52 cases and 52 controls. A clinical examination was performed on the children who completed the Big Five Personality Questionnaire (BFQ-NA) and the Child Perfectionism Inventory. Parents completed a bruxism diagnostic questionnaire according to the AASM criteria, BFQ and Frost multidimensional perfectionism scale questionnaires. t-Tests for independent samples and multivariate logistic regression models were used for statistical analysis. RESULTS: A significant relationship between PSB and a self-demanding personality (OR = 1.11, p = .01), restless sleep (OR = 4.41, p = .004), and a family history of clenching and grinding teeth (OR = 3.07, p = .0006) was found in a binary logistic regression model. When adjusted, only restless sleep showed a significant relationship with PSB (p = .03, OR 3.32, 95% CI 1.13-9.81). CONCLUSION: Children whose parents reported as clenching or grinding their teeth while asleep in the previous 6 months, and who were found to have abnormal dental wear, had significantly more nightmares, sleep disruption, daytime sleepiness, family history of bruxism, and tended to be more perfectionist.

Effects of different interventions on bruxism: an overview of systematic reviews.

OBJECTIVE: This study aimed to evaluate, qualify, and summarize evidence presented in systematic reviews (SR) on treatments for bruxism. METHODS: The overview was conducted using the PICO strategy: children, adolescents, and adults with bruxism (P) were submitted to different treatments (I) compared to other treatments, placebo, or no treatment (C) in order to evaluate incidence, prevalence, and number of episodes of bruxism (O). The search was carried out in six databases and gray literature up to July 2023. Data were extracted, and the ROBS tool was used, followed by a descriptive synthesis of the results. RESULTS: A total of 31 SR were included. Sixteen showed a positive effect on episodes of bruxism (BE), while two had negative, one had neutral, and nine had inconclusive effects. Using the risk of bias in systematic reviews tool (ROBIS), risk of bias varied from low (n = 23) to high (n = 5) among the SR. Pharmacological treatment, oral rehabilitation, and other therapeutic approaches presented inconclusive or negative effects on BE, while oral appliances showed controversial effects. Biofeedback, physical therapy, laser therapy, and botulinum toxin showed positive effects on the reduction of BE. CONCLUSION: Biofeedback, physical therapy, laser therapy, and botulinum toxin showed positive effects on the reduction of BE; there is still a lack of studies to support the safe and long-term use of these therapies. REGISTRATION NUMBER: PROSPERO CRD42021273905.

Association between Psychological Distress and Possible, Probable, and Definite Sleep Bruxism-A Comparison of Approved Diagnostic Procedures.

(1) Background: The relationship between sleep bruxism (SB) and psychological distress has been investigated in numerous studies and is heterogeneous. Different diagnostic procedures have been applied to determine SB. The aim of this study was to directly compare the association between psychological distress and SB diagnosed by different accepted methods. (2) Methods: Data of N = 45 subjects were analyzed, including group comparisons and correlation analyses. Following diagnostic methods for the determination of SB were used in one sample: self-report, clinical assessment, polysomnography with audio-video recording and a novel diagnostic sheet with analyzing software. Psychological distress was measured using the global severity index (GSI) of the Symptom Checklist-90-Standard (SCL-90-S). (3) Results: The GSI did not differ significantly between subjects with and without SB, regardless of the underlying diagnostic classification (p > 0.05). In-depth correlation analyses of self-report and clinical data revealed a weak-to-medium correlation with the GSI (r = 0.12-0.44). Due to non-normally distributed data, a test of statistical significance was not possible. Variables of instrumental methods such as the SB index (amount of SB activity per hour) of polysomnography (PSG) showed almost no correlation with psychological distress (r = -0.06-0.05). (4) Conclusions: Despite these limitations, the results provide an indication that the choice of diagnostic procedure may elucidate the variance in the correlation between SB and psychological distress.

Sleep architecture as a candidate for phenotyping sleep bruxism: A narrative physiological review.

BACKGROUND: Sleep bruxism (SB), an oral behaviour in otherwise healthy individuals, is characterised by frequent rhythmic masticatory muscle activity (RMMA) during sleep. RMMA/SB episodes occur over various sleep stages (N1-N3 and rapid eye movement (REM)), sleep cycles (non-REM to REM), and frequently with microarousals. It currently remains unclear whether these characteristics of sleep architecture are phenotype candidates for the genesis of RMMA/SB. OBJECTIVES: This narrative review investigated the relationship between sleep architecture and the occurrence of RMMA as a SB phenotype candidate. METHODS: PubMed research was performed using keywords related to RMMA/SB and sleep architecture. RESULTS: In non-SB and SB healthy individuals, RMMA episodes were most frequent in the light non-REM sleep stages N1 and N2, particularly during the ascending phase of sleep cycles. The onset of RMMA/SB episodes in healthy individuals was preceded by a physiological arousal sequence of autonomic cardiovascular to cortical activation. It was not possible to extract a consistent sleep architecture pattern in the presence of sleep comorbidities. The lack of standardisation and variability between subject complexified the search for specific sleep architecture phenotype(s). CONCLUSION: In otherwise healthy individuals, the genesis of RMMA/SB episodes is largely affected by oscillations in the sleep stage and cycle as well as the occurrence of microarousal. Furthermore, a specific sleep architecture pattern cannot be confirmed in the presence of sleep comorbidity. Further studies are needed to delineate sleep architecture phenotype candidate(s) that contribute to the more accurate diagnosis of SB and treatment approaches using standardised and innovative methodologies.

Examination of the relationship between masseter muscle activity during sleep and wakefulness measured by using a wearable electromyographic device.

Purpose This study aimed to measure masseter muscle activity throughout the day in outpatients suspected of having awake bruxism (AB) and/or sleep bruxism (SB) and examine the relationship between AB and SB by comparing muscle activity during daytime wakefulness and nighttime sleep.Methods Fifty outpatients with suspected SB and/or AB participated in this study. A single-channel wearable electromyogram (EMG) device was used for EMG recording. The selected EMG bursts were divided into bursts during sleep (S-bursts) and bursts during awake state (A-bursts). The number of bursts per hour, average burst duration, and ratio of burst peak value to maximum voluntary contraction were calculated for both the S- and A-bursts. These values of the S- and A-bursts were then compared, and the correlations between them were analyzed. Additionally, the ratios of phasic and tonic bursts in the S- and A-bursts were compared.Results The number of bursts per hour was significantly higher for A-bursts than for S-bursts. No significant correlation was found between the numbers of S- and A-bursts. The ratio of phasic bursts was large and that of tonic bursts was small in both the S- and A-bursts. A comparison of the S- and A-bursts showed that the S-bursts had a significantly lower ratio of phasic bursts and higher ratio of tonic bursts than the A-bursts.Conclusions The number of masseteric EMG bursts during wakefulness did not show any association with that during sleep. It became clear that sustained muscle activity was not dominant in AB.