Sleep Bruxism Group Research Articles

Is sleep bruxism in obstructive sleep apnea only an oral health related problem?

BackgroundThe 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.Methods106 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.ResultsOSA 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.ConclusionIncreased 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 registrationThe 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).

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

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 withOSA patients regarding the effect of optimal positive airway pressure (PAP). 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. 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 5s 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. Among 100 patients enrolled, mean age was 50.8 ± 16.7yearsand 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 SBand 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 ofnocturnal 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 endorsementofnocturnal 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 ofnocturnal 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). 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.

Salivary signatures of oral-brain communication in sleep bruxers.

Microbiota and their interaction with hosts have been of great interest in brain research in recent years. However, the role of oral microbiota in mental illness and the underlying mechanism of oral-brain communication remains elusive. Sleep bruxism (SB) is an oral parafunctional activity related to the nervous system and is considered a risk factor for harmful clinical consequences and severe systemic conditions. Exploring the connection between oral microbiota and sleep bruxism may deepen our understanding of the complex relationship between oral-brain axis and provide insights for treatment. In this study, salivary samples were collected from 22 individuals with SB and 21 healthy controls, and metagenomics with metabolomics was performed. Nonparametric Wilcoxon test were applied for the statistical analysis between the two groups. Microbial dysbiosis and altered oral metabolites were found in the SB individuals. The characteristic metabolite N-acetylglucosamine (GlcNAc) (VIP=8.4823, P<0.05) was correlated to a statistically lower Streptococcus mitis level in SB individuals. Salivary IFN-g level and IFN-g/IL-4 ratio were detected with significant changes in a chip assay. Amino acid metabolism pathways were upregulated, and the pathway with the largest number of differentially expressed genes is related to amino-tRNA charging pathway, while the most significantly enriched pathway is related to arginine biosynthesis. Neurotransmitter-associated pathways with glutamatergic and GABAergic synapses and cardiovascular system-related pathways were enriched in the SB group. These results indicate a possible neuroimmune regulatory network of oral-brain communication in SB, which helps explain the mechanism of the oral microbiome with the host in sleep bruxers and provides a reference for early clinical and therapeutic intervention to improve the diagnosis and treatment of SB and similar diseases.

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

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

Investigation of the relationship between probable sleep bruxism, awake bruxism and temporomandibular disorders using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD).

The causal relationship between bruxism and temporomandibular disorders (TMD) is not clear. The present study investigated which TMD are associated with probable sleep bruxism (SB) and awake bruxism (AB) according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). The study further evaluated the association between probable SB and AB and TMD. A total of 143 patients were selected - bruxers (SB and AB) and non-bruxers. A diagnosis of probable bruxism was made after a physical examination and when the symptoms were detected. The patients were evaluated using DC/TMD. From among Axis I assessment instruments, the TMD Pain Screener, the Symptom Questionnaire and the Clinical Examination Form were used. Moreover, the Graded Chronic Pain Scale (GCPS) (v. 2), the Jaw Functional Limitation Scale-8 (JFLS-8), the Patient Health Questionnaire-4 (PHQ-4), and the Oral Behaviors Checklist (OBC) were applied within the scope of Axis II. Diagnoses of muscle disorders and disk displacement with reduction were significantly more frequent in the SB and AB groups than in non-bruxers. A diagnosis of arthralgia was significantly more prevalent in the AB group than in non-bruxers. The JFLS-8 scores and the TMD Pain Screener scores were higher in the AB group than in the SB group and in non-bruxers. Distress levels, and the GCPS and OBC scores were higher in the SB and AB groups as compared to non-bruxers. The results of binary logistic regression analysis showed that only the OBC score was significantly higher in the TMD subgroup (OR (odds ratio) = 1.228; 95% CI (confidence interval): 1.014-1.488). Both SB and AB were associated with pain-related TMD and intra-articular joint disorders. The muscle disorders and disk displacement with reduction subtypes were associated with SB and AB. Unlike SB, AB was also associated with arthralgia. Bruxers (both SB and AB) displayed parafunctional habits. However, AB was associated with greater functional limitation of the jaw as compared to SB.

Ceramic Crowns and Sleep Bruxism: First Results from a Randomized Trial.

Background: This randomized clinical trial was conducted to assess whether sleep bruxism (SB) is associated with an increased rate of technical complications (ceramic defects) in lithium disilicate (LiDi) or zirconia (Z) molar single crowns (SCs). Methods: Adult patients were classified as affected or unaffected by SB based on structured questionnaires, clinical signs, and overnight portable electromyography (BruxOff) and block randomized into four groups according to SB status and crown material (LiDi or Z): LiDi-SB (n = 29), LiDi-no SB (n = 24), Z-SB (n = 23), and Z-no SB (n = 27). Differences in technical complications (main outcome) and survival and success rates (secondary outcomes) one year after crown cementation were assessed using Fisher’s exact test with significance level α = 0.05. Results: No technical complications occurred. Restoration survival rates were 100% in the LiDi-SB and LiDi-no SB groups, 95.7% in the Z-SB group, and 96.3% in the Z-no SB group (p > 0.999). Success rates were 96.6% in the LiDi-SB group, 95.8% in the LiDi-no SB group (p > 0.999), 91.3% in the Z-SB group, and 96.3% in the Z-no SB group (p ≥ 0.588). Conclusions: With a limited observation time and sample size, no effect of SB on technical complication, survival, and success rates of molar LiDi and Z SCs was detected.

Relationship between Oral Parafunctional and Postural Habits and the Symptoms of Temporomandibular Disorders: A Survey-Based Cross-Sectional Cohort Study Using Propensity Score Matching Analysis.

Temporomandibular disorders (TMDs) are a multifactorial joint disease of the masticatory system. The possible etiological factors involved in the onset and progression of TMDs include oral parafunctional habits (OPFHs) and postural habits (PHs). However, little information is available on the association between OPFHs and PHs and a predisposition to TMDs. Thus, to investigate whether the presence of OPFH and PH predisposes individuals to TMDs, a survey-based cross-sectional cohort study of self-reported TMD was performed. A total of 2292 patients with TMD were recruited for the survey. Through one-to-one propensity score matching, 166 patients with and without sleep bruxism (SB) were selected. The SB group had a significantly higher risk of masticatory muscular pain or fatigue than the non-SB group (p = 0.018). Furthermore, the SB group without other OFPHs and PHs did not show a significantly higher risk of TMD symptoms than the non-SB group. Diurnal clenching and bad posture also affect the stomatognathic system, causing pain or fatigue; however, it did not result in TMDs in patients without any OPFHs and PHs. This implies that OPFHs and PHs may increase the risk of TMD symptoms in coexistence with other habits.

Evaluation of mandibular trabecular bone by fractal analysis on panoramic radiograph in paediatric patients with sleep bruxism.

To evaluate the trabecular bone density in the mandible of paediatric patients diagnosed with sleep bruxism (SB) using the fractal analysis method on panoramic radiographs. A total of 37 patients whose anamnesis and clinical signs were compatible with SB were diagnosed with SB using BiteStrip® . Three areas were identified on the panoramic radiographs of the patients: the geometric center of the condyle, the angulus region under the mandibular canal, and the distal region of the mental foramen. Regions of interest (ROIs) of 60×60pixels were selected in these three locations, and fractal dimensions (FDs) were calculated. Results were compared with the control group. There was no statistically significant difference between the right and left FD values, and male and female FD values in all regions and both groups (p>.05). In the angulus (p=.03) and condyle (p=.03) regions, the SB group had a significantly higher FD value than the control group. There was no statistically significant difference between the SB and control groups in the corpus region (p=.98). A moderate negative correlation arose between age and condyle FD values among controls (r=-0.38, p=.02). Fractal dimension values evaluating trabeculation of the mandibular bone are affected by SB in the angulus and condyle regions.

Polysomnographic characteristics of sleep-related bruxism: What are the determinant factors for temporomandibular disorders?

ABSTRACT This study aimed to evaluate the clinical and polysomnographic characteristics of sleep bruxism (SB) and delineate the determinant factors for temporomandibular disorders (TMD). Forty-six patients were allocated into the SB group (n = 26) and control group (n = 20). The signs and symptoms of TMD were recorded using the Research Diagnostic Criteria for TMD. Patients underwent a full-night polysomnographic recording and masseter and temporal muscle electromyographic recordings. Clinical and polysomnographic data in patients with SB were analyzed in relation to TMD. The presence of TMJ sounds was significantly correlated with the number of bruxism bursts. Intra-articular pain in the TMJ was neither correlated with clinical nor polysomnographic parameters in patients with SB. Lower sleep efficiency in patients with SB was caused by a higher number of bruxism episodes. Morning headaches were associated with the severity of SB during rapid eye movement sleep.

When should sleep bruxism be considered in the diagnosis of temporomandibular disorders?

Both temporomandibular disorders (TMDs) and sleep bruxism (SB) are known to be destructive to the masticatory system. However, the association between the 2 conditions is poorly understood. The aim of our study was to assess the relationship between TMD and SB through the signs and symptoms in 2 patient groups: TMD only and TMD with SB. A retrospective chart review was conducted from November 1, 2015, to April 1, 2018, on patients with completed International Network for Orofacial Pain and Related Disorders Methodology history questionnaires and Diagnostic Criteria for Temporomandibular Disorder clinical examinations. Fifty-two patients, including 12 with TMD only and 40 with TMD with SB, met the study criteria. Subjective descriptions and objective measurements of patient symptoms were investigated. The χ2 test and Fisher's exact test were used for statistical analysis. The TMD with SB group exhibited increased oral behaviors compared with the TMD-only group (P=.0004). The TMD with SB group also experienced more headaches compared with the TMD-only group (P=.045). Our results revealed that patients with jaw pain who self-report increased oral behaviors and/or exhibit temporal headaches should be evaluated for sleep bruxism.

First night effect on polysomnographic sleep bruxism diagnosis varies among young subjects with different degrees of rhythmic masticatory muscle activity

ObjectiveThis study investigated the first night effect on the polysomnographic diagnosis of sleep bruxism (SB). MethodsPolysomnographic recordings were performed for two consecutive nights in forty-three subjects (mean age 23.7 ± 0.32 years [range: 20.0–33.0]). Sleep variables and rhythmic masticatory muscle activity (RMMA) were scored for two nights. The diagnosis of SB was graded by the frequency of RMMA with cut-off values of two and four times per hour of sleep. ResultsParticipants were classified into control (n = 15), low (n = 13) and moderate-high (n = 15) groups. Among the three groups, the concordance of the SB diagnosis was compared between the two nights. Sleep variables showed a significant first-night effect with lower sleep efficiency, longer sleep latency and higher frequency of arousals. The frequency of RMMA significantly increased from the first to the second night in the moderate-high SB group only. The concordance rate of the severity between the two nights was 93.3% (14/15) in the control group, 76.9% (10/13) in the low SB group and 60% (9/15) in the moderate-high SB group. When the severity was determined on the first night, it remained the same on the second night in 77.8% (14/18) of the control group, 66.7% (10/15) of the low SB group and 90.0% (9/10) of the moderate-high SB group. ConclusionThe results showed that the first night effect on the occurrence of RMMA differed among the different degrees of the RMMA frequency, and suggest that, due to the first night effect, single-night polysomnography may underestimate the moderate-high level of SB but differentiate the low level of SB from controls.

Impact of Sleep Bruxism on Oral Health-Related Quality of Life.

To determine the prevalence of possible tooth grinding (TG) and possible sleep bruxism (SB) and to examine their impacts on oral health-related quality of life (OHRQoL) among Asian adults. A total of 3,072 subjects (18 to 65 years of age) from 12 dental centers were invited to complete a self-administered questionnaire on TG/SB and OHRQoL, and 2,417 were included in the study. Participants were subsequently categorized into three groups (no TG/SB, possible TG, and possible SB) based on the International Classification of Sleep Disorders. The 14-item Oral Health Impact Profile (OHIP-14) severity, extent, and prevalence scores were subsequently computed and compared. Data were examined using Kruskal-Wallis and Mann-Whitney U tests, Spearman correlation, and univariate regression analysis (P < .05). Of the 2,417 subjects (mean age 24.79 ± 7.49 years), 42.82% reported either possible TG (n = 921; 38.11%) or possible SB (n = 114; 4.72%). Significant differences in global and domain OHIP-14 scores were found between the groups, except for the extent scores in functional limitation and physical disability. Mean global severity scores of the possible SB group (9.36 ± 9.45) were 1.5- and 2.2-fold larger than the possible TG (6.39 ± 7.61) and no TG/SB (4.22 ± 6.15) groups, respectively. A significant but weak correlation (r = 0.14 to 0.19) was found between the number of positive responses for TG/SB and OHIP-14 severity scores. A high prevalence of possible TG and SB was found among the Asian cohort studied. Possible TG and SB were significantly associated with poorer OHRQoL. The physical pain, psychologic discomfort, and psychologic disability domains were most influenced by TG/SB. More epidemiologic studies on the functional, physical, and psychosocial influences of SB are required.

Severity of Sleep Bruxism and its Implications for the Stomatognathic System in Healthy Subjects

BACKGROUND: Sleep bruxism (SB) changes the functionality patterns of the stomatognathic system. However, its severity can be an aggravating factor in the function of this complex system.&#x0D; AIM: The purpose of the study was to investigate the stomatognathic system of healthy subjects with different severity of SB, as determined by BiteStrip.&#x0D; METHODS: Thirty-four subjects were divided into two groups: Mild SB (n = 15) and severe SB (n = 19). Electromyograph was used to evaluate the electromyographic activity of the right masseter (RM), left masseter (LM), right temporal (RT), and left temporal (LT) muscles at mandibular rest, right and left laterality, protrusion, and maximum voluntary contraction. Molar bite force was measured by the dynamometer. The data were tabulated and submitted for statistical analysis (p &lt; 0.05).&#x0D; RESULTS: Molar bite force was significantly lower in the severe SB group. There was a significant increase in electromyographic activity in the severe SB group for the mandibular rest tasks (RM, RT, and LT), protrusion (RM, LM, RT, and LT), and right and left laterality in the temporalis muscles. There was a significant decrease in electromyographic activity in the severe SB group in maximum voluntary contraction for the masseter and temporalis muscles.&#x0D; CONCLUSION: Subjects with severe SB demonstrated greater functional impairment of the stomatognathic system, mainly affecting the electromyographic activity and molar bite force.

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

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

Sleep stage dynamics in young patients with sleep bruxism.

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). 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. 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. 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.

Impact of sleep bruxism on training-induced cortical plasticity

PurposeTo investigate if sleep bruxism (SB) influences training-induced cortical plasticity and performance in terms of accuracy and precision of a tooth-clenching task (TCT). MethodsThirty-eight participants were allocated into SB group (N=19) and control group (N=19) according to presence of SB based on a 2-week screening. The participants were instructed to perform a standardized TCT for 58min at three different force levels (10%, 20% and 40% of maximum voluntary contraction; MVC) in three series (first and third without visual-feedback and second with visual-feedback). Accuracy and precision of the TCT were calculated from actual bite force values. Transcranial magnetic stimulation was applied to elicit motor evoked potentials (MEPs) from the masseter and first dorsal interosseous muscle (FDI) before the TCT (pre-TCT-session) and 5-min after the TCT (post-TCT-session). ResultsAccuracy was significantly dependent on the series and target force level (P<0.001), however, there was a significant decrease only in the control group at 10% MVC from first to third session (P<0.001). No significant differences between groups were observed for the precision of the TCT. Masseter MEPs in the SB group in the pre-TCT-session at 120% and 160% motor threshold were significantly lower than in the control group (P<0.05). Masseter MEPs of the control group in the post-TCT-session were significantly higher than the pre-TCT-session (P<0.05) but not SB. FDI MEPs were only dependent on stimulus intensity (P<0.001). ConclusionsSB is associated with significant changes not only in excitability of corticomotor control but also motor learning of jaw movements and force control.

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

Background The literature does not report any association between habitual snoring and sleep bruxism, but these situations can be a reason for frequent complaints of individuals, impairing the quality of life. This study was performed to investigate the sleep period and amount of habitual snoring in individuals with sleep bruxism observing expiratory, inspiratory, and mixed snoring. Material and Methods A total of 90 individuals were screened and divided into the following groups: with sleep bruxism (n=45) and those without sleep bruxism (n=45). Single night sleep polysomnography was performed to diagnose sleep bruxism, quantify habitual snoring and sleep period. The results were tabulated and submitted to a Multivariate analysis of variance (MANOVA) to compare the means of the two independent groups, considering the affected diagnosis of sleep bruxism, snoring (independent variables) and age as covariate. For the post hoc, was used correcting for multiple comparisons (Bonferroni test, P <.05). Results There was statistically significant difference among the groups ( p =.001) in the sleep period, in that individuals with sleep bruxism slept for a longer duration (with sleep bruxism group: 460 minutes and without sleep bruxism group: 401 minutes). There were no statistically significant differences among the groups for the number of inspiratory, expiratory and mixed snores, but was observed greater amount of snoring in the with sleep bruxism group. Conclusions The main finding of this study is that individuals with sleep bruxism slept longer than the control group. It may also be suggested that individuals with sleep bruxism tended to increase the amount of habitual snoring during sleep. Key words:Bruxism, adult, sleep disordered breathing, polysomnography.

Influence of sleep bruxism severity on masticatory efficiency: electromyographic analysis.

The objective of the present study was to ascertain masticatory efficiency by evaluating electromyographic activity in the masseter and temporalis muscles in subjects with sleep bruxism of varying severity, as determined by BiteStrip. Thirty-four subjects with sleep bruxism were divided into two groups: a mild sleep bruxism group with a mean (± standard deviation) age of 31.3 ± 6.2 years (n = 15) and a severe sleep bruxism group with a mean age of 29.8 ± 7.1 years (n = 19). Full-night polysomnography (PSG) was performed in eligible subjects. The linear envelope integral was used to determine masticatory efficiency on the basis of the electromyographic signal of the masseter and temporalis muscles during habitual and non-habitual chewing. There was significantly higher (p .05) electromyographic activity in the severe bruxism group than in the mild bruxism group during both peanut chewing in the right (p = .03) and left (p = .03) temporalis muscles and raisin chewing in the right (p = .01) and left (p = .05) temporalis muscles. Furthermore, Parafilm M chewing showed similar results in the right (p = .008) and left (p = .02) temporalis muscles. These results suggested that subjects with severe sleep bruxism had lower masticatory efficiency.

Association between patterns of jaw motor activity during sleep and clinical signs and symptoms of sleep bruxism.

The aim of this study was to investigate the association between patterns of jaw motor activity during sleep and clinical signs and symptoms of sleep bruxism. A total of 35 university students and staff members participated in this study after providing informed consent. All participants were divided into either a sleep bruxism group (n=21) or a control group (n=14), based on the following clinical diagnostic criteria: (1) reports of tooth-grinding sounds for at least two nights a week during the preceding 6months by their sleep partner; (2) presence of tooth attrition with exposed dentin; (3) reports of morning masticatory muscle fatigue or tenderness; and (4) presence of masseter muscle hypertrophy. Video-polysomnography was performed in the sleep laboratory for two nights. Sleep bruxism episodes were measured using masseter electromyography, visually inspected and then categorized into phasic or tonic episodes. Phasic episodes were categorized further into episodes with or without grinding sounds as evaluated by audio signals. Sleep bruxism subjects with reported grinding sounds had a significantly higher total number of phasic episodes with grinding sounds than subjects without reported grinding sounds or controls (Kruskal-Wallis/Steel-Dwass tests; P<0.05). Similarly, sleep bruxism subjects with tooth attrition exhibited significantly longer phasic burst durations than those without or controls (Kruskal-Wallis/Steel-Dwass tests; P<0.05). Furthermore, sleep bruxism subjects with morning masticatory muscle fatigue or tenderness exhibited significantly longer tonic burst durations than those without or controls (Kruskal-Wallis/Steel-Dwass tests; P<0.05). These results suggest that each clinical sign and symptom of sleep bruxism represents different aspects of jaw motor activity during sleep.

Sleep bruxism is related to decreased inhibitory control of trigeminal motoneurons, but not with reticulobulbar system.

Sleep bruxism (SB) is a stereotyped movement disorder characterized by grinding or clenching of the teeth during sleep. We aimed to understand the abnormal networks related to the excitability of masticatory pathways in patients with SB. Eleven patients with SB and age- and gender-matched 20 healthy subjects were prospectively enrolled in our study. The masseter inhibitory reflex (MIR) after electrical stimulation and auditory startle reaction (ASR) were examined. For MIR responses, durations of early and late silent period (SP) were shorter and the degree of suppression of SPs was significantly lower in SB group in comparison to those obtained in healthy subjects. The ASR responses even of the masseter muscle, however, were similar between patients with SB and healthy individuals. Abnormal MIR provides support for the decreased inhibitory control of the central masticatory circuits in SB whereas normal ASR suggests the integrity and normal functioning of brainstem pathways mediating startle reaction. Although the sample size is small, our results are in line with previous findings and suggest an abnormally decreased inhibition in trigeminal motoneurons to masseter muscle rather than reticulobulbar pathways in patients with SB.