International consensus on the assessment of bruxism: Report of a work in progress

Effect of masseter muscle activity during wakefulness and sleep on tooth wear

PURPOSE

To investigate the effect of masseter muscle activity during wakefulness and sleep on tooth wear.

METHODS

Sixteen participants with no or mild tooth wear (NMTW group) and sixteen participants with moderate-to-severe tooth wear (MSTW group) were enrolled. The severity of tooth wear was evaluated using the occlusal and incisal indices of the tooth wear index. Surface electromyography was performed to record the electrical activity of the left masseter muscle during wakefulness and sleep. Electromyographic activity was detected using an electromyographic threshold of 5% and 20% of maximal voluntary clenching (MVC). The total duration of electromyographic activity and bruxism episodes were calculated.

RESULTS

The mean ages of the NMTW and MSTW groups were 71.75 ± 7.61 years and 71.69 ± 7.49 years, respectively. The mean cumulative duration of electromyographic activity during wakefulness using a threshold of >5% MVC was 6.44 ± 4.52 min/h and 13.62 ± 10.08 min/h for the NMTW and MSTW groups, respectively (p=0.048). The mean total durations of electromyographic activity during wakefulness and sleep using a threshold of >20% MVC were 1.08 ± 1.70 min/h and 1.05 ± 3.02 min/h, respectively, in the NMTW group and 4.78 ± 6.37 min/h and 1.61 ± 1.79 min/h, respectively, in the MSTW group (p=0.048 and p=0.003, respectively).

CONCLUSION

These results suggest that masseter electromyographic activity during wakefulness and sleep may be related to the severity of tooth wear.

Management of idiopathic sleep bruxism in children and adolescents: A systematic review of the literature

AIM

Primary sleep bruxism (SB) affects between 6 and 30% of children and adolescents. Its frequency increases with age, reaching a peak at 10-14 years of age, after which it drops until adulthood. The treatment of SB has not been extensively documented, resulting in a lack of reference points and legitimate concerns for dentists in their everyday practice. The aim of this literature review was to summarize the available evidence on the management of SB in children and adolescents and the efficacy of the different approaches.

METHOD

A systematic literature search was conducted according to PRISMA guidelines from January 2006 to December 2020 using the PubMed, The Cochrane Library, Science Direct, and Google Scholar databases. All types of SB treatment were accepted. Eight studies were selected for their protocol quality, according to the PICOS tool.

RESULTS

Several treatment methods were assessed from the eight clinical studies selected, such as occlusal splint, palatal expansion, and pharmacological treatment. Assessment of the treatment methods was difficult because only eight studies were selected, and both the treatment methods and the study protocols used were different. The therapeutic strategies found in the literature were based on the general condition of the case. Treatment approaches were distinguished into treatments for isolated SB and those for SB associated with ventilatory disorders.

CONCLUSION

The current study shows the need to define diagnostic criteria adapted to SB in children in order to improve epidemiological surveys and subsequently clinical practice. To overcome the difficulties related to SB diagnostic criteria, a multidisciplinary approach, involving pediatricians, otorhinolaryngologists, and dental practitioners, is essential for a better management and follow-up of young patients. A case-by-case approach, taking into account the specificities of each young patient, seems the most appropriate management today.

The Association between Emotional Stress, Sleep, and Awake Bruxism among Dental Students: A Sex Comparison

Psychosocial factors may play an important role in the etiology of sleep and awake bruxism. The purpose of this study was to assess the relationship between emotional stress and bruxism in male and female dental students at various stages of their education. Dental education in Israel is based on a six-year curriculum, divided into three stages: pre-medical studies (yr. 1-2), manual skills (yr. 3-4), and clinical experience (yr. 5-6). Each stage requires different capabilities and skills. Questionnaires regarding psychological state (SCL-90) measuring depression, anxiety, and somatization as well as stress evaluation questioners (Perceived Stress Scale questionnaire 14) were completed by 387 dental students in the 1st to 6th years. Sleep and awake bruxism were evaluated based on the respondent's awareness. During the manual stage of studies, a significant increase was identified, albeit with weak correlations, between stress scales, depression, anxiety, somatization, and the prevalence of awake bruxism, particularly among males. Only in females was sleep bruxism correlated with emotional parameters, whereas no significant difference in sleep bruxism was observed in males throughout the stages of the study. The manual years of dental education were found to be linked to higher levels of emotional distress and awake bruxism, particularly in men. Sleep bruxism, on the other hand, was not directly linked to emotional factors, implying a distinct etiology.

Lower serotonin levels in severe sleep bruxism and its association with sleep, heart rate, and body mass index

BACKGROUND

Sleep bruxism (SB) is a complex behaviour that seems to be associated with the serotoninergic pathway.

OBJECTIVES

This exploratory research aimed to evaluate the levels of serotonin in individuals with sleep bruxism diagnosed by video polysomnography. The study also evaluated whether the levels of serotonin were associated with body mass index, heart rate, and sleep parameters.

METHODS

The study participants were adults hospitalised in the Department and Clinic of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology at the Wroclaw Medical University. They underwent a single-night video polysomnography during which sleep and SB parameters and heart rate were evaluated. Additionally, body mass index and blood serotonin levels were evaluated for each patient.

RESULTS

A total of 105 patients were included in this study (80 women and 25 men). All the patients were Caucasians aged 18-63 years, with a mean age ± (standard deviation) of 33.43± 10.8 years. Seventy-five patients (71.43%) presented sleep bruxism (bruxism episodes index ≥2) and 30 (28.57%) did not. Fifty patients (47.62%) presented severe sleep bruxism (bruxism episodes index >4). The results showed that lower blood serotonin levels were associated with severe sleep bruxism; increased bruxism episodes index, rapid eye movement sleep, and body mass index; and decreased maximal pulse.

CONCLUSION

Severe sleep bruxism and the associated phenomena seem to co-occur with lower blood serotonin levels. The study supports the hypothesis on the relationship between the serotoninergic pathway and sleep bruxism.

Is sleep bruxism related to the levels of enzymes involved in the serotonin synthesis pathway?

OBJECTIVES

This exploratory research aimed to evaluate the levels of tryptophan hydroxylase 1 (TPH1) and aromatic l-amino acid decarboxylase (DDC), which play an important role in the serotonin synthesis pathway, in individuals with sleep bruxism (SB) diagnosed using audio-video polysomnography (vPSG) and compare them with that of individuals not presenting with SB.

MATERIALS AND METHODS

The study included adult patients hospitalized in the Department and Clinic of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology at the Wroclaw Medical University. The participants underwent a single-night vPSG for the evaluation of the SB parameters. Peripheral blood samples were also collected from them for estimating the serum levels of TPH1 and DDC.

RESULTS

A total of 105 patients (80 women and 25 men) were included in the study. All the patients were Caucasians and aged 18-63 years (mean age: 33.43 ± 10.8 years). Seventy-five patients (71.43%) presented with SB, of which 50 (47.62%) had severe SB, while the remaining 30 patients (28.57%) did not. No statistically significant differences in TPH1 and DDC levels were observed between the individuals with SB and without SB. A significant negative correlation was found between tonic SB episodes and DDC levels (p = 0.0012). Other correlations between the SB parameters and the levels of the studied enzymes were statistically insignificant (p > 0.05 for all comparisons).

CONCLUSIONS

The levels of the enzymes that are crucial for serotonin synthesis (TPH1 and DDC) did not seem to influence SB.

CLINICAL RELEVANCE

This study provides important insights for further research on the relationship between the serotonin pathway and SB, which should take into account not only the process of serotonin synthesis but also the effect of serotonin-dependent neurotransmission on SB.

Microbiological and clinical evaluation of ultrasonic debridement with/without erythritol air polishing during supportive periodontal therapy in arches with full-arch fixed implant-supported prostheses: protocol for a randomised controlled trial

INTRODUCTION

Implant-supported prostheses are often successfully used in edentulous patients. However, the incidences of peri-implant mucositis and peri-implantitis increase over time. The accumulation of pathogenic bacteria adjacent to prostheses can induce peri-implant disease. Plaque removal is recommended to prevent and manage peri-implant diseases. The purpose of this study is to compare the plaque removal efficacy of ultrasonic debridement with/without erythritol air-polishing powder around implants and bridges in patients with full-arch fixed implant-supported prostheses as well as the effects of these two methods on the rates of peri-implant mucositis and peri-implantitis, and the submucosal microbiota composition over 5 years in patients undergoing supportive periodontal therapy.

METHODS AND ANALYSIS

We plan to enrol 10 edentulous (maxilla and/or mandible) patients seeking full-arch fixed implant-supported prostheses. The study will use a split-mouth model in which contralateral quadrants are randomly assigned to two groups. Group 1: one contralateral quadrant of full-arch fixed implant-supported prostheses will undergo ultrasonic debridement combined with erythritol air-polishing powder. Group 2: a separate contralateral quadrant of full-arch fixed implant-supported prostheses will undergo ultrasonic debridement. The 5-year trial will involve a total of 10 re-examinations per participant. The mucosal conditions around the implants will be recorded at 6-month intervals after restoration. Peri-implant submucosal plaque will be collected at each re-examination, and the bacterial flora will be analysed by 16s ribosomal RNA gene sequencing. X-ray examinations will be conducted at 12-month intervals to evaluate the marginal bone level around implants.

ETHICS AND DISSEMINATION

This prospective single-centre, randomised controlled trial (PKUSSIRB-202054045) has been approved by the Ethics Committee of Stomatology School and Hospital of Peking University. Data will be registered with the International Clinical Trials Registry Platform. Additionally, we will disseminate the results via publication in scientific journals.

TRIAL REGISTRATION NUMBER

ChiCTR-2000032431.

Variability of sleep bruxism-findings from consecutive nights of monitoring

OBJECTIVES

To determine sleep bruxism (SB) behavior during five consecutive nights and to identify correlations between SB episodes per hour (SB index) and sleep-time masseter-muscle activity (sMMA).

MATERIAL AND METHODS

Thirty-one participants were included in the study. Of these, 10 were classified as sleep bruxers (group SB-1) and nine as non-sleep bruxers (group non-SB). The bruxism status of these 19 patients was identified by means of questionnaires, an assessment of clinical symptoms, and electromyographic/electrocardiographic data (Bruxoff® device). The remaining 12 participants were also identified as bruxers, but based exclusively on data from the Bruxoff device (group SB-2). Data analysis included descriptive statistics and Spearman's correlation to assess the relationship between the SB index and sMMA.

RESULTS

Participants in group SB-1 showed an overall mean SB index of 3.1 ± 1.6 and a mean total sMMA per night of 62.9 ± 38.3. Participants in group SB-2 had an overall mean SB index of 2.7 ± 1.5 and a mean total sMMA of 56.0 ± 29.3. In the non-SB group, participants showed an overall mean SB index of 0.8 ± 0.5 and a mean total sMMA of 56.8 ± 30.3. Spearman's correlation yielded values of - 0.27 to 0.71 for the correlation between sMMA and SB index.

CONCLUSIONS

The data revealed variable SB activity and the absence of a reliable correlation between sMMA and the SB index.

CLINICAL RELEVANCE

The high variation in SB activity and lack of correlation between sMMA and the SB index should be considered when diagnosing SB.

TRIAL REGISTRATION

Clinical Trials [NIH], clinical trial no. NCT03039985.

Comparison of the Effects of Myotherapy in Patients with Myofascial Pain with and without Self-Reported Sleep Bruxism Using The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I Questionnaire

Background

This study aimed to compare the effects of myotherapy using sublingual relaxation splints and stretching exercises in 110 patients with myofascial pain with and without self-reported sleep bruxism using The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I Questionnaire.

Material/Methods

The study involved 110 patients with myofascial pain. The diagnosis was based on the RDC/TMD questionnaire. The number of painful muscle sites (PMS) and the range of maximum mouth opening (MMO) were assessed 2 times – at the first visit and after 3 months. Then, the influence of possible bruxism on the treatment was assessed.

Results

The mean age of the patients was 26.8 years (SD 5.4); 89% of the subjects were women; and 60.9% of the patients reported bruxism. Each patient was instructed to perform muscle stretching at the first visit and after 1 week all patients received a sublingual relaxation splint. The number of PMS decreased and the range of MMO increased in both groups after a period of 3 months of treatment (P<0.05). Significant differences were observed in the obtained treatment effects between the patients with and without possible bruxism.

Conclusions

This study evaluated the effectiveness of the sublingual relaxation splint and stretching exercises in patients with myofascial pain. Patients at a single center in Poland who reported myofascial pain that was not associated with self-reported sleep bruxism had a significantly better response to myotherapy when compared to patients with self-reported sleep bruxism.

Comparison of Kinesio Taping and manual therapy in the treatment of patients with bruxism using shear-wave elastography-A randomised clinical trial

BACKGROUND

Bruxism is significantly associated with craniofacial pain, feeling of stiffness or fatigue of the jaw and neck pain. Various physiotherapeutic strategies are used in the treatment of bruxism; however, it is not clear which method leads to greater decrease in pain.

OBJECTIVE

The aim of this study is to compare the effects of two physiotherapy methods (manual therapy [MT] and Kinesio taping with manual therapy [KTMT]) in patients with bruxism.

METHODS

Patients were randomised into MT or KTMT groups. Evaluations were performed at baseline and following 4 weeks of physiotherapy. Muscle thickness and stiffness were assessed via shear wave elastography; pain thresholds were evaluated using algometer. Sleep quality was assessed using Pittsburgh Sleep Quality Index, and quality of life was assessed with Likert scales regarding the associated symptoms.

RESULTS

Significant decreases were found in muscle stiffness, pain threshold, sleep quality and quality of life (P < .05) in both MT and KTMT groups. Pain in bilateral temporalis and right occipital region of the trapezius muscle decreased more in the KTMT group compared with the MT group (P < .05). No significant differences in muscle thickness (P > .05) were found in either of the groups.

CONCLUSION

Both MT and KTMT methods were effective in the treatment of bruxism. Kinesio Tape used in conjunction with MT has additionally decreased jaw pain and temporal region pain compared with MT intervention only. Therefore, if jaw pain is the primary complaint of a patient, our results recommend including Kinesio Tape application in the physiotherapeutic treatment program.

ORAL HEALTH CONDITIONS AND SELF-REPORTED PRESENCE OF PAIN IN ROWERS: AN EPIDEMIOLOGY STUDY

ABSTRACT Introduction: Rowers are especially prone to oral health problems due to the massive consumption of supplements and isotonic drinks that lead eating disorders, due to the need for weight control, and to the development of teeth clenching caused by the constant activation of the chewing muscles during sports activity. Objective: To evaluate the oral health status of a group of Brazilian rowers and to identify the main risk factors influencing their oral health. Methods: One hundred and twenty rowers (84 men and 36 women) with an age of 24.16 ± 5.74 years participated in this study; an average height of 1.79 ± 0.09 cm and body mass of 75.02 ± 11.64 kg were detected by means of a questionnaire focused on the main factors that influence the deterioration in athletes’ oral health. Results: The dental results revealed a significant number of rowers with the oral breathing pattern (46.7%), malocclusion (65.8%), bruxism (33.3%) and noise and/or pain in the TMJ (temporomandibular joint) (20.8%). The use of supplements and isotonic drinks (48.3%) and the incidence of bleeding gums (30.83%) were also found. Conclusion: The results show the importance of making rowers aware of the relevance of oral health and the need for prevention systems, ideally including sports dentistry specialists within the sports medicine departments of rowing clubs. Level of evidence II; Retrospective study.

Botulinum toxin and occlusal splints for the management of sleep bruxism in individuals with implant overdentures: A randomized controlled trial

BACKGROUND

The available treatment options fail to provide definitive or curative management for bruxer patients rehabilitated with implant overdentures (OD). The data regarding Botulinum toxin (BTX) injection as a management strategy for bruxism remains unclear. This randomized, single-blinded, control-group, pretest-posttest prospective trial evaluated the occlusal guard and Botox injections (BTX) effectiveness in managing sleep bruxism (SB) in subjects whose one of the edentulous arches had been restored with the implant-supported OD.

METHODS

Forty-two patients diagnosed with definite bruxism were selected, all of which had implant-retained ODs opposing natural dentition. The participants were allocated randomly to three equal groups. Participants in group I (control group) were instructed to remove the OD at night; group II was managed with conventional occlusal stents. Those in group III were given BTX injections. New ODs were constructed for all groups, and all ball attachments were replaced with a new nylon cap. A baseline assessment (one month of OD insertion) of patient satisfaction and sleep quality was conducted, and then again at 3, 6, 9, and 12 months of treatment. Subjective sleep quality was evaluated using Pittsburgh Sleep Quality Index (PSQI). Patients' satisfaction was evaluated using Temporomandibular disorders/numeric scales (TMD/NS). Prosthodontic (mechanical) complications were recorded during the follow-up period.

RESULTS

Group III showed a statistically significant improvement in patient satisfaction and sleep quality compared to the other two groups at 3, 6, 9, and 12 months follow-up period ( P  = 0 0.001, 0.0001, 0.0013, and 0.0001 respectively). Regarding prosthodontic (mechanical) complications, the highest number of events was revealed in the control group.

CONCLUSIONS

BTX and occlusal appliances effectively improve patient satisfaction and sleep quality of Bruxer patients rehabilitated with single arch implant overdentures.

Bruxism in children and adolescents with cerebral palsy

This study aims to summarize the existing evidence from primary studies in order to answer the following question: "are children and adolescents with cerebral palsy (CP) frequently affected by bruxism?". For such, databases Web of Science, Medline (via PubMed), Lilacs, SciELO, Scopus and Wiley Online Library were used, with the keywords “Cerebral Palsy” and “Bruxism” alone and in combination, without the restriction of the publication date. The search included all articles published until May 2020. A total of 229 publications were found, of which 12 were selected, after careful analysis. Retrospective data analyses, cross-sectional studies and observational case-control studies published in English and with samples composed of children and/or adolescents were included. Case reports, literature reviews and studies whose sample consisted of adults-only were excluded. In the evaluated studies, bruxism was present in all samples with cerebral palsy. However, oral signs and symptoms resulting from this parafunction were reported only in three studies, in which the presence of dental wear and pain was evaluated. Therefore, bruxism in children and adolescents with cerebral palsy is a frequent oral condition, however, knowledge about the associated and risk factors for the occurrence of this problem in these patients remains limited.

Is there an association of genetic polymorphisms of the catechol-O-methyltransferase gene (rs165656 and rs174675) and the 5-hydroxytryptamine receptor 2A gene (rs4941573 and rs6313) with sleep bruxism in individuals with obstructive sleep apnea?

OBJECTIVE

To evaluate the association of single-nucleotide polymorphisms within the catechol-O-methyltransferase and 5-hydroxytryptamine receptor 2A genes with sleep bruxism in individuals diagnosed with obstructive sleep apnea.

DESIGN

Sixty-nine individuals with suspected sleep-related problems were evaluated by polysomnography, following the recommendations of the American Academy of Sleep Medicine. Deoxyribonucleic acid (DNA) samples were collected only from 48 of the study participants because of missing polysomnographic data. DNA samples were collected and two single-nucleotide polymorphisms in the 5-hydroxytryptamine receptor 2A encoding HTR2A gene (rs4941573 and rs6313) and two in the catechol-O-methyltransferase gene (rs165656 and rs174675) were selected to be genotyped using real-time polymerase chain reaction. The association between sleep bruxism and genetic polymorphisms was investigated by recessive and dominant models. Association analyses were performed using a 95% confidence interval and the level of statistical significance was p < 0.05.

RESULTS

From the 69 study participants, 48 were included in the polymorphism analysis and sleep bruxism was present in 35.4%. No significant differences were observed in the dominant and recessive models (p > 0.05). Haplotype and diplotype analyses revealed the predicted four haplotypes and two diplotypes were not associated with sleep bruxism.

CONCLUSION

Polymorphisms rs174675 and rs165656 in the catechol-O-methyltransferase gene and rs4941573 and rs6313 in the 5-hydroxytryptamine receptor 2A gene were not significantly associated with sleep bruxism in individuals with obstructive sleep apnea.

Associations between sleep bruxism and other sleep-related disorders in adults: a systematic review

OBJECTIVE

Systematic reviews on sleep bruxism (SB) as a comorbid condition of other sleep-related disorders are lacking. Such reviews would contribute to the insight of sleep clinicians into the occurrence of SB in patients with other sleep-related disorders, and into the underlying mechanisms of such comorbid associations. This systematic review aimed: 1. to determine the prevalence of SB in adults with other sleep-related disorders; and 2. to determine the associations between SB and other sleep-related disorders, and to explain the underlying mechanisms of these associations.

METHODS

A systematic search on SB and sleep-related disorders was performed in PubMed, Embase, Cochrane Library, and Web of Science to identify eligible studies published until May 15, 2020. Quality assessment was performed using the Risk of Bias Assessment tool for Non-randomized Studies.

RESULTS

Of the 1539 unique retrieved studies, 37 articles were included in this systematic review. The prevalence of SB in adult patients with obstructive sleep apnea, restless leg syndrome, periodic limb movement during sleep, sleep-related gastroesophageal reflux disease, REM behavior disorder (RBD), and sleep-related epilepsy was higher than that in the general population. The specific mechanisms behind these positive associations could not be identified.

CONCLUSIONS

SB is more prevalent in patients with the previously mentioned disorders than in the general population. Sleep arousal may be a common factor with which all the identified disorders are associated, except RBD and Parkinson's disease. The associations between SB and these identified sleep-related disorders call for more SB screening in patients with the abovementioned sleep-related disorders.

Use of Buspirone in the Treatment of Nonpharmacological Bruxism: About 4 Cases

OBJECTIVE

The aim of the study was to describe the efficacy of buspirone in controlling nonpharmacological awake and sleep bruxism.

METHODS

Four cases of nonpharmacological awake and sleep bruxism, one of them with a 20-year-long history, in which buspirone succeeded to control bruxism, are described and discussed.

RESULTS

Two of the 4 cases had sleep bruxism, and the other 2 cases had sleep and awake bruxism. Besides anxiety, no other predisposing condition was identified. Buspirone was effective in reducing bruxism symptoms in the 4 cases. Mean percentage of bruxism reduction after buspirone was ranked as 65% by subjects.

CONCLUSIONS

In this small series of cases, buspirone proved effective in the control of nonpharmacological awake and sleep bruxism.

Association between Self-Reported Bruxism, Peripartum Depression and Myogenous Temporomandibular Disorders among Postpartum Women in Turkey

Background/Aim: It is possible to find studies in the literature evaluating the relationship among self-reported bruxism, psychological factors, and myogenous temporomandibular disorder. In addition, the relationship between these issues has not yet been clarified. The objective of this study was to evaluate the association between peripartum depression, self-reported bruxism, and myogenous temporomandibular disorders among postpartum women in Turkey.

Material and Methods: This study included 220 women, whom were asked about their bruxism behaviour during day and during sleep. Besides, all of them assessed with Short-Form Fonseca’s Anamnestic Index for myogenous temporomandibular disorder and the Edinburgh postnatal depression scale for peripartum depression.

Results: The results showed that, self-reported bruxism was observed at a statistically significantly higher rate (94.3%) in peripartum depression group. 86.5% of the patients with self-reported bruxism had myogenous temporomandibular disorder (p<0.001). As a result, 80.0% of the patients with peripartum depression had myogenous temporomandibular disorder (p<0.001).

Conclusions: In conclusion, a significant relationship has been found between peripartum depression and self-reported bruxism, self-reported bruxism and myogenous temporomandibular disorder, and peripartum depression and myogenous temporomandibular disorder. The present study is the first to evaluate the relationship between peripartum depression, self-reported bruxism, and myogenous temporomandibular disorder so it could be considered as a pilot attempt, and further studies using more representative samples are encouraged.

Bruxist Activity Monitor System (BAMS): An instrumental approach tool in the assessment of Bruxism

The magnitude of harmful effects on dental structures, periodontium, masticatory muscles, and the temporomandibular joint, derived from temporomandibular disorders, specifically from sleep Bruxism, generates evidence that needs to be objectively collected. This paper introduces a portable device aiming at extracting and analyzing parameters (like timestamp, duration, or latency) from recordings obtained from the monitoring of occlusal activity, throughout a complete sleep cycle. An electronic device embedded in a mid-density medical grade silicon occlusal splint detects the moment in which the subject exerts sustained force, and records the time and length of the event, keeping the device on hold until a new event arises. The electronic device, based on a microcontroller, identifies occlusive events from an array of two piezo-resistive sensors and has a storage capacity of up to 36 hours of continuous activity. The collected data is wirelessly transmitted to an external module that is connected via USB to a PC. In the PC, the data is decoded, processed, analyzed, displayed, and stored in ordered files for case subjects, updating every recorded test for a complete history review. The proposed Bruxist Activity Monitor System (BAMS) was tested in one subject for more than 40 hours (5 sessions in 7 days). Preliminary results show the oral appliance endure without any significant damage over its surface nor undermining its functionality.

Impact of the COVID-19 Pandemic on Stress, Sleep, and Oral Health in University Students

Background: The COVID-19 pandemic, a disease caused by Sars-CoV-2, has become a worldwide stressor, especially as it represents a new viral infection, which spreads quickly and easily, without prior knowledge about vaccination, and absence, to this moment, of a medication that is totally effective against the disease.

Objective: The aim of this observational study was to provide a general evaluation, through a questionnaire applied to students in the health field of the Federal University of Rio de Janeiro, on the psychological impacts and behavioral changes generated by the COVID-19 pandemic on oral health, especially the triggering or exacerbation of bruxism and temporomandibular disorders (TMD).

Methods: In order to verify the impacts of the pandemic on the health of UFRJ healthcare students, a non-randomized survey was performed with 370 students.

Results: It was found that 72% of the students had their sleep routine altered, 65% had greater difficulty in keeping their spirits up, there was a statistically significant increase in emotional stress, headaches, and daytime teeth clenching.

Conclusion: It was possible to conclude that the outbreak of COVID-19 resulted in psychological, physiological and behavioral impacts on students.

Type D Personality and Stomatognathic System Disorders in Physiotherapy Students during the COVID-19 Pandemic

Background: A person’s response to stressors is largely dependent on their personality traits that affect the way stress is controlled and relieved. This article is a quantitative analysis assessing the importance of the distressed personality in the development of stomatognathic system disorders (SSDs) in physiotherapy students during the COVID-19 pandemic. Objective: The goal of the research was to assess the presence of type D personality in students with symptoms of stomatognathic system disorders. Material and Method: The research was carried out among 300 physiotherapy students. The data were collected using the form of the occurrence of symptoms of SS disorders developed for the purpose of the study and the standardized psychological DS14 questionnaire. Results: In a group of 300 students, the presence of type D personality was found in 160 people (53.3%). People with type D personality had symptoms of SS disorders more often than the group without stressful personality traits. There was a significant difference between the groups regarding all the examined symptoms. In the group of people with type D personality, the most frequently reported symptoms of SS disorders included: headache (51.3%), pain in the neck and shoulder girdle (43.1%), and teeth clenching (35.6%). As many as 70% of the respondents in the group with symptoms of SS disorders (P1) had type D personality, whereas in the asymptomatic group (P2) this result was 23.3%. There was a significant difference between the groups (p = 0.00). Statistically significantly higher values of both D personality dimensions were observed in women than in men with symptoms of SS disorders. In people reporting symptoms of SS disorders, higher average values were observed in both dimensions of type D personality. There were significant differences between the groups. Conclusion: type D personality may contribute to the development of symptoms of stomatognathic disorders.

Temporal relationship between sleep-time masseter muscle activity and apnea-hypopnea events: A pilot study

BACKGROUND

Obstructive sleep apnea (OSA) is the most common sleep disorder due mainly to peripheral causes, characterized by repeated episodes of obstruction of the upper airways, associated with arousals and snoring. Sleep bruxism (SB) is a masticatory muscle activity during sleep that is characterized as rhythmic (phasic) or nonrhythmic (tonic) and is not a movement disorder or a sleep disorder in otherwise healthy individuals. Given the potentially severe consequences and complications of apnea, the concurrent high prevalence of SB in daily dental practice, getting deeper into the correlation between these phenomena is worthy of interest..

STUDY OBJECTIVES

The aim of this study was to investigate the correlation between SB-related masseter muscle activity (MMA) and apnea-hypopnea events as well as to assess their temporal sequence.

METHODS

Thirty (N = 30) patients with sleep respiratory disorders and clinical suspicion of sleep bruxism (SB) were recruited. Ambulatory polygraphic recording was performed to detect apnea-hypopnea events (AHEs) and sleep bruxism episodes (SBEs). Pearson test was used to assess the correlation between apnea-hypopnea index (AHI) and SB index (SBI). A 5-s time window with respect to the respiratory events was considered to describe the temporal distribution of SBEs. Furthermore, SBI was compared between groups of patients with different AHI severity (i.e., mild, moderate and severe) using ANOVA.

RESULTS

On average, AHI was 27.1 ± 21.8 and SBI 9.1 ± 7.5. No correlation was shown between AHI and SBI. Most of SBEs (66.8%) occurred without a temporal relationship with respiratory events. Considering OSA, 65.7% of SBEs occurred within 5 s after AHEs, while in the case of central apnea (CA) 83.8% of SBEs occurred before the respiratory event. The participants with severe apnea (N = 9) show a tendency to have higher bruxism indexes when compared to patients with mild (N = 11) and moderate apnea (N = 10).

CONCLUSIONS

Findings suggest that: 1. At the study population level, there is no correlation between AHI and SBI, as well as any temporal relationship between SBEs and respiratory events. 2. Specific patterns of temporal relationship might be identified with future studies focusing on the different types of apnea-hypopnea events and bruxism activities.

Bone apposition at the mandibular angles as a radiological sign of bruxism: a retrospective study

Background

The main objective of this investigation was to determine on panoramic radiographs the prevalence of macroscopically visible alterations (bone apposition in combination with directional change) in the mandibular angle region in bruxism patients. Another aim was to describe and detect different morphological characteristics of the jaw angles.

Methods

Two hundred panoramic radiographs were studied: 100 images of adults with clinically diagnosed bruxism (73 women, 27 men, age range 21–83 years), 100 images of a comparison group consisting of adolescents (66 girls, 34 boys, age range 12–18 years).

Results

The morphological changes of the 400 jaw angles could be classified into four degrees. In the adult group, almost half of mandibular angles showed bone apposition. Conversely, the prevalence in the control group was zero. The localization of the appositions corresponds to the insertions of the masseter and medial pterygoid muscles at the mandibular angle.

Conclusions

The bone apposition at the mandibular angles should be interpreted as a functional adaptation to the long-term increased loads that occur during the contraction of the jaw closing muscles due to bruxism. Hence, radiologically diagnosed bone apposition may serve as an indication or confirmation of bruxism.

Risk Factors Associated with Cusp Fractures in Posterior Permanent Teeth—A Cross-Sectional Study

Objectives: This cross-sectional study aimed to evaluate the frequency and risk factors associated with cusp fractures in posterior permanent teeth. Methods: Patients presented cusp fractures on posterior permanent teeth, clinically assessed in up to 7 days after the event, and requesting dental treatment at two public services were included in this cross-sectional study. Fractured teeth already treated, with antagonist absence, or with prosthesis (total or removable) were excluded. Demographic and clinical data were collected to draw the patient profiles and establish how teeth were affected individually. Statistical analysis was performed by the Fisher exact test, and uni- and multivariate logistic regression (α = 0.05). Results: One hundred and seventy-seven (177) patients from 16 to 66 years old (±41.56), from 1998 to 2016, were included in this study. Non-functional and lingual cusps presented a higher fracture than functional and buccal cusps, respectively. Fractures were more common in teeth with isthmus wider than 1/3 of the intercuspid distance and/or more than three restored surfaces. Teeth with endodontic treatment presented a higher subgingival fracture. On lingual cusps, fracture type and location were significantly associated, being that total fractures were 3.2 times more likely to occur than partial fractures, and subgingival were 3.62 times more likely to occur than supragingival fractures. Conclusion: Indications of classic protection on functional cusps (LUBL) was refuted since, generally, nonfunctional cusps fractured more than the functional cusps. However, upper pre-molars showed more fractures in functional cusps and lower molars presented more fractures on the nonfunctional cusps. In general, lingual cusps were the most fractured and were associated with a higher prevalence of severe fractures (total fractures at the subgingival level). Fractures were more common in teeth where the restoration had an isthmus wider than 1/3 of the intercuspid distance and/or involved more than three restored surfaces. Most of the patients did not show previous symptoms and signs. Overall, teeth with endodontic treatment presented a higher subgingival fracture.

Polymorphic variants in genes related to stress coping are associated with the awake bruxism

BACKGROUND

Chronic stress is one of the leading predisposing factors in bruxism aetiology, but the influence of genetic factors is also suggested. We aimed to study whether sequence variants in genes involved in stress regulation pathways: NTRK2 and BDNF, may be associated with awake bruxism susceptibility, clinical presentation, and patients' perceived stress level.

METHODS

The study group included 104 patients with probable awake bruxism and 191 population controls. Patients underwent dental examination concerning the symptoms of bruxism and psychological testing. Genotyping was performed using HRMA and sequencing. Statistical analyses were conducted, and P values below 0.05 were considered statistically significant.

RESULTS

We observed a positive correlation of measured stress level and pathological teeth attrition in the anterior segment (r = 0.45, P < 0.001), enamel attritions (r = 0.44, P < 0.001), tongue impressions (r = 0.50, P < 0.001) and posterior teeth attrition (r = 0.27, P = 0.005). Moreover, the c.196A variant (p.66Met) of the BDNF gene and c.1397-31392G allele of the NTRK2 gene were present with elevated frequency, comparing to controls.

CONCLUSIONS

This study hence the thesis that perceived stress level is a substantial contributing factor to awake bruxism occurrence and its clinical manifestations. Moreover, sequence variants in genes related to stress coping may be correlated with awake bruxism's susceptibility via elevated perceived stress level.

Psychosocial and Behavioral Factors in Awake Bruxism-Self-Report versus Ecological Momentary Assessment

The issue of psychosocial factors and concurrent conditions associated with AB is a relatively new approach in the study of Awake Bruxism (AB). In the present study a population of 84 dental students were assessed for probable AB with two modes of AB assessment: Single point self-report (SR) and ecological momentary assessment through a designated smartphone application (BA). The two assessment modes were compared with regard to their ability to phenotype subjects as far as the following psychosocial and behavioral variables are concerned: Gender; depression; somatization; oral behaviors; chronic pain and associated pain symptoms in the head, neck and scapula. Two-way ANOVA showed main effect of SR for the following variables: Chronic Pain Intensity score (F_(1,49) = 6.441, p < 0.02), migraine/headache (F_(1,81) = 7.396, p < 0.01), pain in neck (F_(1,81) = 6.726, p < 0.05), pain in scapula (F_(1,81) = 8.546, p < 0.005) and the oral behaviors of pushing the tongue forcefully against the teeth (F_(1,81) = 5.222, p < 0.05) and inserting the tongue between the upper and lower teeth (F_(1,81) = 5.344, p < 0.03). The effect of SR on the habit of chewing gum was borderline (F_(1,81) = 3.369, p = 0.07). Main effect of BA was found for depression (F_(1,81) = 6.049, p < 0.05), while the effect of BA on somatization was borderline (F_(1,81) = 3.657, p = 0.059). An interaction between SR and BA groups could be observed for the behavior of biting, chewing or playing with the tongue, cheeks or lips (F_(1,81) = 4.117, p < 0.05). The results suggest that a combination of a single-point self-report referring to the past 30 days, and an ecological momentary assessment supplying information about the actual timing of the report, can help us to better assess AB, as well as increase our ability to define the phenotype of subjects with AB as far as psychosocial and behavioral factors are concerned.

Non-carious cervical lesions (NCCLs) and associated factors: A multilevel analysis in a cohort study in southern Brazil

AIM

To investigate the prevalence of non-carious cervical lesions (NCCLs) and their association with individual and tooth-related factors in adults from the 1982 Pelotas Birth Cohort.

MATERIALS AND METHODS

Participants were interviewed and clinically examined at the age of 31. NCCL was defined as loss of dental tissue without bacterial involvement in the cervical region. Independent variables were the socioeconomic, demographic, behavioural, and clinical characteristics. Associations were tested using a multilevel Poisson regression model.

RESULTS

Five-hundred and thirty-nine participants were clinically examined, with a 26% prevalence of NCCLs, which were more prevalent in the maxilla (56.5%) and in premolars (72.9%). In the multilevel analysis, women presented lower prevalence than men [prevalence ratio (PR) 0.59 (0.48-0.73)]; those who reported smoking at both 22 and 30 years of age had more NCCLs than those who never smoked [PR 1.65 (1.31-2.07)]; and high-frequency brushers presented higher prevalence than low-frequency brushers [PR 1.26 (1.03-1.55)]. Gingival recession increased 10 times the prevalence of NCCLs [PR 10.03 (8.15-12.35)], while the presence of periodontal pockets (≥4 mm) reduced the prevalence of NCCLs [PR 0.43 (0.28-0.66)].

CONCLUSIONS

NCCLs were more prevalent in males, smokers, and those with higher frequency of toothbrushing. While the presence of periodontal pockets was associated with a lower prevalence of NCCLs, gingival recession was a strong clinical indicator for the presence of NCCLs.

Utility of Smartphone-based real-time report (Ecological Momentary Assessment) in the assessment and monitoring of awake bruxism: A multiple-week interval study in a Portuguese population of university students

PURPOSE

The Ecological Momentary Assessment (EMA) concept was the basis for developing a smartphone application for the on-time report of awake bruxism (AB) activities. This study aims to monitor AB report over time in a population of healthy young adults.

METHODS

A population of young adults recruited among dental students in good general health was recruited. All answered to a questionnaire, including the Oral Behavior Checklist (OBC-1). They were then monitored with a smartphone application for AB report during seven consecutive days and completed three further observation periods (EMA-1, 2 and 3) at one-month intervals. After the third period (EMA-3), participants answered again the OBC questionnaire (OBC-2). Changes over time were described, and Pearson Correlation test was performed to assess the correlation between EMA and OBC items reports. A significance level of p = .01 was set.

RESULTS

Thirty-one University students completed the study protocol. Answers to the OBC showed an increase in the prevalence of self-reported bracing and teeth clenching from the first to second report (38.7%-54.8% and 77.4%-90.3%, respectively). A slight increase in the 'relaxed' condition (62.5%-69.0%) was observed with EMA-based smartphone application over time. No correlation between OBC items and EMA was detected between OBC-1 and EMA-1. A moderate positive correlation in bracing report (+0.509, p = .01) and weak positive correlation in teeth contact report (+0.380, p = .05) were found between OBC-2 and EMA-3.

CONCLUSION

Using a smartphone-based approach to AB report may be helpful to monitor AB over time and increase an individual's awareness to recognise actions such as bracing and teeth contact concerning the single-time report.

Circadian preference and its relationship with possible sleep and awake bruxism in adults assisted by the public health system

Modern lifestyle and social demands induce changes in sleep routines that may not meet individual circadian preferences (chronotype). Such changes may be associated with the development of unhealthy lifestyles and the emergence of diseases relevant to public health services, such as obesity, hypertension, and diabetes mellitus, as well as sleep bruxism (SB) and awake bruxism (AB). The present study aimed to assess the relationship between the evening, morning or intermediate chronotypes with the report of possible SB and AB in adult individuals assisted by the Family Health Strategy (FHS). The selection of participants was performed through probabilistic cluster analysis. The sample size (n = 384) was calculated to include a representative sample of the 52,628 adults registered in the FHS of a countryside city located in the Southeast Region of Brazil. The Morningness-Eveningness Questionnaire (MEQ) was used to determine the chronotype, and Questionnaire-Based Self-Reported Bruxism was used for identifying possible SB and AB. The following clinical and social-behavioral variables were also evaluated: age, sex, BMI, income, physical activity, schooling, alcohol consumption and smoking, chronic diseases and depression. Two logistic regression models were used: one for SB and one for AB. Possible SB was associated with female sex, lack of physical activity and income above 2 minimum wages. Regarding chronotype, a 19% reduction in the chance of possible SB was observed in morning individuals compared to evening individuals (p = .017). Possible AB was associated with younger individuals, smoking and depression. In conclusion, compared with the evening circadian preference, the morning circadian preference was associated with greater protection against possible SB in an adult population assisted by the FHS.

Sleep Bruxism in Children: Etiology, Diagnosis, and Treatment-A Literature Review

(1) Background: Bruxism, a condition characterized by grinding and involuntary clenching of the teeth, is a risk factor for the development of masticatory dysfunction. It can occur together with sleep disturbances and may be associated with abnormal body movements, breathing difficulties, increased muscle activity, and heart rate disturbances. This disorder is becoming an important dental concern in children. (2) Methods: A literature review was carried out based on a search in PubMed and Google Scholar databases for articles on bruxism in children, published between 2014 and 2021. The etiology, diagnosis, and treatment of bruxism in children were of particular interest in the study. (3) Results: A total of 40 articles were included in the review. The analyzed studies indicated that the prevalence rates of bruxism in children vary widely from 13% to 49%. The etiology of bruxism is complex and incomprehensible, and the main diagnostic criteria for this condition in children are subjective observation, clinical history, and clinical examination. The recommended therapy for sleep bruxism in children is physiotherapy and psychotherapy. (4) Conclusions: Dentists and primary care physicians should correctly diagnose bruxism in children, educate parents, prevent potential consequences for oral health, and identify possible comorbidities. Appropriate clinical guidelines for the treatment and prophylaxis of bruxism in children should also be developed.

Smartphone-based evaluation of awake bruxism behaviours in a sample of healthy young adults: findings from two University centres

A smartphone-based ecological momentary assessment (EMA) strategy was used to assess the frequency of awake bruxism behaviours, based on the report of five oral conditions (ie relaxed jaw muscles, teeth contact, mandible bracing, teeth clenching and teeth grinding). One hundred and fifty-three (N = 153) healthy young adults (mean ± SD age = 22.9 ± 3.2 years), recruited in two different Italian Universities, used a dedicated smartphone application that sent 20 alerts/day at random times for seven days. Upon alert receipt, the subjects had to report in real-time one of the above five possible oral conditions. Individual data were used to calculate an average frequency of the study population for each day. For each condition, a coefficient of variation (CV) of frequency data was calculated as the ratio between SD and mean values over the seven recording days. Average frequency of the different behaviours over the seven days was as follows: relaxed jaw muscle, 76.4%; teeth contact, 13.6%; mandible bracing, 7.0%; teeth clenching, 2.5%; and teeth grinding, 0.5%. No significant differences were found in frequency data between the two University samples. The relaxed jaw muscles condition was more frequent in males (80.7 ± 17.7) than in females (73.4 ± 22.2). The frequency of relaxed jaw muscles condition over the period of observation had a very low coefficient of variation (0.27), while for the different awake bruxism behaviours, CV was in a range between 1.5 (teeth contact) and 4.3 (teeth grinding). Teeth contact was the most prevalent behaviour (57.5-69.7). Findings from this investigation suggest that the average frequency of AB behaviours over one week, investigated using EMA-approach, is around 23.6%.

Association between sleep and awake bruxism in patients with migraine

IntroductionWhen migraine undergoes transformation from episodic to chronic form it becomes more disabling due to the refractoriness in treatment and the emergence of comorbidities, with the establishment of a bidirectional relationship between sleep bruxism and chronic migraine. This study aimed to assess whether sleep and awake bruxism are more prevalent in chronic migraine when compared to episodic migraine and also to establish possible clinical correlations with the process of chronification.Methods210 patients were allocated to the study, 97 with episodic migraine and 113 with chronic migraine, who underwent face-to-face interviews with the completion of the scales: specific questionnaire for the diagnosis of sleep and awake bruxism, PHQ-9 (depression), GAD-7 (anxiety), Epworth Scale (daytime sleepiness), MIDAS (migraine incapacity) and HIT-6 (impact of headache). ResultsThe prevalence of sleep and awake bruxism was similar in patients with episodic versus chronic migraine (p = 0.300 and p = 0.238). The correlation of patients with concomitant awake and sleep bruxism and with high scores on the migraine incapacity (MIDAS) and headache impact (HIT-6) scales was higher among patients with chronic migraine than in patients with episodic migraine. (p <0.001 and p <0.001). ConclusionSleep and awake bruxism alone are not more prevalent in chronic migraine when compared to episodic migraine, although bruxism causes greater impact and disability on individuals with chronic migraine.

A world panorama of bruxism in children and adolescents with emphasis on associated sleep features: A bibliometric analysis

BACKGROUND AND OBJECTIVES

To present a world panorama of the published papers on bruxism in children and adolescents, emphasising the characteristics of studies related to the sleep features of these patients.

METHODS

Literature searches were conducted in six databases without language or date restrictions. Data on the titles, types of study, main subjects, countries of origin, keywords, years of publication, authors and their network collaborations, journals and sleep studies were extracted and analysed using VantagePoint™ software.

RESULTS

A total of 725 studies met the eligibility criteria. Most included only children (75.31%), with observational design (66.34%), and risk or aetiology (53.93%) as the main subject. Brazil (18.06%) and Brazilian authors (54.84%) had the largest number of studies, with a low amount of network collaboration. The Journal of Oral Rehabilitation published most of the studies (6.2%); publications in this field have grown considerably from 2000 to 2020. Of the studies, 123 (16.96%) included sleep studies; night sweating, restless sleep, sleep talking, mouth breathing, snoring, obstructive sleep apnoea syndrome, sleep-disordered breathing, nightmares, poor sleep quality and duration, and daytime naps were significantly associated with bruxism in most.

CONCLUSION

Studies on bruxism in children and adolescents have increased in the past 20 years, with most being observational, and risk or aetiology as the main subject. Brazil and the Journal of Oral Rehabilitation have published most in the field. Sleep studies have shown some features associated with bruxism, such as night sweating, restless sleep, somniloquy, snoring, breathing problems, nightmares, daytime naps, and poor sleep quality and duration.

Role of occlusal factors on probable bruxism and orofacial pain: Data from the 1982 Pelotas birth cohort study

OBJECTIVES

This study aimed to explore the association between occlusal features and temporomandibular disorder (TMD) pain complaints and probable awake or sleep bruxism METHODS: Path analysis was used to estimate direct, indirect and total effects of occlusal features on probable bruxism and pain-related TMD in adults aged 31 years from the 1982 Pelotas Birth Cohort. A total of 539 cohort members had an oral examination in 2013. Occlusal features were assessed through the Dental Aesthetic Index (DAI), orofacial pain complaints through the TMD pain screener and probable bruxism based on self-reports in combination with clinical findings.

RESULTS

Malocclusions were found in 28.8% of the participants, while awake bruxism was reported in 35.2%, sleep bruxism in 15.2%, and pain-related TMD in 52.5% of the sample. Occlusion had no direct effect on either awake bruxism [standardized coefficient (SC) -0.002; p = 0.995] or pain-related TMD (SC -0.06; p = 0.115). Conversely, probable awake bruxism was associated with pain-related TMD (SC 0.35; p < 0.001). Similar results were found when sleep bruxism was set as the mediator of interest, as malocclusion did not directly affect sleep bruxism (SC 0.05; p= 0.220) nor pain-related TMD (SC -0.06; p = 0.167). A direct effect of sleep bruxism on pain-related TMD was observed with an SC of 0.16 (p < 0.001).

CONCLUSION

Our findings suggested that malocclusion during adulthood did not directly influence probable awake or sleep bruxism nor TMD pain complaints. Instead, probable awake and sleep bruxism was associated with TMD pain complaints.

CLINICAL SIGNIFICANCE

Malocclusion did not impact the presence of bruxism nor TMD complaints in adulthood, but awake and sleep bruxism were associated with TMD pain complaints. The significance of malocclusion should be reconsidered in contemporary dentistry and oral rehabilitation.

A lack of specific motor patterns between rhythmic/non-rhythmic masticatory muscle activity and bodily movements in sleep bruxism

Purpose The aims of the present study were to investigate the temporal relationships between jaw and bodily movements and clarify motor processes in the genesis of rhythmic masticatory muscle activity (RMMA) in sleep bruxism (SB).Methods Video-polysomnography recordings were obtained from ten subjects with SB (mean age: 23.4 ± 1.6 years) and ten matched normal controls (CTL) (mean age: 24.4 ± 3.2 years). RMMA and nonspecific masseter activity (NSMA) were scored in association with bodily movements in the leg, arm, head, and trunk using electromyography and video recordings. The relationship between oromotor episodes and bodily movements was assessed in terms of sleep stage distributions and temporal relationships. Cardiac changes preceding oromotor episodes in stage N2 were assessed.Results Approximately 80% of RMMA and NSMA were associated with movements in one or more body sites. RMMA and NSMA were more frequently associated with movements of the leg (70-75%) and arm (40-55%) than movements of the head (17-22%) and trunk (5-25%). The relationship between oromotor episodes and bodily movements did not significantly differ among sleep stages. Oromotor episodes and bodily movements did not show a consistent temporal pattern in the SB and CTL groups. Regardless of the temporal relationship between oromotor episodes and bodily movements, the mean heart rate significantly increased by 5 beats before the onset of oromotor episodes.Conclusions No specific temporal motor patterns were found between RMMA and bodily movements. RMMA and NSMA represent a repertoire of arousal-related autonomic motor responses during sleep.

Sleep stage-dependent changes in tonic masseter and cortical activities in young subjects with primary sleep bruxism

STUDY OBJECTIVES

The present study investigated the hypothesis that subjects with primary sleep bruxism (SB) exhibit masseter and cortical hyperactivities during quiet sleep periods that are associated with a high frequency of rhythmic masticatory muscle activity (RMMA).

METHODS

Fifteen SB and ten control participants underwent polysomnographic recordings. The frequencies of oromotor events and arousals and the percentage of arousals with oromotor events were assessed. Masseter muscle tone during sleep was quantified using a cluster analysis. Electroencephalography power and heart rate variability were quantified and then compared between the two groups and among sleep stages.

RESULTS

The frequency of RMMA and percentage of arousals with RMMA were significantly higher in SB subjects than in controls in all stages, while these variables for non-rhythmic oromotor events did not significantly differ between the groups. In SB subjects, the frequency of RMMA was the highest in stage N1 and the lowest in stages N3 and R, while the percentage of arousals with RMMA was higher in stage N3 than stages N1 and R. The cluster analysis classified masseter activity during sleep into two clusters for masseter tone and contractions. Masseter muscle tone showed typical stage-dependent changes in both groups, but did not significantly differ between the groups. Furthermore, no significant differences were observed in electroencephalography power or heart rate variability between the groups.

CONCLUSION

Young SB subjects exhibited sleep stage-dependent increases in the responsiveness of RMMA to transient arousals, but did not show masseter or cortical hyperactivity during sleep.

Effects of vibratory feedback stimuli through an oral appliance on sleep bruxism: a 6-week intervention trial

PURPOSE

Various biofeedback stimulation techniques of managing sleep bruxism (SB) have recently emerged; however, the effect of successive application of vibratory feedback stimulation has not been clarified. This study elucidated the effect of vibration feedback stimulation via an oral appliance (OA) on SB when vibration feedback was applied for 4 weeks.

METHODS

This was a prospective, single-arm, open-label, intervention study. Ten participants diagnosed with "definite" SB wore a specially designed OA for 45 nights in a home-setting. A force-based SB detection system, including a pressure-sensitive piezoelectric film placed internally in the OA, triggered a vibrator attached to the OA. Vibratory stimulation was withheld during the first 2-week adaptation period (1st-15th nights), applied during the 4-week stimulation period (16th-43rd nights), and again withheld during the post-stimulation period (44th and 45th nights). The number and duration of SB episodes/hour of sleep were calculated based on masseter electromyographic activity recorded with in-home portable polysomnography and compared between the 15th and 45th nights (without stimulation) and the 17th and 43rd nights (with stimulation).

RESULTS

The number and duration of SB episodes significantly decreased after vibratory stimulation (15th vs. 17th nights: p = 0.012 and p = 0.012, respectively), then significantly increased upon cessation of vibratory stimulation after the stimulation period (43rd vs. 45th nights: p = 0.023 and p = 0.023, respectively).

CONCLUSION

Contingent vibratory stimulation through an OA may suppress SB-related masticatory muscle activity continuously for 4 weeks and may be an effective alternative for the management of SB.

TRIAL REGISTRATION

https://jrct.niph.go.jp/ ; trial registration number: jRCTs032190225.

Temporomandibular disorders in patients with polysomnographic diagnosis of sleep bruxism: a case-control study

BACKGROUND

Temporomandibular disorders (TMD) is a collective term that refers to complaints of temporomandibular joint (TMJ) pain, fatigue and/or pain of the craniocervical muscles, limitation of movement of the mandible, and TMJ noises. Sleep bruxism (SB) is a disorder involving rhythmic (phasic) or non-rhythmic (tonic) masticatory muscle activity during sleep and is not a movement disorder or a sleep disorder in otherwise healthy individuals. The present study aimed to support or reject the null hypothesis that there is no association between SB and TMD.

METHODS

The study population was recruited from patients who visited the Artmedica Clinic, Mossoro city, Rio Grande do Norte, Brazil. Patients who underwent polysomnography received information about the research and were invited to participate following the inclusion and exclusion criteria. The study sample consisted of 40 individuals with age ranging from 19 to 76 years. The subjects were administered the questionnaire of the European Academy of Craniomandibular Disorders (AEDC). Those who answered affirmatively to at least one question of the questionnaire were recommended to visit the primary researcher's dental clinic for examination; those who met the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) were evaluated, and their condition was classified into one or more subtypes of TMD. The subjects were divided into 4 groups according to the polysomnographic findings and the responses to the AEDC questionnaire. Of the 40 individuals who answered the AEDC questionnaire and underwent polysomnography, 28 presented with TMD symptoms. The data were expressed as simple frequency and percentage values using statistical software. Values of p < 0.05 were considered to be significant.

RESULTS

The results showed that the frequency of TMD in individuals diagnosed to have SB was 46.4%. According to the DC/TMD of the 28 individuals, the most prevalent TMD subtype was local myalgia (85.7%). Of the total subjects, 32.5% had TMD and SB, 36.4% were males, and in the age range of 31 to 40 years (40%).

CONCLUSION

In this study sample, there was no association between SB as currently defined and TMD, thus confirming previous findings on this topic.

Oral behaviors, bruxism, malocclusion and painful temporomandibular joint clicking: is there an association?

The present cross-sectional case-control study aimed to determine if there is an association between specific oral behaviors, sleep bruxism (SB), awake bruxism (AB), and painful temporomandibular joint (TMJ) clicking. Ninety individuals were dived into three groups; Group 1 (n = 30): painful TMJ clicking; Group 2 (n = 30): painless TMJ clicking; and Group 3 (n = 30): control group. The following clinical data were studied: oral behaviors (unilateral chewing, gum chewing, nail biting, foreign objects biting, leaning with jaw against the hand, and sleeping in a position that pressures the jaw), SB, AB (including the frequency in 10 days, evaluated by ecological momentary assessment), and malocclusions investigated based on clinical inspections (anterior open bite, posterior cross-bite, abnormal overbite/overjet, occlusal guidance, mediotrusive and/or laterotrusive interferences, retruded contact position to maximum intercuspation slide, missing posterior teeth). All statistical tests (Kolmogorov-Smirnov, chi-square, and one-way ANOVA) were performed with a 5% significance level. Group 1 had the highest frequency of and a significant association with leaning with jaw in the hand, sleeping position that pressures the jaw, gum chewing, nail biting, and AB (p<0.05). Gum chewing, nail biting, and AB were associated with Group 2 only when compared to Group 3 (p<0.05). No significant difference among groups was found for other behaviors (unilateral chewing and foreign objects biting), SB, and all malocclusions (p>0.05). It can be concluded that patients with painful TMJ clicking had a higher frequency of and a significant association with some specific harmful behaviors and AB.

Temporomandibular Myofascial Pain Syndrome-Aetiology and Biopsychosocial Modulation. A Narrative Review

This review elaborates on the aetiology, diagnosis, and treatment of temporomandibular (TMD) myofascial pain syndrome (MPS) regulated by psychosocial factors. MPS impairs functioning in society due to the accompanying pain. Directed and self-directed biopsychosocial profile modulation may be beneficial in the treatment of MPS. Moreover, nutrition is also a considerable part of musculoskeletal system health. A fruit and vegetable diet contributes to a reduction in chronic pain intensity because of its anti-inflammatory influence. Cannabidiol (CBD) oils may also be used in the treatment as they reduce stress and anxiety. A promising alternative treatment may be craniosacral therapy which uses gentle fascia palpation techniques to decrease sympathetic arousal by regulating body rhythms and release fascial restrictions between the cranium and sacrum. MPS is affected by the combined action of the limbic, autonomic, endocrine, somatic, nociceptive, and immune systems. Therefore, the treatment of MPS should be deliberated holistically as it is a complex disorder.

Association of psychological distress and widespread pain with sympatoms of temporomandibular disorders and self-reported bruxism in students

Objectives

The aim of this study was to evaluate the association of psychosocial distress and widespread pain with self‐reported symptoms of temporomandibular disorders (TMD) and bruxism, in two cross‐sectional surveys in 2012 and 2016, and whether there are temporal changes in the magnitude of associations.

Materials and methods

The data were gathered from Finnish university students in 2012 and 2016. TMD symptoms were assessed with three validated questions and bruxism with one frequently used question. Psychosocial distress was assessed with the General Health Questionnaire‐12 (GHQ‐12), and widespread pain with questions of pain in the extremities, the neck or upper back, and lower back. The associations of GHQ‐12, widespread pain and background variables with TMD symptoms and bruxism were analyzed with chi‐square tests, t‐test and binary logistic regression models stratified by gender, and adjusted for age‐group, self‐reported general health/wellbeing and presence of widespread pain.

Results

Higher GHQ‐12 score and presence of widespread pain were significantly associated with TMD symptoms in both genders at both time points. The association of higher GHQ‐12 score with sleep bruxism and awake bruxism were inconsistent. In the adjusted model higher GHQ‐12 score and widespread pain were significantly related to TMD pain symptoms in both genders at both time points, and to bruxism in 2012. Between the two time points a greater variability in these associations was seen in men than in women.

Conclusions

Psychological distress and widespread pain are significant determinants in perceived TMD pain and bruxism among students. No significant temporal alterations were observed.

Oral behaviours and wake-time masseter activity in patients with masticatory muscle pain

BACKGROUND

Little is known about wake-time masseter activity of patients with masticatory muscle pain in real-life settings.

OBJECTIVES

The aims of this study were (1) to assess wake-time masseter activity of women with masticatory muscle pain (MMP) and compare it with that of pain-free women; and (2) to investigate the association between objectively measured masseter contractions and self-reported oral behaviours.

METHODS

Adult women (N = 27) diagnosed with MMP were age-matched with pain-free women (N = 26). The electromyographic (EMG) activity of the masseter muscle when awake was recorded unilaterally for two consecutive days. The number of contraction episodes and relative contraction time (%) were calculated using cut-off thresholds of 3%, 5% and 10% of maximum voluntary contraction (MVC). Self-reported daytime oral activity was assessed using the Oral Behaviours Checklist (OBC, items 3-21). Data were analysed using univariate tests and mixed-model analyses.

RESULTS

The number of contraction episodes was similar between groups for all detection thresholds, but the relative contraction time at the lower detection thresholds (i.e. 3% MVC and 5% MVC) was significantly longer (1.5-fold) in the MMP than in the pain-free group. The OBC scores were significantly higher in the women with MMP than in controls, but no positive association could be found between EMG variables and OBC scores.

CONCLUSION

Women with MMP engage in low-level masseter muscle contractions, which last longer than those of pain-free controls. There was no relationship between self-reported oral behaviours and masseter activity when awake. These findings support the notion that prolonged low-level clenching when awake may play a role in the pathophysiology of MMP.

Association between waking-state oral behaviours, according to the oral behaviors checklist, and TMD subgroups

OBJECTIVES

To assess the association between waking-state oral behaviours and temporomandibular disorder (TMD) subgroups and to develop new scoring methods for the Oral Behavior Checklist (OBC).

METHODS

Patients with any TMD diagnosis, according to the diagnostic criteria for TMD (DC/TMD), were divided into subgroups: 'Dysfunctional-TMD' (n = 70), only mechanical dysfunction; 'Painful-TMD' (n = 204), only myalgia, arthralgia or both; and 'Painful-Dysfunctional TMD' (n = 95), combined pain and dysfunction. A group of individuals without TMD, 'Non-TMD' (n = 374), was used for testing associations. Participants completed the OBC. An exploratory factor analysis, followed by a confirmatory factor analysis of the OBC responses, identified 2 major factors, named non-functional activities (NFA) and functional activities (FA). Component total scores were computed. Differences among subgroups for OBC-MS (mean score) and NFA and FA factor scores were estimated using one-way ANOVA and Tukey post hoc tests. Significance was set at p < .05.

RESULTS

The OBC-MS in Non-TMD, Painful-TMD and Painful-Dysfunctional TMD subgroups was higher than in the Dysfunctional-TMD subgroup (p ≤ .001). NFA in Painful-TMD and Painful-Dysfunctional TMD subgroups were higher than in the Non-TMD group (p < .05); NFA in the Dysfunctional-TMD subgroup were lower than in the Painful-TMD subgroup (p = .034). In contrast, FA in Painful-TMD, Dysfunctional-TMD and Painful-Dysfunctional TMD subgroups were lower than in the Non-TMD group (p < .0001).

CONCLUSIONS

A new scoring method for the OBC results in item reduction and creation of meaningful subscales for functional and non-functional behaviours, which are differentially associated with painful and dysfunctional TMDs. This may help clinicians to better tailor treatment for the management of subtypes of TMD patients.

Painful and non-painful symptoms evoked by experimental bracing and thrusting of the mandible in healthy individuals

BACKGROUND

Bruxism may involve bracing and thrusting of the mandible, in addition to clenching or grinding of the teeth. It is unclear how bracing and thrusting may contribute to potential musculoskeletal symptoms associated with bruxism.

OBJECTIVE

To examine the effect of experimental bracing and thrusting of the mandible on the development of musculoskeletal symptoms in healthy volunteers.

METHODS

Thirty healthy volunteers performed six trials of 5 min of repeated bracing and thrusting of the mandible. Bracing involved forcefully maintaining maximum protruded position (5 s with 1 s rest in between), whereas thrusting involved forcefully moving the mandible in a forward direction and back (1 Hz). The participants rated pain, unpleasantness, soreness, fatigue, tension, stiffness, stress and headache on 10-cm visual analogue scales (VAS) before, immediately and 24 h after the tasks. Pain drawings were obtained and maximum voluntary protrusive force (MVPF) was determined before and after the tasks. The outcome parameters for each task were compared between the time points.

RESULTS

There was a significant increase in the VAS scores (2-4/10) of pain, unpleasantness, soreness, fatigue, tension, stiffness and stress immediately following the tasks compared to baseline and 24 h after the tasks (p < .008). Pain was frequently reported in masseter muscles. MVPF values were significantly higher immediately (p < .001) and 24 h after thrusting (p < .001) and bracing (p = .012) tasks compared to the baseline.

CONCLUSIONS

Experimental bracing and thrusting of the mandible evoked transient, mild-to-moderate levels of muscle pain, fatigue, tension and stiffness and increased unpleasantness and stress scores in healthy volunteers.

Technical and Biological Complications of Screw-Retained (CAD/CAM) Monolithic and Partial Veneer Zirconia for Fixed Dental Prostheses on Posterior Implants Using a Digital Workflow: A 3-Year Cross-Sectional Retrospective Study

Objective

The introduction of CAD/CAM and the development of zirconia-based restorations have allowed clinicians to use less expensive materials and faster manufacturing procedures. The purpose of the study was to analyze the differences, in terms of mechanical and biological complication, in multiunit zirconia fixed dental prosthesis (FPDs) on posterior implants produced using a digital workflow. Method and Materials. This study was a retrospective investigation, and patients treated with screw-retained monolithic or partial veneer FPDs on dental implants were selected. Periapical radiographs were taken at baseline and at the 3-year follow-up. Complications were recorded and classified as technical and biological ones.

Results

The study population included 25 patients. The occlusal and interproximal corrections were not clinically significant. In the study sample, the survival rate and success rate of the FPDs after 3 years were 100% and 96%, respectively. One implant failed immediately after placement.

Conclusion

Monolithic zirconia FPDs and partial veneer FPDs showed a 100% survival rate, presenting an interesting alternative to metal ceramic restorations. The partial veneer FPDs had a higher technical complication rate than the monolithic FPDs; however, no statistically significant difference was found.

The neurophysiological basis of bruxism

Mesencephalic trigeminal nucleus (MTN) neurons innervate the stretch receptors of the jaw elevator muscles and periodontal ligament mechanoreceptors, Bruxism activates the MTN. We analyzed how MTN cells are structured, their anatomy and physiology, and the effects of their activation.

To induce and maintain sleep, gamma-aminobutyric acid (GABA), an inhibitor neurotransmitter, is released from the ventro-lateral preoptic area of the hypothalamus and acts on the ascending reticular activating system (ARAS) nuclei. The GABA neurotrasmitter induces the entry of chlorine into cells, hyperpolarizing and inhibiting these. MTN cells, on the contrary, are depolarized by GABA, as their receptors are activated upon GABA binding. They “let out” chlorine and activate ARAS cells. MTN cells release glutamate, an excitatory neurotransmitter onto their target cells, in this case onto ARAS cells. During wakefulness, ARAS activation causes cerebral cortex activation; instead, during sleep (sleep bruxism), ARAS activation avoids an excessive reduction in ARAS neurotransmitters, including noradrenaline, dopamine, serotonin, acetylcholine and glutamate. These neurotransmitters, in addition to activating the cerebral cortex, modulate vital functions such as cardiac and respiratory functions. Polysomnography shows that sleep bruxism is always accompanied by cardiac and respiratory activation and, most importantly, by brain function activation. Bruxism is not a parafunction, and it functions to activate ARAS nuclei.

[Dental disorders with a psychosocial background]

While the mouth and teeth play a lifelong central role in a person's development and wellbeing, psychosocial aspects of disease and health are still only reluctantly included in dental explanatory models. Only dental anxiety with its disease quality of a specific phobia is generally recognized as a mental disorder requiring intervention. It is interpreted as an emotional reaction to aspects of dental treatment, which results in distress for the affected person and appears to be unreasonably intense given the actual dangers involved. Apart from that, the tendency to provide a somatic explanation for symptoms in the dental context persists. This bears implications for the expectations of those affected as well as for interdisciplinary cooperation. In order to improve interdisciplinary support and mutual understanding, the following article introduces the clinical pictures of craniomandibular dysfunction, bruxism, occlusal dysaesthesia, and somatoform prosthesis intolerance alongside dental anxiety. Psychosocial factors can profoundly influence the development, course, and management of these conditions.