The bruxism construct: From cut‐off points to a continuum spectrum

Botulinum Toxin for Bruxism: An Overview

This overview aimed at assessing botulinum toxin type A (BoNT-A)'s effectiveness in managing bruxism compared to a placebo, the absence of treatment, or other interventions in adults. Only systematic reviews (SRs), with or without a meta-analysis, were included. A comprehensive literature search was conducted on 16 June 2024, encompassing seven databases and grey literature sources. Experts and reference lists of the included SRs were also consulted. Study selection was conducted in two phases by two independent authors. Methodological quality was evaluated using AMSTAR-2. Overlap was assessed using the corrected covered area. The 14 included SRs addressed several outcomes. In most studies, BoNT-A showed effectiveness in reducing pain (n = 10), the frequency of bruxism events (n = 7), and the maximum bite force (n = 5). None of the SRs effectively evaluated BoNT-A's impact on functional movements. All of the included SRs scored "critically low" and "low" confidence rates in AMSTAR-2. Only one SR attempted to assess the certainty of the evidence, although unsuccessfully. The overlap across included SRs was rated as "high", with a corrected covered area of 10.11%. The current systematic reviews on BoNT-A for bruxism lack methodological quality, limiting the reliability of their findings. Despite evidence indicating a potential reduction in pain, bruxism events, and the maximum bite force, methodological limitations prevent definitive conclusions from being drawn. High-quality research with standardized methodologies is essential to establish BoNT-A's efficacy and support evidence-based clinical practice.

The Impact of Acute National Stress on Awake Bruxism Behaviour Among Young Adults-An Ecological Momentary Assessment Study

BACKGROUND

Awake bruxism (AB) is characterised by repetitive jaw muscle activity during wakefulness and is influenced by various stressors. Objective To investigate the effect of national stress (war) on AB muscle behaviours in young adults, the study was planned as a repeated cross-sectional study.

METHODS

Two groups were compared: one during peaceful times (no-national stress group, NoNS; n = 106, 63% female, age 25.4 ± 2.9 years) and one during wartime (an acute national stress group, AcuteNS; n = 82, 77% female, age 28.3 ± 3.3 years). AB behaviours were assessed through a single-point self-report and ecological momentary assessment using a dedicated smartphone application that recorded the frequencies of relaxed muscles, clenching, teeth contact, bracing and teeth grinding. The AcuteNS group additionally completed questionnaires on anxiety and depression, perceived stress, stress coping, ability to bounce back from stressful events, adjustment disorder and medication use.

RESULTS

AcuteNS group exhibited a lower frequency of relaxed muscle behaviour compared to the NoNS group (50.51 ± 29.76 vs. 63.04 ± 27.8, respectively, p < 0.005). Within the AcuteNS group, 68% of individuals were identified as having adjustment disorder. Subjects with adjustment disorder showed a lower frequency of relaxed behaviour and higher frequencies of clenching and teeth grinding than subjects without the disorder. A higher ability to bounce back from a stressful event was associated with an increased frequency of relaxed muscle behaviour, while AB presence and psychotropic medication use were associated with a reduced frequency of relaxed muscle behaviour (linear regression, R2 = 0.229).

CONCLUSION

Subjects' ability to bounce back or recover from stress is an important predictor of relaxed masticatory muscle behaviour during acute national stress.

Exploring post-traumatic stress among patients at a clinic for orofacial pain and dysfunction

OBJECTIVE

To explore the associations between traumatic events and post-traumatic stress on the one hand, and painful TMD, awake bruxism and sleep bruxism on the other.

METHODS

At a clinic for Orofacial Pain and Dysfunction, 701 patients completed self-report screening questionnaires between May 2023 and November 2024. On the basis of these data, we calculated descriptive characteristics, including the prevalence of PTSD. We tested our hypotheses using univariate and multivariate logistic regression analyses and Spearman's correlations and partial correlations.

RESULTS

The prevalence of PTSD (9.0 %) was higher (p < .001) than the general population's prevalence (3.8 %). The presence of PTSD was associated with the presence of painful TMD and awake bruxism. When no PTSD was present, there was no association between the three orofacial conditions and the experience of a traumatic event. Post-traumatic stress symptoms were significantly correlated to awake bruxism.

CONCLUSION

The presence of PTSD in this clinical sample was associated with the presence of painful TMD and awake bruxism. The presence of a reported potentially traumatic event without PTSD was not associated with painful TMD or awake bruxism. Finally, when examining symptom severity, the severity of awake bruxism was correlated to post-traumatic stress symptoms.

CLINICAL RELEVANCE

Increased knowledge about the role of post-traumatic stress in the aetiology of these orofacial conditions may enable tailoring treatment to these specific patient groups, and thus to increase the likelihood of treatment success.

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.

Orofacial pain symptoms in sleep bruxer or non-sleep bruxer: Insights from a population-based survey of puerperal women

OBJECTIVE

This study aimed to investigate the prevalence of orofacial pain (OP) symptoms among a large sample of women who self-identified as sleep bruxers or non-sleep bruxers and who had given birth in 2019 in the municipality of Rio Grande, RS, Southern Brazil.

METHODS

A standardized self-questionnaire was administered to assess OP symptoms. Chi-square tests were employed to compare proportions, and multivariate Poisson regression analysis with robust variance adjustment was used to estimate associations with sleep bruxers and non-sleep bruxers.

RESULTS

A total of 2225 women were included in the study, with 78 (3.5 %) reporting OP symptoms. In the adjusted analysis, self-reported OP symptoms were significantly associated with non-sleep bruxer women living with three or more people in the household (PR=8.40; 95 % CI 1.85-38.11), as well as severe anxiety (PR= 4.73; 95 % CI 2.00-11.18). Among sleep bruxers, a significantly lower OP symptoms prevalence for those who were able to rely on their friends in times of distress (PR= 0.17; 95 % CI 0.10-0.30), while those with personality disorders exhibited significantly higher OP symptoms prevalence (PR= 3.30; 95 % CI 1.04-10.45).

CONCLUSIONS

The prevalence of OP symptoms was higher among non-sleep bruxer women living with three or more individuals in the household and among those experiencing severe anxiety. Indeed, sleep bruxer women with personality disorders had a higher prevalence of OP symptoms, while those with strong social support demonstrated a lower prevalence.

Updating the Bruxism Definitions: Report of an International Consensus Meeting

BACKGROUND

Bruxism is receiving increasing attention from both clinicians and researchers over the past decades. Recently, it has become clear that some aspects of the currently proposed, expert-driven bruxism definitions raise questions and cause confusion among clinicians, researchers, educators and patients.

OBJECTIVES

The aim of this report is threefold: (1) to provide the reader with a glossary of the existing definitions, (2) to discuss frequently asked questions regarding these definitions and (3) to suggest a road map for the next steps to be taken towards a better understanding of bruxism.

MATERIAL AND METHODS

A closed (invitation-only) full-day workshop at the 2024 General Session & Exhibition of the International Association for Dental, Oral and Craniofacial Research (IADR) convened international bruxism experts to discuss the current definitions. Insights from these discussions were compiled, analysed and summarised.

RESULT

The present report provides a glossary of the constituent terms of the currently proposed definitions, an overview of the frequently asked questions and insights into the next steps to be taken. By current consensus and to avoid any further confusion, the addendum 'in otherwise healthy individuals' has been removed from the specific definitions of sleep and awake bruxism. In addition, the grading system's hierarchical organisation, as proposed previously, was revised and clarified, proposing the inclusion of terms based on self-reporting, clinical examination and device-based assessment tools.

CONCLUSION

To ascertain that we all use the same terminology, we recommend using the current publication when referring to the definitions of bruxism and its constituent terms.

Comparison Between Ecological Momentary Assessment and Self-Report of Awake Bruxism Behaviours in a Group of Healthy Young Adults

OBJECTIVE

The aim of this investigation was to compare the self-reported frequency of awake bruxism (AB) behaviours by means of a validated single-observation point questionnaire (i.e., Oral Behaviour Checklist [OBC]) with the frequency reported in real-time with an Ecological Momentary Assessment (EMA) over 1 week.

MATERIALS AND METHODS

One hundred healthy young adults took part in the study. The frequency of some activities belonging to the spectrum of AB behaviours (i.e., teeth contact, mandible bracing, teeth clenching, teeth grinding) was evaluated using the EMA approach with smartphone technology support over 1 week. The OBC questionnaire was used to evaluate the self-reported frequency of the same AB behaviours. Spearman's rank correlation coefficient was adopted to test the correlation between the average score of each OBC question considered (i.e., teeth contact, mandible bracing, teeth clenching, teeth grinding) and the average frequency of the corresponding EMA item.

RESULTS

Statistical analysis showed a weak-to-moderate level of correlation between the two different AB assessment methods. Mandible bracing showed the highest level of correlation, while teeth grinding had the lowest one.

CONCLUSIONS

While the OBC represents a valid and easy-to-administer screening tool for evaluating bruxism behaviours, the EMA approach provides a more detailed real-time report on AB behaviours.

Standardised Tool for the Assessment of Bruxism: Translation, Cultural Adaptation and Pilot Testing in Italy

BACKGROUND

Recently, the Standardised Tool for the Assessment of Bruxism (STAB) has been developed for use in clinical and research settings.

OBJECTIVES

The aim of the present study is to describe the process of forward and back translation and pilot testing of the STAB into Italian.

METHODS

The English version of the STAB was adopted as a template for translation into other languages, according to a step-by-step procedure led by the expert STAB bruxism panel and mother tongue experts in the field. In detail, the translation team was made up of 12 subjects: three study coordinators, two forward translators, two back-translators and five expert panellists. Following the translation process, a pilot test in patients, dentists and dental students was performed using the 'probing' method (i.e., subjects were questioned by the examiners about the perceived content and interpretation of the items) with the aim to assess the comprehensibility of the questions and response options, and the feasibility of the tool.

RESULTS

This paper describes the translation process of the STAB and provides the outcomes of the pilot testing phase and the face validity assessment. The preliminary results suggest that, from a global point of view, the STAB reflects the characteristics required in clinical and research settings.

CONCLUSION

Thanks to the translation process, the Italian version of the STAB can be assessed on-field and introduced in the clinical and research field to get deeper into the study of bruxism epidemiology in Italy.

Efficacy of occlusal splint versus sleep hygiene and progressive muscle relaxation on perceived stress and sleep bruxism: A randomized clinical trial

PURPOSE

The objective was the comparison of an occlusal device (OD), and sleep hygiene and progressive muscle relaxation (SH & PMR) on perceived stress and sleep bruxism activity (burst/episode and episode/hour) in participants with sleep bruxism.

MATERIAL AND METHODS

Sixty-six participants with self-reported sleep bruxism were selected and randomly allocated into two groups: OD group or SH & PMR group. Assessment of perceived stress and sleep bruxism activity were the primary outcomes. The Perceived Stress Scale-10 (PSS-10 scale) was used to measure perceived stress and bruxism episodes/hour and bursts/episode recorded by electromyography of masseter and temporalis. These outcomes were assessed at baseline, 1 month, 6 months, and 1 year. The paired t-test assessed changes in PSS-10 scores and sleep bruxism activity within the same group over different time points (baseline, 1 month, 6 months, and 1 year). The unpaired t-test compared scores between two groups (OD and SH & PMR) at each time point to evaluate intervention differences. The chi-square test compared gender distribution between both groups.

RESULTS

PSS-10 scores were found to decrease with the OD at 1 month and 6 months compared to baseline and SH & PMR at all subsequent follow-ups. This decrease was not statistically significant (p > 0.05) between the OD and SH & PMR groups at all follow-ups. OD and SH & PMR significantly reduced bruxism episodes/hour and bursts/episode at all follow-ups (p < 0.05). There were no adverse effects related to any intervention.

CONCLUSIONS

The OD and SH & PMR both effectively reduced PSS-10 scores over 6 months and significantly decreased bruxism episodes and bursts per episode. Both methods are safe and effective for managing sleep bruxism and reducing stress.

Moving beyond bruxism episode index: Discarding misuse of the number of sleep bruxism episodes as masticatory muscle pain biomarker

The objective of the current study was to evaluate the clinical utility of bruxism episode index in predicting the level of masticatory muscle pain intensity. The study involved adults (n = 220) recruited from the Outpatient Clinic of Temporomandibular Disorders at the Department of Experimental Dentistry, Wroclaw Medical University, during the period 2017-2022. Participants underwent medical interview and dental examination, focusing on signs and symptoms of sleep bruxism. The intensity of masticatory muscle pain was gauged using the Numeric Rating Scale. Patients identified with probable sleep bruxism underwent further evaluation through video-polysomnography. Statistical analyses included the Shapiro-Wilk test, Spearman's rank correlation test, association rules, receiver operating characteristic curves, linear regression, multivariate regression and prediction accuracy analyses. The analysis of correlation and one-factor linear regression revealed no statistically significant relationships between bruxism episode index and Numeric Rating Scale (p > 0.05 for all analyses). Examination of receiver operating characteristic curves and prediction accuracy indicated a lack of predictive utility for bruxism episode index in relation to masticatory muscle pain intensity. Multivariate regression analysis demonstrated no discernible relationship between bruxism episode index and Numeric Rating Scale across all examined masticatory muscles. In conclusion, bruxism episode index and masticatory muscle pain intensity exhibit no correlation, and bruxism episode index lacks predictive value for masticatory muscle pain. Clinicians are advised to refrain from employing the frequency of masticatory muscle activity as a method for assessing the association between masticatory muscle pain and sleep bruxism.

Exploring the associations of sleep bruxism and obstructive sleep apnea with migraine among patients with temporomandibular disorder: A polysomnographic study

BACKGROUND

Migraine is the most common disabling headache disorder in the world. Temporomandibular disorders (TMDs) are a group of conditions characterized by pain/dysfunction of masticatory muscles or their associated structures. There is a lack of studies concerning the association between sleep disorders such as sleep bruxism (SB), obstructive sleep apnea (OSA), migraine, and TMD, despite the increased prevalence of these conditions in TMD patients.

OBJECTIVE

Our case-control study assesses the potential relationship among SB, OSA, and migraine using polysomnography (PSG) among the group with TMD.

METHODS

One hundred nineteen patients with TMD were recruited and hospitalized in the Department and Clinic of Internal Medicine, Occupational Diseases, Hypertension, and Clinical Oncology at Wroclaw Medical University. Their sleep parameters were assessed by PSG according to American Academy of Sleep Medicine guidelines. Migraine diagnosis was based on the third edition of the International Classification of Headache Disorders. The group of 30 patients with median age 35.0 years (interquartile range [IQR]: 26.0, 41.0) were diagnosed with migraine and this group consisted of 17 without aura (MwoA) and 13 with aura (MwA). Thirty patients with migraine were compared to 89 patients with TMD without migraine (controls) with median age 37.0 years (IQR: 26.0, 44.0).

RESULTS

Sleep bruxism was detected in 86% of the migraine group and 71.9% of control participants. The median bruxism episode index (BEI) among patients with migraine was 3.8 n/h (IQR: 2.7, 5.8) and 3.5 n/h (IQR: 1.8, 6.0) in the control group. SB and severe SB (respectively, BEI > 2 and BEI > 4) were not associated with migraine (odds ratio [OR] = 2.68, 95% confidence interval [CI]: 0.84-8.55, p = 0.095; OR = 0.98, 95% CI: 0.42-2.32, p = 0.966). However, mixed bruxism episodes were more frequent in the migraine group compared to study participants not experiencing migraine (median 0.7 n/h [IQR: 0.4, 1.6] vs. median 0.5 n/h [IQR: 0.2, 0.9], p = 0.044; OR = 1.96 with 95% CI: 1.16-3.32, p = 0.013). The median average duration of SB episodes in the migraine group was longer than in the controls (7.0 s [IQR: 5.5, 8.4] vs. 5.9 s [IQR: 5.1, 6.6], p = 0.005). The apnea-hypopnea index (AHI) value was not associated with migraine compared to controls (OR = 1.01, 95% CI: 0.96-1.06, p = 0.605), but MwoA had significantly increased AHI values compared to MwA (mean AHI = -0.1, standard deviation [SD] = 1.5 for MwA vs. mean AHI = 0.9 with SD = 1.3 for MwoA, p = 0.049).

CONCLUSION

Sleep bruxism may not be associated with migraine among patients with TMD; however, mixed bruxism episodes were more frequent in the migraine group. The increased duration of SB episodes in patients with migraine may suggest the common background of these conditions. OSA is also not associated with migraine; however, MwoA might increase the odds of OSA. There is a need to further explore sleep disturbances and migraine, especially in groups with their increased prevalence, such as patients with TMD.

The link between sleep bruxism and oxidative stress based on a polysomnographic study

Oxidative stress is proven to increase cardiovascular risk and to diminish healthy life expectancy. Sleep bruxism (SB) is a prevalent masticatory muscle activity during sleep characterized by heterogeneous etiology and inadequately recognized pathophysiology. Recent theories have proposed a potential association between SB and oxidative stress. The aim of the research was to compare the antioxidant status between individuals with SB in contrast to those without SB. A total of 80 adults participated in a full-night polysomnography, assessed according to the American Academy of Sleep Medicine (AASM) standards. Blood samples were subsequently drawn via venipuncture for analysis. Participants were stratified into two groups based on their bruxism episode index (BEI). Using successive receiver operating characteristic (ROC) curves, optimal cut-off values were identified, enabling the detection of correlations with moderate (BEI > 2) and severe (BEI > 4) sleep bruxism. In the investigated group of patients we observed the relationship between bruxism and the examined parameters: total antioxidant status (TAS), advanced protein products (AOPP) and thiobarbituric acid-reacting substances (TBARS). Low TAS (≤ 0.14 mM and ≤ 0. 16 mM), high AOPP (≥ 82.44 µmol/l) and high TBARS (≥ 723.03 µmol/l and ≥ 1585.45 µmol/l) serum levels result in significantly higher sleep bruxism parameters. Sleep bruxism is related to oxidative stress markers. Elevated markers of lipid and protein peroxidation may be associated with endovascular damage and cardiovascular risk in sleep bruxers, but further research is needed in this topic.

Long-Term Study on the Fluctuation of Self-Reported Awake Bruxism in a Cohort of Healthy Young Adults

BACKGROUND

The introduction of a smartphone-based ecological momentary assessment (EMA) approach has allowed achieving data on the frequency of different awake bruxism (AB) behaviours (i.e., teeth contact, teeth clenching, teeth grinding, and mandible bracing) reported by an individual in the natural environment.

STUDY OBJECTIVES

The fluctuation of AB reports over time has a certain degree of variability that has never been investigated. Therefore, the aim of this investigation was to assess the long-term fluctuation of AB behaviours in a population of young adults.

METHODS

A smartphone application was used to assess a real-time report on five specific oral conditions related to AB in a sample of 77 young adults, aged 24.0 ± 0.8 years. Data were recorded over three periods of 7 days, with a three-month interval for a total of 6 months.

RESULTS

The average frequency of the relaxed condition was 72.9%, 78.2%, and 80.8% at the end of the first, second, and third sessions, respectively. On average, teeth contact and mandible bracing were the most frequently reported conditions, with a mean prevalence of 12.9% and 7%, respectively, whilst the frequency of teeth clenching and teeth grinding was less than 3%. The ANOVA test showed an absence of significant differences (p < 0.05) between the three recording periods, and the frequency was in general only moderately variable from day-to-day (e.g., the coefficient of variation (CV) for the condition "relaxed jaw muscles" was 0.3). No gender differences were detected either.

CONCLUSIONS

Findings suggest that in a population of healthy individuals, the frequency of AB behaviours over a six-month monitoring period is quite constant. This investigation represents a standpoint for future comparisons on the study of natural fluctuations of AB behaviours as well as on AB frequency in populations with risk/associated factors and possible clinical consequences.

Sleep bruxism and GERD correlation in a general population convenience sample

OBJECTIVE

To investigate the relationship between sleep bruxism(SB) and gastroesophageal reflux disease (GERD) with the use of validated questionnaires in a general population convenience sample.

METHODS

SB behaviour was evaluated in accordance with the Subject-Based Assessment strategy recommended in the Standardized Tool for the Assessment of Bruxism (STAB). .To evaluate GERD-related symptoms, the GERD-Q questionnaire was adopted. To study the correlation between current SB and GERD, Spearman test was performed. Mann-Whitney-U test was adopted to compare GERD-related symptoms in two distinct group comparisons based on the presence of current SB and a history of SB, respectively.

RESULTS

A significant but weak positive correlation between current SB and GERD was found (r = .112; p = .044). No significant differences in GERD-related symptoms between groups emerged.

CONCLUSIONS

This investigation showed a positive but weak correlation between current SB and GERD-related symptoms. Larger scale studies in representative samples are needed to further explore this correlation.

Effects of orthodontic aligners on the ecological report of awake bruxism

BACKGROUND

The demand for orthodontic treatment with aligners has recently increased, but their effects on awake bruxism (AB) behaviours have to be evaluated yet.

OBJECTIVES

This investigation assessed if aligners can affect oral behaviours (i.e. tooth contact, teeth clenching, teeth grinding and mandible bracing) that are related with the AB spectrum.

METHODS

The investigation was performed in a sample of 32 consecutively recruited healthy adult patients who required orthodontic treatment. The study protocol involved three different sessions of 1-week monitoring without aligners, with passive aligners and with active aligners, respectively. All patients underwent an orthodontic treatment with aligners and used a smartphone-based application for a real-time report (i.e. ecological momentary assessment [EMA]) of their AB behaviours. Recording time was set from 8.00 to 12.30 and from 14.30 to 22.00. Analysis of variance (ANOVA) was used to compare the average reported frequency for each activity within and between the different sessions. The coefficient of variation (CV) was assessed to evaluate daily fluctuations within the 7 days monitoring periods.

RESULTS

The average reported frequency of the relaxed condition was 64.9%, 63.0% and 60.0% during the sessions without aligners, with passive aligners and with active aligners, respectively. ANOVA showed no significant differences in any of the AB behaviours within (i.e. between 7 days of evaluation) and between the monitoring sessions (i.e. before orthodontic treatment, with passive aligners, with active aligners). No sex differences were detected, except for the 'tooth contact' report that showed a higher frequency in females.

CONCLUSION

The impact of our results in the orthodontic field is not negligible; clinicians can find support for the hypothesis that from a global point of view, wearing or not wearing aligners (passive and/or active) does not influence the frequency of AB behaviours at the short term.

Sleep Disorders Affecting Prognosis of Dental Treatment

This study provided an overview of the knowledge on the main sleep-related disorders and conditions affecting the prognosis of dental treatment: sleep bruxism (SB), obstructive sleep apnea (OSA), and gastroesophageal reflux disease (GERD). Current scientific evidence seems to suggest that these phenomena (ie, SB, OSA, GERD) belong to a circle of mutually relating sleep disorders and conditions where dental practitioners can play a key role in diagnosis and treatment.

3D printed versus milled stabilization splints for the management of bruxism and temporomandibular disorders: study protocol for a randomized prospective single-blinded crossover trial

BACKGROUND

Nowadays, stabilization splints for the management of bruxism and temporomandibular disorders (TMD) can be produced utilizing a digital workflow comprising a digital impression of the teeth, digital splint design, and computer-aided manufacturing of the splints. The latter is usually a milling process, however, more recently 3D printing gained popularity due to its better cost and time efficiency. It remains unknown whether 3D printed stabilization splints are inferior to milled splints regarding clinical outcomes.

METHODS

This clinical trial assesses the non-inferiority of 3D printed occlusal splints compared to milled occlusal splints in a monocentric prospective randomized single-blinded crossover trial with two cohorts. One cohort includes 20 participants with bruxism, the other 20 participants with pain-related TMD, i.e., myalgia, myofascial pain, or arthralgia of the jaw muscles/the temporomandibular joint(s) diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Michigan-type stabilization splints are fabricated in a digital workflow by milling or 3D printing using CE-marked materials within their intended purpose. The participants wear a milled and a 3D printed splint in a randomized order for 3 months each, with follow-up visits after 2 weeks and 3 months. Investigated outcome parameters are oral health-related quality of life (OHRQoL) evaluated by the Oral Health Impact Profile (OHIP-G14), participant satisfaction as rated on a visual analog scale, therapeutic efficacy, and technical result of the splints. In this context, therapeutic efficacy means antagonist wear and-in the TMD group-reduction of pain/disability assessed by the Graded Chronic Pain Scale (GCPS v2.0) and clinical assessment following the DC/TMD standard, while technical outcome measures splint fit, wear and fracture rate.

DISCUSSION

The trial will provide important information on the clinical outcome of 3D printed stabilization splints in comparison to milled splints and will, therefore, enable an evidence-based decision in favor of or against a manufacturing process. This, in turn, will guarantee for a maximum of the patient's OHRQoL during splint therapy, therapeutic efficacy, and longevity of the splints.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS) DRKS00033904. Registered on March 15, 2024.

A Two-Sample Mendelian Randomization Study of Neuroticism and Sleep Bruxism

Sleep bruxism (SB) affects a considerable part of the population and is associated with neuroticism, stress, and anxiety in various studies. However, the causal mechanisms between neuroticism and SB have not been examined. Understanding the reasons for SB is important as understanding bruxism may allow improved comprehensive management of the disorders and comorbidities related to it. Previous studies on the association of risk factors to SB have provided important symptomatic insight but were mainly questionnaire based or limited in sample size and could not adequately assess causal relationships. The aim of this study was to elaborate the possible causal relationship of neuroticism as a risk factor for SB through a Mendelian randomization (MR) approach by combining questionnaires, registry data, and genetic information in large scale. We performed a two-sample MR study using instrumental genetic variants of neuroticism, including neuroticism subcategories, in the UK Biobank (n = 380,506) and outcome data of probable SB using FinnGen (n [cases/controls] = 12,297/364,980). We discovered a causal effect from neuroticism to SB (odds ratio [OR] = 1.38 [1.10-1.74], P = 0.0057). A phenotype sensitive to stress and adversity had the strongest effect (OR = 1.59 [1.17-2.15], P = 0.0028). Sensitivity analyses across MR methods supported a causal relationship, and we did not observe pleiotropy between neuroticism and SB (MR-Egger intercept, P = 0.87). Our findings are in line with earlier observational studies that connect stress and SB. Furthermore, our results provide evidence that neurotic traits increase the risk of probable SB.

Performance evaluation of portable respiratory polygraphy for assessing sleep bruxism in adults

Background

Polysomnography (PSG) is the gold standard for sleep bruxism (SB) assessment, it is expensive, not widely accessible, and time‐consuming.

Objective

Given the increasing prevalence of SB, there is a growing need for an alternative, readily available, reliable and cost‐effective diagnostic method. This study aimed to evaluate the diagnostic validity of portable respiratory polygraphy (PRPG) compared with PSG for SB diagnosis.

Methods

One hundred and three subjects underwent simultaneous examinations using PRPG (NOX T3, NOX Medical) and PSG (NOX A1, NOX Medical) in a sleep laboratory.

Results

The mean Bruxism Episodes Index (BEI) measured by PRPG was 4.70 ± 3.98, whereas PSG yielded a mean BEI of 3.79 ± 3.08. The sensitivity for detecting sleep bruxism (BEI >2) by PRPG was 48.3%, with a specificity of 81.2%. The positive predictive value was estimated at 51.9%, and the negative predictive value at 78.9%. However, when distinguishing between mild bruxism (BEI >2 < 4) and severe bruxism (BEI >4), PRPG demonstrated a sensitivity of 77.8% and 68.3% and a specificity of 48.6% and 71.4%, respectively.

Conclusion

Polysomnography continues to be the SB diagnostic gold standard tool, as the sensitivity and specificity of PRPG are significantly lower when compared with PSG. Nevertheless, PRPG could serve as an alternative tool for SB screening or diagnosis, despite its limitations. Furthermore, our data indicate that comorbidities such as sleep apnea and sleep quality do not influence the diagnostic accuracy of PSG, suggesting its potential as a screening instrument in individuals with other sleep disorders.

Efficacy of wireless sensors in assessing occlusal and bite forces: A systematic review

BACKGROUND

The noteworthy correlation between bite force and masticatory performance emphasizes its significance as a meaningful and objective method for assessing oral function. Furthermore, in the study of bruxism, the measurement of intraoral bite force assumes critical importance. Given the importance of assessing occlusal forces and bite force, this systematic review aims to assess the efficacy of wireless sensors in measuring these forces.

METHODS

The search methodology employed in this systematic review adhered to the guidelines outlined by PRISMA. The strategy involved the exploration of various databases, including PubMed/MEDLINE, SCOPUS and SCIELO. An assessment tool was employed to evaluate the bias risk and study quality.

RESULTS

This systematic review encompassed six prospective clinical studies involving a total of 89 participants. Wireless sensors for measuring occlusal forces and bite forces were predominantly employed in healthy adults or individuals with bruxism, along with children undergoing orthodontic treatment. All wireless sensors employed in the studies underwent validation and reproducibility assessments, affirming their reliability. The findings indicated that all wireless sensors exhibited efficacy in detecting occlusal forces and bite forces.

CONCLUSION

Wireless sensors offer real-time monitoring of occlusal and bite forces, aiding in understanding force distribution and identifying bruxism patterns. Despite limited studies on their application, these sensors contribute to evolving insights. Integration into clinical practice requires careful consideration of factors like calibration and patient compliance. Ongoing research is crucial to address limitations and enhance the efficacy of wireless sensors in measuring occlusal and bite forces and managing bruxism.

The reports of specific waking-state oral behaviours, including awake bruxism activities, and psychological distress have a dose-response relationship: A retrospective medical record study

OBJECTIVE

To investigate if there are dose-response relationships between self-reported waking-state oral behaviours, including awake bruxism, and three indicators of psychological distress (depression, anxiety, stress).

METHODS

The study sample consisted of 1,886 patients with function-dependent TMD pain. Relationships between six non-functional and six functional waking-state oral behaviours, scored on a 5-point ordinal scale, and the psychological factors were investigated using ordinal logistic regression.

RESULTS

Mean age was 42.4 (±15.3) years, 78.7% being female. The odds of reporting the higher categories of non-functional oral behaviours depended on the severity of depression, anxiety, and stress. Most OR coefficients followed a quadratic dose-response distribution, the others increased linearly as the severity of the psychological scales increased. Almost no such associations were found with normal jaw function behaviours.

CONCLUSION

Within the limitations of this study, it may be concluded that non-functional waking-state oral behaviours, including awake bruxism, and psychological distress have a dose-response relationship, with higher levels of distress being associated with higher reports of oral behaviours.

Effects of orthodontic aligners on 24-hour masseter muscle activity: a multiple-day electromyographic study

OBJECTIVE

This study aimed to assess the effects of aligners on masseter muscle activity by using an electromyographic device in the home environment.

METHODS

The study was performed on healthy patients who required orthodontic treatment. Three different 24 h-EMG recording sessions were performed in different conditions: without aligners, with passive aligners, and with active aligners. The non-functional MMA work index (nfMMA-WI) and the non-functional MMA time index (nfMMA-TI) for both awake and sleep hours were assessed. ANOVA test was used to compare the average activity during the three recording conditions.

RESULTS

On average, a total recording time of 204.7 ± 7.9 hours were provided for each patient. For most patients, ANOVA test showed an absence of significant differences between the recording sessions.

CONCLUSIONS

The impact of our results is not negligible: clinicians can find remarkable support to the hypothesis that the use of aligners affects the MMA only in a minority of subjects.

Obstructive sleep apnoea, sleep bruxism and gastroesophageal reflux - mutually interacting conditions? A literature review

The purpose of the present manuscript is to provide an overview for researchers and clinicians summarizing the knowledge concerning the relationship between some of the main sleep-related conditions of dental interest: sleep bruxism (SB), obstructive sleep apnoea (OSA) and gastroesophageal reflux disease (GERD). Starting with the discussion of the evolving current knowledge on SB, the interconnections are discussed. Most of the available literature focused on the possible relationship between OSA and SB, but a clear pathophysiological connection or temporal relationship has not been identified. Despite the paucity of data on the possible commonalities, SB, OSA and GERD constitute a complex network of conditions that may affect the clinical and research dental practice, and they are rarely found in isolation. In this scenario, the key role of dental practitioners as sentinel in the case of these sleep-related conditions is important, thanks to their ability and the knowledge to identify signs, symptoms and risk factors that are signs of ongoing sleep-related conditions. Thus, dental practitioners are recommended to view bruxism as a potential gateway to medicine.

Relationship between sleep bruxism and obstructive sleep apnoea: A population-based survey

OBJECTIVE

Sleep bruxism (SB) and obstructive sleep apnoea (OSA) seem to be mutually associated. This study investigates the relationship between current SB and OSA-related symptoms and the difference in OSA-related symptoms between groups based on a history of SB.

METHODS

An online survey was drafted to report the presence of SB and OSA in sample of 243 individuals (M = 129;F = 114;mean(SD)age = 42.4 ± 14.4 years). The Subject-Based Assessment strategy recommended in the 'Standardized Tool for the Assessment of Bruxism' (STAB) was adopted to assess SB. To evaluate OSA-related symptoms, Epworth Sleepiness Scale (ESS) and STOP-BANG questionnaires were adopted. Correlations between current SB and OSA-related symptoms were evaluated by Spearman test. ESS and STOP-BANG scores were compared by Mann-Whitney U test in individuals with and a without positive SB history.

RESULTS

Current SB and SB history were reported by 45.7% and 39.1% of the sample, respectively. 73.7%, 21% and 5.3% of the responders showed a low, intermediate and high risk of OSA, respectively. Neither significant correlations between current SB and OSA nor significant differences between SB groups emerged.

CONCLUSIONS

This study did neither find any significant correlation between self-report of current SB and OSA nor significant differences in ESS and STOP-BANG scores between groups based on SB history.

Benefits of the combination of digital and analogic tools as a strategy to control possible awake bruxism: A randomised clinical trial

BACKGROUND

Awake Bruxism (AB) management includes cognitive and behavioural changes. Digital and analogic tools can be used to remind the individual to control/avoid AB behaviours. However, no study addressed both tools together.

OBJECTIVE

To compare the efficacy of the combination of digital (smartphone application) and analogic (adhesive reminders) tools versus digital tool alone for AB management.

METHODS

Seventy-two individuals diagnosed with probable AB were divided into 3 groups: Group 1 (n = 24), used both digital and analogic tools during 30 days; Group 2 (n = 24), used only a digital tool during 30 days and Group 3 (n = 24), used only a digital tool for the first 15 days and then added the analogic tool for 15 days. The AB frequency was measured in real-time with a smartphone app, which sent alerts asking the individuals if they were doing any AB behaviours (bracing, teeth contact, clenching or grinding). Groups were compared using one-way ANOVA and before-after adding an analogic tool (group 3) by paired t-test, considering α = 0.05.

RESULTS

All groups showed a decrease in AB behaviours at the end of the evaluation period. Group 1 (digital and analogic tools) showed the lowest average of AB behaviours among all groups; however, statistically significant differences were found only for the comparison between groups 1 and 2. In group 3, a significantly greater reduction in AB behaviours was found after combining both approaches.

CONCLUSION

The combination of digital and analogic tools showed the greatest reduction of AB frequency and can be recommended for AB control.

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.

Network analysis of sleep bruxism in the EPISONO adult general population

Sleep bruxism (SB) has been associated with biological and psychosocial factors. The assessment of SB includes self-report, clinical evaluation, and polysomnography. This study aimed to investigate the associations of self-reported SB with other sleep disorders and demographic, psychological, and lifestyle factors in the adult general population, and to investigate whether self-reported SB and polysomnographically (PSG) confirmed SB provide similar outcomes in terms of their associated factors. We recruited 915 adults from the general population in Sao Paulo, Brazil. All participants underwent a one-night PSG recording and answered questions about sex, age, BMI, insomnia, OSA risk, anxiety, depression, average caffeine consumption, smoking frequency, and alcohol consumption frequency. We investigated the link between SB and the other variables in univariate, multivariate, and network models, and we repeated each model once with self-reported SB and once with PSG-confirmed SB. Self-reported SB was only significantly associated with sex (p = 0.042), anxiety (p = 0.002), and depression (p = 0.03) in the univariate analysis, and was associated with insomnia in the univariate (p < 0.001) and multivariate (β = 1.054, 95%CI 1.018-1.092, p = 0.003) analyses. Network analysis showed that self-reported SB had a direct positive edge to insomnia, while PSG-confirmed SB was not significantly associated with any of the other variables. Thus, sleep bruxism was positively associated with insomnia only when self-reported, while PSG-confirmed SB was not associated with any of the included factors.

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

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

Self-reported bruxism in patients with post-traumatic stress disorder

OBJECTIVE

The present study aimed to investigate the association between self-reported awake/sleep bruxism, and orofacial pain with post-traumatic stress disorder (PTSD).

METHODS

A case-control study with a convenience sample was designed. Participants were recruited from a university-based Trauma Ambulatory. The diagnosis of PTSD was established through a clinical interview and the Structured Clinical Interview (SCID-I/P). Thirty-eight PTSD patients and 38 controls completed the Research Diagnostic Criteria for Temporomandibular Disorders Axis-II to categorize awake/sleep bruxism and orofacial pain. Following this, we performed a short clinical examination of the temporomandibular joint and extraoral muscles.

RESULTS

Adjusted logistic regression analysis showed that awake bruxism was associated with PTSD (OR = 3.38, 95% CI = 1.01-11.27, p = 0.047). Sleep bruxism was not associated with any covariate included in the model. In a Poisson regression model, PTSD (IRR = 3.01, 95% CI = 1.38-6.55, p = 0.005) and the muscle pain/discomfort (IRR = 5.12, 95% CI = 2.80-9.36, p < 0.001) were significant predictors for current orofacial pain.

CONCLUSIONS

PTSD was associated with self-reported awake bruxism and low-intensity orofacial pain. These conditions were frequent outcomes in patients previously exposed to traumatic events.

CLINICAL RELEVANCE

We suggest including a two-question screening for bruxism in psychiatry/psychology interviews to improve under-identification and to prevent harmful consequences at the orofacial level.

Influence of malocclusion on sleep bruxism and orofacial pain: data from a study in school children

OBJECTIVES

This cross-sectional school-based study explored the influence of malocclusion on temporomandibular disorders (TMD) pain complaints, and whether this association would be mediated by sleep bruxism in a representative sample of 7- to 8-year-old children.

METHODS

Path analysis estimated direct, indirect, and total effects of occlusal features on sleep bruxism and TMD pain in 7- to 8-year-old children. Occlusal features were assessed with Dental Aesthetic Index (DAI), orofacial pain complaints using the TMD pain screener, possible sleep bruxism based on self-reports, and probable sleep bruxism based on self-reports combined with clinical findings. Structural equation modeling analyzed data with confounding factors.

RESULTS

From 580 participants, possible sleep bruxism was observed in 136 children (31.5%), probable sleep bruxism in 30 children (6.7%), and TMD pain complaints in 78 children (13.8%). Malocclusion had no direct effect on either possible sleep bruxism [standardized coefficient (SC) 0.000; p = 0.992], or TMD pain complaints (SC - 0.01; p = 0.740). When probable sleep bruxism was set as the mediator of interest, malocclusion did not directly affect probable sleep bruxism (SC 0.01; p = 0.766), nor TMD pain complaints (SC - 0.02; p = 0.515). A direct effect of probable sleep bruxism on TMD pain complaints was observed with an SC of 0.60 (p < 0.001). However, in neither case, malocclusion indirectly affected TMD pain complaints via bruxism.

CONCLUSION

Malocclusion in 7- to 8-year-old children did not directly influence possible or probable sleep bruxism or TMD pain complaints. Instead, probable sleep bruxism was strongly associated with TMD pain complaints.

CLINICAL SIGNIFICANCE

The impact of occlusal features on TMD pain complaints and bruxism has been a long-standing controversy in dentistry. However, the scientific literature linking this association may be inconsistent, mainly due to biased sample selection methods with inadequate consideration of confounders. Further research should try to identify additional risk factors for TMD pain in addition to probable sleep bruxism in children.

Is there an association between sleep bruxism and obstructive sleep apnea? A case-control polysomnographic investigation

OBJECTIVES

To estimate the statistical and epidemiological association between Sleep bruxism (SB) and Obstructive sleep apnea (OSA) based on OSA severity, and to describe sleep data findings within the analyzed population.

METHODS

A case-control study (N = 37) was conducted on subjects with and without OSA. All subjects underwent a full-night polysomnographic recording at the Sleep Unit (Clinical Neurophysiology Department) of San Carlos University Hospital. The diagnosis and severity of OSA were determined using ICSD-3 and AASM-2.6 scoring. The definitive SB diagnosis was obtained through a self-report test, physical examination, and PSG recordings. Variables used to study the association between both conditions included the apnea and hypopnea episodes, the Apnea-hypopnea index (AHI), the number of SB episodes per night, and the bruxism index. Chi2, correlations, and ANOVA were calculated. The epidemiological association was calculated using the OR.

RESULTS

SB showed an epidemiological association with OSA, with an OR of 0.15 (0.036-0.68), suggesting it could be considered a protective factor (p < 0.05). OSA patients presented fewer average SB episodes (6.8 ± 12.31) than non-OSA patients (25.08 ± 31.68). SB episodes correlated negatively (p < 0.05) with the AHI and the number of hypopneas (p < 0.05). The average number of SB episodes was significantly higher in patients with mild OSA compared to those with severe OSA.

CONCLUSIONS

In this sample of patients with subclinical and mild OSA, SB may act as a protective factor. However, confirmation of these results with a larger sample size is necessary.

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

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

The bruxism screener (BruxScreen): Development, pilot testing and face validity

BACKGROUND

To assess awake and sleep bruxism, the Standardised Tool for the Assessment of Bruxism (STAB) is currently being developed. The STAB will be a comprehensive tool for the detailed assessment of bruxism behaviour itself as well as of its possible consequences, causes, and comorbid conditions.

OBJECTIVE

Since the STAB cannot fully meet the 'A4 principle' for a bruxism assessment tool, i.e., being Accurate (reliable and valid), Applicable (feasible), Affordable (cost-effective), and Accessible (suitable for everyday clinical use), the Bruxism Screener (BruxScreen) has been developed to be used in large-scale epidemiological research projects and, especially, in general, dental practices.

METHODS

The BruxScreen consists of two parts: a questionnaire (BruxScreen-Q) to be completed by patients, and a clinical assessment form (BruxScreen-C) to be completed by dentists.

RESULTS

This paper describes the development of the BruxScreen and provides the outcomes of the pilot testing phase and the face validity assessment (i.e. that the first impressions of the tool indicate that it adequately reflects the construct to be measured).

CONCLUSION

The resulting BruxScreen is considered ready for more profound psychometric testing in the general dental setting.

Correlations between sleep architecture and sleep-related masseter muscle activity in children with sleep bruxism

BACKGROUND

Sleep bruxism (SB) occurring during No-REM (nREM) sleep and increase in microarousals per hour have been described in adults, but not in children.

OBJECTIVE

To assess the correlation between sleep architecture and masseter muscle activity related to sleep bruxism (SB/MMA) in children.

MATERIALS AND METHODS

Forty-three children aged 7-12 years (mean age: 9.4 ± 1.3) with confirmed SB underwent a two-night polysomnographic (PSG) study in a sleep laboratory, for accommodation (first night) and data collection (second night). Data on sleep architecture (total sleep duration (TSD), sleep efficiency (SE), sleep onset latency (SOL), REM and nREM sleep duration and proportion and microarousals/hour during REM and nREM sleep) and episodes/hour of SB/MMA were recorded. Single and multiple-variable linear regression analyses were performed to assess the correlation between data on sleep architecture (predictors) and SB/MMA (dependent variable).

RESULTS

Shorter TSD, REM and nREM stage 1 sleep duration, longer SOL and more microarousals/hour during REM and nREM sleep were found to be positive predictors of SB/MMA in children in the multiple-variable regression analysis (R2  = 0.511).

CONCLUSION

Within the limitations of this study, it can be concluded that SB/MMA is correlated with altered sleep architecture in children (shorter total sleep duration (TSD), shorter nREM and REM sleep and higher microarousals during REM and nREM sleep). Nevertheless, the clinical significance of these findings need to be demonstrated in future studies.

Smartphone application to report awake bruxism: Development and testing of the Swedish version and a pilot study to evaluate family history in young adults and their parents

BACKGROUND

Together with psychosocial and hereditary factors, bruxism is a possible risk factor for orofacial pain. Bruxism is defined as a masticatory muscle activity characterized by repetitive or sustained tooth contact, or by bracing or thrusting of the mandible. A smartphone application to report awake bruxism (AB) has been developed and translated into more than 25 languages.

OBJECTIVE(S)

To translate the application into Swedish, adapt it to Swedish culture and conduct a study to evaluate the usability of the application for studies on family history and associated risk factors.

METHODS

Translation and cultural adaption of the Swedish version of the application (BruxApp) was carried out in a four-step sequential process. Ten young adults (22-30 years) were recruited together with ten parents (42-67 years) and reported their AB with the application over two seven-day periods. Pain, stress and parafunctional behaviours were assessed by questionnaires.

RESULTS

The back translation check showed minimal discrepancies between the translation and the English version. Participants did not report any problems with the application. Response rates for both groups were 65%. A difference in frequency of AB was shown between young adults and parents (22.0% vs. 12.5%, p < .001). A positive moderate correlation was found between AB and stress (r = 0.54, p = .017).

CONCLUSION

The use of application strategies enables data collection on AB which can be used in both clinical and research settings. The results suggest that the Swedish version is ready for implementation and for studies on the relationships between AB, family history and psychosocial factors.

Psychological distress and the belief that oral behaviours put a strain on the masticatory system in relation to the self-report of awake bruxism: Four scenarios

BACKGROUND

It is assumed that other factors than masticatory muscle activity awareness could drive the self-report of awake bruxism.

OBJECTIVES

To investigate the extent to which the report of awake bruxism is associated with psychological distress, and with the belief that oral behaviours put a strain on the masticatory system among TMD-pain patients.

MATERIALS AND METHODS

The study sample consisted of 1830 adult patients with reported function-dependent TMD pain. Awake bruxism was assessed through six items of the Oral Behaviors Checklist. Psychological distress was assessed by means of somatic symptoms, depression and anxiety. Causal attribution belief was measured with the question 'Do you think these behaviours put a strain on your jaws, jaw muscles, and/or teeth?'

RESULTS

Mean age of all participants was 42.8 (±15.2) years, 78.2% being female. Controlled for sex, positive, yet weak, correlations were found between awake bruxism and somatic symptom severity (rs  = 0.258; p < .001), depression (rs  = 0.272; p < .001) and anxiety (rs  = 0.314; p < .001): patients with the highest scores reported approximately twice as much awake bruxism compared to those with minimal scores. Controlled for age and sex, a positive, moderate correlation was found between awake bruxism and causal attribution belief (rs  = 0.538; p < .001). Patients who believed that performing awake oral behaviours put 'very much' a strain on the masticatory system reported four times more awake bruxism than patients who did not believe that these behaviours are harmful.

CONCLUSIONS

Based on the results and relevant scientific literature, the theoretical background mechanisms of our findings are discussed in four scenarios that are either in favour of the use of self-report of awake bruxism being a representation of masticatory muscle activity awareness, or against it.

Secondary bruxism: A valid diagnosis or just a coincidental finding of additional masticatory muscle activity? A narrative review of literature

INTRODUCTION

Bruxism is defined as a repetitive masticatory muscle activity that can manifest it upon awakening (awake bruxism-AB) or during sleep (sleep bruxism-SB). Some forms of both, AB and SB can be associated to many other coexistent factors, considered of risk for the initiation and maintenance of the bruxism. Although controversial, the term 'secondary bruxism' has frequently been used to label these cases. The absence of an adequate definition of bruxism, the non-distinction between the circadian manifestations and the report of many different measurement techniques, however, are important factors to be considered when judging the literature findings. The use (and abuse) of drugs, caffeine, nicotine, alcohol and psychoactive substances, the presence of respiratory disorders during sleep, gastroesophageal reflux disorders and movement, neurological and psychiatric disorders are among these factors. The scarcity of controlled studies and the complexity and interactions among all aforementioned factors, unfortunately, does not allow to establish any causality or temporal association with SB and AB. The supposition that variables are related depends on different parameters, not clearly demonstrated in the available studies.

OBJECTIVES

This narrative review aims at providing oral health care professionals with an update on the co-risk factors and disorders possibly associated with bruxism. In addition, the authors discuss the appropriateness of the term 'secondary bruxism' as a valid diagnostic category based on the available evidence.

CONCLUSION

The absence of an adequate definition of bruxism, the non-distinction between the circadian manifestations and the report of many different measurement techniques found in many studies preclude any solid and convincing conclusion on the existence of the 'secondary' bruxism.

Standardised Tool for the Assessment of Bruxism

OBJECTIVE

This paper aims to present and describe the Standardised Tool for the Assessment of Bruxism (STAB), an instrument that was developed to provide a multidimensional evaluation of bruxism status, comorbid conditions, aetiology and consequences.

METHODS

The rationale for creating the tool and the road map that led to the selection of items included in the STAB has been discussed in previous publications.

RESULTS

The tool consists of two axes, specifically dedicated to the evaluation of bruxism status and consequences (Axis A) and of bruxism risk and etiological factors and comorbid conditions (Axis B). The tool includes 14 domains, accounting for a total of 66 items. Axis A includes the self-reported information on bruxism status and possible consequences (subject-based report) together with the clinical (examiner report) and instrumental (technology report) assessment. The Subject-Based Assessment (SBA) includes domains on Sleep Bruxism (A1), Awake Bruxism (A2) and Patient's Complaints (A3), with information based on patients' self-report. The Clinically Based Assessment (CBA) includes domains on Joints and Muscles (A4), Intra- and Extra-Oral Tissues (A5) and Teeth and Restorations (A6), based on information collected by an examiner. The Instrumentally Based Assessment (IBA) includes domains on Sleep Bruxism (A7), Awake Bruxism (A8) and the use of Additional Instruments (A9), based on the information gathered with the use of technological devices. Axis B includes the self-reported information (subject-based report) on factors and conditions that may have an etiological or comorbid association with bruxism. It includes domains on Psychosocial Assessment (B1), Concurrent Sleep-related Conditions Assessment (B2), Concurrent Non-Sleep Conditions Assessment (B3), Prescribed Medications and Use of Substances Assessment (B4) and Additional Factors Assessment (B5). As a rule, whenever possible, existing instruments, either in full or partial form (i.e. specific subscales), are included. A user's guide for scoring the different items is also provided to ease administration.

CONCLUSIONS

The instrument is now ready for on-field testing and further refinement. It can be anticipated that it will help in collecting data on bruxism in such a comprehensive way to have an impact on several clinical and research fields.

Research routes on awake bruxism metrics: Implications of the updated bruxism definition and evaluation strategies

BACKGROUND

With time, due to the poor knowledge on it epidemiology, the need to focus on awake bruxism as a complement of sleep studies emerged.

OBJECTIVE

In line with a similar recent proposal for sleep bruxism (SB), defining clinically oriented research routes to implement knowledge on awake bruxism (AB) metrics is important for an enhanced comprehension of the full bruxism spectrum, that is better assessment and more efficient management.

METHODS

We summarised current strategies for AB assessment and proposed a research route for improving its metrics.

RESULTS

Most of the literature focuses on bruxism in general or SB in particular, whilst knowledge on AB is generally fragmental. Assessment can be based on non-instrumental or instrumental approaches. The former include self-report (questionnaires, oral history) and clinical examination, whilst the latter include electromyography (EMG) of jaw muscles during wakefulness as well as the technology-enhanced ecological momentary assesment (EMA). Phenotyping of different AB activities should be the target of a research task force. In the absence of available data on the frequency and intensity of wake-time bruxism-type masticatory muscle activity, any speculation about the identification of thresholds and criteria to identify bruxers is premature. Research routes in the field must focus on the improvement of data reliability and validity.

CONCLUSIONS

Probing deeper into the study of AB metrics is a fundamental step to assist clinicians in preventing and managing the putative consequences at the individual level. The present manuscript proposes some possible research routes to advance current knowledge. At different levels, instrumentally based and subject-based information must be gathered in a universally accepted standardised approach.

The development of the Standardised Tool for the Assessment of Bruxism (STAB): An international road map

This paper summarises the background reasoning and work that led to the selection of the items included in the Standardised Tool for the Assessment of Bruxism (STAB), also introducing the list of items. The instrument is currently being tested for face validity and on-field comprehension. The underlying premise is that the different motor activities included in the bruxism spectrum (e.g. clenching vs. grinding, with or without teeth contact) potentially need to be discriminated from each other, based on their purportedly different aetiology, comorbidities and potential consequences. Focus should be on a valid impression of the activities' frequency, intensity and duration. The methods that can be used for the above purposes can be grouped into strategies that collect information from the patient's history (subject-based), from the clinical assessment performed by an examiner (clinically based) or from the use of instruments to measure certain outcomes (instrumentally based). The three strategies can apply to all aspects of bruxism (i.e. status, comorbid conditions, aetiology and consequences). The STAB will help gathering information on many aspects, factors and conditions that are currently poorly investigated in the field of bruxism. To this purpose, it is divided into two axes. Axis A includes the self-reported information on bruxism status and potential consequences (subject-based report) together with the clinical (examiner report) and instrumental assessment (technology report). Axis B includes the self-reported information (subject-based report) on factors and conditions that may have an etiological or comorbid role for bruxism. This comprehensive multidimensional assessment system will allow building predictive model for clinical and research purposes.

Assessment of awake bruxism by a novel bruxism screener and ecological momentary assessment among patients with masticatory muscle myalgia and healthy controls

BACKGROUND

Bruxism is a masticatory muscle activity occurring during sleep or wakefulness, involving grinding and clenching of teeth and/or jaw bracing. As yet, the aetiology, epidemiology and consequences of awake bruxism (AB) are largely unknown.

OBJECTIVES

The aims of the study were to AB behaviours using a novel bruxism screener (BruxScreen) questionnaire part and Ecological Momentary Assessment (EMA; BruxApp©) on AB behaviours, and to investigate AB's prevalence among masticatory muscle myalgia patients and non-patients.

METHODS

Altogether, 115 participants (masticatory myalgia patients referred to a specialist clinic (n = 67) and non-patients (n = 46)) filled in a bruxism screener questionnaire to report bruxism behaviours and jaw symptoms. A selection of both groups did a week-long EMA (patients n = 12, non-patients n = 11) to report AB behaviours. The chi-squared test was used to determine group differences in categorical variables. A logistic regression model was fitted to study the probability of AB.

RESULTS

According to BruxScreen, bruxism behaviours and jaw symptoms were more frequent in patients than in non-patients (p < .001). Based on EMA, 14.6% of the behaviour in patients was tooth clenching; for non-patients, this was 0.5% (p < .000). Relaxed muscles were reported by patients and non-patients at 20.6% and 56.4%, respectively (p < .021). Logistic regression, adjusted by age and sex, revealed that patients reported AB 5 times more often than non-patients (OR 4.8, 95% CI 2.1-11.2).

CONCLUSION

Awake bruxism behaviours are significantly more frequent in masticatory muscle myalgia patients than non-patients and associate with frequent bruxism-related symptoms. Self-reported teeth clenching seems to be the most significant sign of AB behaviour.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL RELEVANCE

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

Diagnostic Accuracy of a Portable Electromyography and Electrocardiography Device to Measure Sleep Bruxism in a Sleep Apnea Population: A Comparative Study

BACKGROUND

The gold standard for diagnosing sleep bruxism (SB) and obstructive sleep apnea (OSA) is polysomnography (PSG). However, a final hypermotor muscle activity often occurs after apnea episodes, which can confuse the diagnosis of SB when using portable electromyography (EMG) devices. This study aimed to compare the number of SB episodes obtained from PSG with manual analysis by a sleep expert, and from a manual and automatic analysis of an EMG and electrocardiography (EKG) device, in a population with suspected OSA.

METHODS

Twenty-two subjects underwent a polysomnographic study with simultaneous recording with the EMG-EKG device. SB episodes and SB index measured with both tools and analyzed manually and automatically were compared. Masticatory muscle activity was scored according to published criteria. Patients were segmented by severity of OSA (mild, moderate, severe) following the American Academy of Sleep Medicine (AASM) criteria. ANOVA and the Bland-Altman plot were used to quantify the agreement between both methods. The concordance was calculated through the intraclass correlation coefficient (ICC).

RESULTS

On average, the total events of SB per night in the PSG study were (8.41 ± 0.85), lower than the one obtained with EMG-EKG manual (14.64 ± 0.76) and automatic (22.68 ± 16.02) analysis. The mean number of SB episodes decreases from the non-OSA group to the OSA group with both PSG (5.93 ± 8.64) and EMG-EKG analyses (automatic = 22.47 ± 18.07, manual = 13.93 ± 11.08). However, this decrease was minor in proportion compared to the automatic EMG-EKG analysis mode (from 23.14 to 22.47). The ICC based on the number of SB episodes in the segmented sample by severity degree of OSA along the three tools shows a moderate correlation in the non-OSA (0.61) and mild OSA (0.53) groups. However, it is poorly correlated in the moderate (0.24) and severe (0.23) OSA groups: the EMG-EKG automatic analysis measures 14.27 units more than PSG. The results of the manual EMG-EKG analysis improved this correlation but are not good enough.

CONCLUSIONS

The results obtained in the PSG manual analysis and those obtained by the EMG-EKG device with automatic and manual analysis for the diagnosis of SB are acceptable but only in patients without OSA or with mild OSA. In patients with moderate or severe OSA, SB diagnosis with portable electromyography devices can be confused due to apneas, and further study is needed to investigate this.

Centric relation-A biological perspective of a technical concept

BACKGROUND

Few terms and concepts have been so extensively debated in dentistry as the words 'centric relation' (CR). Debates involve its biological, diagnostic and therapeutic usefulness.

METHODS

A review of the literature on the current concepts on CR as a diagnostic or therapeutic aid in dentistry was provided. Clinical trials assessing the superiority of one CR recording method over the others to identify patients with temporomandibular disorders (diagnostic use) or to manage patients with prosthodontic or orthodontic needs (therapeutic use) were tentatively included.

RESULTS

Due to the absence of literature addressing either of the above targets, a comprehensive overview was provided. The diagnostic use of CR as a reference position to identify the correct position of the temporomandibular joint condyle within the glenoid fossa is not supported and lacks anatomical support. From a therapeutic standpoint, the use of CR can be pragmatically useful in prosthodontics as a maxillo-mandibular reference position when occlusal re-organization is warranted and/or when the position of maximum intercuspation is no longer available.

CONCLUSIONS

The derived occlusal goals from a diagnostic misuse of CR are generally the result of circular reasoning, that is a technique is based on the recording of a certain condylar position that is believed to be 'ideal' and the treatment is considered successful when such position is shown by the specific instrument that was manufactured for that purpose. The term 'Centric Relation' might be replaced with the term 'Maxillo-Mandibular Utility Position'.

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.

The association between sleep bruxism and awake bruxism: Polysomnographic and electromyographic recordings in women with and without myofascial pain

BACKGROUND

Sleep bruxism (SB) and awake bruxism (AB) are masticatory muscle activities that are rarely assessed in the same individuals and are thought to be associated with different behaviours.

OBJECTIVES

To investigate whether individuals engaging in SB also engage in AB, that occurs during rest and during stress-related activity, and to investigate whether SB and AB are associated with different characteristics.

METHODS

Females with myofascial pain (N = 122) and non-myofascial pain controls (N = 46) were evaluated for SB events and for AB events at rest and AB during stress-related activity, using electromyographic (EMG) recordings and a standardised scoring of bruxism events. The joint distributions between SB and AB events and EMG activity were evaluated, and the characteristic qualities of SB and AB were assessed.

RESULTS

Neither SB event rates nor the EMG activity associated with those events was associated with AB events rates or EMG activity, either at rest or during stress-related activity. On the contrary, event rates and EMG activity when awake and at rest were positively associated with events and activity during stress-related activity. SB was characterised mainly by grinding, while AB was characterised mainly by clenching.

CONCLUSION

Sleep bruxism and awake bruxism do not tend to occur in the same individuals.

Does dental rehabilitation under general anaesthetic contribute to the development of temporomandibular disorders in children and adolescents? A scoping review

BACKGROUND

Temporomandibular disorders (TMDs) have multiple aetiological factors. Although some evidence suggests invasive and lengthy dental procedures may contribute towards TMD development, there is a relative paucity in the literature regarding an association between elements of paediatric dental general anaesthesia (pDGA) and TMDs. This review aims to consider the impact of dental rehabilitation (and its constituent elements) performed under general anaesthesia on the development of TMDs in childhood and adolescence and identify theories and/or gaps in knowledge which may benefit from future research.

METHODS

Due to the need to preliminarily examine the nature and extent of the current evidence base, a scoping review approach was chosen. The review was conducted based on the framework provided by the methodological working group of the Joanna Briggs Institute (JBI) for conducting systematic scoping reviews. Electronic databases MEDLINE, Embase, Scopus, Web of Science and Cochrane Library were searched as well as the grey literature using OpenGrey, Nexis, Ethos, Google Scholar and ProQuest, with eligible studies uploaded onto Zotero (Mac Version 5.0.96.2).

RESULTS

A total of 810 records were identified. After removing duplicates and those not available in English, 260 were identified for title and abstract screening. Seventy-six records underwent full-text review of which only one met the broad inclusion criteria. The most common reasons for exclusion were no specific relation to general anaesthesia, not specifically relating to dental treatment and only being concerned with TMD management. The included study found that while development of TMDs following dental rehabilitation under GA did occur in children, whether the problems caused by treatment were exacerbated by other elements of the pDGA process remains unknown.

CONCLUSION

This review has confirmed a distinct paucity of research in this field. While there is no current tangible scientific evidence that common and routine dental procedures lead to TMD, the literature shows that alterations to any one or a combination of critical factors can contribute to TMD development, which may be collectively exacerbated by iatrogenic macrotrauma during the pDGA process. We have highlighted elements of pre-, peri- and post-operative pDGA, alongside biopsychosocial factors, which may contribute to TMD development in childhood and adolescence and may benefit from future research.