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Objective: To consider the possible role of the vagus nerve (VN) in the pathophysiology of sleep bruxism (SB) and introduce a multimodal protocol of transcutaneous auricular stimulation of the VN in the treatment of SB patients., Methods: Ten patients with SB underwent four sessions of electric transcutaneous auricular vagus nerve stimulation (ta-VNS) in specific auricular areas. The patients were advised to manually stimulate the same areas between sessions. Masticatory muscle activity and sleep parameters were measured by a polysomnography (PSG) before and after the treatment. Heart rate variability (HRV) parameters were measured during each stimulation., Results: PSG analysis revealed a statistically significant reduction in tonic SB index and tonic contraction time. HRV parameters showed a statistically significant increase in mean values of the vagal tone after each session of stimulation. No side effect was reported., Conclusion: The stimulation of the VN might have a role in the treatment of SB.

Background: Sleep-related bruxism (SB) is the habit of grinding or clenching the teeth during sleep, mediated by the non-peripheral central nervous system., Purpose: The objectives of this cross-sectional study were to evaluate associations between SB, microarousals and oxyhaemoglobin desaturations and to compare the frequency of SB and microarousals in sleep stages, in an apnoeic population., Methods: Two hundred and forty individuals composed the sample, who underwent a single full-night polysomnography. Self-reports and clinical inspections were not considered for assessing SB. The polysomnographic assessment of SB was performed using electrodes placed on masseter muscles and chin. SB was defined as more than two events of rhythmic masticatory muscle activity per hour of sleep. Microarousals were considered when there were abrupt changes in electroencephalogram frequencies, without complete awakening, lasting from 3 to 15 s. Oxyhaemoglobin desaturations were defined as significant drops (≥3%) in basal oxygen saturations. With these data, SB, microarousals and oxyhaemoglobin desaturations were evaluated and submitted to statistical analysis., Results: Statistically significant differences were observed between bruxers and non-bruxers when comparing the rates of microarousals (p < .001) and oxyhaemoglobin desaturations (p = .038). There was a higher number of SB and microarousals in NREM (non-rapid eye movement) two sleep stage (p < 0.001). Bruxers had a greater risk of higher numbers of microarousals (OR = 1.023; p = .003), which did not occur for oxyhaemoglobin desaturations (OR = 0.998; p = .741)., Conclusions: A higher number of microarousals presents relationship with SB; associations between SB and oxyhaemoglobin desaturations remained inconclusive; higher frequency of SB and microarousals was observed in NREM 2 sleep stage., (© 2024 John Wiley & Sons Ltd.)

Objective: This study aims to evaluate the effects on bite force and muscle thickness of the botulinum toxin (BoNT) injection for patients with sleep bruxism (SB) by comparing injections into the masseter muscle only and both the masseter and the anterior belly of the digastric muscle (ABDM) in a clinical trial., Methods: Twelve SB patients received BoNT-A injections using US-guided techniques into the masseter muscle only (Group A), while the remaining 12 SB patients received injections into both the masseter and ABDM (Group B). Bite force and muscle thickness were measured before injection, as well as 1 and 2 months after injection., Results: The bite force and masseter muscle thickness decreased in both Group A and Group B before injection, and at 1 and 2 months after injection. However, there was no significant difference (p > .05, repeated measures analysis of variance) between the two groups, and there was also no significant difference in ABDM thickness (p > .05, repeated measures analysis of variance)., Conclusion: This study is the first to assess the short-term effects of BoNT injected into ABDM for SB control. Results show no influence on SB reduction, suggesting the need for further research on BoNT's effectiveness in controlling intense ABDM contractions during sleep and assessing suprahyoid muscle potential impact on rhythmic masticatory muscle activity occurrence., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Background: Although biofeedback with contingent electrical stimulation (CES) has demonstrated the reduction effect on sleep bruxism (SB), the relationship between the actual applied CES intensity and efficacy remains uncertain., Objective: This study aimed to investigate whether the reduction of bruxism events and jaw muscle symptoms could vary according to the intensity of CES and in probable sleep bruxers., Methods: Twenty probable sleep bruxers were initially screened for bruxer confirmation based on a 2-week recording of SB events with a portable electromyography recorder (BUTLER®GrindCare®, GC4). A 3-week recording was conducted without CES using a GC4, followed by another 3-week recording with CES. At baseline and before and after the CES (+) session, clinical muscle symptoms were assessed using a 0-10 numerical rating scale (NRS). The relationships between the actual applied CES intensity and the number of SB events/hour, as well as the NRS of clinical muscle symptoms, were analysed., Results: The actual applied CES intensity was positively correlated with the reduction rate of the number of SB events/hour (R = .643, p = .002), as well as with the reduction rate of NRS for pain, unpleasantness, fatigue, tension and stiffness (R > .500, p < .011)., Conclusion: Higher CES elicited a more robust reduction in SB events and clinical muscle symptoms, in probable bruxers. Prior to selecting CES biofeedback as a management option for SB, it would be beneficial to assess the tolerance threshold of CES in each bruxer in order to predict the effectiveness of CES in probable sleep bruxers., (© 2024 John Wiley & Sons Ltd.)

Diagnosis of bruxism is challenging because not all contractions of the masticatory muscles can be classified as bruxism. Conventional methods for sleep bruxism detection vary in effectiveness. Some provide objective data through EMG, ECG, or EEG; others, such as dental implants, are less accessible for daily practice. These methods have targeted the masseter as the key muscle for bruxism detection. However, it is important to consider that the temporalis muscle is also active during bruxism among masticatory muscles. Moreover, studies have predominantly examined sleep bruxism in the supine position, but other anatomical positions are also associated with sleep. In this research, we have collected EMG data to detect the maximum voluntary contraction of the temporalis and masseter muscles in three primary anatomical positions associated with sleep, i.e., supine and left and right lateral recumbent positions. A total of 10 time domain features were extracted, and six machine learning classifiers were compared, with random forest outperforming others. The models achieved better accuracies in the detection of sleep bruxism with the temporalis muscle. An accuracy of 93.33% was specifically found for the left lateral recumbent position among the specified anatomical positions. These results indicate a promising direction of machine learning in clinical applications, facilitating enhanced diagnosis and management of sleep bruxism.

It has been suggested that sleep bruxism may interrupt sleep continuity, hence potentially influencing sleep quality. The aim of this study was to systematically review the relationship between possible, probable, and definite sleep bruxism and sleep quality in otherwise healthy individuals. A systematic search on sleep bruxism and sleep quality was performed in seven databases until 19 December 2022. Eligible articles were screened, and quality assessment was performed via the Joanna Briggs Institute Scale. Of 3681 articles screened, 13 were included in this study. Of these, six evaluated the relationship between sleep quality and possible sleep bruxism, three with probable sleep bruxism, and four with definite sleep bruxism. An association between poor sleep quality and sleep bruxism was found among those individuals diagnosed with possible and probable sleep bruxism. However, the studies conducted in individuals with definite sleep bruxism failed to demonstrate any association. With more reliable measures to evaluate sleep bruxism, a relationship between sleep bruxism and sleep quality was not evident., (© 2023 European Sleep Research Society.)

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 ± standard deviation = 42.8 ± 12.2 years; mean body mass index ± standard deviation = 26.7 ± 4.7 kg/m 2 ) without previous treatment for snoring. SB was diagnosed based on the frequency of the biomarker of SB: rhythmic masticatory muscle activity (SB when rhythmic masticatory muscle activity ≥ 2 episodes/h). Logistic regression was performed, with SB as the dependent variable and with age, sex, body mass index, 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 (odds ratio = 0.965 [0.944, 0.987]) and shorter total sleep time (odds ratio = 0.760 [0.609, 0.948]) significantly increased the risk of SB ( P < .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: onderzoekmetmensen.nl; Name: A Large Sample Polysomnographic Study on Sleep Bruxism; URL: https://trialsearch.who.int/Trial2.aspx?TrialID=NL-OMON19947; Identifier: NL8516., Citation: Li D, Lobbezoo F, Hilgevoord AAJ, de Vries N, Aarab G. Prevalence and risk factors of sleep bruxism in adults with primary snoring: a large-scale polysomnographic study. J Clin Sleep Med . 2024;20(8):1331-1337., (© 2024 American Academy of Sleep Medicine.)

Rhythmic masticatory muscle activity (RMMA) is a periodic muscle activity that characterises sleep bruxism (SB) events. These can occur as a single event, in pairs, or in clusters. Since RMMA episodes often occur in clusters and the relevance of this occurrence is unknown, we conducted a study to investigate the effect of RMMA clusters on sleep fragmentation and the severity of orofacial muscle pain. This study involved a secondary analysis using data from 184 adult subjects with orofacial muscle pain who underwent definitive polysomnography (PSG) for sleep bruxism diagnosis. Self-reported orofacial muscle pain (OFMP) was assessed using the numeric rating scale, and additional evaluation of side-to-side equivalence (symmetry) was described using a binary system. Among the 184 participants, 60.8% (n = 112) did not exhibit clusters and among the 72 participants with clusters, 36.1% (n = 26) and 63.9% (n = 46) were in the high and low RMMA frequency groups, respectively. The high SB group had significantly three times more phasic RMMA events than the noncluster group. A total of 89.67% (n = 165) of subjects reported orofacial muscle pain. While there was no difference in the severity of OFMP among groups, a significant decrease in symmetry between the severity of temporal muscle pain on the left and right sides was noted in the cluster group compared with the noncluster group. Clustering of RMMA events is associated with sleep fragmentation. The asymmetry of temporal muscle pain is related to the presence of RMMA clusters in sleep bruxism., (© 2023 European Sleep Research Society.)

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&#95;sup) and in non-supine positions (RMMA&#95;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&#95;sup index and RMMA&#95;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&#95;sup index was significantly higher than the RMMA&#95;nsup index (p < .001). RMMA&#95;sup index was significantly associated with the arousal index (p = .002) and arousal index in supine position (p < .001). RMMA&#95;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., (© 2024 The Authors. Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Background: The etiology of sleep bruxism in obstructive sleep apnea (OSA) patients is not yet fully clarified. This prospective clinical study aimed to investigate the connection between probable sleep bruxism, electromyographic muscle tone, and respiratory sleep patterns recorded during polysomnography., Methods: 106 patients with OSA (74 males, 31 females, mean age: 56.1 ± 11.4 years) were divided into two groups (sleep bruxism: SB; no sleep bruxism: NSB). Probable SB were based on the AASM criteria: self-report of clenching/grinding, orofacial symptoms upon awakening, abnormal tooth wear and hypertrophy of the masseter muscle. Both groups underwent clinical examination for painful muscle symptoms aligned with Temporomandibular Disorders Diagnostic Criteria (DC/TMD), such as myalgia, myofascial pain, and headache attributed to temporomandibular disorder. Additionally, non-complaint positive muscle palpation and orofacial-related limitations (Jaw Functional Limited Scale-20: JFLS-20) were assessed. A one-night polysomnography with electromyographic masseter muscle tone (EMG) measurement was performed. Descriptive data, inter-group comparisons and multivariate logistic regression were calculated., Results: OSA patients had a 37.1% prevalence of SB. EMG muscle tone (N1-N3, REM; P = 0.001) and the number of hypopneas (P = 0.042) were significantly higher in the sleep bruxism group. While measures like apnea-hypopnea-index (AHI), respiratory-disturbance-index (RDI), apnea index (AI), hypopnea-index (HI), number of arousals, and heart rate (1/min) were elevated in sleep bruxers, the differences were not statistically significant. There was no difference in sleep efficiency (SE; P = 0.403). Non-complaint masseter muscle palpation (61.5%; P = 0.015) and myalgia (41%; P = 0.010) were significant higher in SB patients. Multivariate logistic regression showed a significant contribution of EMG muscle tone and JFLS-20 to bruxism risk., Conclusion: Increased EMG muscle tone and orofacial limitations can predict sleep bruxism in OSA patients. Besides, SB patients suffer more from sleep disorder breathing. Thus, sleep bruxism seems to be not only an oral health related problem in obstructive apnea. Consequently, interdisciplinary interventions are crucial for effectively treating these patients., Trial Registration: The study was approved by the Ethics Committee of Philipps-University Marburg (reg. no. 13/22-2022) and registered at the "German Clinical Trial Register, DRKS" (DRKS0002959)., (© 2024. The Author(s).)

This systematic review answers the question: "Does occlusal appliance use influence masticatory muscle function of dentate individuals with sleep bruxism?". The literature search included six databases, grey literature, and manual search for articles. Randomized and non-randomized clinical trials were included comparing muscle function of sleep bruxers before and after receiving occlusal appliances. Risk of bias was assessed with risk of bias assessment for randomized and non-randomized clinical trials tool. Twelve studies, three represent randomized clinical trials, were included. Risk of bias was considered low, moderate, or serious. Meta-analyses indicated that soft and hard appliances did not influence muscle activity and bite force of bruxers. Qualitative analysis showed that occlusal appliance use did not influence masticatory performance and muscle volume. However, it was effective in reducing tongue force. Certainty of evidence was considered very low for muscle activity when evaluated with hard appliances, and for bite force evaluated with both appliance materials. Low certainty of evidence was observed for muscle activity with soft appliances. Based on the findings of this meta-analysis, occlusal appliances do not affect masticatory muscle function of sleep bruxers. Regardless of appliance material, the activity of masseter and temporal, and bite force of sleep bruxers was not influenced., (© 2024 Scandinavian Division of the International Association for Dental Research. Published by John Wiley & Sons Ltd.)

Sleep bruxism, characterized by involuntary grinding or clenching of the teeth and/or by bracing or thrusting of the mandible during sleep, is common in children. Sleep bruxism occurs while the patient is asleep. As such, diagnosis can be difficult as the affected child is usually unaware of the tooth grinding sounds. This article aims to familiarize physicians with the diagnosis and management of sleep bruxism in children. A search was conducted in May 2023 in PubMed Clinical Queries using the key terms "Bruxism" OR "Teeth grinding" AND "sleep". The search strategy included all observational studies, clinical trials, and reviews published within the past 10 years. Only papers published in the English literature were included in this review. According to the International classification of sleep disorders, the minimum criteria for the diagnosis of sleep bruxism are (1) the presence of frequent or regular (at least three nights per week for at least three months) tooth grinding sounds during sleep and (2) at least one or more of the following (a) abnormal tooth wear; (b) transient morning jaw muscle fatigue or pain; (c) temporary headache; or (d) jaw locking on awaking. According to the International Consensus on the assessment of bruxism, "possible" sleep bruxism can be diagnosed based on self-report or report from family members of tooth-grinding sounds during sleep; "probable" sleep bruxism based on self-report or report from family members of tooth-grinding sounds during sleep plus clinical findings suggestive of bruxism (e.g., abnormal tooth wear, hypertrophy and/or tenderness of masseter muscles, or tongue/lip indentation); and "definite" sleep bruxism based on the history and clinical findings and confirmation by polysomnography, preferably combined with video and audio recording. Although polysomnography is the gold standard for the diagnosis of sleep bruxism, because of the high cost, lengthy time involvement, and the need for high levels of technical competence, polysomnography is not available for use in most clinical settings. On the other hand, since sleep bruxism occurs while the patient is asleep, diagnosis can be difficult as the affected child is usually unaware of the tooth grinding sounds. In clinical practice, the diagnosis of sleep bruxism is often based on the history (e.g., reports of grinding noises during sleep) and clinical findings (e.g., tooth wear, hypertrophy and/or tenderness of masseter muscles). In childhood, sleep-bruxism is typically self-limited and does not require specific treatment. Causative or triggering factors should be eliminated if possible. The importance of sleep hygiene cannot be over-emphasized. Bedtime should be relaxed and enjoyable. Mental stimulation and physical activity should be limited before going to bed. For adults with frequent and severe sleep bruxism who do not respond to the above measures, oral devices can be considered to protect teeth from further damage during bruxism episodes. As the orofacial structures are still developing in the pediatric age group, the benefits and risks of using oral devices should be taken into consideration. Pharmacotherapy is not a favorable option and is rarely used in children. Current evidence on the effective interventions for the management of sleep bruxism in children is inconclusive. There is insufficient evidence to make recommendations for specific treatment at this time., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Different oral appliances (OAs) have been proposed to control sleep bruxism (SB) detrimental effects on the stomatognathic system., Objective: The aim of the study was to evaluate the effect of different OAs on SB activity and masticatory muscle activity (sMMA) measured by EMG., Methods: This longitudinal cohort study was conducted on 51 patients (21 M, 30 F, mean age 26,5 ± 3,5) suffering from SB diagnosed with a validated portable EMG-ECG holter and wearing different OAs: occlusal splints, functional appliance with metallic bites and clear aligners followed after 1 week, 1 month, 3 months, 6 months and 12 months from delivery. A control group of 16 non-treated SB patients (6 M, 10 F mean age 27,1 ± 1,4) was used as a reference. A multiple regression analysis was performed to estimate the differences between groups. The level of significance was set as P value <0,05., Results: Occlusal splint reduced sleep bruxism index after 1 week, 3, 6 and 12 months from delivery while functional appliance only after 12 months. Occlusal splints reduced general phasic contractions only in the first week and sleep bruxism-related phasic contractions at 1 week, 3 and 6 months after delivery with no significant reductions after 12 months. Patients wearing clear aligners showed a reduction in general tonic contractions after 6 and 12 months., Conclusion: Resin and metal bites can reduce sleep bruxism index, while resin bites can reduce sleep bruxism-related phasic contractions. Clear aligners do not influence sleep bruxism index but can reduce tonic contractions., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The present study aimed to assess the influence of gender and age on snoring and sleep bruxism in non-apneic snoring patients. Adult participants with clinical suspicion of snoring and with no other significant medical history were recruited. Single-night video polysomnography was performed to detect snoring and sleep bruxism. Finally, 137 snoring non-apneic participants were included. Statistical analysis of gender groups showed that the total snore index and snore train were significantly higher in men than in women. Men also presented severe bruxism, with significantly more frequent episodes and higher bruxism episodes index scores. The correlation analysis showed the presence of significant linear relationships in the supine sleep position between age and snore index, snore index in non-rapid eye movement 2 (N2) sleep stage, and snore train. The analysis of groups separated according to the criterion of third age quartile showed that the average, maximum and minimum audio volume in the non-supine sleep position was significantly higher in the older group. The analysis of groups separated according to the criterion of median age showed that the bruxism episode index and bruxism phasic episodes were significantly higher in the younger group. Thus, it can be concluded that both age and gender influence snoring and sleep bruxism. Snoring and sleep bruxism seem to be more intensive in men. Older patients seem to snore more in N2 sleep and the supine sleep position and present lower bruxism episodes, especially the phasic type. The results of the present study indicate the need for further research on this topic to establish the possible relationship between snoring and sleep bruxism., (© 2020 European Sleep Research Society.)

The vision of adult sleep bruxism (SB) has changed over time. Thus, among the most important concomitant factors of SB noted are the pathophysiological aspect, namely sleep arousal, obstructive sleep apnea, gastroesophageal pH/gastroesophageal reflux disease, and the use or abuse of certain substances. The aim of this article was to review the main clinically relevant pathophysiological SB-associated factors and a proposal for a diagnostic process., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The purpose of this study is to evaluate the effects of botulinum toxin type A (BoNT-A) for managing sleep bruxism (SB) in a randomized, placebo-controlled trial. Thirty SB subjects were randomly assigned into two groups evenly. The placebo group received saline injections into each masseter muscle, and the treatment group received BoNT-A injections into each masseter muscle. Audio-video-polysomnographic recordings in the sleep laboratory were made before, at four weeks after, and at 12 weeks after injection. Sleep and SB parameters were scored according to the diagnostic and coding manual of American Academy of Sleep Medicine. The change of sleep and SB parameters were investigated using repeated measures analysis of variance (RM-ANOVA). Twenty-three subjects completed the study (placebo group 10, treatment group 13). None of the SB episode variables showed a significant time and group interaction ( p > 0.05) except for electromyography (EMG) variables. The peak amplitude of EMG bursts during SB showed a significant time and group interaction ( p = 0.001). The injection decreased the peak amplitude of EMG bursts during SB only in the treatment group for 12 weeks ( p < 0.0001). A single BoNT-A injection cannot reduce the genesis of SB. However, it can be an effective management option for SB by reducing the intensity of the masseter muscle.

Study Objectives: We hypothesized that sleep stage dynamics are different in patients with sleep bruxism (SB) and that these changes are associated with the occurrence of rhythmic masticatory muscle activity (RMMA)., Methods: Fifteen healthy controls and 15 patients with SB underwent overnight polysomnography. Sleep variables and survival curves of continuous runs of each sleep stage were compared between the groups. Stage transition dynamics and the probability of stage fragmentation were analyzed for three epochs before and after the epoch with RMMA. Survival curves of continuous runs of each sleep stage, terminated with or without RMMA, were also compared., Results: There were no significant differences in sleep variables between the groups, except for shorter sleep latency, shorter rapid eye movement (REM) latency, and longer total N1 duration in SB patients than in controls. REM sleep and N2 were significantly less continuous in SB patients than in controls. In the SB group, stage fragmentation probability was significantly increased for the epoch with RMMA compared with the baseline for all stages. Meanwhile, the occurrence of RMMA did not affect the continuity of N2 or REM; however, the occurrence of RMMA was preceded by more continuous N3 runs., Conclusions: Sleep stage dynamics differed between SB patients and controls. RMMA does not result in sleep disruption but is likely associated with dissipation of sleep pressure. Less continuity of REM sleep in SB may provide insights into the underlying pathophysiological mechanisms of SB, which may be related to REM sleep processes such as cortical desynchronized states or brainstem activation., (© Sleep Research Society 2019. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.)

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:.

Background: The purpose of this systematic review was to evaluate the association between sleep bruxism (SB) and anxiety symptoms in adults., Methods: A systematic review was performed and studies assessing SB by means of questionnaires, clinical examination and/or polysomnography (PSG), and validated questionnaires to assess anxiety, were included. Search strategies were developed for seven main electronic databases. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross-Sectional Studies, and confidence in cumulative evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation criteria., Results: Eight cross-sectional studies were included, of which five were judged with low and three with moderate risk of bias. No association with SB was observed in three studies that investigated generic levels of anxiety, while other two papers that evaluated generic anxiety levels through the State-Trait Anxiety Inventory (STAI) found a positive association with probable and definite SB in both STAI-1 and STAI-2 subscales. Only one study evaluated dental anxiety in particular and an association with probable SB was observed regarding very anxious or extremely anxious scores. Two studies assessed specific symptoms of anxiety using the panic-agoraphobic spectra evaluation (PAS-SR) questionnaire. Significantly higher PAS-SR total scores were observed in both studies with regard to SB. No study with definitive assessment of SB was identified., Conclusion: Current literature is controversial regarding an association between SB and generic symptoms of anxiety in adults. It seems that some specific symptoms of the anxiety disorders spectrum might be associated with probable SB., (© 2019 John Wiley & Sons Ltd.)

Background: Most rhythmic masticatory muscle activities (RMMAs) have been shown to be accompanied with limb movements (LMs) in sleep bruxism (SB) patients during sleep., Objectives: To compare the relationships between RMMAs and LMs in SB patients and normal subjects., Methods: Polysomnographic recordings were performed on eight SB patients and nine normal subjects and the frequencies and durations of RMMAs as well as LMs were determined. Linear regression and correlation analysis were performed to study the relationship between durations of RMMAs and LMs when RMMAs occurred with LMs., Results: Most LMs in SB patients, but not in normal subjects, were accompanied with RMMAs. RMMAs in SB patients were more likely to be isolated, phasic or mixed, while RMMAs in normal subjects were more likely to be tonic. The frequencies of LMs, isolated RMMAs and RMMAs accompanied with LMs in SB patients were significantly higher than those in normal subjects. Furthermore, linear regression and correlation analysis showed that duration of RMMAs was significantly associated with that of LMs when RMMAs occurred with LMs. The duration of RMMAs, when accompanied with LMs, in SB patients was significantly longer than that in normal subjects., Conclusions: Close relationships between LMs and RMMAs exist in SB patients and normal subjects, and SB episodes may be part of cortical arousal responses and the increased cortical activities associated with SB episodes may not just be localised to the central nervous system (CNS) that controls jaw movements but may also include other parts of CNS that controls LMs., (© 2018 John Wiley & Sons Ltd.)

Purpose: Although sleep bruxism (SB) is one of the most important clinical problems in dental practice, there is no definitive method for controlling it. This pilot study evaluated the effects of contingent vibratory feedback stimuli using an occlusal splint for inhibition of sleep bruxism., Methods: Thirteen subjects with clinically diagnosed SB participated after providing an informed consent. Portable polysomnographic recordings were conducted in the subjects' home environment to make a definitive SB diagnosis and to evaluate the effects of the vibratory stimuli on SB. A force-based bruxism detection system, which used a pressure-sensitive piezoelectric film embedded in the occlusal splint, was utilized to trigger vibration feedback stimuli, which was scheduled to be applied intermittently for 30 min, at 30-min intervals., Results: The number of SB episodes (times/hour), the total SB duration (seconds/hour), the mean duration of SB episodes (seconds/episode), and the micro-arousal index (times/hour) were scored for each time period (with and without vibration). The effects of the vibration on these scores were tested (paired t test; p < 0.05). The number of SB episodes tended to decrease with the vibration stimuli, and the decrease in the total SB duration was statistically significant (14.3 ± 9.5 vs. 26.0 ± 20.0, p = 0.03). No substantial change was found in terms of the micro-arousal index., Conclusions: These study results suggested that the SB inhibitory system employing a vibratory stimulus might be able to suppress the total SB duration without disturbing sleep.

Objectives: The aim of this study was to assess the correlation between chronic stress and temporalis muscle activity during four nights., Material and Methods: Forty-four female subjects were recruited in five dental practices located in different areas of the federal state of Saarland, Germany (dental practice network in Saarland). The following inclusion criteria were used: female, aged between 18 and 65, no somatization or depression, and no pain medication, graded chronic pain status < 3. Both subjects reporting about sleep bruxism and subjects negating sleep bruxism during anamnesis were included. Anamnestic issues, sleep bruxism, anxiety, and chronic stress were assessed using validated questionnaires. Temporalis muscle activity was measured for four nights using a portable electromyographic device. Correlation coefficient was used to assess the correlation (Spearman-correlation) between chronic stress and number of temporalis muscle episodes/hour and between anxiety and the number of episodes/hour., Results: The analysis showed that the factors "work overload" (adulthood chronic stress because of too many demands at work) and "pressure to perform" (necessity to be successful at work) were significantly correlated with the number of temporalis muscle episodes per hour. In contrast, anxiety was not correlated with temporalis muscle episodes per hour., Conclusions: Work-related chronic stress seems to be associated with an increased level of temporalis muscle activity during sleep., Clinical Relevance: During anamnesis, work-related aspects should be assessed in females presenting with sleep-bruxism.

Objective: In this study, we examined if 6-9 Hz jaw tremor, an indirect indicator of Periodontal Mechanoreceptor (PMR) activity, is different in bruxists compared to healthy participants during production of a low-level constant bite force., Methods: Bite force and surface EMG from the masseter muscle were recorded simultaneously as participants (13 patients, 15 controls) held a force transducer between the upper and lower incisors very gently., Results: Tremor in 6-9 Hz band for bruxists was greater on average compared to controls, but the difference was not significant, both for force recordings and EMG activity., Conclusions: The low effect sizes measured with the current protocol contrast highly with those of our previous study, where larger, dynamic bite forces were used, and where jaw tremor was markedly different in bruxists compared with controls., Significance: We have now gained important insight into the conditions under which abnormal jaw tremor can be elicited in bruxism. From a scientific standpoint, this is critical for understanding the 'abnormality' of PMR feedback in bruxism. From a clinical perspective, our results represent progress towards the development of an optimal protocol in which jaw tremor can serve as a biological marker of bruxism., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objective: Salivary cortisol levels and biological rhythms could be hypothesized as part of the multifactorial framework that explains bruxism etiology. The objective of this study was to examine salivary cortisol levels and biological rhythms in schoolchildren with sleep bruxism (SB)., Methods: This is a cross-sectional study with a school-based sample. The Biological Rhythms Interview for Assessment in Neuropsychiatry for Kids (BRIAN-K) was used to evaluate biological rhythms. Salivary samples were collected by the spitting method. The salivary cortisol level was measured by electrochemiluminescence. The criteria proposed by the American Academy of Sleep Medicine (AASM) were used to evaluate SB., Results: The SB prevalence was 16%. The SB presence was associated with belonging to families of lower economic status (p = 0.003). In addition, children with SB showed greater difficulty in maintaining biological rhythm (p = 0.002) and had higher levels of salivary cortisol (p = 0.034) compared with children without SB., Conclusions: Higher levels of cortisol and disruption of biological rhythm was associated with SB in schoolchildren., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objective: To evaluate the utility of vacuum-pressed, BruxChecker ® sheets for the diagnosis of sleep bruxism., Methods: Twenty subjects participated in this study. Tooth contact during sleep was recorded using a 0.1 mm-thick polyvinyl chloride sheet called BruxChecker ® . The area of the BruxChecker ® in which the red dye was removed was measured. In addition, the EMG activity of the masseter muscle during sleep was recorded. The numbers of bruxism bursts and episodes were counted, and their correlations with the peeled area of the red dye on the BruxChecker ® were evaluated., Results: The number of bruxism bursts and episodes/hr significantly correlated with the peeled area at all cut-off values. The peeled area significantly correlated with the number of phasic type bruxism episodes but not with tonic or mixed type bruxism episodes., Discussion: Since the BruxChecker ® peeled area reflected phasic type sleep bruxism, the sheets may be useful in sleep bruxism screening.

The aim of this article is to introduce transcranial magnetic stimulation (TMS) to dental practitioners and to explain its use in obstructive sleep apnea (OSA) and sleep bruxism (SB). In these 2 sleep disorders, TMS has proven to be a useful tool to explore pathophysiological pathways and disease mechanisms, and in a more limited way, to recruit upper airway muscles in OSA and reduce muscle activity and pain intensity in SB. Although promising, research using TMS in these conditions is still very limited and future investigations should be conducted before its clinical application can be considered., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Sleep-related bruxism may directly impact sleep quality. This study aims to evaluate potential relationships between sleep bruxism events and related daytime symptoms. We investigated 22 patients (42.1 ± 11.6 yr of age) with sleep bruxism in comparison with 12 good sleeper control subjects of similar age (41.0 ± 11.5 yr). Sleep bruxism was visually analyzed and categorized according to sleep stage, bruxism type (tonic/phasic) and duration. Clinical instruments comprised the Epworth Sleepiness, the Brugmann Fatigue Scale, and the Hospital Anxiety and Depression Rating Scale. Sleep quality was measured using the Pittsburgh Sleep Quality Index. Controls and patients with sleep bruxism presented similar sleep architecture. However, patients with sleep bruxism displayed significantly decreased sleep efficiency and higher sleep fragmentation. Perceived sleep quality was significantly worse in patients with sleep bruxism than in control subjects. Additionally, patients presented with significantly greater fatigue intensity and more affective symptoms than controls. The cumulative durations of sleep bruxism events (phasic, tonic, and combined) were significantly correlated with deterioration of sleep quality, whereas neither the event index per hour of sleep nor the count of event types (phasic/tonic) were related to sleep quality. Patients with sleep bruxism present with higher levels of daytime fatigue and sleepiness than control subjects who experience good sleep and may also exhibit impairments of sleep quality which are related to the duration of bruxism occurrence rather than to its frequency., (© 2018 Eur J Oral Sci.)

Background: Sleep bruxism is a phenomenon associated with masticatory muscle hyperactivity. While stretching of limb and trunk muscles has been extensively studied for musculoskeletal disorders, little is known about the effectiveness of stretching of masticatory muscles in the management of bruxism., Objective: The aim of this study is to determine the effectiveness of stretching of the masticatory muscles for sleep bruxism., Methods: Twenty four pain-free individuals with sleep bruxism were randomly assigned to either an intervention group or a control group. Both groups were given sleep hygiene advice and the intervention group additionally received muscle-stretching exercises for 10 days. Primary outcome measures, bruxism bursts and episodes per hour of sleep, were measured by ambulant polysomnography. Secondary outcome measures were among others pain-free active maximum mouth opening (MMO) and masseter pressure pain threshold (PPT)., Results: The number of bruxism episodes per hour of sleep increased more in the intervention group than in the control group (by 1.1 episodes, P = 0.066), as did the number of bruxism bursts per hour of sleep (by 8.6 bursts, P = 0.049). MMO and PPT increased significantly more in the intervention group (by 3.2 mm, P = 0.020; and by 1.0 kg/cm 2 , P = 0.036, respectively)., Conclusion: Static stretching of the masticatory muscles resulted in a minor increase in sleep bruxism episodes (not significant) and bursts (significant). It also led to a significant increase in MMO and PPT. Therefore, masticatory muscle stretching was not effective in reducing sleep bruxism in the absence of pain and/or dysfunction., (© 2018 John Wiley & Sons Ltd.)

Study Objectives: To evaluate the prevalence of probable sleep bruxism (SB) and its association with sleep features, orthodontic fixed appliance wearing, and extraoral and intraoral clinical signs and symptoms in a population of adolescents., Methods: Two hundred thirty-nine 12-year-old adolescents enrolled in private and public schools in Brumadinho, southeast Brazil, and their parents were invited to participate. They answered a questionnaire containing information regarding adolescents' sleep features and history of SB. Extraoral and intraoral examination was performed to identify some clinical signs (ie, absence of lip competence, presence of mouth breathing, clicks in the temporomandibular joint [TMJ], tooth wear) and symptoms (ie, pain in the masseter muscle upon palpation), and ongoing orthodontic treatment with fixed appliances. Parental report and clinical examination were used to determine probable SB. Descriptive statistics and logistic regression were performed to identify association of probable SB with independent variables., Results: Of 239 adolescents initially selected, 231 (96.6%) participated in the study. Prevalence of probable SB was 16.9%. Adolescents who snored during sleep (odds ratio [OR] = 3.14; 95% confidence interval [CI] = 1.47-6.70), adolescents who did not have clicks in the TMJ (OR = 3.37; 95% CI = 1.11-10.15), and those who wore orthodontic appliances (OR = 2.72; 95% CI = 1.04-7.14) were more likely to be in the group with probable SB., Conclusions: Snoring, absence of clicks in the TMJ, and fixed appliance wearing were associated with probable SB among adolescents. This study adds to the ongoing research on SB in adolescents and its associated factors., Commentary: A commentary on this article appears in this issue on page 1281., (© 2018 American Academy of Sleep Medicine.)

Study Objectives: To examine the presence of a first-night effect (FNE) and the level of internight variability in sleep bruxism (SB) activity when a self-applicable electrode set is used in home polysomnography (PSG) in a sample of subjects with possible SB., Methods: Fourteen females and two males aged 38.3 ± 9.1 years (mean ± standard deviation) with self-reported SB underwent home-PSG on three consecutive nights. The subjects applied PSG sensors themselves, including self-applicable electrode sets used to record sleep and masseter muscle activity. Repeated-measures analysis of variance was used to compare SB and sleep variables between the nights., Results: Surprisingly, there were statistically significant elevations in the rhythmic masticatory muscle activity (RMMA) episode index ( P = .009), burst index ( P = .016), and bruxism time index ( P = .049) throughout the course of 3 nights. More bruxers were diagnosed on the second (6 bruxers, ≥ 2 episodes/h) and third night (7 bruxers) compared to the first night (2 bruxers). Most subjects (14/16) had their highest RMMA index on the second or third night. The mean coefficient of variation for RMMA episode index was 50.7%. No statistically significant differences were detected in other sleep variables., Conclusions: The results indicate that a FNE may be present in SB activity, possibly lasting several nights in some subjects. Furthermore, FNE appears to be combined with high internight variability of SB activity without indications of internight changes in sleep macrostructure. To confirm the level of ongoing SB activity, several nights of PSG may be required, especially in subjects with low first-night SB activity., Commentary: A commentary on this article appears in this issue on page 1281., (© 2018 American Academy of Sleep Medicine.)

Rhythmic masticatory muscle activity can be a normal variant of oromotor activity, which can be exaggerated in patients with sleep bruxism. However, few studies have tested the possibility in naturally sleeping animals to study the neurophysiological mechanisms of rhythmic masticatory muscle activity. This study aimed to investigate the similarity of cortical, cardiac and electromyographic manifestations of rhythmic masticatory muscle activity occurring during non-rapid eye movement sleep between guinea pigs and human subjects. Polysomnographic recordings were made in 30 freely moving guinea pigs and in eight healthy human subjects. Burst cycle length, duration and activity of rhythmic masticatory muscle activity were compared with those for chewing. The time between R-waves in the electrocardiogram (RR interval) and electroencephalogram power spectrum were calculated to assess time-course changes in cardiac and cortical activities in relation to rhythmic masticatory muscle activity. In animals, in comparison with chewing, rhythmic masticatory muscle activity had a lower burst activity, longer burst duration and longer cycle length (P < 0.05), and greater variabilities were observed (P < 0.05). Rhythmic masticatory muscle activity occurring during non-rapid eye movement sleep [median (interquartile range): 5.2 (2.6-8.9) times per h] was preceded by a transient decrease in RR intervals, and was accompanied by a transient decrease in delta elelctroencephalogram power. In humans, masseter bursts of rhythmic masticatory muscle activity were characterized by a lower activity, longer duration and longer cycle length than those of chewing (P < 0.05). Rhythmic masticatory muscle activity during non-rapid eye movement sleep [1.4 (1.18-2.11) times per h] was preceded by a transient decrease in RR intervals and an increase in cortical activity. Rhythmic masticatory muscle activity in animals had common physiological components representing transient arousal-related rhythmic jaw motor activation in comparison to human subjects., (© 2017 European Sleep Research Society.)

Purpose: Concomitant occurrence of respiratory events can be often overlooked in the clinical practice of SB. This study assessed physiological characteristics of rhythmic masticatory muscle activity (RMMA) and concomitant respiratory events in young sleep bruxism (SB) subjects asymptomatic to obstructive sleep apnea (OSA)., Methods: Twenty-two subjects (age: 24.1±1.9years; F 8: M 14; BMI: 20.2±1.9kg/m 2 ) were polysomnographically diagnosed as moderate-severe SB. Sleep architecture, oromotor (RMMA and non-specific masseter activity [NSMA]) and apnea/hypopnea events were scored., Results: All subjects showed normal sleep architecture whereas 6 exhibited respiratory events at a mild level of OSA. In all subjects, RMMA predominantly occurred in Stage N1+N2 while NSMA occurred in Stage N1+N2 (approximately 60 %) and in Stage R (up to 30 %). Up to 50% of respiratory events were scored in Stage R. RMMA occurred more frequently in close association (e.g., within 10s) with respiratory events in 6 subjects with OSA than those without. The percentage of RMMA occurring closely to respiratory events was positively correlated with apnea-hypopnea index (AHI) in Stage N1+N2 only while that of NSMA was positively correlated with AHI in Stage N1+N2 and Stage R. A sub-analysis in 6 subjects with OSA, RMMA after respiratory events was followed to arousals while those before respiratory events were mostly associated with central apnea., Conclusions: A subpopulation of young SB subjects can show concomitant respiratory events. Further large sample studies are needed to demonstrate that the occurrence of subclinical respiratory events represents a clinical subtype of SB., (Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.)

The purpose of this study was to systematically review the literature for studies that investigated the association between use of psychotropic medications and presence of sleep bruxism (SB). Observational studies were selected in a two-phase process. Searches were performed on six electronic databases, and a grey literature search was conducted on three databases. SB diagnosis was based on questionnaires or clinical examinations; no polysomnography examinations were performed. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross-Sectional Studies. Overall quality of evidence was evaluated according to the Grading of Recommendations Assessment, Development and Evaluation criteria. Five analytical cross-sectional studies were included, evaluating antidepressants, anticonvulsants and psychostimulants. One study was judged as low risk of bias, three as moderate risk and one high risk. Antidepressants were evaluated in adult populations only; duloxetine (Odds Ratio [OR] = 2.16; 95% Confidence Interval [95% CI] = 1.12-4.17), paroxetine (OR = 3.63; 95% CI = 2.15-6.13) and venlafaxine (OR = 2.28; 95% CI = 1.34-3.86) were positively associated with SB risk. No increased odds of SB were observed considering use of citalopram, escitalopram, fluoxetine, mirtazapine and sertraline. With regard to anticonvulsants, only barbiturates were associated with SB in children (OR = 14.70; 95% CI = 1.85-116.90), while no increased odds were observed for benzodiazepine, carbamazepine and valproate. The only psychostimulant evaluated was methylphenidate, and an association with SB was observed in adolescents (OR = 1.67; 95% CI = 1.03-2.68). Findings from this SR suggested that medications such as duloxetine, paroxetine, venlafaxine, barbiturates and methylphenidate might be associated with SB; however, overall quality of evidence was considered very low, and therefore, caution is recommended., (© 2018 John Wiley & Sons Ltd.)

This study updates the review published by Wang et al in 2014 (Sleep Breath 2014;18(2):235-242). The review focuses on the most recent literature on management of sleep bruxism (SB) with biofeedback. An electronic search was conducted in five databases searching for articles published later than the date of Wang et al's search, viz., October 2012. Six articles of 2320 identified citations involving 86 adult participants were included in the qualitative synthesis. Of them, 4 were randomised controlled trials (RCTs) and 2 were uncontrolled before-after studies. Different feedback modalities (electrical, auditory and vibratory stimulus) were investigated. The overall quality of the selected studies was assessed using the GRADE criteria. Due to heterogeneity between studies, the quantitative synthesis was performed out of three RCTs, of which two were retrieved from the previous review. The meta-analysis indicated a non-significant difference in electromyographic-measured SB episodes per hour after one night of contingent electrical stimulation (CES) compared with placebo control, yet a significant difference was shown after five nights of CES. The quality of evidence identified through GRADEpro was from low to moderate, due to imprecision and inconsistency between studies. Qualitative synthesis did not present a reliable reduction in clinical pain levels; however, no substantial sleep disturbances were indicated following the intervention. In conclusion, one of the biofeedback modalities, CES, is effective in reducing SB-related motor activities after a short-term treatment period. However, evidence of long-term effects is lacking. Further longitudinal studies with larger samples are necessary to acknowledge the clinical application of biofeedback., (© 2018 John Wiley & Sons Ltd.)

Purpose: To evaluate the effects of sleeping with or without a maxillary mucosa-supported complete denture (CD) in edentulous patients wearing a mandibular fixed implant-supported CD on sleep quality, sleep bruxism (SB) activity, and signs of obstructive sleep apnea syndrome (OSAS)., Materials and Methods: A total of 18 female patients with maxillary mucosa-supported CDs opposing mandibular fixed implant-supported CDs were selected and tested for sleep quality, SB activity, and signs of OSAS during one night while wearing the maxillary CD and another night without wearing it, with a washout period of 7 days in between. The validated Brazilian Portuguese versions of the Pittsburgh Sleep Quality Index (PSQI-BR), Sleep Assessment Questionnaire (SAQ), and Epworth Sleepiness Scale (ESSBR) were used to assess subjective sleep quality. Diagnosis of OSAS followed the American Academy of Sleep Medicine (AASM) guidelines and was confirmed with an objective and validated type 3 portable cardiorespiratory monitor (ApneaLink Plus v.9.00) by measuring the respiratory disturbance index (RDI). SB activity was assessed with a subjective self-report questionnaire and an objective and validated portable electromyographic device (BiteStrip)., Results: The objective measurements of SB activity and the RDI showed significant reduction (ie, improvement) when patients did not wear the maxillary CD. The subjective measurements of sleep quality and self-reports of SB activity showed no significant differences between wearing and not wearing a maxillary CD., Conclusion: The present results have shown that not wearing a maxillary CD at night is preferable as far as SB and OSAS are concerned, but larger-scale studies are still needed.

Sleep bruxism (SB) in children has been associated with several sleep characteristics, which may alter their sleep pattern. This change affects the internal biological clock and consequently the chronotype profile. The aim of this study was to evaluate the existence of an association between possible SB in children with specific chronotype profiles and sleep characteristics. The study included 207 parents/guardians of children aged between 3 and 12 years who were waiting for their children's dental treatment at the Pediatric Dentistry Clinic of the Federal University of Rio de Janeiro, Brazil. A questionnaire on the socio-demographic characteristics of parents and children as well as on the features of the children's sleep was applied. In addition, the CIRENS scale (Circadian Energy Scale) was completed by the parents to identify the children's chronotype. A chi-squared test was used to determine the association between possible SB, the chronotype, and sleep characteristics. A multiple logistic regression model was implemented to observe the influence of chronotype, age, and other independent variables on the possible SB. The logistic regression model demonstrated that nocturnal agitation (p = 0.009; OR = 3.42) and nightmares (p = 0.045; OR = 3.24) were associated with possible SB in children. Although no significant association (p = 0 .089) between the chronotype profile and possible SB was observed in the 3 to 5 years age group, a proportional difference was observed between the chronotype categories in this age group-12.5% of children with SB had a morning type, while 26.4% had an intermediate type and 47.8% an evening type compared to those without possible SB. Nocturnal agitation and nightmares were associated with possible SB. In addition, young children with an evening chronotype had a tendency toward possible SB.

Objective: Bruxism-induced mechanical load causes various dental problems, and its treatment is challenging. The present study analyzed upper and lower tooth contacts to determine actual occlusal contact during sleep bruxism., Methods: Tooth contact patterns were analyzed in 49 patients attending dental clinics, using a Bruxchecker®, cephalograms, and condylographs., Results: Approximately 80% of individuals demonstrated contact from the anterior teeth to the molar region (ICPM); about 96% had mediotrusive grinding and contact. The tooth contact area increased with the flatness of the anterior occlusal plane. The ratio of the contact area of the anterior teeth to the overall tooth contact area increased with overbite. Bilateral ICPM and mediotrusive contact patterns were associated with a high frequency of temporomandibular disorder symptoms, clicking, and/or pain., Discussion: The tooth contact area, anterior occlusal plane, and overbite are closely related, suggesting that tooth contact with the anterior teeth should be controlled with occlusal therapy.

Background: One of the widespread problems of oral health is bruxism and is defined as a parafunctional habit with involuntary grinding and gnashing of the teeth occurring during sleep. However, bruxism is connected to anxiety and stress, but the published literature on bruxism among prison inmates is scanty. Objective: The objective of the study was to determine the prevalence of active sleep bruxism and its impact on oral health-related quality of life (OHRQoL) among inmates in Central Penal Institution, Mysore., Materials and Methods: The study was cross sectional and conducted among eligible male inmates at Central Penal Institution, Mysore. The information on active sleep bruxism and OHRQoL was collected using a predesigned structured questionnaire by means of personal interview by a trained investigator. The active sleep bruxism was assessed using the criteria of American Academy of Sleep Medicine and OHRQoL through modified oral health impact profile (OHIP-14). The data analysis was done using descriptive statistics, Chi-square test, t-test, analysis of variance, and linear regression model., Results: A total of 212 male inmates aged between 18 and 80 years were considered for the study. The prevalence of active sleep bruxism among the study population was 31.6%. The mean OHIP-14 score was significantly higher (P < 0.001) among the inmates having active sleep bruxism (38.52 ± 12.8) suggesting a high oral health impact as compared to inmates without this disorder (31.67 ± 12)., Conclusion: The prevalence of active sleep bruxism was higher among the inmates of penal institution as compared to the general population. The active sleep bruxism had a negative impact on OHRQoL., Competing Interests: There are no conflicts of interest

Purpose: To provide a scientific data related to the tonic activity of masseter muscle in subjects with and without history of orofacial pain during their normal daily life., Methods: Thirty-three subjects were divided into two groups, a pain history group (PHG) and a non-pain history group (non-PHG), based on their responses to the Research Diagnostic Criteria for Temporomandibular Disorders questionnaire. After excluding four subjects with incomplete recordings, full-day masseter muscle surface EMGs of 29 subjects (10 men, 19 women; mean age 24.1 years) were analyzed. Tonic episode (TE) was defined as continuous EMG activity with a duration at least 2s with intensities above twice the baseline noise level. TEs were classified into 6 strength categories (<7.5%, 7.5-10%, 10-15%, 15-25%, 25-40% and >40% of the maximum voluntary clenching (MVC)). The mean duration of activity observed in the non-PHG+2 SD was adopted as a cutoff for identifying sustained TE., Results: During waking hours, the incidence of sustained TEs was significantly higher in the PHG than in the non-PHG (p<0.05). The incidence and total duration of sustained TEs were significantly higher in the PHG than in the non-PHG at intensities of 7.5-10% MVC, 10-15% MVC, and 15-25% MVC (p<0.05). No significant difference was observed during sleep., Conclusions: Within the limitations of this study, it would be concluded that sustained TEs may have a correlation with orofacial pain and the intensity range of 7.5-25% MVC would be an important range for future clenching studies., (Copyright © 2017. Published by Elsevier Ltd.)

The possible effects on sleep bruxism (SB) of clear aligners in orthodontics are unknown. This study was conducted to analyze the effects of clear aligners on SB. Sixty subjects needing orthodontic treatment and affected by SB (33 m, 27 f, 20±;5 years) were enrolled in the study and randomly assigned to one of the following three groups: 20 were given clear aligners (CAT) (12 m, 8 f, 19±5 years), 20 occlusal splint (MOS) (9 m, 11 f, 22±5 years) and 20 a placebo splint (PMS) (12 m, 8 f, 24±3 years). All groups were followed for 6 consecutive months and monitored for SB with a portable electromyographic-electrocardiographic (EMG-ECG) device (Bruxoff®, OT Bioelettronica, Torino, Italy). MOS subjects reduced masseter contractions after 6 months of treatment (t3) (MD=-29.11, std. error 11.74, p=0.017) but increased phasic contractions related to SB after 3 months of treatment (t2) (MD=4.73, std. error 2.36, p=0.048) and tonic contractions related to SB during all the six months of treatment (t1, t2, t3) when compared to PMS. CAT subjects increased phasic contractions related to SB during the first (t1) (MD=3.94, std. error 2.27, p=0.04) and the third month (t2) of treatment (MD=4.62, std. error 2.36, p=0.046) when compared to PMS. No significant differences were found for SB index at any time for all the three groups. Although MOS and CAT affected EMG signals during sleep time differently, they did not influence the overall SB index.

Objectives: To confirm the relationship between sleep bruxism (SB) and autonomic nervous (AN) activities to elucidate SB physiology., Methods: Subjects included 11 healthy males (mean age, 24.7 ± 2.3 years). These data were recorded in the sleep laboratory using a system composed of a two-axis accelerometer, an infrared camera, electroencephalography, electromyography, and electrocardiography. Time lapse analysis confirmed correlations between AN activity and SB events during sleep in subjects. Relationships between SB strength and length and AN activity were evaluated., Results: Sympathetic nerve (SN) and parasympathetic nerve (PSN) activities occurred significantly in 93.3% of cases (p < 0.01), with similar predictable patterns during SB. Furthermore, SB length and SN activity in seven of the subjects (four subjects, p < 0.05; three subjects p < 0.01), and PSN and SB muscle activities (% maximum voluntary contraction) in five subjects (four subjects, p < 0.05; one subject, p < 0.01) were significantly correlated., Discussion: The authors believe that SB is closely related to SN as well as PSN activities and may control the AN system.

The aim of the present study was to evaluate factors associated with sleep bruxism in five-year-old preschool children. A preschool-based cross-sectional study was conducted with 761 pairs of children and their parents/caregivers. Sleep bruxism was diagnosed using a questionnaire administered to the parents/caregivers, who also answered questionnaires addressing sociodemographic data and parent's/caregiver's sense of coherence. Clinical oral evaluations of the children to determine dental caries, traumatic dental injuries, malocclusion and tooth wear were performed by two researchers who had undergone a training exercise (interexaminer Kappa: 0.70 to 0.91; intraexaminer Kappa: 0.81 to 1.00). Descriptive analysis and logistic regression for complex samples were carried out (α = 5%). The prevalence of sleep bruxism among the preschool children was 26.9%. The multivariate analysis revealed that bruxism was associated with poor sleep quality (OR = 2.93; 95 CI: 1.52-5.65) and tooth wear (OR = 2.34; 95%CI: 1.39-3.96). In the present study, sleep bruxism among preschool children was associated with tooth wear and poor sleep quality of the child. In contrast, psychosocial aspects (sense of coherence) were not associated with sleep bruxism.

Sleep bruxism (SB) and psychological stress are commonly considered as contributing factors in the aetiology of temporomandibular disorder (TMD) pain. However, the lack of longitudinal studies and fluctuating nature of SB, psychological stress and TMD pain have led to contradictory results regarding the association between the possible aetiological factors and TMD pain. In the present study we investigated the contribution of SB and psychological stress to TMD pain in a longitudinal study of 2 clinical TMD pain cases during a 6-week study protocol. Two female volunteers with clinically diagnosed myalgia based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) participated in the study. Questionnaires were used to record jaw-muscle pain and psychological stress experience, and an ambulatory polysomnography technique was used to record SB intensity. Visual analysis of the data revealed that the intensity of TMD pain was not hardwired, neither with psychological stress experience nor with increased SB activity. Within the limitations of single-patient clinical cases design, our study suggested that the presence of TMD pain cannot be explained by a simple linear model which takes psychological stress or SB into account. It also seems that psychological stress was a more important predictor factor for TMD pain than SB., (© 2017 John Wiley & Sons Ltd.)

Currently, definite diagnosis of sleep bruxism requires polysomnography. However, it is restrictedly available, and too cumbersome and expensive for the purpose. The aim of this study was to introduce an ambulatory electrode set and evaluate its feasibility for more cost-effective diagnostics of sleep bruxism. Six self-assessed bruxers (one male, five females; aged 21-58 years) and six healthy controls (four males, two females, aged 21-25 years) underwent a standard polysomnographic study and a concurrent study with the ambulatory electrode set. Bruxism events, cortical arousals and sleep stages were scored for the two montages separately in a random order, and obtained sleep parameters were compared. In addition, the significance of video recording and sleep stage scoring for the diagnostic accuracy of ambulatory electrode set was determined. Ambulatory electrode set yielded similar diagnoses as standard polysomnography in all subjects. However, compared with standard polysomnography the median (interquartile range) tonic bruxism event index was significantly higher in the control group [+0.38 (+0.08 to +0.56) events per hour, P = 0.046], and the phasic bruxism event index was significantly lower in the bruxer group [-0.44 (-1.30 to +0.07) events per hour, P = 0.046]. Exclusion of video recording and both video recording and sleep stage scoring from analysis increased overestimation of the tonic bruxism event index in the control group +0.86 (+0.42 to +1.03) and +1.19 (+0.55 to +1.39) events per hour, P = 0.046 and P = 0.028, respectively], resulting in one misdiagnosed control subject. To conclude, ambulatory electrode set is a sensitive method for ambulatory diagnostics of sleep bruxism, and video recording and sleep stage scoring help reaching the highest specificity of sleep bruxism diagnostics., (© 2017 European Sleep Research Society.)

The review focuses on the last decade of research regarding the use of various oral appliances (OAs) in the management of sleep bruxism (SB) in adults. Sixteen (n = 16) papers of 641 identified citations involving 398 participants were included in the review. Of them, seven were randomised controlled trials (RCTs), seven were uncontrolled before-after studies and two were crossover trials. Analysis of the included articles revealed a high variability of study designs and findings. Generally, the risk of bias was low-to-unclear for RCTs and high for crossover studies, whilst the before-after studies exhibited several structural limitations. Nine studies used polysomnography/polygraphy/electromyography for SB diagnosis, whilst others were based on history taking and clinical examination. Most of them featured small samples and were short term. Of the studies using objective SB evaluations, eight showed positive results for almost every type of OA in reducing SB activity, with a higher decrease for devices that are designed to provide a certain extent of mandibular advancement. Among the studies using a subjective SB evaluation, one demonstrated a significant reduction in SB activity, and additional two showed a myorelaxant effect of OA in SB patients. Although many positive studies support the efficiency of OA treatment for SB, accepted evidence is insufficient to support its role in the long-term reduction of SB activity. Further studies with larger samples and sufficient treatment periods are needed to obtain more acknowledgements for clinical application., (© 2017 John Wiley & Sons Ltd.)

Background: Polysomnography (PSG) is the gold standard for sleep bruxism (SB) assessment. High economical costs, complex technical equipment, and unfamiliar laboratory setting limit its use in children., Aim: To determine the night-to-night variability of electromyography (EMG) episodes during a five-night recording with the GrindCare Measure (GCM), and the agreement in the assessment of masticatory muscle activity (MMA) between GCM and PSG in children., Design: Forty-seven children from clinics of Universidad CES participated. Each participant was assessed with GCM for five consecutive nights. The last night, children underwent a single-night PSG study, together with the GCM. Spearman correlation coefficients were used to analyze data., Results: The frequency of SB occurrence was 'sometimes' in 12 (25.5%) and 'usually' in 19 (40.4%) children. Simultaneous measurements with GCM and PSG obtained during the fifth night of measurement were not significantly correlated. Correlation between GCM total EMG episodes and EMG episodes/h and PSG total SB episodes, SB episodes/h, total bursts and burst/h measured with PSG was also not significant., Conclusion: EMG measurement with GCM was not accurate to detect PSG/SB in children. There was not advantage of multiple assessment for five nights with GCM, reducing the impact of night-to-night EMG episodes' variability on the GCM/PSG correlation., (© 2017 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Clinical and radiographic characteristics of a subset of South East Asian temporomandibular disorder (TMD) patients with comorbid upper airway resistance syndrome (UARS) were documented in a multi-center prospective series of 86 patients (26 men and 60 women / mean age 35.7 years). All had excessive daytime sleepiness, high arousal index and Apnoea-Hypopnoea Index (AHI) <5. The mean body mass index was 20·1, mean arousal index 16·2, mean respiratory disturbance index 19·6, mean AHI 3·9 while the mean Epworth Sleepiness Scale was 14·8. Many had functional somatic complaints; 66·3% headaches, 41·9% neck aches, 53·5% masticatory muscle myalgia, 68·6% temporomandibular joint (TMJ) arthralgia while 90·7% reported sleep bruxism (SB). Unlike patients with obstructive sleep apnoea (OSA), hypertension was uncommon (4·7%) while depression was prevalent at 68·6% with short REM latency of <90 min and an increased REM composition >25% documented in 79·6% and 57·6% of these depressed patients, respectively. 65·1% displayed a posteriorly displaced condyle at maximum intercuspation with or without TMJ clicking. Most exhibited a forward head posture (FHP) characterised by loss of normal cervical lordosis (80·2%), C0-C1 narrowing (38·4%) or an elevated hyoid position (50%), and 91·9% had nasal congestion. We postulate the TMD-UARS phenotype may have originally developed as an adaptive response to 'awake' disordered breathing during growth. Patients with persistent TMD and/or reporting SB should be screened for UARS and chronic nasal obstruction, especially when they also present with FHP. The lateral cephalogram is a useful tool in the differentiation of UARS from other OSA phenotypes., (© 2017 John Wiley & Sons Ltd.)

Background: An increasing number of studies have indicated that the central and autonomic nervous systems play roles in the genesis of sleep bruxism (SB). The role of specific neurochemicals in SB has been a subject of interest., Objective: In this study, we use proton magnetic resonance spectroscopy ( 1 H-MRS) to determine whether the levels of γ-aminobutyric acid (GABA) and glutamate (Glu) are different in the brainstem and bilateral cortical masticatory area (CMA) between possible sleep bruxism (SB) patients and controls, and discuss whether the brainstem or cortical networks which may affect the central masticatory pathways are under the genesis of SB., Methods: Twelve possible SB patients and twelve age- and gender-matched controls underwent 1 H-MRS using the "MEGA-Point Resolved Spectroscopy Sequence" (MEGA-PRESS) technique in the brainstem and bilateral CMA. Proton magnetic resonance spectroscopy data were processed using LCModel. Because the signal detected by MEGA-PRESS includes contributions from GABA, macromolecules (primarily proteins) and homocarnosine, the GABA signal is referred to as "GABA+". The glutamate complex (Glx) signal contains both glutamate (Glu) and glutamine (Gln), which mainly reflect glutamatergic metabolism., Results: Edited spectra were successfully obtained from the bilateral CMA in all subjects. There were no significant differences in neurochemical levels between the left and right CMA in possible SB patients and controls. In the brainstem, significantly lower GABA+ levels were found in possible SB patients than in controls (P = .011), whereas there was no significant difference (P = .307) in Glx levels between the 2 groups., Conclusions: SB patients may possess abnormalities in the GABAergic system of brainstem networks., (© 2017 John Wiley & Sons Ltd.)

Purpose: The aim of this article was to assess the sleep behaviors that serve as risk factors related to bruxism in children ages 0 to 12 years by performing a systematic review and meta-analysis of published studies., Methods: Seven databases were searched to identify all peer-reviewed articles potentially relevant to the review. Data were pooled for random-effects modeling. Sleep risk factors related to bruxism in this age group are summarized using pooled odds ratios (ORs), 95% confidence intervals (CIs), and P values., Results: Of 5637 initially identified articles, 14 met inclusion criteria. Study qualities of all case-control studies were high. Quality of cross-sectional studies was more variable. The pooled ORs, 95% CIs, and P values were as follows: snoring (2.86, 1.85-4.42, <0.0001), mouth breathing (1.51, 1.04-2.18, 0.029), restless sleep (2.31, 1.89-2.83, <0.0001), drooling (1.79, 1.07-2.97, 0.026), stomach position during sleep (1.70, 1.0-2.39, 0.003), and inadequate sleep time (2.56, 1.48-4.43, 0.001)., Conclusions: Snoring, mouth breathing, restless sleep, drooling, stomach position during sleep, and lack of sleep were the risk factors related to bruxism in children.