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

Current evidence and future perspectives in the exploration of sleep-related eating disorder-a systematic literature review

Sleep-related eating disorder (SRED) is a non-REM parasomnia with potentially significant negative effects on general health (dangerous activities during night eating episodes, obesity, or metabolic syndrome, for example). Although the history of SRED encompasses more than six decades, public awareness and even the awareness of the mental health specialists of this disorder is very limited, a phenomenon that hinders the development of research in this field. Therefore, a systematic review based on PRISMA 2020 guidelines explored the available evidence for SRED found in four electronic databases (PubMed, Cochrane Collaboration, Google Scholar, and Clarivate/Web of Science). A number of 94 primary and secondary reports were retrieved, investigating aspects regarding the risk factors, epidemiology, clinical data and differential diagnosis, epidemiology, structured evaluation, and treatment of SRED. Based on the results of these reports, Z-drugs, but also certain benzodiazepines, antidepressants, antipsychotics, and psychostimulants may trigger the onset of SRED. Psychiatric and neurologic disorders have also been associated with SRED, either as risk factors or comorbid conditions. Cerebral glucose metabolism dysfunctions, neurotransmitter dysfunctions, and genetic factors have been invoked as pathogenetic contributors. Structured assessment of SRED is possible, but there is a dearth of instruments dedicated to this purpose. Data on the prevalence and treatment of SRED exist, but good-quality epidemiological studies and clinical trials are still missing. In conclusion, future research is expected to address the shortcomings of SRED exploration by creating the conditions for better quality and larger group clinical research. The need for such investigation is granted by the importance of this pathology and its negative functional consequences.

Effects of the low Fowler's sleep position and methazolamide treatment on sleep bruxism: A randomized controlled trial

Intracranial pressure is one of the determinants of sympathetic activities, and sleep bruxism is associated with increased sympathetic activities. This study aimed to investigate effects of the low Fowler's sleep position and methazolamide treatment on the occurrence of rhythmic masticatory muscle activities/sleep bruxism episodes in patients with sleep bruxism in a randomized controlled trial. Polysomnographic recordings were performed on the patients with sleep bruxism sleeping in the low Fowler's (15°-30°) or supine position (n = 11), and with methazolamide or placebo treatment (100 mg, 3-4 hr before bedtime, P.O., n = 9), and changes in sleep variables and heart rate variance during sleep in the low Fowler's position or with methazolamide treatment were determined. Sleep bruxism index, number of masseter muscle electromyographic bursts per hour of sleep, ratio of rhythmic masticatory muscle activities/sleep bruxism duration to the total sleep duration, index of total limb movements, index of limb movements with rhythmic masticatory muscle activities, and number of sleep bruxism clusters per hour of sleep in the low Fowler's position and after methazolamide intake were significantly smaller (p < 0.05-0.001) than those in the supine position and after placebo intake, respectively. The low-frequency heart rate variance powers during non-rapid eye movement sleep stage 2 (N2) in the low Fowler's position and with methazolamide treatment were significantly lower (p < 0.05) than those during sleep in the supine position and with placebo treatment, respectively. In conclusion, sleep in the low Fowler's position and methazolamide treatment were associated with significant decreases in the occurrence of rhythmic masticatory muscle activities/sleep bruxism episodes, which might be due to a reduction in intracranial pressure and sympathetic activities mainly during non-rapid eye movement sleep stage 2.

Why am I grinding and clenching? Exploration of personality traits, coping strategies, oral parafunctional behaviors, and severe sleep bruxism in a polysomnographic study

Introduction

Causal relationships between psychopathological symptoms, personality traits, coping mechanisms, and sleep bruxism (SB) were studied in the past, giving inconsistent results mostly based on self-assessment evaluations. This polysomnography-based cross-sectional study aimed to explore the relationships between severe SB, personality traits (according to the Big Five model), and coping strategies with objective polysomnographic verification.

Methodology

The study included 66 participants divided into severe SB (SSB) (n=32) and no or mild SB (n=34) groups based on video-polysomnography performed in the sleep laboratory. Questionnaire assessment included the use of the Beck Depression Inventory, Beck Anxiety Inventory, Mini-COPE, International Personality Item Pool Big Five Markers 20-Item version, and Oral Behavior Checklist.

Results

Participants with SSB presented with fewer self-reported anxiety (p=0.008) and depressive (p=0.01) symptoms than the non- or mild-SB groups. The SSB group scored significantly higher in Big Five personal traits such as extraversion (p=0.007), emotional stability (p=0.013), and intellect (p=0.004), while regarding coping strategies, the SSB group was less likely to use negative strategies: self-distraction (p=0.036), denial (p=0.006), venting (p=0.03), behavioral disengagement (p=0.046), and self-blame (p=0.003), and turning to religion (p=0.041). The intensity of oral parafunctional behaviors was comparable in both groups (p=0.054). Emotional stability was a moderate protective factor (p=0.004), and the self-blame strategy was a strong risk factor (p<0.001) for increased oral parafunctional behavior intensity. Phasic activity negatively correlated with anxiety symptom severity (p=0.005), whereas tonic (p=0.122) and mixed (p=0.053) phenotypes did not. SB intensity was a protective factor against anxiety symptoms (p=0.016).

Conclusion

In terms of psychopathology, severe sleep bruxers tend to present less severe anxiety and depressive symptoms, while some of their personality traits (extraversion, emotional stability, and intellect) were more strongly pronounced. SSB is possibly related to the lesser use of the "maladaptive" coping strategies and there were no specific coping strategies preferred by SSB participants, compared to the other group. These observations require further studies, as it should be determined whether SB (especially phasic activity) might be a form of a somatization/functional disorder. Further research should focus on the psychogenic background of oral parafunctional behaviors, which occur more often in less emotionally stable personalities and in people using self-blame coping strategies.

Sleeping and waking-state oral behaviors in TMD patients: their correlates with jaw functional limitation and psychological distress

OBJECTIVES

This study investigated oral behaviors in various temporomandibular disorder (TMD) subtypes, assessing their frequency, extent, and associations with both jaw functional status and psychological distress.

MATERIALS AND METHODS

Anonymized data from consecutive "initial-visit" TMD patients at a university-affiliated oral medicine clinic were obtained. Alongside demographic information, patients completed various questionnaires including the Diagnostic Criteria for TMD (DC/TMD) Symptom Questionnaire, Oral Behavior Checklist (OBC), Jaw Functional Limitation Scale-20 (JFLS-20), Patient Health Questionnaire-9 (PHQ-9), and General Anxiety Disorder Scale-7 (GAD-7). Patients underwent a protocolized clinical examination and received diagnoses of pain-related (PT), intra-articular (IT), or combined (CT) TMD using the DC/TMD diagnostic algorithms. Data were evaluated with Chi-square/non-parametric tests and logistic regression analyses (α = 0.05).

RESULTS

The study comprised 700 patients (mean age 37.4 ± 15.7 years), with 12.6%, 15.1%, and 72.3% diagnosed with PT, IT, and CT, respectively. For all TMD subtypes, oral activities during sleep were more prevalent than those during wakefulness. While variations in total/subscale OBC scores were insignificant, substantial differences were observed in global/subscale JFLS (PT, CT > IT), depression (PT, CT > IT), and anxiety (CT > IT) scores. Near-moderate correlations (rs = 0,36-0.39) were discerned between overall/waking-state non-functional oral behaviors and depression/anxiety. Multivariate analysis indicated that the odds of different TMD subtypes were influenced by sex, age, and jaw functional status.

CONCLUSIONS

For all TMD patients, sleep-related oral activities were more commonly reported than waking-state activities. Factors such as sex, age, and jaw functional limitation are associated with the likelihood of different TMD subtypes.

STATEMENT OF CLINICAL RELEVANCE

Oral behaviors, in themselves, do not predict distinct TMD subtypes, in contrast to factors such as sex, age, and jaw functional status.

Correlation between benign joint hypermobility syndrome and headache in children and adolescents

BACKGROUND

Benign Joint Hypermobility Syndrome (BJHS) is a most common hereditary connective tissue disorders in children and adolescents. This study aimed to investigate the prevalence and subtypes of headache in children with BJHS.

METHODS

This observational-analytical study was conducted in a case-control setting on school children aged 7 to 16 years in 2021-2023 in Isfahan, Iran. Students were examined for BJHS using Beighton criteria by a pediatric rheumatologist. Headache disorder was diagnosed according to the Child Headache-Attributed Restriction, Disability, and Social Handicap and Impaired Participation (HARDSHIP) questionnaires for child and adolescent and International Classification of Headache Disorders (ICHD-III).

RESULTS

A total of 4,832 student (mean age 10.3 ± 3.1 years), 798 patients with BJHS and 912 healthy children were evaluated. The probability of headache in children aged 7-11 with hypermobility was 3.7 times lower than in children aged 12-16 with hypermobility (P = 0.001). The occurrence of headache in children with BJHS was more than the control group (P = 0.001), and the probability of headache in children with BJHS was 3.7 times higher than in healthy children (P = 0.001). Migraine was the most common headache type reported of total cases. The probability of migraine in children with BJHS was 4.5 times higher than healthy children ( P = 0.001).

CONCLUSION

This study showed a significant correlation between BJHS and headache (especially migraine) in children and adolescents.

Hidden risk factors and the mediating role of sleep in work-related musculoskeletal discomforts

OBJECTIVE

Musculoskeletal discomforts (MSDs) are prevalent occupational health issues that are associated with a wide range of risk factors. This study aimed to investigate some of the occupational hidden risk factors and the mediating role of sleep in work-related musculoskeletal discomforts.

METHODS

In a cross-sectional study, the role of job stress and shift work as two hidden risk factors and sleep problems as the mediator in work-related musculoskeletal discomforts was investigated in 302 healthcare workers using the path analysis models. For this aim, healthcare workers' Occupational Stress and musculoskeletal discomforts were evaluated using the Health and Safety Executive questionnaire and Cornell questionnaire, respectively. Moreover, the Pittsburgh Sleep Quality Index (PSQI) and the Insomnia Severity Index (ISI) were used to examine the sleep characteristics of participants. Shift work and job stress as predictor variables and sleep characteristics as mediating variables were analyzed.

RESULTS

The results showed that the path coefficients of job stress on indexes of quality sleep and insomnia severity were significant. Also, the path coefficient of shift work on quality sleep index was significant. In return, the path coefficients of shift work on the insomnia severity index were not significant. Additionally, there was a mutually significant association between indexes of quality sleep and the severity of insomnia and musculoskeletal discomforts. The direct effect coefficient of job stress on MSDs was significant, whereas the direct effect coefficient of shift work on MSDs was insignificant. This means that shift work alone does not significantly impact these disorders.

CONCLUSION

It would seem that shift work and job stress as two occupational hidden risk factors can mediate sleep indexes and indirectly play a critical role in the incidence of musculoskeletal discomforts. Moreover, sleep disorders and musculoskeletal discomforts are mutually related and have a bidirectional relationship.

The relationship between pregnancy and temporomandibular disorder (TMD) through diagnostic criteria for temporomandibular disorders (DC/TMD) axis II evaluation: a case-control cross-sectional study

INTRODUCTION

This study focuses on temporomandibular disorders (TMDs), which affect the temporomandibular joint and related muscles and have multiple causes. Recent studies have examined the connection between menstrual cycles, estrogen levels, and TMDs, but results are inconsistent, highlighting the need for more research. The aim is to explore the prevalence of TMDs in pregnant women and consider how hormonal changes during pregnancy might influence these disorders.

METHODS

In this cross-sectional case-control study, we compared 32 pregnant women with 35 non-pregnant women. We evaluated several TMD-related factors such as pain levels, chronic pain classification, scores on the Jaw Functional Limitation Scale-20 and Oral Behaviors Checklist, and psychological health. We used various statistical methods including descriptive statistics, chi-square tests, linear regression, and adjustments for multiple comparisons to analyze the data.

RESULTS

Pregnant women showed different pain perceptions, generally reporting less pain and lower severity. Nonetheless, these differences were not uniform across all TMD-related measures. Linear regression did not find a consistent link between pregnancy and TMD scores, except for chronic pain grade, which was not significant after adjusting for multiple comparisons. There was a significant relationship between depression and TMD severity, emphasizing the need to consider mental health in TMD evaluations.

DISCUSSION

The findings suggest that pregnancy is neither a risk nor a protective factor for TMD. Differences in pain perception, functional status, and psychological health were observed in pregnant women but were not consistent for all TMD-related aspects. The role of estrogen in TMJ health and TMD risk is complex and requires further study. The research highlights the necessity of including mental health, especially depression, in TMD assessments. More comprehensive research with larger sample sizes is essential to better understand the connections between pregnancy, TMD, and hormones, aiming to improve TMD management in pregnant women and others.

Accuracy of temporomandibular disorders diagnosis evaluated through the diagnostic criteria for temporomandibular disorder (DC/TDM) Axis II compared to the Axis I evaluations: a systematic review and meta-analysis

BACKGROUND

The temporomandibular joint (TMJ) is a complex joint that facilitates mandibular movements during speech, chewing, and swallowing activities. The Axis I evaluation of the DC/TMD focuses on assessing physical diagnoses related to TMDs. It includes an assessment of pain and functional limitations, such as jaw opening range, joint sounds, and joint tenderness. The Axis II evaluation of the DC/TMD provides information on the patient's psychological status and quality of life. This Systematic Review with Meta-Analysis aimed to evaluate the accuracy of Temporomandibular Disorders diagnosis considered through the Diagnostic Criteria for Temporomandibular Disorder (DC/TDM) axis II compared to the Axis I evaluations.

METHODS

A search was made in PubMed, Web of Science and Lilacs for articles published from the inception until 20 January 2023. We applied the Population, Exposure, Comparator, and Outcomes (PECO) model [1] to assess document eligibility. Only studies that evaluated patients by DC/TMD Axis I and Axis II were considered. Review Manager version 5.2.8 (Cochrane Collaboration) was used for the pooled analysis. We measured the odds ratio (OR) between the two groups (Axis I and Axis II).

RESULTS

Fifty-one articles were selected because of the search. Four papers were excluded before the screening: 2 pieces were not in English, and two were reviewed. The remaining 47 articles were selected for the title and abstract screening to evaluate whether they met the PECO criteria. Among these, four papers were established; the overall effect showed that there was no difference in TMD diagnosis between Axis I and Axis II (RR 1.17; 95% CI: 0.80- 1.71; Z:0.82; P = .41), suggesting that there is no difference between Axis I and Axis II.

CONCLUSION

In conclusion, DC/TMD is an effective tool for the diagnosis of TMD. It improves the accuracy of TMD diagnosis, allows for the classification of subtypes, and assesses psychosocial factors that may impact the development or maintenance of TMD symptoms.

Correlates of jaw functional limitation, somatization and psychological distress among different temporomandibular disorder diagnostic subtypes

OBJECTIVES

This study investigated the jaw functional status and severity of somatic/psychological symptoms in different Diagnostic Criteria for temporomandibular disorders (DC/TMD) diagnostic subtypes and established the correlates between jaw functional limitation, somatization, depression and anxiety.

METHODS

Data were accrued from consecutive 'first-visit' patients seeking TMD treatment at a university-based oral medicine/diagnosis clinic. Axis I physical TMD diagnoses were derived using the DC/TMD methodology and patients were categorized into pain-related (PT), intra-articular (IT) and combined (CT) TMD groups. Axis II measures were also administered and included the Jaw Functional Limitation Scale-20 (JFLS-20), Patient Health Questionnaire-15 and 9 (PHQ-15 and PHQ-9) and General Anxiety Disorder Scale-7 (GAD-7). Chi-square/Kruskal-Wallis tests and Spearman's correlation were employed for statistical evaluations (α = .05).

RESULTS

The final dataset consisted of 772 TMD patients (mean age of 37.7 ± 15.9 years; 70.2% females). The prevalence of PT, IT and CT was 11.9%, 15.7% and 72.4%, respectively. Significant differences in functional jaw limitations, somatization, depression (CT, PT > IT) and anxiety (CT > PT, IT) were observed. Moderate-to-severe somatization, depression and anxiety were detected in 12.6%-15.7% of patients. For all three TMD groups, JFLS global scale/subscale scores were weakly associated with somatization, depression and anxiety scores (rs  < 0.4). Moderate-to-strong correlations were noted between somatization, depression and anxiety (rs  = 0.50-0.74).

CONCLUSIONS

Functional jaw limitations were associated with painful TMDs but appear to be unrelated to somatization and psychological distress. Somatization and depression/anxiety were moderately correlated, underscoring the importance of somatic symptom screening when managing TMD patients.

Relationship Between Occlusal Factors and Temporomandibular Disorders: A Systematic Literature Review

Temporomandibular disorders (TMD) originate from various components within the temporomandibular joint (TMJ), causing an impact on the masticatory muscles, the joint itself, and associated structures. They are a widely prevalent issue across the world. According to epidemiological research, up to 50% of adults in the population have TMD-related symptoms. The objective of this work was to analyze the existing scientific literature regarding the association between malocclusion classes, bruxism, and tooth loss in relation to the etiology of TMD. This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 analysis protocol. For the development of the question focus, the population, intervention, control, and outcomes (PICO) study design protocol was used. The question in focus according to the PICO format was: "Do malocclusion, tooth loss, and bruxism contribute to temporomandibular disorders?". The review was performed with articles from PubMed, Web of Science, and Google Scholar databases according to the specified inclusion and exclusion criteria. The included articles were not older than five years. The risk of bias was assessed in the included studies by using the Cochrane Risk-of-bias 2 (RoB-2) tool. Out of a total of 32 results received, 21 articles were chosen according to the established criteria after conducting a review and analysis of their full texts. The article search sequence was presented in the PRISMA 2020 flow diagram, and the outcomes of the chosen articles were presented. The literature results revealed a relationship between occlusion and the development of TMD. The influence of occlusal factors on the TMJ was explained by an examination of joint anatomy and symptoms related to TMD. This study revealed variations in TMJ factors across different malocclusion classes. Additionally, it was observed that the occurrence and attributes of TMD are influenced by the number of tooth loss quadrants and the frequency of missing teeth. Furthermore, a correlation was found between bruxism and the symptoms of TMD, including myofascial pain, disc displacement, arthralgia, and muscle disorders. This literature review provides comprehensive information on the relationship between malocclusion classes, bruxism, tooth loss, and TMDs. This prompts healthcare professionals to prioritize patients' occlusal assessment and TMJ condition.

Influence of psychiatric symptom profiles of parents on sleep bruxism intensity of their children

OBJECTIVE

The objective of this study was to evaluate the effects of parental anxiety, depression levels and psychiatric symptom profiles of parents on the occurrence of sleep bruxism in children.

MATERIAL & METHODS

This cross-sectional study was carried out with a sample of 94 children aged 6 to 12 years, divided into two groups: with sleep bruxism (bruxism group-BG) and without sleep bruxism (control group-CG). Beck Depression Inventory (BDI), Symptom Checklist (SCL-90-R), Symptom Checklist and Screen for Child Anxiety Related Emotional Disorders-Parent (SCARED-P) scale were used to assess anxiety and depression levels of parents. All questionnaires were filled out by parents of children. Intraoral and extraoral examinations were carried out of children in the clinic and sleep bruxism was determined. All stress conditions were investigated by logistic regression analysis. In the comparison of the qualitative data, chi-square and Fisher exact tests were used.

RESULTS

The data revealed that participants whose mothers had high anxiety and interpersonal sensitivity scores, and participants whose fathers had a medium level of obsessive-compulsive disorder were more likely to have an SB problem (p < 0.05). According to the results of BDI, the fathers' results between the BG and the CG were not statistically significant (p > 0.05). However, the mothers' results between the BG and the CG were statistically significant (p < 0.05) When all subscales of SCARED-P were evaluated, the separation anxiety disorder subscore was statistically significant in the bruxism group.

CONCLUSION

The psychological status of parents is a significant risk factor associated with SB development in school-age children.

Validation of the Malay version of Epworth sleepiness scale for children and adolescents (MESS-CHAD)

BACKGROUND

Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD) is a valid and reliable eight-item self-administered questionnaire for the assessment of excessive daytime sleepiness and is commonly used to screen sleep-disordered breathing for children and adolescents. The cross-sectional study aimed to translate and cross-culturally adapt ESS-CHAD into a Malay version of Epworth Sleepiness Scale for Children and Adolescents (MESS-CHAD) for the Malaysian population, and to assess the validity and reliability of MESS-CHAD.

METHODS

Forward-backward translation method was used to translate and cross-culturally adapt ESS-CHAD. Three linguistic experts and two paediatricians content validated the translated version. Face validity was conducted through audio-recorded semi-structured in-depth interviews with 14 native Malay-speaking children and adolescents followed by thematic analysis. The revised questionnaire was then proofread by a linguistic expert. A total of 40 subjects answered the MESS-CHAD twice, 2 weeks apart, for test-retest reliability and internal consistency. For criterion validity, 148 eligible subjects and their parents answered MESS-CHAD and the Malay version of Sleep-Related Breathing Disorder scale extracted from the Paediatric Sleep Questionnaire (M-PSQ:SRBD) concurrently. Variance Inflation Factor (VIF) and P values of the model's outer weight and outer loading were analysed using SmartPLS software to assess the indicator's multicollinearity and significance for formative construct validity.

RESULTS

Intraclass Correlation Coefficient (ICC) ranging from 0.798 to 0.932 and Cronbach's alpha ranging from 0.813 to 0.932 confirmed good to excellent test-retest reliability and internal consistency, respectively. Spearman Correlation Coefficient value of 0.789 suggested a very strong positive correlation between MESS-CHAD and M-PSQ:SRBD. VIF ranging from 1.109 to 1.455 indicated no collinearity problem. All questionnaire items in MESS-CHAD were retained as the P value of either outer model weight or outer model loading was significant (P < 0.05).

CONCLUSION

ESS-CHAD has been translated and cross-culturally adapted into Malay version for the Malaysian population, and found to be valid and reliable.

Prevalence of awake bruxism in the adult population: a systematic review and meta-analysis

OBJECTIVES

To evaluate the prevalence of awake bruxism (AB) in the adult population.

MATERIALS AND METHODS

Six main electronic databases and three sources of grey literature were searched to identify cross-sectional studies in which AB was assessed. The studies were independently selected by two reviewers in two phases, based on their eligibility criteria. The first one consisted of reading titles and abstracts, and the second one involved reading the full articles. The study quality assessment was obtained by using the "Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data", and the "R Statistics" software was used to perform meta-analyses.

RESULTS

Seventeen out of 3086 identified studies were included. None of the studies scored high in methodological quality across all 9 items of the JBI checklist. However, "the use of valid methods to identify pathology" and "appropriate statistical analysis" were considered to have high methodological quality in all the studies. The overall pooled prevalence of the meta-analysis was 15.44% (99% confidence interval: 10.81 to 20.72%) and there was no difference for sex, sampling method and according to consensus-based classification.

CONCLUSIONS

The prevalence of AB in adults was low. There was substantial methodological variability, which highlights the need for standardized guidelines.

CLINICAL RELEVANCE

Prevalence data are useful for raising patients' and clinicians' awareness of the AB. Moreover, since AB can lead to possible pain and overload of the stomatognathic system, this knowledge can also guide dentists to achieve an early diagnosis of AB and to provide appropriate care management.

Do myofascial trigger points in masseter muscles affect the symptoms of disc displacement with reduction? A cross-sectional study

OBJECTIVE

The aim of this study was to demonstrate the effect of myofascial pain with referral from the trigger points in the masseter muscles on the clinical symptoms and functional limitations of the temporomandibular joint in participants with disc displacement with reduction.

METHODS

This prospective, cross-sectional study recruited participants aged 18-45 years with disc displacement with reduction with/without myofascial pain with referral in the masseter muscles based on the inclusion criteria. Maximum mouth opening and the presence of probable awake bruxism were assessed. The "Graded Chronic Pain Scale version 2.0" and "Jaw Function Limitation Scale-8" were used to evaluate Diagnostic Criteria for Temporomandibular Disorders Axis II. Pain levels were measured using the Visual Analog Scale.

RESULTS

A comparison between the disc displacement with reduction and disc displacement with reduction+myofascial pain with referral groups revealed statistically significant differences in Visual Analog Scale (p<0.001), the presence of awake bruxism (p=0.038), and Graded Chronic Pain Scale version 2.0 (p=0.010). However, no statistically significant difference was observed between the two groups concerning maximum mouth opening and Jaw Function Limitation Scale-8.

CONCLUSION

Participants with both disc displacement with reduction and myofascial pain with referral in the masseter muscle exhibited higher pain intensity, a higher prevalence of awake bruxism, and increased pain-related disability compared to those with disc displacement with reduction alone.

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.

Systematic Review on the Link between Sleep Bruxism and Systemic Chronic Inflammation

Sleep bruxism (SB) is a sleep-related behavior characterized as rhythmic (phasic) or non-rhythmic (tonic) masticatory muscle activity. SB is a common sleep behavior with a predominantly central origin. The aim of this systematic review was to evaluate the relationship between inflammatory status and SB according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 (PRISMA 2020). The research was registered at PROSPERO (CRD42023395985). We performed a systematic literature analysis using five different databases. Furthermore, the backward snowballing technique was applied to identify additional papers. Initially, 28 papers were screened from the database search, and 162 papers were revealed in the backward snowballing process. Eventually, five articles were included. Data concerning the inflammatory status of patients experiencing SB were investigated and summarized. Due to the heterogeneity of the compared studies, only a qualitative comparison and narrative summary were performed. The results suggest that SB could be associated with systemic inflammation. In fact, this systematic review revealed that there are no papers conclusively showing that the inflammatory status in bruxers is comparable to non-bruxers. However, each of the examined studies utilized different methods of assessing systemic inflammation, which makes the results dubious.

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

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

Temporomandibular Disorders Related Pain among Sleep & Awake Bruxers: A Comparison among Sexes and Age

According to the current international consensus [...].