Bruxism: An umbrella review of systematic reviews

Bruxism and direct and indirect restorations failure: A scoping review

OBJECTIVE

To analyze and present the relationship between bruxism and the failure of direct and indirect dental restorations.

METHODOLOGY

The reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Human studies reporting on the failure of dental restorations in relation to bruxism were included.

SOURCES

MEDLINE (Ovid), Scopus and Pub Med databases were searched from 2012 to 2024. Additional hand searching was made using Google Scholar, and Scopus were utilized for snowball searching.

STUDY SELECTION

An initial systematic search was made of bruxism and dental restorations failures based on key terms using MeSH and other thesaurus terms appropriate for each database published between 2012 and 2024. Two reviewers screened ten articles using the established criteria for inclusion and exclusion, and a level of agreement of 90 % was established. The available literature on the frequency of studies of the relationship between Bruxism and failure of direct and indirect dental restorations and also identify gaps in the literature for further investigation.

CONCLUSIONS

There were 66 manuscripts for full-text evaluation. After further exclusion, 46 manuscripts were selected for data charting. The studies were on the relationship between bruxism and restorations failure: dental implants studies were 58.7 %; mixed restorations were 10.9 %; indirect restoration (Full Coverage Crowns and Fixed Partial Dentures) 15.2 %; indirect partial coverage restoration (inlays/onlays/overlays/crowns) 6.5 %; indirect restoration (veneers) 4.3 %; direct restoration also 4.3 %. The 87.5 % of the implant studies addressed the effects of bruxism on single implant restorations failure.

LIMITATIONS OF EVIDENCE

Most of the included studies were retrospective, with few prospective studies or clinical trials. However, Bruxism is a risk factor for the failure of direct and indirect restorations.

CLINICAL SIGNIFICANCE

Clinicians should be aware that direct and indirect restorations are at risk of failure in the presence of bruxism, with the exception of indirect monolithic Zirconia.

Evaluation of the relationship between bruxism and/or temporomandibular disorders and stress, anxiety, depression in adults: A systematic review and qualitative analysis

OBJECTIVE

The objective of this study was to map and systematically review the available evidence regarding the relationship between bruxism and/or temporomandibular disorders, psychological factors (stress, anxiety, depression) in adults.

MATERIAL AND METHOD

A systematic review has been conducted following the criteria described in Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020). A systematic search was performed in the Web of Science database with the last search updated as of November 2024. Observational studies in adults in which bruxism is assessed by questionnaires or clinical examination were included in the search. 10 of the 92 articles met the inclusion and exclusion requirements and were subject to a qualitative analysis.

RESULTS

There seems to be an association between bruxism, temporomandibular disorders and psychological factors. Clenching and grinding may be associated with overload of the chewing structures and give rise to symptoms typical of temporomandibular disorders, all under the probable influence of psychological factors.

CONCLUSIONS

Bruxism, associated with psychological factors, leads to the appearance of symptoms typical of temporomandibular disorders. More research is needed to understand how the factors interact.

CLINICAL SIGNIFICANCE

Clinicians should be aware of the psychological factors associated with bruxism and the relationship with temporomandibular disorders.

Are sleep and awake bruxism associated with sleep quality and duration in adults? A systematic review and meta-analysis

The objective of this systematic review was to investigate the association between sleep quality with awake bruxism or sleep bruxism in adult individuals. Inclusion criteria comprised observational studies conducted in adults related to the research question, assessing bruxism by instrumental or non-instrumental approaches, and sleep quality by subjective or objective measures, or sleep duration. Sleep disorders, syndromes, neurological and psychiatric disorders, or psychotropic medications were excluded. PubMed, Embase, Web of Science, Scopus, Cochrane Library, and Google Scholar databases were searched until August 2024. Risk of bias was assessed by the JBI Critical Appraisal Checklist tool for cross-sectional studies, and the Newcastle-Ottawa scale for case-control studies. Independent meta-analyses comparing awake or sleep bruxism individuals with control individuals were performed when there were at least two studies for each sleep outcome. Thirty-two studies assessing a total of 4706 individuals were included. Meta-analyses showed no differences between sleep bruxism and control individuals regarding polysomnography parameters (sleep efficiency, sleep latency, awakenings, wake after sleep onset, and sleep duration). Pittsburgh Sleep Quality Index showed higher scores for sleep bruxism individuals compared to control individuals (MD = 1.98; 95 % CI = 0.96-3.00) and for awake bruxism individuals compared to control individuals (MD = 1.99; 95 % CI = 0.42-3.57). In total, 12 studies were rated as low risk of bias, 15 as moderate risk of bias, and 5 as high risk of bias. The certainty of evidence was rated as very low. Objective sleep quality was not associated with sleep bruxism, while subjective sleep quality was associated with both sleep and awake bruxism.

The BruxChecker System for Quantitatively Assessing Sleep Bruxism at the Dental Level: Reliability, Reference Values and Methodological Considerations

BACKGROUND

There is a need for reliable instruments that can quantitatively assess sleep bruxism at the dental level.

OBJECTIVES

This study aimed to determine the test-retest reliability of the occlusal peeled area using the BruxChecker, the methodological aspects that affect this reliability, and the reference values in a population of dental students.

METHODS

Eighty-four dental students participated in this test-retest study (median age, 21.7 years; 74 women). A BruxChecker was worn for 3 consecutive nights and scanned after each night in the plaster model and by transillumination. The relative and absolute peeled areas were measured using the FIJI software, and BruxChecker perforation was determined visually. Reliability was assessed by the intraclass correlation coefficient (ICC) and Cohen's kappa.

RESULTS

The absolute and relative peeled areas of the BruxChecker by transillumination after 2 or 3 nights provided the highest ICC values, which ranged from 0.918 to 0.929. BruxChecker perforation was present in 45% of the participants, with a kappa value of 0.777. The respective median peeled areas were 84.3 mm2 and 9.9% for the absolute and relative values after using the BruxChecker for three nights. Ranges for the 10th-90th percentiles were 4.7%-17.0% and 39.4%-143.4 mm2, respectively.

CONCLUSIONS

The BruxChecker system demonstrates excellent reliability in measuring the occlusal peeled area in the studied population. This study proposes reference values for absolute and relative peeled areas after using the BruxChecker for three nights and scanning by transillumination.

Sleep Bruxism in Thai Obstructive Sleep Apnea Patients

OBJECTIVES

To investigate the prevalence of sleep bruxism (SB) in Thai obstructive sleep apnea (OSA) patients and to identify demographic characteristics and specific sleep parameters associated with SB.

METHODS

A total of 119 medical records, each containing full-night type I polysomnography from Thai patients with OSA, were included. SB was detected using surface electromyography of the masseter muscle. SB was diagnosed when the SB index reached at least two episodes per hour of sleep. The differences in demographic characteristics and sleep parameters between SB and non-SB groups were analysed. Multivariate logistic regression analysis was performed to determine the associated factors for SB.

RESULTS

Among Thai patients diagnosed with OSA, 50.4% concurrently experienced SB, predominantly of the tonic type. The study revealed a higher prevalence of SB in males compared to females. The SB group demonstrated significantly higher values in the apnea-hypopnea index (AHI), Epworth Sleepiness Scale (ESS), Arousal Index (AI), and Respiratory Arousal Index (RAI) compared to the non-SB group. Multivariate logistic regression analysis indicated that a lower body mass index (BMI), higher ESS, and increased severity of AHI were significantly associated with SB.

CONCLUSIONS

The study revealed that half of Thai patients diagnosed with OSA also exhibited SB. Male, AHI, ESS, AI, and RAI appeared to be potential correlates for the presence of SB. Lower BMI, higher ESS, and elevated AHI can be factors associated with SB in Thai OSA patients.

CLINICAL RELEVANCE

The prevalence of SB among Thai patients diagnosed with OSA and the factors associated with its occurrence were investigated.

A Comparative Analysis of Three Large Language Models on Bruxism Knowledge

BACKGROUND

Artificial Intelligence (AI) has been widely used in health research, but the effectiveness of large language models (LLMs) in providing accurate information on bruxism has not yet been evaluated.

OBJECTIVES

To assess the readability, accuracy and consistency of three LLMs in responding to frequently asked questions about bruxism.

METHODS

This cross-sectional observational study utilised the Google Trends tool to identify the 10 most frequent topics about bruxism. Thirty frequently asked questions were selected, which were submitted to ChatGPT-3.5, ChatGPT-4 and Gemini at two different times (T1 and T2). The readability was measured using the Flesch Reading Ease (FRE) and Flesch-Kincaid Grade Level (FKG) metrics. The responses were evaluated for accuracy using a three-point scale, and consistency was verified by comparing responses between T1 and T2. Statistical analysis included ANOVA, chi-squared tests and Cohen's kappa coefficient considering a p value of 0.5.

RESULTS

In terms of readability, there was no difference in FRE. The Gemini model showed lower FKG scores than the Generative Pretrained Transformer (GPT)-3.5 and GPT-4 models. The average accuracy of the responses was 68.33% for GPT-3.5, 65% for GPT-4 and 55% for Gemini, with no significant differences between the models (p = 0.290). Consistency was substantial for all models, with the highest being in GPT-3.5 (95%). The three LLMs demonstrated substantial agreement between T1 and T2.

CONCLUSION

Gemini's responses were potentially more accessible to a broader patient population. LLMs demonstrated substantial consistency and moderate accuracy, indicating that these tools should not replace professional dental guidance.

Potential predisposing features of external cervical resorption: An observational study

AIM

To assess the occurrence of external cervical resorption (ECR) in relation to patient characteristics and potential predisposing factors.

METHODOLOGY

In total, 215 ECR lesions (194 patients) referred to the Endodontic postgraduate Unit at King's College London or Specialist Endodontic practice (London, UK) between September 2017 and January 2022. The clinical records were readily accessible for evaluation. At the time of initial presentation, patients diagnosed with ECR were interviewed regarding potential predisposing factors using a checklist based on existing literature of reported predisposing factors. Absolute and relative frequencies for all variables were computed. Inferential analysis was carried out to determine if there was any potential association between the type and location of tooth in the jaw as well as sex, age of the patient and potential predisposing factors.

RESULTS

No identifiable predisposing factor were detected in 22.3% (48/215 teeth) of the cases, 57.7% (124/215 teeth) had a sole, identifiable predisposing factor and 20% (43/215 teeth) had combined (several) factors. The most common (sole or combined) potential predisposing factors were previous/existing history of orthodontic treatment (25.6%, 55/215 teeth), dental trauma injury (DTI) (20.9%, 45/215 teeth), domestic cat ownership (15.8%, 34/215 teeth) and parafunctional habits (10.2%, 22/215 teeth). The highest occurrence of sole predisposing factors was recorded for males (62%, 75/121 teeth), all other ethnic groups combined (non-white) patients (58.5%, 24/41 teeth), incisor teeth (64.4%, 56/87 teeth) and maxillary teeth (62.4%, 68/109 teeth). While the highest occurrence of combined predisposing factors was found in females (22.3%, 21/94 teeth), white patients (20.1%, 35/174 teeth), premolars (29%, 9/31 teeth) and mandibular teeth (21.7%, 23/106 teeth). There were significant associations between tooth type and trauma (p < .001), cat ownership (p = .003) and parafunctional habits (p = .017). The association between trauma (p < .001), cat ownership (p = .002) and jaw location were found to be significant. Concerning parafunctional habits, female patients had significantly (p = .015) more ECR occurrence than male patients.

CONCLUSION

Most cases had 1 (sole) identified predisposing factor; orthodontic treatment, dental trauma history and (previous) cat ownership were the most identified factors. The information may be helpful in diagnosing early stage ECR.

Association between exposure to environmental pollutants and increased oral health risks, a comprehensive review

The burden of disease and death attributable to environmental pollution is a growing public health challenge worldwide, particularly in developing countries. While the adverse effects of environmental pollution on oral health have garnered increasing attention, a comprehensive and systematic assessment remains lacking. This article delves into the intricate relationship between environmental pollution and oral health, highlighting significant impacts on various aspects such as dental caries, periodontal diseases, oral facial clefts, cancer, as well as other oral diseases. Our results suggested that secondhand smoke, particulate matters (PM) and heavy metals are the most important risk factors affecting oral health. Additional contributors, such as radiation pollutants, electronic cigarette, phthalates, gaseous air pollutants, pesticides, solvents, wood dust, formaldehyde and excessive fluoride were investigated, though evidence for their impacts remains limited and often inconclusive. The review also explores potential mechanisms underlying these impacts, including microorganism, inflammation, oxidative stress, genetic influences, and toxicant exposures from heavy metals and other pollutants. For instance, PM2.5 may contribute to dental caries by disrupting oral pH balance and absorbing heavy metals such as lead and cadmium which have been considered as caries promoting elements. It is also associated with adverse inflammatory responses and tissue damage in periodontal tissues by causing oxidative stress, potentially leading to periodontitis. Drawing on current evidence, it provides a comprehensive analysis of these associations, offering critical insights to guide the development of preventive strategies and public health interventions. The findings highlight the pressing need for future research to validate the causal links between environmental pollution and oral diseases and to unravel the underlying biological mechanisms. Ultimately, greater attention must be directed toward addressing the relationship between environmental pollution and oral diseases, with a focus on pollution control and the reduction of preventable environmental risks to safeguard oral health on a broader scale.

Influence of gender and bruxism on the masseter muscle: A population-based magnetic resonance imaging study

INTRODUCTION

This study aimed to (1) examine the cross-sectional area (CSA) of the masseter muscle in relation to bruxism and (2) investigate if there are gender-related differences in the masseter muscle in a population-based magnetic resonance imaging (MRI) study.

METHODS

The study included 720 subjects aged 30-89 years (391 women and 329 men) from the Study of Health in Pomerania, a cross-sectional population-based study assessing the prevalence and incidence of common population-relevant diseases and their risk factors in Northeastern Germany. The participants underwent both a whole-body MRI and a full oral examination. The CSAs of the masseter muscles on both sides were measured from MRI images. The presence or absence of awake and/or sleep grinding and clenching, unilateral chewing, and other parafunctional activities were obtained from the dental interview. Linear and ordinal logistic regression models were used to examine the associations between the CSAs of the masseter, bruxism, and gender.

RESULTS

The frequency of bruxism and reports of muscle or joint pain were significantly higher in women. The analysis revealed that a larger masseter CSA was significantly associated with bruxism only in men. The larger CSA was manifested only in the higher frequency bruxers.

CONCLUSIONS

Bruxism had heterogeneous effects on the masseter muscle between genders. Although a higher prevalence of bruxism was reported by women, the larger CSA of the masseter muscle was significantly higher in bruxing men but not in women. This study emphasizes the need for a gender-specific approach when evaluating the clinical implications of bruxism on the masseter muscle.

Evaluation of fractal analysis and radiomorphometric measurements of mandibular bone structure in bruxism and non-bruxism paediatric patients

OBJECTIVES

The goal of this examination was to compare the impact of probable sleep/awake bruxism on the mandibular trabecular bone structure by fractal analysis (FA) with digital panoramic radiograph (DPR) and radiomorphometric measurements in paediatric patients with bruxism.

METHODS

The examination included 130 participants with 63 patients with probable sleep/awake bruxism and 67 control groups. Bilateral regions of interest (ROI) in three regions were examined as ROI1: mandibular ramus, ROI2: mandibular angulus, ROI3: anterior to the molar teeth. Radiomorphometric measurements were taken of the mandibular cortical width (MCW), panoramic mandibular index (PMI), and mandibular cortical index (MCI). p < 0.05 was approved for statistical significance.

RESULTS

The ROI-1, ROI-2, and ROI-3 values were defined to be statistically significantly high in the bruxism group (p < 0.05). No significant difference was found between the groups in the other values (p > 0.05). There was no difference in the age and gender for any of the parameters (p > 0.05).

CONCLUSION

In children and adolescents, the mandibular trabecular bone can be affected by bruxism. FA can be used as an auxiliary method for finding the mandibular trabecular differences of patients with bruxism in paediatric dentistry just as it can for adults.

Condylar Parameters and Mandibular Movement Patterns in Bruxers Using an Optical Jaw Tracking System

Background/Objectives: Eccentric bruxism is a complex parafunctional activity that involves grinding of teeth and occurs more frequently during sleep. This study aimed to assess differences in condylar parameters (sagittal condylar inclination -SCI and Bennett angle -BA) and mandibular and condylar kinematics during functional and parafunctional movements in bruxers and non-bruxers and to assess a digital method for quantifying eccentric bruxism using an optical jaw tracking system (Modjaw®). Methods: The study group included subjects diagnosed with eccentric bruxism according to validated clinical diagnostic criteria. A control group of non-bruxer subjects with demographic characteristics similar to the study group was considered. Each participant underwent Modjaw® examination twice to assess the recordings' repeatability. The anterior guidance, mastication, and simulated eccentric bruxism were recorded. The SCI and BA were computed. The trajectories of interincisal inferior point (IIP), left condyle (LC), and right condyle (RC) in the frontal (F), sagittal (S), and horizontal (H) planes were outlined in rectangles to calculate areas of mastication and areas of eccentric bruxism (mm2). Intraclass correlation coefficient (ICC) was used to assess the recordings' repeatability. Comparisons between groups were performed using Student's t- and Mann-Whitney tests. The receiver-operator characteristic (ROC) curve was used to assess the diagnostic quality of the digital method. Results: Twenty bruxers (10 F and 10 M) and 20 non-bruxers (10 F and 10 M) were included. The ICC had values higher than 0.85. SCI, BA, and area of mastication for IIP, LC, and RC were similar between the groups (p > 0.05). The area of eccentric bruxism was significantly wider in the bruxers (p < 0.001). According to the ROC curve, the following cut-off areas (mm2) for eccentric bruxism were found in F, S, and H planes: IIP (18.05, 13.43, 16.28); LC (3.74, 10.83, 3.35); and RC (4.21, 10.63, 2.9), corresponding to sensitivity > 0.8, specificity > 0.75 and area under the curve (AUC) > 0.85. Conclusions: Mandibular and condylar kinematics during functional movements were similar in bruxers and non-bruxers. A novel digital method for quantifying eccentric bruxism was found using Modjaw®, which could serve as a tool for early detection of eccentric bruxism before the onset of clinical consequences.

Is there an association between parenting styles, personality traits, and parent-reported sleep bruxism in Brazilian children?

OBJECTIVE

To explore the relationship between parenting styles and children's personality traits and parental-reported sleep bruxism (SB).

METHODS

A total of 301 parents/caregivers of Brazilian children participated in this cross-sectional study and answered an online questionnaire addressing sociodemographic characteristics, sleep-related behaviors and parent-reported SB. The Brazilian versions of the Parenting Styles and Dimensions Questionnaire and the Eysenck Personality Questionnaire-Junior assessed children's parenting styles and personality traits. Descriptive analysis and multinomial logistic regression were used.

RESULTS

Boys (OR=2.07; 95% CI=1.09-3.91) whose snoring (OR=2.98; 95% CI=1.55-5.73) were associated with mild parent-reported SB. Boys (OR=2.61; 95% CI=1.20-5.70) and high levels of neuroticism (OR=2.27; 95% CI=1.06-4.860) were associated with moderate/severe parent-reported SB. Authoritarian parenting attitudes decreased the likelihood of moderate/severe parent-reported SB (OR=0.37; 95% CI=0.16-0.86).

CONCLUSIONS

Parents/caregivers who exhibited more authoritarian attitudes reported a lower prevalence of moderate/severe children SB. Neuroticism trait and snoring influenced the severity of parent-reported SB.

Sleep bruxism (SB) may be not associated with obstructive sleep apnea (OSA): A comprehensive assessment employing a systematic review and meta-analysis

Associations between obstructive sleep apnea (OSA) and sleep bruxism (SB) are the subject of discussion but have not been confirmed definitively. Therefore, the objective of this meta-analysis was to examine the relationship between OSA and SB. This systematic review was conducted in accordance with PRISMA 2020 guidelines. PubMed, Embase and Web of Science were screened up to February 2024. The risk of bias was assessed with the Joanna Briggs Institute tool. 2260 records were identified, but only 14 studies were included. The odds of SB presence in OSA did not differ from the control group (OR: 1.23, 95 % CI: 0.47-3.20). The chance of SB compared to controls also did not differ in mild OSA (OR: 1.56, 95 % CI: 0.76-3.18), in moderate OSA (OR: 1.51, 95 % CI: 0.77-2.94) and in severe OSA (OR: 1.50, 95 % CI: 0.68-3.29). Additionally, the odds of SB were not increased in moderate OSA in comparison to mild OSA (OR: 1.14, 95 % CI: 0.63-2.94), in severe OSA compared to moderate OSA (OR: 1.31, 95 % CI: 0.61-2.79) or in severe OSA compared to mild OSA (OR = 1.42, 95 % CI: 0.69-2.93). The presence of SB in OSA did not differ between genders (OR: 2.14, 95 % CI: 0.65-7.05). The quality of the major studies included is low; therefore, the noted lack of correlation between OSA and SB may require further research. The relationship between OSA and SB seems to be multi-faceted. Presented results should not exempt clinicians from exact diagnosis of concomitant sleep conditions in OSA subjects.

Genetic polymorphisms and bruxism: A scoping review

BACKGROUND

Recent studies have highlighted the multifactorial nature of bruxism, with behavioral, psychosocial, and physiological factors, including genetic predisposition, contributing to its development. However, the role of genetic markers in determining susceptibility to bruxism remains poorly understood, with limited studies offering significant findings.

OBJECTIVES

To identify the current knowledge to investigate the susceptibility of genetic markers for sleep (SB) and/or awake bruxism (AB).

MATERIALS AND METHODS

Seven electronic databases and two grey literature platforms were searched up to January 2024. We included studies that related different types of genes and/or genetic polymorphisms with different types of bruxism, regardless of age or sex of the participants. To be included the study must have described the form of detection of bruxism.

RESULTS

A total of 21 reports were included. Of these, 16 were primary research reports. The remaining five articles consisted of four systematic reviews and a literature review incorporating a systematic mapping process, and network visualization. Within the pool of 16 primary study reports, seven focused on the association of genetic polymorphisms with both SB and AB, while seven concentrated solely on the association with SB. One primary study reported results related to probable AB and one article did not specify the bruxism type. Regarding all the studied genes and polymorphisms, significant association results were obtained for 15 polymorphisms from 11 different genes. Self-reported SB was associated with genes from the serotonergic (5HTR2A) and dopaminergic pathways (DRD2, DRD3, and ANKK1), as well as genes encoding enzymes (COMT and MMP9) and proteins (ACTN3 and ANKK1). Instrumentally reported SB was linked only to the reverse telomerase gene (TERT). Self-reported AB was associated with the ACTN3 and ANKK1 genes.

CONCLUSION

This review identified 30 genes and 56 polymorphisms variations potentially associated with either SB or AB. However, few presented significant results regarding positive associations, mostly acting at neurotransmitter pathways. The authors recommend further studies to determine the susceptibility of genetic markers as a risk factor for bruxism.

The Role of Occlusal Appliances in Reducing Masseter Electromyographic Activity in Bruxism

Background/Objectives: Bruxism is a masticatory muscle activity, phasic or tonic, with/without teeth contact, that appears in sleep or an awake state. An instrumental technique used to measure the surface electromyographic (sEMG) activity of the masseter muscle is used to diagnose bruxism activity during sleep and while awake. The objective of this study was to compare the variation in bruxism (sleep and awake) indices and masseter activity indices in low sleep bruxism and moderate sleep bruxism before and after wearing an occlusal appliance (OA) for 3 months each night. Methods: A clinical interventional study was designed in which subjects diagnosed with sleep bruxism were randomly selected to be included in the study. After the first sEMG recording, two groups were formed: a low sleep-bruxism group (number of sleep-bruxism events/h between 2 and 4) and a moderate sleep-bruxism group (number of sleep-bruxism events/h equal or higher than 4). All subjects received treatment with a 3D-printed occlusal appliance and wore it each night for 3 months, at which point the second sEMG recording was performed. For each participant of this study, a chart was created that included anamnestic data, clinical data, and sEMG data. The data were statistically analyzed with SPSS, using the Mann-Whitney U and Wilcoxon signed-rank tests. Results: A total of 21 participants were included in the final analysis, 18 women and 3 men, with a mean age of 24.5 ± 2.7 years. The OA lowered all bruxism indices in the whole group, but clusters analysis showed a significant reduction in sleep-bruxism indices in the moderate sleep-bruxism group, while in the low-bruxism group, the sleep and awake indices varied insignificantly, and the number of sleep-bruxism events/h remained constant. Conclusions: The 3D-printed occlusal appliances significantly lowered the sleep-bruxism indices and sleep masseter activity indices recorded with a portable sEMG device in the moderate sleep-bruxism group. The OA lowered the awake-bruxism indices and awake masseter activity indices in the moderate sleep-bruxism group.

The Importance of Genetic Background and Neurotransmission in the Pathogenesis of the Co-Occurrence of Sleep Bruxism and Sleep-Disordered Breathing-Review of a New Perspective

Sleep bruxism (SB) and sleep-disordered breathing (SDB) are two prevalent conditions that significantly impact overall health. Studies suggest that up to 49.7% of individuals with SDB also exhibit symptoms of SB. This review aims to provide a comprehensive analysis of the role of genetic background and neurotransmission in the pathogenesis of the co-occurrence of SB and SDB. It seeks to synthesize current knowledge, highlight gaps in the existing literature, and propose a new perspective that integrates genetic and neurobiological factors. This review shows that both SB and SDB may be influenced by a combination of genetic, neurochemical, and environmental factors that contribute to their shared pathophysiology. The key neurotransmitters-dopamine, serotonin, and GABA-may play a significant role in their co-occurrence by regulating motor activity, sleep architecture, and respiratory control. Understanding genetic and neurochemical mechanisms may allow for more precise diagnostic tools and more personalized treatment approaches regarding SB and SDB. Clinically, there is a need for interdisciplinary collaboration between sleep specialists, dentists, neurologists, and geneticists. There is also a need to conduct large-scale genetic studies, coupled with neuroimaging and neurophysiological research, uncovering additional insights into the shared mechanisms of SB and SDB.

Bruxism, temporomandibular disorders, and headache: a narrative review of correlations and causalities

ABSTRACT

The co-occurrence of bruxism, temporomandibular disorders (TMDs), and headache is common in patients. However, there is conflicting evidence regarding whether this association is simply a result of their high prevalence or whether there are indeed causal relationships. This review provides an overview of the current state of research while taking into account the controversies surrounding research methods, particularly in definitions and diagnostic standards. Bruxism-defined as repetitive jaw muscle activity during sleep or wakefulness-is not a painful disorder but may-particularly in co-occurrence with TMD-worsen pre-existing headache. It seems important to differentiate between sleep and awake bruxism because of different impact on pathophysiological processes in different primary headache disorders such as migraine and tension-type headache. Temporomandibular disorder is a heterogenous entity with both myofascial and arthrogenous types of pain in addition to nonpainful disorders. Research suggests a correlation between TMD pain and migraine, as well as between awake bruxism and tension-type headache. However, psychosocial factors may act as confounders in these relationships. Determining causality is challenging because of the limited number of experimental and clinical studies conducted on this topic. The main finding is an apparent lack of consensus on the definition and assessment criteria for bruxism. Treatment wise, it is important to differentiate all 3 conditions because treatment of one condition may have an effect on the other 2 without proving causality. For future research, it is crucial to establish greater consistency and applicability in diagnostic procedures and definitions. In addition, more experimental and clinical studies investigating the question of causality are needed.

Botulinum toxin for the management of bruxism: an overview of reviews protocol

INTRODUCTION

Bruxism is characterised by a repetitive activity in the masticatory muscles that involves teeth clenching or grinding and/or forceful mandibular movements. Its management is typically initiated when individuals start experiencing the adverse effects of the condition. One of the available intervention forms is the administration of botulinum toxin type A (BoNT-A). Numerous systematic reviews have addressed the use of BoNT-A to manage bruxism; however, the results are controversial. The current overview aims to determine BoNT-A's effectiveness for managing bruxism in relation to placebo, the absence of treatment or alternative interventions in the adult population.

METHODS AND ANALYSIS

This study will include systematic reviews (SRs), with or without meta-analysis, aiming to evaluate the efficacy of BoNT-A for bruxism in adults. A broad literature search will be carried out on Cochrane Library, EMBASE, LILACS, Livivo, PubMed/MEDLINE, Scopus, Web of Science and the grey literature. Experts in the topic and reference lists of included SRs will also be consulted. The study selection will be conducted in two phases by two independent reviewers. Data collection will be performed by one author and cross-checked by another. The methodological quality of included SRs will be evaluated using AMSTAR-II. A narrative synthesis will be employed as the formal method to combine individual study data. The overlap across studies will be quantified by the corrected covered area and illustrated by the Graphical Representation of Overlap for Overviews.

ETHICS AND DISSEMINATION

This overview does not require ethics approval, as it uses secondary data from previously published studies. The results will be disseminated through the publication in a high-impact journal.

OSF OF REGISTRATION

DOI: 10.17605/OSF.IO/RB45T.

What do Brazilian paediatric dentists know about bruxism in children? Cross-sectional study

PURPOSE

Little is known about the knowledge of paediatric dentists on bruxism in children. The aim of this cross-sectional study was to assess the knowledge of paediatric dentists on the concept, associated factors of bruxism and management of sleep bruxism (SB) in children'.

METHODS

An electronic questionnaire was sent to paediatric dentists in the state of Goiás, Brazil. Information was collected on (1) characteristics of the participants; (2) the concept of bruxism; (3) diagnosis; (4) associated factors; (5) strategies for the management of SB; and (6) updated knowledge on bruxism in children. The data were analysed descriptively.

RESULTS

Fifty-seven paediatric dentists participated (10.7% of the total number of professionals). A high level of agreement was found with statements on the concepts of SB (94.7%) and awake bruxism (96.5%). The main strategy for the diagnosis was the combination of a parental report and a clinical examination (79.0%). Most participants indicated that bruxism is associated with anxiety/stress (96.5%), screen use (93%), airway obstruction (91.2%), and sleep apnoea (91.2%). In suspected cases of bruxism, the dentists would send the child for assessment by other health care providers (87.7%). The management options frequently indicated were the use of an occlusal splint, aromatherapy, and homeopathy. More than 70% of them considered themselves to be updated on the issue and sought information through scientific articles and discussions with colleagues.

CONCLUSION

Paediatric dentists have knowledge on the concept of bruxism and associated factors. However, further information is needed on the management of this condition in children.

Sleep-related bruxism, microarousals and oxyhaemoglobin desaturations in sleep stages: A cross-sectional study in a large apnoeic population

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.

Genetics and sleep bruxism: a systematic review and meta-analysis of studies with twins

OBJECTIVE

To systematically review the literature regarding the concordance of sleep bruxism (SB) between monozygotic (MZ) and dizygotic (DZ) twins.

METHODS

The registration for this systematic review was accomplished in the International Prospective Register of Systematic Reviews (PROSPERO, No. CRD42021251751). As of July 2022, four databases were searched, including PubMed, Scopus, Embase, and Web of Science, as well as the grey literature in Google Scholar and OpenGrey. Observational studies evaluating SB in MZ and DZ twins of any age and sex were included. For the evaluation of the risk of bias, the Joanna Briggs checklist was utilized. The certainty of evidence was assessed via the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Pooled and subgroup meta-analyses were performed to estimate concordance of SB ​​between twins (p < 0.05).

RESULTS

In total, 3,155 records were identified. In the qualitative analysis, eleven studies were included; of these, seven were included in the meta-analysis. The majority of the articles exhibited a low risk of bias (63.6%). Greater SB concordance was observed between MZ twins than between DZ twins in the analysis of general concordance (OR = 1.47; 95% CI = 1.07-2.02) and also positive concordance (OR = 1.53; 95% CI = 1.29-1.81). Within the subgroup analyses, the significance of the findings remained only for the reported/self-reported SB regarding general concordance (OR = 1.44; 95% CI = 1.07-1.95) and positive concordance (OR = 1.55; 95% CI = 1.28-1.88). Low certainty of the evidence was observed for the general concordance analysis, while moderate certainty was observed for the positive concordance.

CONCLUSION

There was a higher concordance of SB in MZ twins compared to DZ twins, indicating a possible genetic influence on the condition's occurrence.

The neural substrates of bruxism: current knowledge and clinical implications

Bruxism is a complex orofacial behavior that can occur during sleep or wakefulness, characterized by the involuntary grinding or clenching of teeth, involving repetitive activity of the jaw muscles. Its etiology is multifactorial, influenced by genetic, psychological, physiological, and lifestyle factors. While the mild bruxism may not necessitate treatment, severe bruxism can lead to significant consequences, including tooth damage, jaw pain, fatigue, and headaches. The bruxism has been associated with medical conditions, such as stress, anxiety, sleep disorders, and various neurological disorders; however, the exact pathophysiology remains elusive. Although the central nervous system is strongly implicated in the development of bruxism, specific neural substrates have not yet been conclusively established. Furthermore, there is evidence to suggest that individuals with bruxism may exhibit neural plasticity, resulting in the establishment of distinct neural circuitry that control the jaw movements. The application of various neurophysiological techniques in both clinical and pre-clinical studies provides valuable insights into the neural mechanisms underlying bruxism. This review aims to comprehensively examine the current literature on the neural pathways involved in bruxism, with the goal of improving the clinical approach and therapeutics for this condition. A deeper understanding of the neural circuitry controlling bruxism holds the potential to advance future treatment approaches and improve the management of patients with bruxism.

Comparative evaluation of salivary melatonin levels in patients with bruxism: a case-control study

Aim: To examine whether there is any difference in the levels of salivary melatonin between bruxism and nonbruxism groups and to compare the stress and anxiety levels between the two groups.Materials & methods: Patients meeting the probable bruxism criteria according to the International Consensus on the Assessment of Bruxism Criteria were included in the bruxism group. The salivary melatonin concentrations of both groups were measured using an ELISA kit. To determine the relationship between stress and bruxism, the State-Trait Anxiety Inventory (STAI) test was used.Results: The bruxism group had a significantly lower night-time salivary melatonin level than the control group (p < 0.05). No significant difference was determined between the bruxism group and the control group in respect of the STAI-T scores (p > 0.05).Conclusion: The study findings revealed a strong relationship between a low melatonin level and bruxism.

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

BACKGROUND

The aetiology of Sleep bruxism includes specific personality traits, related to perfectionism.

AIM

To investigate the relationship between probable sleep bruxism (PSB) and personality traits in children and their parents, determining whether children with PSB and their parents are more perfectionists.

DESIGN

This case-control study included 104 children aged 8-9 years, 52 cases and 52 controls. A clinical examination was performed on the children who completed the Big Five Personality Questionnaire (BFQ-NA) and the Child Perfectionism Inventory. Parents completed a bruxism diagnostic questionnaire according to the AASM criteria, BFQ and Frost multidimensional perfectionism scale questionnaires. t-Tests for independent samples and multivariate logistic regression models were used for statistical analysis.

RESULTS

A significant relationship between PSB and a self-demanding personality (OR = 1.11, p = .01), restless sleep (OR = 4.41, p = .004), and a family history of clenching and grinding teeth (OR = 3.07, p = .0006) was found in a binary logistic regression model. When adjusted, only restless sleep showed a significant relationship with PSB (p = .03, OR 3.32, 95% CI 1.13-9.81).

CONCLUSION

Children whose parents reported as clenching or grinding their teeth while asleep in the previous 6 months, and who were found to have abnormal dental wear, had significantly more nightmares, sleep disruption, daytime sleepiness, family history of bruxism, and tended to be more perfectionist.

Probable sleep and awake bruxism in adolescents: A path analysis

BACKGROUND

Bruxism has a multifactorial etiology, including the influence of sleep characteristics and chronotypes.

AIM

To identify the pathways that influence the occurrence of probable sleep bruxism (PSB) and probable awake bruxism (PAB) in adolescents.

DESIGN

A total of 403 adolescents, aged 12-19 years, participated in the study. Parents/caregivers filled out a questionnaire about sociodemographic issues and the adolescent's health conditions, and the adolescents about sleep characteristics, occurrence of bruxism (based on previous study and the International Consensus of Bruxism), and chronotype (Circadian Energy Scale). Clinical examinations were performed. Statistical analysis included descriptive analysis and path analysis.

RESULTS

PSB and PAB are related to each other, with moderate and positive correlation (β = .390). Poor sleep quality and higher household income had a direct effect on both PSB (β = -.138; β = .123, respectively) and PAB (β = -.155; β = .116, respectively). Chronotype had a direct effect on PSB, in such a way that adolescents with a morningness chronotype tend to have PSB (β = -.102). Adolescents that drool on the pillow (β = .184) and/or have agitated sleep (β = .104) tend to have PSB.

CONCLUSION

Poor sleep quality, household income, morningness chronotype profile, drooling on the pillow, and agitated sleep influence the paths taken by PSB. PAB was influenced by the quality of sleep and family income.

Effects of the COVID-19 Pandemic on College Students in Brazil

The implementation of restrictive measures during the pandemic drastically changed the routine and habits of the population. In the academic sphere, the sudden closure of universities difficulted any advance planning. The objective of this study was to verify the effects of the pandemic on the routine, physical and mental health of students at a public university in southern Brazil. This is a cross-sectional study that applied a questionnaire from May to August 2020. The target population comprised 528 undergraduates. The questionnaire addressed questions about sociodemographic characteristics, physical and mental health. A response was obtained from 406 participants. During the quarantine period evaluated, the main results were: 66.2% reported worsening of anxiety symptoms; 57.6% declared that their physical health was "reasonable" to "bad". As for the quality of sleep there was an increase in 98.8% in the responses "bad sleep quality" and "very bad sleep quality"; increase in 26.6% for presence bruxism; 12.5% for orofacial pain, 3.8% for headache. It is concluded that there were several negative effects, among these effects, it was observed higher levels of anxiety, worsening physical health and quality of sleep, increase in the prevalence of bruxism, as well as the presence of orofacial pain and headache.

Automatic cephalometric landmark identification with artificial intelligence: An umbrella review of systematic reviews

OBJECTIVES

The transition from manual to automatic cephalometric landmark identification has not yet reached a consensus for clinical application in orthodontic diagnosis. The present umbrella review aimed to assess artificial intelligence (AI) performance in automatic 2D and 3D cephalometric landmark identification.

DATA

A combination of free text words and MeSH keywords pooled by boolean operators: Automa* AND cephalo* AND ("artificial intelligence" OR "machine learning" OR "deep learning" OR "learning").

SOURCES

A search strategy without a timeframe setting was conducted on PubMed, Scopus, Web of Science, Cochrane Library and LILACS.

STUDY SELECTION

The study protocol followed the PRISMA guidelines and the PICO question was formulated according to the aim of the article. The database search led to the selection of 15 articles that were assessed for eligibility in full-text. Finally, 11 systematic reviews met the inclusion criteria and were analyzed according to the risk of bias in systematic reviews (ROBIS) tool.

CONCLUSIONS

AI was not able to identify the various cephalometric landmarks with the same accuracy. Since most of the included studies' conclusions were based on a wrong 2 mm cut-off difference between the AI automatic landmark location and that allocated by human operators, future research should focus on refining the most powerful architectures to improve the clinical relevance of AI-driven automatic cephalometric analysis.

CLINICAL SIGNIFICANCE

Despite a progressively improved performance, AI has exceeded the recommended magnitude of error for most cephalometric landmarks. Moreover, AI automatic landmarking on 3D CBCT appeared to be less accurate compared to that on 2D X-rays. To date, AI-driven cephalometric landmarking still requires the final supervision of an experienced orthodontist.

Sleep Bruxism and Obstructive Sleep Apnea Are Not Risk Factors for Tension-Type Headache (TTH): A Polysomnographic Study

Background: Tension-type headache (TTH) is the most common primary headache. Obstructive sleep apnea (OSA) and sleep bruxism (SB) are two of the most common sleep disorders; however, the relationship between TTH, OSA, and SB has not been conclusively proved in the literature. The objective of our study was to estimate potential associations with OSA and SB in TTH subjects. Methods: 108 adult individuals who underwent polysomnography (vPSG) were included, and the group was divided into two subgroups: TTH (n = 34) and control (n = 74). The International Classification of Headache Disorders (ICHD-3) guidelines were used to diagnose TTH. OSA and SB diagnoses were based on vPSG examination with electromyographic (EMG) recordings and the American Academy of Sleep Medicine (AASM) criteria. The results were analyzed, where p < 0.05 was considered to be statistically significant. Results: In the TTH group, the incidence of SB was more than two times lower than the control (OR = 0.41, 95% CI: 0.17-0.96, p < 0.05). However, the incidence of severe SB (BEI > 4) was similar in the TTH and control groups (OR = 0.54, 95% CI: 0.21-1.35, p > 0.05). Additionally, phasic and tonic SB episodes were less frequent in the TTH group compared to the controls (p < 0.05). The mean apnea-hypopnea index (AHI) was not significantly different between the TTH and control groups (p > 0.05). The sleep architecture and respiratory disturbances did not differ between the examined groups (p > 0.05). Conclusions: SB is not a risk factor for TTH. Moreover, severe SB is not connected with TTH. OSA is not a risk factor for TTH. Sleep quality did not differ between both groups during PSG; therefore, TTH may not change sleep structure. The mechanism of these findings is still unclear, and further studies should explain in detail the association between TTH and OSA.

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.

Comparison of the efficacy of occlusal splint and botulinum toxin therapies in patients with temporomandibular disorders with sleep bruxism

PURPOSE

This study aims to evaluate the efficacy of occlusal splint and botulinum toxin (BTX) therapies for improving the pain scores and mouth opening in patients with temporomandibular disorders (TMD) with sleep bruxism (SB).

MATERIALS AND METHODS

A retrospective cohort study was conducted based on clinical record reviews of patients with TMD symptoms (e.g., temporomandibular joint [TMJ] pain, masticatory muscle pain, TMJ internal derangements, joint sounds, and limited mouth opening) and SB. The patients were divided into two groups: occlusal splint group and BTX group. Maximum unassisted mouth opening (MMO) and pain score on a visual analogue scale (VAS) before treatment and at 1‑, 3‑, and 6‑month follow-up were analyzed to evaluate the clinical outcomes.

RESULTS

A total of 60 patients (49 women and 11 men, mean age 34.63 ± 11.85 years) were enrolled. Each group had 30 patients. The comparisons of the groups at 1 and 3 months after treatment indicated that the BTX group had higher MMO values (P = 0.013 and 0.034, respectively) and lower VAS scores than the occlusal splint group (P = 0.000 and 0.001, respectively). No difference between the two groups was observed 6 months after treatment (P > 0.05).

CONCLUSIONS

Both occlusal splint and BTX treatment methods were successful in treating TMD with SB. BTX provided patients with rapid relief in the early period; therefore, BTX can be recommended as a primary treatment option in patients with greater pain.

Relationship between Sleep Bruxism Determined by Non-Instrumental and Instrumental Approaches and Psychometric Variables

Sleep bruxism (SB) can be determined with different diagnostic procedures. The relationship between psychometric variables and SB varies depending on the diagnostic method. The aim of the study was to compare the association between SB and oral health-related quality of life (OHRQoL; measured by the Oral Health Impact Profile, OHIP), anxiety (measured by the State-Trait anxiety inventory, STAI), and stress (single scale variable) depending on the diagnostic method in the same sample. N = 45 participants were examined by non-instrumental (possible/probable SB) and instrumental methods (definite SB). The OHIP differed significantly between possible SB (median = 4) and non-SB (median = 0) with W = 115, p = 0.01, and probable SB (median = 6) and non-SB (median = 0) with W = 101, p = 0.01). There was no significant difference in the OHIP score between definite SB and non-SB. For the other psychometric variables, the analyses revealed no significant differences between SB and non-SB in all diagnostic procedures. The results suggest that there is a difference between possible/probable and definite SB with respect to the association with OHRQoL. Certain aspects of possible/probable SB might be responsible for the poor OHRQoL, which are not measured in definite SB.

Effects of respiratory exercises in sleep bruxism and associated obstructive sleep apnea: a double-blind, placebo-controlled randomized clinical trial

PURPOSE

The aim of this study is to assess the effects of respiratory exercises (inspiratory and expiratory) in individuals with sleep bruxism (SB) and associated obstructive sleep apnea (OSA).

METHODS

This is a double-blind, placebo-controlled randomized clinical trial including individuals with SB and associated respiratory events in OSA. Respiratory physical therapy was performed using inspiratory (Threshold® IMT), expiratory (Threshold® PEP) muscle training, and compared with a placebo group. A total of 30 daily respiratory cycles (inspiration and expiration) were performed five times a week for 12 weeks. Individuals were reassessed at two times, at baseline (T1) and after 12 weeks of training (T2) by means of the Pittsburgh Sleep Quality Index and Polysomnography.

RESULTS

Awakening was significantly different (p ≤ 0.05) between the inspiratory group and placebo 12 weeks after respiratory physical therapy. The number of contractions of the masseter muscle differed between the inspiratory, expiratory, and placebo groups (p ≤ 0.05).

CONCLUSION

Respiratory physical therapy for OSA improved awaking levels in 80 and 67% of the number of masseter muscle contractions, when compared to placebo.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (No. RBR-9F6JKM).

Computational ensemble expert system classification for the recognition of bruxism using physiological signals

This study aimed to develop an automatic diagnostic scheme for bruxism, a sleep-related disorder characterized by teeth grinding and clenching. The aim was to improve on existing methods, which have been proven to be inefficient and challenging. We utilized a novel hybrid machine learning classifier, facilitated by the Weka tool, to diagnose bruxism from biological signals. The study processed and examined these biological signals by calculating the power spectral density. Data were categorized into normal or bruxism categories based on the EEG channel (C4-A1), and the sleeping phases were classified into wake (w) and rapid eye movement (REM) stages using the ECG channel (ECG1-ECG2). The classification resulted in a maximum specificity of 93% and an accuracy of 95% for the EEG-based diagnosis. The ECG-based classification yielded a supreme specificity of 87% and an accuracy of 96%. Furthermore, combining these phases using the EMG channel (EMG1-EMG2) achieved the highest specificity of 95% and accuracy of 98%. The ensemble Weka tool combined all three physiological signals EMG, ECG, and EEG, to classify the sleep stages and subjects. This integration increased the specificity and accuracy to 97% and 99%, respectively. This indicates that a more precise bruxism diagnosis can be obtained by including all three biological signals. The proposed method significantly improves bruxism diagnosis accuracy, potentially enhancing automatic home monitoring systems for this disorder. Future studies may expand this work by applying it to patients for practical use.

The incidence of dental fractures in the Italian population during the COVID-19 pandemic: An observational study

Background

The COVID-19 infection has become a pandemic after breaking out in China in the past months of 2019 and spreading rapidly worldwide. To counter this pandemic, several governments worldwide have taken several drastic measures to try to stop the spread of the virus, including a very strict lockdown that has caused a sudden and, in many cases, negative change in people's daily lives. In the literature, several studies have shown how the pandemic has significantly impaired many people's mental health, causing short- and long-term stress, anxiety, and sleep disturbances.

Introduction

This study aims to analyze the correlation between the stress caused by the COVID-19 pandemic and the parafunctions of the temporomandibular joint and masticatory muscles, which in turn, have led to an increase in the incidence of fractures and dental injuries. The ultimate goal is to understand the best choice the dentist must make in the preventive and therapeutic fields.

Materials and Methods

A questionnaire called "Incidence of tooth fractures during the COVID-19 pandemic" was prepared using the Google® Forms platform. This questionnaire consists of 13 questions. This electronic questionnaire was addressed to all dentists in the Campania Region (ITA) and disseminated through social networks such as WhatsApp® or Facebook® or E-mail.

Results

A total of 730 dentists completed the survey. Of these, 450 (61.7%) stated that the number of patients reporting muscle and joint pain in the morning had increased during the COVID-19 pandemic. 414 (56.7%) dentists noted an increase in parafunction and 392 (53.6%) an increase in dental fractures during the pandemic period.

Discussion and Conclusions

As can be seen from the study results, an important correlation was found between the stress resulting from the COVID-19 pandemic and dental fractures. The dental elements treated endodontically, depending on the extent of the damage, require restoration, which is also the best preventive strategy in the case of dental fractures.

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

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

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

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

Effects on Sleep Bruxism Activity of Three Different Oral Appliances: One Year Longitudinal Cohort Study

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.

Sleep Bruxism in Children: A Narrative Review

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.

A worldwide bibliometric analysis of the research trends and hotspots of bruxism in adults during 1991-2021

BACKGROUND AND OBJECTIVES

With the increasing attention to bruxism, the research on bruxism is increasing rapidly. However, there is still a lack of systematic bibliometric analysis in the field of bruxism in adults. This study aimed to comprehensively explore and visualize the global trends and research hotspots in the field of bruxism in adults during 1991-2021.

METHODS

The study searched the literature published during 1991-2021 in the Web of Science Core Collection database without language restrictions. VOSviewer, CiteSpace and Microsoft Excel were applied to analyse the authors, institutions, journals, countries, cited references, keywords and other information of the included publications, and construct visualized cooperation networks.

RESULTS

A total of 878 articles were finally included. The top two most productive authors in the past 30 years were Lobbezoo F and Manfredini D. ACTA-Amsterdam, Univ Sao Paulo, Univ Helsinki, Univ Padua, Univ Montreal, et al. were prominent institutions in this field. Journal of Oral Rehabilitation made outstanding contributions in this field. The United States produced the most documents in this field, followed by Brazil. Both countries and authors cooperated closely around the world. The two most cited articles focused on the definition, assessment and classification of bruxism. In recent years, diagnostic criteria and stress have begun to receive a lot of attention.

CONCLUSION

From 1991 to 2021, the attention to bruxism in adults continued to increase. Diagnostic criteria and stress may be potential research hotspots in this field. This study references relevant scholars on development trends and research hotspots.

Prevalence of awake Bruxism: A systematic review

OBJECTIVES

To identify the prevalence of Awake Bruxism (AB).

SOURCES

The electronic search was done in Embase, PubMed/MEDLINE, LILACS, Livivo, Scopus, and Web of Science databases up to January 2nd, 2023. The search strategies combined terms such as "bruxism," "awake," and related terms when conducting searches in databases. Grey literature was consulted through Google Scholar, ProQuest, and OpenGrey.

STUDY SELECTION

Two independent reviewers participated in the study selection stages and included observational studies assessing the prevalence of AB, detected using reporting feedback (self or family report), clinical examination, and/or instrumental methods, regardless of the sex and age of the population.

DATA

Methodological quality was assessed using the Joanna Briggs Institute's checklist for prevalence studies. Ratio meta-analyses were performed using R Statistics software.

RESULTS

From a total of 3,083 studies identified by the searches on databases, 322 articles were reviewed the full-text and a total of 81 (quantitative synthesis) and 83 (narrative synthesis) studies were included. Only fifteen studies reached complete methodological quality. Two overall meta-analyses were performed, grouped based on convenience and population-based samples. The overall prevalence for possible AB was 32.08 % and 16.16 %, respectively. For the subgroup analyses, the prevalence rate showed a wide variation in different studied populations, approximately 14 %-32 % for women and 19 %-30 % for men, for population-based and convenience studies, respectively.

CONCLUSION

Possible AB prevalence was set from 16 % to 32 %. Studies with probable AB and definitive AB are still necessary.

CLINICAL SIGNIFICANCE

Studying the prevalence of waking bruxism is of interest to both dentists and patients. Knowing the probability of patients having awake bruxism allows the dentist to offer comprehensive preventive approaches to patients, avoiding deleterious consequences resulting from this condition. The present study reveals that the condition of bruxism during wakefulness is present in one out of every six adult patients studied. In pediatric patients, although this condition seems to be equally present, not enough studies were found to support this information for probable and definitive bruxism.

Comparison of the Oral Health-Related Quality of Life, Sleep Quality, and Oral Health Literacy in Sleep and Awake Bruxism: Results from Family Medicine Practice

Objectives

Bruxism is a common oral behaviour. This study aimed to compare oral health-related quality of life, sleep quality, and oral health literacy in patients with and without possible sleep bruxism (SB) and awake bruxism (AB).

Materials and Methods

A cross-sectional study including 249 volunteers was conducted in a family medicine clinic of a tertiary hospital in Istanbul, Turkey. The American Sleep Medicine Association Bruxism Diagnostic Criteria, Pittsburgh Sleep Quality Index (PSQI), Oral Health-Related Quality of Life (OHRQoL) tool, Decay Missing Filled Total Teeth (DMFT) score, and Health Literacy Dental Scale-Short Form (HeLD-14) were assessed by face-to-face interviews. Data were examined using Kruskal-Wallis and Mann-Whitney U tests, Spearman correlation, and logistic regression analysis.

Results

The presence of SB and AB was detected as 41.4% and 21.7%, respectively, among 91 males and 158 females, with a mean age of 36.64 ± 11.60 years. Sleep and awake bruxers had a lower oral health-related quality of life (odds ratio (OR): 0.816, 95% confidence interval (CI) = 0.770-0.864 and OR: 0.923, 95% CI = 0.956-0.982, respectively). Poor sleep quality was detected 1.28 times higher in sleep bruxism (OR: 1.277, 95% CI = 1.152-1.415) and 1.14 times higher in awake bruxism (OR: 1.141, 95% CI = 1.230-1.058). The DMFT score was found to be 1.13 times higher in SB (OR: 1.129, 95% CI = 1.043-1.223). A higher HeLD-14 score was associated with a lower DMFT score (p < 0.001; r = -0.240). The oral health literacy score was lower in AB and SB groups than in patients without bruxism, but it was not statistically significant (p = 0.267, p = 0.376).

Conclusion

A lower oral health-related quality of life and poor sleep quality would be expected in the presence of SB or AB. However, patients may not be aware of it unless asked by a physician regardless of oral health literacy level.

Marginal Adaptation of In Vitro Class II Restorations Made Out of Bulk or Conventional Composite Using Single- or Multi-Layered Techniques

Objective: Testing the influence of various restorative materials (conventional or bulkfill composites) and filling techniques (single- or multi-layered techniques) on the in vitro marginal adaptation of large class II direct composites with supra and sub-gingival margins subjected to thermomechanical loading (TML). Methods: A total of 40 prepared teeth were attributed randomly to five experimental groups. In Group 1, restorations were made of multi-layered high-viscosity conventional composite (Tetric EvoCeram); in Groups 2 and 3, restorations were made of a high viscosity bulkfill composite (Tetric EvoCeram Bulk Fill) applied in one (Group 2) or three layers (Group 3); in Groups 4 and 5, restorations were made of a flowable bulkfill composite (SDR flow) applied in one (Group 4) or two layers (Group 5), covered with a layer of high-viscosity conventional composite (Ceram-X Universal). A single adhesive (OptiBond FL) was used in all groups. All specimens were submitted to a staged TML comprising three phases (2 × 500,000 and 1,000,000 cycles) at 50 N with 3350 thermal cycles (5 to 55 °C) every 500,000 cycles. The tooth-restoration interfaces on proximal surfaces were evaluated quantitatively by scanning electron microscopy, before and after each TML phase, hence at three timepoints (T0, T1, T2 and T3). The following segments were considered for evaluation: proximal, vertical enamel margins (assessed individually on both restoration sides), cervical enamel (restoration side above CEJ) and cervical dentin margin (restoration side below the CEJ). Results: TML induced a significant reduction in continuous adaptation at both enamel and dentin margins in all groups, with percentages of continuous margins ranging from 75.2 to 91.8% at T0, and decreasing to values ranging from 21.3 to 73.9% at T3. Both composite systems and layering protocols had a significant influence on marginal adaptation of the restorations, with statistical associations depending on the restoration group and the timepoint considered. Defective margins in enamel were all of a cohesive nature with micro-fractures, while in dentin, interfacial gaps were the main defect observed. Conclusions/Clinical significance: The present results highlighted significant degradation of marginal adaption after long-term in vitro fatigue test using materials even with high-viscosity conventional resin composites, applied with a proper layering approach in medium-large sub-gingival cavities. While no significant differences were observed at the dentin cervical margins, there was a tendency for better adaptation at the enamel margin when using a higher modulus material with a multi-layered technique.

Oral behaviors in young adults: a multidimensional evaluation of the influence of personality, coping, and distress

OBJECTIVES

This study explored the relationship of oral parafunction to the psychological variables of personality, coping, and distress. Correlates of sleeping/waking-state oral activities with the different psychological factors were also examined, along with psychological predictors for high parafunction.

MATERIALS AND METHODS

Young adults from a large private university were enrolled. The frequency of oral behaviors was appraised with the oral behavior checklist (OBC), and participants were stratified into low and high parafunction (LP/HP) groups following the DC/TMD. Personality traits, coping styles, and psychological distress were assessed with the Big Five Personality Inventory-10 (BFI-10), brief-COPE Inventory (BCI), and Depression, Anxiety, Stress Scales-21 (DASS-21) correspondingly. Statistical evaluations were performed using the chi-square/Mann-Whitney U tests, Spearman's correlation, and logistic regression analyses (α = 0.05).

RESULTS

Among the 507 participants (mean age 22.2 ± 1.5 years), 84.6% and 15.4% had low and high parafunction respectively. While personality profiles did not vary substantially, the HP group exhibited significantly greater emotion-focused/dysfunctional coping, general distress, depression, anxiety, and stress scores than the LP group. Associations between OBC and the various psychological variables were weak when significant or insignificant. Neuroticism and dysfunctional coping were moderately correlated to general distress, depression, anxiety, and stress (rs = 0.44-0.60/0.45-0.51). Multivariate analyses indicated that high parafunction was predicted by dysfunctional coping style (OR = 2.55) and anxiety (OR = 1.33).

CONCLUSIONS

Dysfunctional coping was the main risk factor for high parafunction, increasing its odds by about 2.5 times.

CLINICAL RELEVANCE

Oral parafunction appears to be a dysfunctional coping response to psychological distress.

Evaluation of mandibular trabecular and cortical bone by fractal analysis and radiomorphometric indices in bruxist and non-bruxist patients

BACKGROUND

The aim of this study was to evaluate the effect of bruxism on the cortical and trabecular bone of the mandible using the radiomorphometric indexes and fractal analysis (FA) additionally to examine the efficiency of FA as diagnostic test for bruxism.

METHODS

Evaluation was performed on panoramic radiographs of 94 bruxists and 94 non-bruxist individuals with the ImageJ program. Cortical bone was assessed with mandibular cortical index, mental index, and panoramic mental index. Trabecular bone in the condyle, gonial, and corpus region was evaluated by FA. An independent sample t and Mann-Whitney-U tests and Pearson and Spearman rank correlations were conducted for statistical analysis.

RESULTS

A total of 188 participants, 112 female, and 76 male, were included in the study. The sample age ranged from 18 to 43, with a mean of 27.55 (± 7.022) years. FA values of the angulus were significantly higher than those of the condyle and corpus, and the mean of the sample for the angulus, condyle, and corpus, respectively, were; 1.36 (± 10), 1.10 (± 0.9), 1.13 (± 0.8). There was a positive correlation between FA of the mandibular corpus and age (r = .163, p = .025). Females' values were smaller than males' in the FAs of three regions, and significant differences were found in FA of the condyle and angulus of the mandible, MCI, and PMI according to gender. There was no statistically significant difference between bruxist and non-bruxist patients in term of FAs of three regions, MCI, MI, and PMI values (p > .05).

CONCLUSIONS

FA of the condyle and angulus of the mandible, MCI, and PMI are significantly affected by gender. However bruxism doesn't cause a significant change in the fractal dimensions of the bone in the mandible and doesn't change substantially MCI, MI, and PMI.

Relationship between bruxism and mandibular bone modifications based on medical imaging: a scoping review

OBJECTIVES

This scoping review aimed to assess the current state of knowledge regarding the relationship between bruxism and changes in density or volume of mandibular bone, based on medical imaging.

METHODS

Literature review was conducted following the PRISMA-ScR protocol. PubMed, Web of Science and Cochrane library databases were searched for peer-reviewed articles by two blinded reviewers. Studies based on the evaluation of mandibular bone density and/or bone volume with imaging examination in adult patients were examined. The selected articles were summarized in PICOS tables and assessed for methodological quality.

RESULTS

Nine articles were included, according to the inclusion criteria. They showed that bruxer patients had more bony exostoses of the mandibular angle, smaller condyles, and morphological changes for cancellous and cortical mandibular bone compared to non-bruxer patients.

CONCLUSION

Bruxism seems to induce morphological and anatomical changes in the different regions of the mandibular bone (condyles, mandibular angle, mandible body). Given the heterogeneity of the included studies, these results should be interpreted with caution. Further studies are needed to support these results, in particular via the analysis of three-dimensional imaging to overcome the limitations of panoramic radiograph.

Accurate Diagnosis and Treatment of Painful Temporomandibular Disorders: A Literature Review Supplemented by Own Clinical Experience

Introduction

Temporomandibular disorders (TMD) is a multifactorial group of musculoskeletal disorders often with combined etiologies that demand different treatment plans. While pain is the most common reason why patients decide to seek help, TMD is not always painful. Pain is often described by patients as a headache, prompting patients to seek the help of neurologists, surgeons, and ultimately dentists. Due to the unique characteristics of this anatomical area, appropriate diagnostic tools are needed, as well as therapeutic regimens to alleviate and/or eliminate the pain experienced by patients. Aim of the Study. The aim of this study is to collect and organize information on the diagnosis and treatment of pain in TMD, through a review of the literature supplemented by our own clinical experience. Material and Methods. The study was conducted by searching scientific databases PubMed, Scopus, and Google Scholar for documents published from 2002-2022. The following keywords were used to build the full list of references: TMD, pain, temporomandibular joint (TMJ), TMJ disorders, occlusal splint, relaxing splints, physiotherapy TMD, pharmacology TMD, natural therapy TMD, diagnostic criteria for TMD, and DC/TMD. The literature review included 168 selected manuscripts, the content of which was important for pain diagnosis and clinical treatment of TMD.

Results

An accurate diagnosis of TMD is the foundation of appropriate treatment. The most commonly described treatments include physiotherapy, occlusal splints therapy, and pharmacological treatment tailored to the type of TMD.

Conclusions

Based on the literature review and their own experience, the authors concluded that there is no single ideal form of pain therapy for TMD. Treatment of TMD should be based on a thorough diagnostic process, including the DC/TMD examination protocol, psychological evaluation, and cone beam computer tomography (CBCT) imaging. Following the diagnostic process, once a diagnosis is established, a treatment plan can be constructed to address the patient's complaints.

Awake and Sleep Bruxism Prevalence and Their Associated Psychological Factors in First-Year University Students: A Pre-Mid-Post COVID-19 Pandemic Comparison

There is a broad consensus accepting that psychological variables such as stress, anxiety, or depression play an important role in bruxism. The COVID-19 pandemic has led to an increase in stress, anxiety, and depression levels. The purpose of this study was to evaluate the impact of the COVID-19 pandemic on possible awake and sleep bruxism prevalence and on the psychological factors associated with bruxism, comparing pre-pandemic, pandemic/lockdown, and post-pandemic samples of first-year students. A total of 274 dentistry students from the Complutense University of Madrid participated in the study: 92 from 2018/2019 (pre-pandemic), 90 from 2020/2021 (pandemic), and 92 students from 2021/2022 (post-pandemic) academic years. The participants filled out a thorough battery of validated questionnaires evaluating bruxism and different psychological characteristics, such as anxiety, depression, somatization, personality, and stress coping styles. While sleep bruxism prevalence was significantly higher for the pandemic group, awake bruxism was smaller in comparison to pre-pandemic and post-pandemic groups. The post-pandemic group also presented higher levels of neuroticism and agreeableness personality traits, and positive reappraisal than the pre-pandemic group, with the pandemic group somewhere in between. Additionally, both the pandemic and post-pandemic group showed higher levels of depression and acceptance/resignation coping styles than the pre-pandemic group. Thus, among the three groups of students, the post-pandemic group was the one that showed a larger effect of the pandemic situation in their psychological variables, presenting higher levels of anxiety (state and trait), depression, acceptation/resignation coping style, higher neuroticism (emotional instability trait), and lower agreeableness trait. Nonetheless, the increase of positive reappraisal in the post-pandemic group (an adaptive coping stress style) might be also a sign of recovery. The higher sleep bruxism for the pandemic group might be related to the pandemic situation and lockdown, passively suffered, possibly promoting feelings of impotency, increased levels of depression and acceptance/resignation (normally considered a passive/maladaptive coping style), while acute stressful situations derived from daily personal social interactions might have increased anxiety levels and induced higher levels of awake bruxism observed in both the pre-pandemic and post-pandemic groups. However, further research, including larger and more representative samples, is needed to confirm this possible relationship.

Clonazepam for the management of sleep disorders

BACKGROUND

The objectives of this review and meta-analysis of polysomnographic data are those to focus on the clinical use of clonazepam for the management of sleep disorders by re-analyzing clinical trials and randomized clinical trials which have been published in peer-reviewed journals.

METHODS

A review of the literature including clinical trials and randomized controlled trials was performed in PubMed®, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement protocol. A random effects model meta-analysis was then carried out for the four more frequently reported polysomnographic measures: total sleep time, sleep latency, sleep efficiency, and periodic leg movement during sleep (PLMS) index.

RESULTS

A total of 33 articles were retrieved and screened in full text, of which 18 met the criteria for review; among the latter, nine met the criteria for meta-analysis. The studies included in the review involved patients with insomnia, REM sleep behavior disorder, sleep bruxism, and restless leg syndrome or PLMS which reported, most often, an increase in total sleep time with clonazepam. A clear sleep-promoting effect of clonazepam was found also by meta-analysis.

DISCUSSION AND CONCLUSIONS

Our results indicate that the pharmacological treatment of sleep disorders with clonazepam must always be personalized according to the type of patient, the risk of addiction and the concomitant presence of respiratory disorders are key factors to take into account. However, in light of the clinical evidence of the few studies in the literature on the different types of disorders, more studies on the use of clonazepam (also in association with first choice treatments) are definitely needed.