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.

Movement disorders of the stomatognathic system: A blind spot between dentistry and medicine.

Movement disorders of the stomatognathic system include oromandibular dystonia (OMD), oral dyskinesia, sleep/awake bruxism, functional (psychogenic) stomatognathic movement disorders (FSMDs), tremors, and hemimasticatory spasm (HMS). Most patients first consult dentists or oral surgeons. The differential diagnoses of these involuntary movements require both neurological and dental knowledge and experience, and some of these movement disorders are likely to be diagnosed as bruxism or temporomandibular disorders (TMDs) by dental professionals. However, excepting movement disorder specialists, neurologists may find it difficult to differentially diagnose these disorders. Patients may visit numerous medical and dental specialties for several years until a diagnosis is made. Therefore, movement disorders of the oral region may represent a blind spot between dentistry and medicine.The present narrative review aimed to describe the clinical characteristics and differential diagnoses of some movement disorders, as well as the problems bridging dentistry and medicine. Movement disorders have the following characteristic clinical features: OMD - task specificity, sensory tricks and the morning benefit; FSMDs - inconsistent and incongruous symptoms, spreading to multiple sites and the lack of sensory tricks; and HMS - the paroxysmal contraction of unilateral jaw-closing muscles, the persistence of symptoms during sleep and the loss of a silent period. A careful differential diagnosis is essential for the adequate and effective treatment of each involuntary movement. Refining the latest definition of bruxism may be necessary to prevent the misdiagnosis of involuntary movements as bruxism.Both dental and medical professionals should take an interest in the movement disorders of the stomatognathic system, and these disorders should be diagnosed and treated by a multidisciplinary team.

Is There an Increase in Possible Sleep Bruxism in Children Over Time? A Longitudinal Study.

BACKGROUND: Bruxism is a behaviour that has several consequences in an individual's life, especially when it starts in childhood. However, bruxism can be a potential protective factor, which is an attribute that reduces the chance of a negative health outcome. OBJECTIVES: To evaluate the incidence of sleep bruxism (SB) and dental wear in children and adolescents. MATERIALS AND METHODS: This longitudinal study began in 2014 and 2016 (baseline) with initial 1816 children followed for 5 and 3 years, respectively. The follow-up data collection started in 2019. The diagnosis of SB was parents report (baseline) and self-report (follow-up) due to age groups of each phase, and questions related to symptoms of SB were collected. Five calibrated examiners (kappa >0.7) collected the clinical data. The clinical variables were dental erosion and dental wear. Contextual, individual, behaviour and clinical characteristics were collected. A multilevel logistic regression model was used to investigate the association of contextual, individual, behaviour and clinical characteristics with SB. Poisson regression for repeated measures was performed to evaluate the incidence of SB and dental wear (incidence rate ratio-IRR and confidence interval-95% CI). RESULTS: Two hundred and fifty-three children and adolescents answered questionnaires and were clinically examined. The mean age of the follow-up in 2019 was 11.25 years old (±2.19). There was no increase in the incidence of SB (95% CI: 0.74-1.35). Children/adolescents had a 2.2 higher risk to present dental wear (95% CI: 1.89-2.60). SB at the follow-up was associated with the contextual variable, earache, erosion and awake bruxism. CONCLUSIONS: In this population, children with SB remained with this behaviour and showed higher dental wear over the years.

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.

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.

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.

Botulinum toxin for bruxism treatment: a nationwide study among oral and maxillofacial surgeons in Germany.

INTRODUCTION: This study aimed to evaluate the use of botulinum toxin (BTX) for the treatment of bruxism in oral and maxillofacial surgery in Germany. MATERIAL AND METHODS: A dynamic online questionnaire comprising 7 to 25 questions was formulated to gather general and specific information regarding using BTX to treat bruxism. The questionnaire underwent internal and external assessments for validation. Subsequently, it was distributed to 906 oral and maxillofacial surgeons (OMFS) affiliated with the German Association for Oral and Maxillofacial Surgery (DGMKG). Weekly reminders were dispatched over four weeks to enhance response rates. Participation in the study was voluntary and anonymized. Descriptive methods were employed for data analysis. RESULTS: 107 OMFS participated in the study, yielding a response rate of 11.81%. On average, 17 patients with bruxism were per month, with 4 of these patients receiving BTX therapy. BTX administration was frequently accompanied by splints and physiotherapy (35.51% of participants). Botox® (Allergan) was the preferred BTX preparation, utilized by 40.79% and reconstituted with saline by 92.11% of participants. The masseter muscles were primarily targeted for BTX treatment (67.57% of participants), averaging 29 BTX (Allergan-) units per side. Injection points for each masseter muscle typically amounted to six per side, preferred by 30.67% of participants. Follow-up assessments post-BTX treatment were conducted regularly, predominantly after four weeks, by 36% of participants. In 8% of cases, additional BTX injections were necessary due to inadequate outcomes. Side effects were reported in 4% of cases, commonly manifesting as a non-disturbing reduction in bite force. Most participating OMFS (61.84%) using BTX for bruxism therapy regarded bruxism treatment with BTX as evidence-based. Notably, 97.37% of respondents expressed their willingness to recommend BTX-based bruxism treatment to their colleagues. Overall, the efficacy of BTX therapy for bruxism was rated as good (53.95%) and very good (40.79%). CONCLUSION: The use of BTX for the management of bruxism among OMFS in Germany has demonstrated efficacy. Substantial variances in certain facets of bruxism treatment employing BTX have been observed. CLINICAL RELEVANCE: Additional research endeavors are warranted to comprehensively investigate distinct elements of BTX therapy for bruxism, including the optimal dosage of BTX units and the precise localization of injection sites across various muscles.

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.

Botox: Current and Emerging Trends for Dental Practitioners in Esthetic Dentistry.

There are numerous medical and dental disorders for which there are no effective traditional therapy options. For various medical and dental disorders, botulinum toxin (BT) can be employed as an alternate therapeutic option that uses the chemodenervation approach. The range of dentistry treatment choices is expanding quickly. Applications of non-traditional therapy alternatives, such as the use of BT, are becoming more and more common in this situation. Although BT has been shown to be effective in a number of circumstances, its application in esthetic operations, such as the treatment of facial wrinkles, has gained widespread acceptance. This research is especially interested in applications of BT related to dentistry in the craniofacial region. For many diseases that a dentist would be interested in treating, BT provides a temporary, reversible, and generally safe therapy option. Due to their extensive knowledge of the anatomy of the faciomaxillary region, dental surgeons are a potential pool of operators who, with a small amount of skill enhancement, can use BT in their toolkit. This broadens the scope of minimally invasive alternatives to invasive protocols or refractory conditions. An online search was conducted for the use of BT in dentistry; all studies and articles pertaining to the subject were chosen, and dental-related content was removed and summarized. The fundamentals of BT and some of its applications in dentistry are covered in this article. The comprehensive details of its application in dentistry will be covered in the upcoming sections.

Driving Stress-Induced Effects on the Orofacial Region and Its Functions and Health Behaviors in Riyadh: A Cross-Sectional Survey.

Driving stress is a multifaceted phenomenon, and the experience of driving invokes stress. Driving causes the activation of stress-response mechanisms, leading to short-term and long-term stress responses resulting in physiological and behavioral changes. The aim of this study was to evaluate driving stress-initiated effects on orofacial functions and health behaviors in the Riyadh population. A cross-sectional survey was conducted in Riyadh using a pre-validated set of questionnaires for habitual information, a driving stress assessment using a driving-behavior inventory, and an assessment of parafunctional habits and effects on orofacial functions. The results indicate that nearly 50% of the sample spends more than two hours commuting, and more than 50% of the sample has inadequate sleep and insufficient exercise. Oral parafunctional habits like nail biting (p = 0.039) and lip or object biting (p = 0.029) had a significant correlation with aggressive driving behaviors, whereas the grinding of teeth (p = 0.011), the clenching of jaws (p = 0.048), lip or object biting (p = 0.018), and pain in mastication (p = 0.036) had a positive correlation with driving dislikes. Driving stress can be detrimental to one's health and not only impacts health behaviors but also induces oral parafunctional habits and adversely affects orofacial regions and functions. Acute driving stress responses may be transient. However, prolonged driving stress can be maladaptive and can increase the risk of chronic diseases including chronic temporomandibular joint disorders and parafunctional habit-related changes in the oral cavity.

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.

Association of Malocclusion with Temporomandibular Disorders: A Cross-Sectional Study.

Background/Objectives: Temporomandibular disorders (TMD) encompass a range of musculoskeletal and neuromuscular conditions affecting the temporomandibular joint (TMJ) and associated structures. This cross-sectional study, conducted in a Portuguese TMD department, aimed to assess the relationship between malocclusion and TMD severity. Methods: Data on demographic variables, TMD clinical symptoms, and malocclusion classes were collected using the EUROTMJ database. The Chi-square test (χ2) identified associations, with their intensity measured by Cramér's V (φc). Results: The study included 1170 patients (932 females and 238 males), with a mean age of 41.73 ± 16.80 years. Most patients exhibited Angle Class I malocclusion (85.5%), followed by Angle Class II (13.5%) and Angle Class III (1.1%). Class II malocclusion was associated with increased TMD severity (p < 0.001), higher myalgia levels (p = 0.002), more frequent disc displacement without reduction (p = 0.002) and lower maximum mouth opening values (Class II: 38.13 ± 7.78 mm, Class I: 39.93 ± 8.67 mm). Significant associations were also found between malocclusion type and arthralgia (p = 0.021), mouth-opening limitation (p = 0.016), and TMJ crepitus (p = 0.017). In cases of malocclusion, the presence of oral signs of bruxism explained the degree of myalgia, disc displacement, and severity (p = 0.003; p = 0.048; p = 0.045). Conclusions: This study highlights that (1) the most common type of dental malocclusion in TMD patients was Class I; (2) Class II malocclusion was associated with increased TMD severity and oral signs of bruxism; and (3) Class III was rarely observed in TMD consultation. The findings suggest that bruxism behavior in cases of malocclusion may be significant in TMD.

Advanced Sensing System for Sleep Bruxism across Multiple Postures via EMG and Machine Learning.

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

The impact of print orientation and graphene nanoplatelets on biaxial flexural strength and cytotoxicity of a 3D printable resin for occlusal splints.

OBJECTIVES: 3D printing found its way into various medical applications and could be particularly beneficial for dentistry. Currently, materials for 3D printing of occlusal splints lack mechanical strength compared to polymethyl methacrylate (PMMA) used for standard milling of occlusal splints. It is known that print orientation and graphene nanoplatelets (GNP) can increase biaxial strength in a variety of materials. Thus, the aim of this study was to assess if adjustment of print orientation and addition of GNP improve biaxial strength and if they affect cytotoxicity of a 3D printable resin for occlusal splints. METHODS: Specimens were printed vertically and horizontally with a stereolithography (SLA) printer and multilayered GNP powder was added to the resin at different concentrations. Printed specimens were characterized by Raman spectroscopy, optical profilometer analysis and scanning electron microscopy. Biaxial strength was evaluated by biaxial flexural testing. Cytotoxicity of specimens on L929 and gingival stromal cells (GSC) was assessed by the toxdent test, the resazurin-based toxicity assay and live-dead staining. RESULTS: Horizontally printed specimens showed significantly higher biaxial strength and lower deformation. GNP did not improve biaxial strength and material deformation of 3D-printed resins. None of the specimens were cytotoxic to L929 cells or GSC. SIGNIFICANCE: Print orientation in SLA printing has a significant impact on biaxial strength and material deformation. 3D printable materials can reach comparable or even improved biaxial strength compared to PMMA when using the optimal print orientation while GNP has no beneficial effects on the biaxial strength of resins for 3D printing of occlusal splints.

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.

Effects of vibratory feedback stimuli through an oral appliance on sleep bruxism: A 14-week intervention trial.

Background/purpose: Various biofeedback stimulation techniques for managing sleep bruxism (SB) have recently emerged; however, the effect of the successive application of vibratory feedback stimulation has not been clarified. This study aimed to elucidate the effect of vibration feedback stimulation via an oral appliance (OA) on SB. Materials and methods: This prospective, single-arm, open-label intervention study included 20 participants diagnosed with "definite" SB who wore a specially designed OA for 98 nights at home. A force-based SB detection system triggered a vibrator attached to the OA. Vibratory stimulation was withheld during the first 3-week adaptation period (weeks 1-3), applied during the 9-week stimulation period (weeks 4-12), and withheld again during the post-stimulation period (weeks 13-14). The number and duration of SB events per hour of sleep were calculated based on piezoelectric signals recorded with the OA-based vibration feedback device and compared between weeks 3 and 4, 8, 12, and 14 and between weeks 12 and 14 using the Friedman test (post-hoc test with Bonferroni correction). Results: The duration of SB events significantly decreased after vibratory stimulation (weeks 3 versus 4, 8, and 12: P < 0.001, P = 0.026, and P = 0.033, respectively) and then significantly increased upon cessation of vibratory stimulation after the stimulation period (weeks 12 versus 14: P < 0.001). Conclusion: Contingent vibratory stimulation through an OA-based vibration feedback device may suppress SB-related masticatory muscle activity continuously for 9 weeks and may be an effective alternative for managing SB.

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.

Comparison between botulinum toxin type A injection on masseter muscle only and additional injection on anterior belly of digastric muscle in sleep bruxism patients: A clinical trial.

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

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.