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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..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.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.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).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.

Objective To investigate the effect of the Coronavirus pandemic on the report of psychological status, bruxism, and TMD symptoms. Methods An online survey was drafted to report the presence of psychological status, bruxism activities, and reported symptoms of TMDs perceived during the COVID-19 pandemic in a population of 506 individuals. Results Mental health is not positive during the Coronavirus pandemic: almost half the subjects reported an increase in bruxism behaviors, while up to one-third reported an increase in their symptoms involving the TMJ and jaw muscles. Specifically, 36% and 32.2% of participants reported increased pain in the TMJ and facial muscles, respectively, and almost 50% of the subjects also reported more frequent migraines and/or headaches. Conclusion Increased psychosocial distress during the COVID-19 pandemic can increase the frequency of TMD symptoms and bruxism behaviors, which, in turn, constitute a triangle of mutually interacting factors with the psychological and emotional status.

Background Based on a variety of studies conducted in recent years, some of the factors that might contribute to the negative treatment responses of some TMD patients have been elucidated. Methods This paper describes known vulnerability factors that make individuals susceptible to developing temporomandibular disorders (TMDs), as well as those that contribute to the perpetuation of such problems. In addition, the topic of iatrogenesis is discussed as a major contributor to the negative outcomes that can be seen in this field. Results At the patient level, anatomical, psychosocial and genetic factors may contribute to individual vulnerability. The anatomy and pathophysiology of muscles, joints, disc and nerves may all be involved in predisposing to TMD symptoms, especially when the patients have pain elsewhere in the body. Among the psychosocial factors, some features may be elucidated by the DC/TMD axis II, while others (eg illness behaviour, Munchausen syndrome, lack of acceptance of non‐mechanical approaches) require careful evaluation by trained clinicians. Genetic predisposition to first onset TMDs and to chronification of symptoms has been identified for individuals with certain psychological traits, presence of comorbid conditions and certain abnormal clinical manifestations. Regarding iatrogenesis, sins of omission may influence the clinical picture, with the main ones being misdiagnosis and undertreatment. Joint repositioning strategies, occlusal modifications, abuse of oral appliances, use of diagnostic technologies, nocebo effect and complications with intracapsular treatments are the most frequent sins of commission that may contribute to chronification of TMDs. The patients who present with massive occlusal and jaw repositioning changes combined with persistent severe orofacial pain are not a rarity within TMD and orofacial pain canters; these patients are the most difficult ones to manage because of this horrific combination of negative factors. Conclusions The information presented in this paper will help clinicians to understand better why some individuals develop temporomandibular disorders, why some of them will progress to becoming chronic patients, and what the appropriate responses may be., This paper describes known vulnerability factors that make individuals susceptible to developing temporomandibular disorders (TMDs), as well as those that contribute to the perpetuation of such problems. In addition, the topic of iatrogenesis is discussed as a major contributor to the negative outcomes that can be seen in this field.

© 2020 The Authors. Journal of Oral Rehabilitation published by John Wiley & Sons LtdBruxism is a repetitive jaw-muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. It can occur during sleep, indicated as sleep bruxism, or during wakefulness, indicated as awake bruxism. Exogenous risk indicators of sleep bruxism and/or awake bruxism are, among others, medications and addictive substances, whereas also several medications seem to have the potential to attenuate sleep bruxism and/or awake bruxism. The objective of this study was to present a narrative literature on medications and addictive substances potentially inducing or aggravating sleep bruxism and/or awake bruxism and on medications potentially attenuating sleep bruxism and/or awake bruxism. Literature reviews reporting evidence or indications for sleep bruxism and/or awake bruxism as an adverse effect of several (classes of) medications as well as some addictive substances and literature reviews on medications potentially attenuating sleep bruxism and/or awake bruxism were used as starting point and guidelines to describe the topics mentioned. Additionally, two literature searches were established on PubMed. Three types of bruxism were distinguished: sleep bruxism, awake bruxism and non-specified bruxism. Generally, there are insufficient evidence-based data to draw definite conclusions concerning medications and addictive substances inducing or aggravating sleep bruxism and/or awake bruxism as well as concerning medications attenuating sleep bruxism and/or awake bruxism. There are insufficient evidence-based data to draw definite conclusions concerning medications and addictive substances inducing or aggravating sleep bruxism and/or awake bruxism as well as concerning medications attenuating sleep bruxism and/or awake bruxism.

To assess the frequency of reported masticatory muscles activity during wakefulness (i.e., awake bruxism [AB]), levels of anxiety, depression, stress, and the oral health-related quality of life (OHRQoL) in college preparatory students.Sixty-nine college preparatory students participated in the study. AB was evaluated by the Oral Behaviors Checklist (OBC) and a smartphone-based ecological momentary assessment (EMA; [Bruxapp®]). Anxiety and depression were measured by the Hospital Anxiety and Depression Scale, stress was evaluated by the Perceived Stress Scale, and OHRQoL was obtained by The Oral Health Impact Profile-14. Data were analyzed by Pearson's correlation coefficient (α = 0.05).The average EMA-reported frequency of AB behaviors was 38.4%. Significant correlations were found between AB and the OBC, anxiety, depression, stress, and OHRQoL (p0.001).College preparatory students demonstrated moderate frequency of AB, which was significantly correlated with psychosocial factors.

Background Sleep bruxism (SB) and awake bruxism (AB) have been considered different entities, although co-occurrence between them has been shown. While genetic factors have a marked influence on phenotypic variance in liability to SB, this remains unclear for AB. Aim To examine the degree of co-occurrence of SB and AB, and whether they have common correlates and also twin similarity of SB and AB bruxism traits by zygosity and sex. Methods A questionnaire was mailed to all twins born 1945-1957 in Finland in 2012 (n = 11 766). Age and sex adjusted logistic regression models were used. Twin similarity was assessed using polychoric correlations, and crosstwin-crosstrait correlations were computed. Results The response rate was 72% (n = 8410). Any SB was reported by 14.8% and >= 3 nights weekly by 5.0%. Percentages for any AB were 18.4% and 6.3%, respectively. There was substantial co-occurrence (29.5%) between SB and AB, and several shared correlates were found. For SB, the polychoric intra-class correlation was 0.366 in monozygotic (MZ) and 0.200 in dizygotic (DZ) pairs, without gender difference. A twofold crosstwin-crosstrait correlation was observed in MZ twins compared to DZ twins. Conclusions The risk factor profiles of SB and AB were largely but not entirely similar. The higher correlation in MZ than in DZ pairs suggests the influence of genetic factors on both SB and AB. The higher crosstwin-crosstrait correlation in MZ than in DZ pairs suggests some degree of genetic influences shared by SB and AB.

Within the orofacial pain discipline, the most common group of afflictions is temporomandibular disorders (TMD). The pathologic and functional disorders included in this condition closely resemble those that are seen in the orthopedic medicine branch of the medical profession, so it would be expected that the same principles of orthopedic diagnosis and treatment are applied. Traditional orthopedic therapy relies on a "Two Pathway" approach involving conservative and/or surgical treatments. However, over the course of the 20th century, some members of the dental community have created another way of approaching these disorders- referred to in this paper as the "Third Pathway"-based on the assumption that signs and symptoms of TMD are due to a "bad" relationship between the mandible and skull, leading to a variety of irreversible occlusal or surgical corrective treatments. Since no other human joint is discussed in these terms within the orthopedic medicine communities, it has become progressively clear that the Third Pathway is a unique and artificial conceptual creation of the dental profession. However, many clinical studies have utilized the medically oriented conservative/surgical Two-Pathway model to diagnose and treat TMD within a biopsychosocial model of pain. These studies have shown that TMD comprise another domain of orthopedic illness that requires a medically oriented approach for good outcomes while avoiding the irreversible aspects of the Third Pathway. This review presents historical and current evidence that the Third Pathway is an example of unorthodox medicine that leads to unnecessary overtreatment and further proposes that it is time to abandon this approach as we move forward in the TMD field.

Background Several studies seek to prove the relationship between bruxism and periodontal status although it remains unclear and debatable. We aimed to assess the association between self-reported (SR) bruxism with the periodontal status in a large scale survey. Material and methods A total of 1064 individuals from the southern region of the Lisbon Metropolitan Area (Portugal) were enrolled. Patients were interviewed for the SR bruxism assessment through a self-report questionnaire. Full-mouth periodontal status was assessed with probing depth (PD), clinical attachment loss (CAL), gingival recession (REC), and bleeding on probing (BoP) being measured. The American Association of Periodontology/European Federation of Periodontology 2018 case definitions were used. Logistic regression analyses provided information on the influence of SR bruxism towards periodontitis. Results SR bruxers exhibited lower prevalence of periodontitis. Additionally, SR bruxers with periodontitis had PD and CAL significantly lower than patients with only periodontitis. Multivariate analysis suggests that SR bruxism was significantly associated with a lower risk of periodontitis (odds ratio [OR] = 0.42 95% CI: 0.32-0.56). Mean PD and CAL were significantly lower in SR bruxers. When assessing the type of SR bruxism, significant differences among mean PD, CAL, and BoP levels were also identified. Conclusion SR bruxism and periodontal status are negatively associated. SR bruxers exhibit lower odds towards periodontitis and better periodontal clinical characteristics. Further studies are mandatory to clarify these findings.

Objectives: This study aimed to assess frequency and multiple-night variability of sleep bruxism (SB) as well as sleep-time masticatory muscle activities (sMMA) in the home environment in healthy young adults using a portable device that provides electrocardiographic (ECG) and surface electromyographic (EMG) recordings from the masticatory muscles. Methods: The study was performed on 27 subjects (11 males, 16 females, mean age 28.3 &plusmn, 1.7 years) selected from a sample of healthy young students. Evaluation was carried out for four nights to record data on masticatory muscle activities using a compact portable device that previously showed an excellent agreement with polysomnography (PSG) for the detection of SB events. The number of SB episodes per sleep hour (bruxism index), and the number of tonic, phasic and mixed sMMA events per hour were assessed. A descriptive evaluation of the frequency of each condition was performed on all individuals, and gender comparison was investigated. Results: Mean sleep duration over the four recording nights was 7 &plusmn, 1.3 h. The average SB index was 3.6 &plusmn, 1.2. Most of the sMMA were tonic (49.9%) and phasic (44.1%). An ANOVA test showed the absence of significant differences between the four nights. No significant gender differences were detected for the SB index, phasic or tonic contractions, conversely, gender differences were detected for mixed sMMA events (p &lt, 0.05). Conclusion: This investigation supports the concept that sMMA events are quite frequent in healthy adults. Differences over the four-night recording span were not significant. These data could be compared to subjects with underlying conditions that may lead to an additive bruxism activity and possible clinical consequences.

© 2021 European Sleep Research SocietyA recent report from the European Sleep Research Society’s task force “Beyond AHI” discussed an issue that has been a long-term subject of debate – what are the best metrics for obstructive sleep apnoea (OSA) diagnosis and treatment outcome assessments? In a similar way, sleep bruxism (SB) metrics have also been a recurrent issue for >30 years and there is still uncertainty in dentistry regarding their optimisation and clinical relevance. SB can occur alone or with comorbidities such as OSA, gastroesophageal reflux disorder, insomnia, headache, orofacial pain, periodic limb movement, rapid eye movement behaviour disorder, and sleep epilepsy. Classically, the diagnosis of SB is based on the patient’s dental and medical history and clinical manifestations; electromyography is used in research and for complex cases. The emergence of new technologies, such as sensors and artificial intelligence, has opened new opportunities. The main objective of the present review is to stimulate the creation of a collaborative taskforce on SB metrics. Several examples are available in sleep medicine. The development of more homogenised metrics could improve the accuracy and refinement of SB assessment, while moving forward toward a personalised approach. It is time to develop SB metrics that are relevant to clinical outcomes and benefit patients who suffer from one or more possible negative consequences of SB.

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 &lt, 0.02), migraine/headache (F(1,81) = 7.396, p &lt, 0.01), pain in neck (F(1,81) = 6.726, p &lt, 0.05), pain in scapula (F(1,81) = 8.546, p &lt, 0.005) and the oral behaviors of pushing the tongue forcefully against the teeth (F(1,81) = 5.222, p &lt, 0.05) and inserting the tongue between the upper and lower teeth (F(1,81) = 5.344, p &lt, 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 &lt, 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 &lt, 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.

© 2021 The Authors. Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.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%.

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 = 0.01 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% to 54.8% and 77.4% to 90.3%, respectively). A slight increase in the "relaxed" condition (62.5% to 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=0.01) and weak positive correlation in teeth contact report (+0.380, p=0.05) was 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 recognize actions such as bracing and teeth contact concerning the single-time report.

Objective : To provide a scoping review of the literature by assessing all the English-language papers that investigated the relationship between sleep bruxism (SB) and temporomandibular disorders (TMDs). Study data and sources : A search was performed in the National Library of Medicine (PubMed) and Scopus databases, in order to identify all the articles published assessing the relationship between SB and TMDs, by several different approaches. The selected articles were then structurally read and summarized in PICO tables. The articles were selected independently by the two authors. Study selection : Out of 185 references that were initially retrieved, 47 articles met the inclusion criteria and were thus included in the review. The studies were divided into four categories based on the type of SB assessment: 1. questionnaire/self-report (n = 26), 2. clinical examination (n = 7), 3. electromyography (EMG) (n = 5), and 4. polysomnography (PSG) (n = 9). Conclusions : Studies based on questionnaire/self-report SB featured a low specificity for SB assessment, and in general they found a positive association with TMD pain. On the contrary, instrumental studies (i.e., electromyography, polysomnography) found a lower level of association or even a negative relationship between SB and TMD pain. Findings from this updated review confirmed the conclusions of a previous review by Manfredini & Lobbezoo, suggesting that literature findings on the relationship between SB and TMDs are dependent on the assessment strategies that are adopted for SB. Future studies should consider SB as a multifaceted motor behavior that must be evaluated in its continuum spectrum, rather than using a simplified dichotomous approach of presence/absence.

BACKGROUND: Ambulatory electromyographic (EMG) devices are increasingly being used in sleep bruxism studies. EMG signal acquisition, analysis and scoring methods vary between studies. This may impact comparability of studies and the assessment of sleep bruxism in patients. OBJECTIVES: (a) To provide an overview of EMG signal acquisition and analysis methods of recordings from limited-channel ambulatory EMG devices for the assessment of sleep bruxism; and (b) to provide an overview of outcome measures used in sleep bruxism literature utilising such devices. METHOD: A scoping review of the literature was performed. Online databases PubMed and Semantics Scholar were searched for studies published in English until 7 October 2020. Data on five categories were extracted: recording hardware, recording logistics, signal acquisition, signal analysis and sleep bruxism outcomes. RESULTS: Seventy-eight studies were included, published between 1977 and 2020. Recording hardware was generally well described. Reports of participant instructions in device handling and of dealing with failed recordings were often lacking. Basic elements of signal acquisition, for example amplifications factors, impedance and bandpass settings, and signal analysis, for example rectification, signal processing and additional filtering, were underreported. Extensive variability was found for thresholds used to characterise sleep bruxism events. Sleep bruxism outcomes varied, but typically represented frequency, duration and/or intensity of masticatory muscle activity (MMA). CONCLUSION: Adequate and standardised reporting of recording procedures is highly recommended. In future studies utilising ambulatory EMG devices, the focus may need to shift from the concept of scoring sleep bruxism events to that of scoring the whole spectrum of MMA. ispartof: JOURNAL OF ORAL REHABILITATION vol:48 issue:7 pages:846-871 ispartof: location:England status: published

Bruxism is a common condition that clinicians come across in both adult and children. Prevalence rates in adults range from 22% to 30% for awake bruxism (AB) and from 8% to 16% for sleep bruxism (SB), while in children they raise up to 40% for SB. Currently, bruxism is considered an ‘umbrella term’ for different jaw muscle activities, occurring during sleep and/or wakefulness. They have a different aetiology, but there is agreement on their central, not peripheral, origin. In otherwise healthy individuals, bruxism can be considered a muscle behaviour, which can be harmless or represent a risk and/or protective factor for clinical consequences, rather than being a disorder per se. Nonetheless, given the merging knowledge on the interaction with several associated factors and concurrent conditions, bruxism should be investigated for being a possible sign of an underlying primary condition. Consequently, treatment should be directed to the management of the possible clinical consequences and/or to the underlying primary conditions. It is generally based on the conservative strategies. The present manuscript summarises the available knowledge on bruxism aetiology, assessment and management for both SB and AB in adults and children, with focus on the future directions to implement the clinical relevance of bruxism researches. Clinical relevance: A narrative overview summarising such a quickly evolving topic as bruxism may be useful to help clinicians understanding the complex relationship among bruxism, the possible underlying primary conditions, and the possible clinical consequences.

A smartphone-based ecological momentary assessment (EMA) strategy to collect real time data on awake bruxism (AB) has been recently introduced. The aim of this study was to assess the compliance with its use over 1 week in a sample of healthy young adults. Sixty (N = 60) healthy young adults (mean age 24.2 ± 4.1 years) used a dedicated smartphone application that sent 20 alerts at random times throughout the day. Upon alert receipt, the subjects had to report in real time their condition among five possible options: relaxed jaw muscles, teeth contact, teeth clenching, teeth grinding, and mandible bracing. Compliance rate with the app was assessed at the individual and group level in terms of percentage of answered alerts as well as number of days that were needed to reach the targeted observation period of 7 days with a compliance of at least 60%. The mean compliance recorded with the smartphone application was 67.8% of the total alerts. On average, 9.8 ± 3.2 days (range 7–19) have been necessary to achieve the targeted goal of 7 days with a minimum of 60% alerts/day. No gender differences were detected in any compliance data. Response rate was not different during weekdays or weekends. This investigation is the first attempt to assess individual compliance with EMA for reporting awake bruxism. Results suggest that a smartphone-based strategy can have interesting potential. The compliance rate reported in this study will serve as a comparison standpoint for future investigations. Based on the recent multidisciplinary focus on the study of awake bruxism, EMA has emerged as a potential approach for use in the clinical and research settings. This investigation suggests that compliance with such strategy is good, thus making it worthy of adoption for the assessment of AB and its clinical implications.

Background: To evaluate whether oro-facial pain experience was related to the type of musical instrument and to learn more about the roles of sleep and sleep-related issues in the pain among professional musicians. Objectives: A standard questionnaire was sent to all Finnish symphony orchestras (n = 19), with altogether 1005 professional musicians and other personnel. Methods: The questionnaire covered descriptive data, instrument group, items on perceived quality of sleep, possible sleep bruxism, stress experience and oro-facial pain experience during the past 30 days. Results: In the present study, which included the musicians only, the response rate was 58.7% (n = 488). All orchestras participated in the study, and there was no significant difference in the response rate between the orchestras. The mean age of men (52.3%) was 47.7 (SD 10.3) and of women (47.7%) was 43.4 (SD 9.8) years (P < 0.001). Overall, current pain in the oro-facial area was reported by 28.9%, frequent bruxism by 12.1% and frequent stress by 20.8%. According to Somers' d, there were statistically significant but moderate correlations between overall pain reports in the oro-facial area and disrupted sleep (d = 0.127, P = 0.001), sleep bruxism (d = 0.241, P < 0.001) and stress experiences (d = 0.193, P < 0.001). Logistic regression revealed, independent of the instrument group (string, woodwind, brass wind, percussion), that current oro-facial pain experience was significantly associated with disrupted sleep (P = 0.001), frequent sleep bruxism (P < 0.001) and frequent stress (P = 0.002) experiences. Conclusions: Among symphony orchestra musicians, oro-facial pain experience seems to be related to perceptions of stress, sleep bruxism and disrupted sleep rather than the instrument group.

This commentary discusses the need to move on from the adoption of cut-off points for the definition of the presence/absence of bruxism and justifies the need to embrace an evaluation based on the continuum of jaw motor behaviours. Currently, the number of events per hour, as identified by polysomnography (PSG), is used to define the presence of sleep bruxism (SB). Whilst PSG still remains the indispensable equipment to study the neurophysiological correlates of SB, the scoring criteria based on a cut-off point are of questionable clinical usefulness for the study of oral health outcomes. For awake bruxism (AB), criteria for a definite diagnosis have never been proposed. Some goal-oriented strategies are proposed to identify bruxism behaviours that increase the risk of negative oral health outcomes (eg, tooth wear, muscle and/or temporomandibular joint [TMJ] pain, restorative complications). One possible strategy would embrace an improved knowledge on the epidemiology and natural variability of bruxism, even including study of the amount of PSG/SB and electromyography masticatory muscle activity (EMG/MMA) during sleep and the frequency/prevalence of bruxism behaviours during wakefulness that are needed to represent a risk factor for clinical consequences, if any. There should not be any preclusion about the diagnostic strategies to pursue that goal, and a combination of instrumental and non-instrumental approaches may even emerge as the best available option. Once data are available, large-scale, non-selected population samples representing the entire continuum of EMG/MMA activities are also needed, in the attempt to estimate untreated health risks in the population.

Objectives: Tooth wear is a common finding in adult patients with dental sleep disorders. The aim of this paper was to review the literature on the possible associations between tooth wear and the following dental sleep disorders: sleep‐related oro‐facial pain, oral moistening disorders, gastroesophageal reflux disease (GERD), obstructive sleep apnoea syndrome (OSAS) and sleep bruxism.Methods: A PubMed search was performed on 1 June 2018 using MeSH terms in the following query: Tooth Wear AND (Facial Pain OR Temporomandibular Joint Disorders OR Xerostomia OR Sialorrhea OR Gastroesophageal Reflux OR Sleep Apnea Syndrome OR Sleep Bruxism).Results: The query yielded 706 reports on tooth wear and the mentioned dental sleep disorders. Several associations between tooth wear and the dental sleep disorders were suggested in the literature. It could be concluded that: (a) tooth wear is associated with dental pain and/or hypersensitivity; (b) oral dryness is associated with tooth wear, oro‐facial pain and sleep bruxism; (c) GERD is associated with tooth wear, oro‐facial pain, oral dryness, OSAS and sleep bruxism; (d) OSAS is associated with oral dryness, GERD and sleep bruxism; and (e) sleep bruxism is associated with tooth wear.Conclusions: Tooth wear is associated with the dental sleep disorders oro‐facial pain, oral dryness, GERD and sleep bruxism. The dental sleep disorders are interlinked with each other, which leads to indirect associations as well, and makes the consequences of each single condition difficult to disentangle. Knowledge of these associations is clinically relevant, but more research is needed to confirm their validity.

Objective: To assess the association between self-reported awake bruxism (AB) and the chronotype profile among Brazilian, Portuguese, and Italian dental students.Methods: A cross-sectional ...

AIMS To review randomized clinical trials on arthrocentesis for managing temporomandibular disorders (TMD) and to discuss the clinical implications. METHODS On March 10, 2019, a systematic search of relevant articles published over the last 20 years was performed in PubMed, as well as in Scopus, the authors' personal libraries, and the reference lists of included articles. The focus question was: In patients with TMD (P), does TMJ arthrocentesis (I), compared to any control treatment (C), provide positive outcomes (O)? RESULTS/CONCLUSION Thirty papers were included comparing TMJ arthrocentesis to other treatment protocols in patients with disc displacement without reduction and/or closed lock (n = 11), TMJ arthralgia and/or unspecific internal derangements (n = 8), or TMJ osteoarthritis (n = 11). In general, the consistency of the findings was poor because of the heterogenous study designs, and so caution is required when interpreting the meta-analyses. In summary, it can be suggested that TMJ arthrocentesis improves jaw function and reduces pain levels, and the execution of multiple sessions (three to five) is superior to a single session (effect size = 1.82). Comparison studies offer inconsistent findings, with the possible exception of the finding that splints are superior in managing TMJ pain (effect size = 1.36) compared to arthrocentesis, although this conclusion is drawn from very heterogenous studies (I2 = 94%). The additional use of cortisone is not effective for improving outcomes, while hyaluronic acid or platelet-rich plasma positioning may have additional value according to some studies. The type of intervention, the baseline presence of MRI effusion, and the specific Axis I diagnosis do not seem to be important predictors of effectiveness, suggesting that, as in many pain medicine fields, efforts to identify predictors of treatment outcome should focus more on the patient (eg, age, psychosocial impairment) than the disease.

Objective. To characterize the closed-mouth temporomandibular joint (TMJ) disc-condyle relationship in a population of individuals who sought hospital services for temporomandibular disorders (TMD). Methods. Two hundred and twenty-four TMJ magnetic resonance images (MRIs) of 112 patients were assessed in all spatial planes to classify disc position with respect to the condyle in a closed-mouth position. Results. Disc displacement (DD) was present in 62.1% and superior disc position in 29.9% of the patients. Position could not be determined in 8% of the cases. Among DD, pure anteriorized position was the most common condition (34.4%), with different combined translational and rotational displacements in all the other joints (27.7%). Conclusion. There is a wide biological variability in disc position in closed mouth among patients seeking for TMD advice. Getting deeper into the correlation with clinical symptoms is recommended to refine the potential relevance of any diagnostic and management strategies based on the imaging evaluation of TMJ disc position.

A gold-standard technique has yet to be found for the treatment of temporomandibular joint ankylosis (TMJa), particularly in patients with recurring ankylosis. A 58-year-old male patient, with a history of multiple TMJ surgeries and severe limitation of mouth opening (maximum interincisal distance [MID] was 10 mm). Computerised tomography (CT) imaging highlighted a bilateral type IV ankylosis. The surgical guides were manufactured using a 3D printing method after obtaining a proper design of the osteotomy lines. The positioning of the fossa and condyle components of the custom TMJ prosthesis was digitally performed. Osteotomies were carried out using surgical guides and TMJ prostheses were placed as per the virtual planning. A human amniotic mambrana is inserted between the two prosthetic components to avoid ranchylosis. The post-operative CT showed the correct positioning of the condylar prosthesis. MID after 10 days was 37 mm. Total joint reconstruction surgery using 3D virtual surgical planning may be an effective surgical option for achieving a precise surgical outcome and making use of a single-stage approach in cases of TMJa and the use of the amniotic membrane, thanks to its healing properties and reduction of pain perception, seems to improve the quality of the immediate post-operative period.

© 2021 by Wroclaw Medical University.Background. Orthodontic tooth movement (OTM) is a complex phenomenon mediated by cytokines, of which interleukin-1 beta (IL-1β) is potently involved in the remodeling of the periodontal ligament (PDL) and bone. Whether the pattern of IL-1β release differs at the sides of tension and compression is not yet clarified. Objectives. The aim of the present study was to evaluate the level of IL-1β and the ratio of IL-1β to interleukin-1 receptor antagonist (IL-1RA) in gingival crevicular fluid (GCF) at the tension and compression sides during orthodontic canine retraction. Material and methods. Seventeen patients scheduled for orthodontic treatment with bilateral extrac-tion of maxillary first premolars and canine retraction were enrolled. Tooth 2.3 was retracted, teeth 1.3 and 3.3 served as controls. Gingival crevicular fluid samples were collected from the tension and compression sides of each tooth at baseline (before the 1st activation – day 0) and at days 2 and 7, and then again before the 2nd activation (day 28) and at days 30 and 35. The levels of IL-1β and IL-RA were evaluated with the enzyme-linked immunosorbent assay (ELISA). Results. After the 1st activation, a statistically significant increase in the level of IL-1β was observed at teeth 2.3 (p < 0.03 mesially and p < 0.05 distally) and 1.3 (p < 0.05 mesially and distally), both at the tension and compression sides. The 2nd activation resulted in a gradual increase in the IL-1β level at both canines; however, statistical significance was reached only for tooth 2.3 (p < 0.05 mesially and p < 0.02 distally). In terms of the IL-1β/IL-1RA ratio, a significant increase was observed only at the compression side of the experimental tooth (p < 0.01). Conclusions. An increase in the IL-1β level in GCF was observed both at the tension and compression sides of the actively retracted canine 2.3 as well as the contralateral canine 1.3; a significant rise in the IL-1β/IL-1RA ratio was noted only at the compression side of the experimental tooth 2.3, indicating the zone of active bone resorption.

© 2021 Editorial Council for the Journal of Prosthetic DentistryStatement of problem: The definition of bruxism has evolved, and the dental profession needs to align with the terminologies adopted in the current literature of sleep and orofacial pain medicine. Purpose: The purpose of this review was to discuss the recent evolution of bruxism concepts and the implications for changing the definition that is currently used by the prosthodontic community. Material and methods: A historical perspective on the evolution of the definition of bruxism, as well as a systematic literature review on the validity of polysomnography (PSG)-based criteria for sleep bruxism diagnosis to detect the presence of clinical consequences, is presented. Selected articles were read in a structured Population, Intervention, Comparison, Outcome (PICO) format to answer the question “If a target population with conditions such as tooth wear, dental implant complications, and temporomandibular disorders (P) is diagnosed with sleep bruxism by means of PSG (I) and compared with a population of nonbruxers (C), is the occurrence of the condition under investigation (that is, the possible pathologic consequences of sleep bruxism) be different between the 2 groups (O)?” Results: Eight studies were eligible for the review, 6 of which assessed the relationship between PSG-diagnosed sleep bruxism and temporomandibular disorder pain, while the other 2 articles evaluated the predictive value of tooth wear for ongoing PSG-diagnosed sleep bruxism and the potential role of sleep bruxism in a population of patients with failed dental implants. Findings were contradictory and not supportive of a clear-cut relationship between sleep bruxism assessed based on available PSG criteria and any clinical consequence. The literature providing definitions of bruxism as a motor behavior and not pathology has been discussed. Conclusions: The bruxism construct has shifted from pathology to motor activity with possibly even physiological or protective relevance. An expert panel including professionals from different medical fields published 2 consecutive articles focusing on the definition of bruxism, as well as an overview article presenting the ongoing work to prepare a Standardized Tool for the Assessment of Bruxism (STAB) to reflect the current bruxism paradigm shift from pathology to behavior (that is, muscle activity). As such, dental practitioners working in the field of restorative dentistry and prosthodontics are encouraged to appraise this evolution.

Aim The aim of this study is to show the anatomical and histological features of the displaced temporomandibular joint (TMJ) disc in joints with degenerative disease. Methods This study was performed on a total of 30 TMJ discs extracted from 22 patients, who underwent surgical discectomy after failure of conservative non‐surgical treatment regimens to control pain and/or limited range of motion. All joints had imaging signs of an anteriorized disc position and degenerative joint disease. Samples of the extracted discs were stored in formalin, cut into 3 micron‐thick sections imbedded in paraffin and processed with hematoxylin‐eosin. Result All the samples present irreversible morphologic and histological alterations. The macroscopical evaluation showed that 14 discs were worn and fragmented in several parts, and one disc was perforated. Morphological alterations with deformation and degenerative signs were shown in all discs, which were all severely worn and compromised. Histologically, various alterations were found, such as pre‐fibrous sclerosis with myxoid degeneration and collagen deposits (N = 25), an increase in fibro‐hyaline and fibrous tissues, with loss of elasticity (N = 25), scattered calcifications (N = 15), and synovial inflammation with microvascular proliferation and increased cellularity, presence of lymphocytes, histiocytes and plasma cells (N = 18). After the intervention, all patients reported decreased pain levels and showed improved function at 6 months. Conclusion These observations suggest that degenerative joint disease is accompanied by a anteriorized discs featuring abnormal macroscopical and histological changes. From a clinical viewpoint, this may suggest that, when treatment escalation leads to consider TMJ surgery, total discectomy is the most reasonable approach.

Objective: This study aimed to evaluate whether self-reported sleep bruxism among musicians is associated with sleep-related problems and/or psychological stress. Methods: Eight hundred-thirty-one Finnish orchestra musicians completed a questionnaire that covered, among others, indicators of sleep-related problems, possible sleep bruxism, and stress. Results: In total, 488 questionnaires were completed. The single variable ordinal logistic regression models revealed at least moderate associations between frequency of sleep bruxism and female gender, shorter sleep duration, longer sleep latency, problems in sleeping during concert season, feeling more often tired during the daytime, restless legs, a poor self-rated sleep quality, and more stress experience. The variables that remained in the final model were sleep duration, gender, and stress. Conclusion: Musicians who sleep 7 hours or less per night report more sleep bruxism, as compared to those who sleep 8 hours or more. Female gender and high-stress experience were associated with more sleep bruxism.

This study assessed the safety and efficacy of three different doses of BoNT-A for persistent myofascial pain (MFP). One hundred female subjects were randomly assigned into five groups (n = 20): oral appliance (OA), saline solution (SS) and three BoNT-A groups with different doses. Pain intensity and pressure pain threshold were evaluated up to 24 weeks after treatment. Adverse effects related to muscle contraction, masticatory performance, muscle thickness and mandibular bone volume were also assessed. Changes over time were compared within and between groups. The &ldquo, nparLD&rdquo, package and Wilcoxon signed-rank test were used to analyze the data. BoNT-A reduced pain intensity (p &lt, 0.0001) and increased pressure pain threshold (p &lt, 0.0001) for up to 24 weeks compared to the placebo. No differences were found between BoNT-A and OA at the last follow-up. A transient decline in masticatory performance (p &lt, 0.05) and muscle contraction (p &lt, 0.0001), and a decrease in muscle thickness (p &lt, 0.05) and coronoid and condylar process bone volume (p &lt, 0.05) were found as dose-related adverse effects of BoNT-A. Regardless of the dose, BoNT-A was as effective as OA on MFP. Notwithstanding, due to BoNT-A dose-related adverse effects, we suggest the use of low doses of BoNT-A in MFP patients that do not benefit from conservative treatments.

Objective: To investigate the association between volumetric measurements of craniofacial morphology and temporomandibular disorders (TMDs). Methods: Computerized tomography (CT) scans of 20 individuals aged 18 to 40 with (TMD group) or without TMJ pain (control group) were gathered based on a case-control design. Three-dimensional reconstructions were performed to evaluate the gonial angle, condylar volume, and the distance between the posterior edge of the condyle and the sigmoid notch. Results: The gonial angle was significantly larger (8% difference) in the TMD group with respect to controls, whereas the condylar volume was significantly higher in the control group (15.2% difference). No significant difference was found in the linear distance. Conclusion: There is an association between the presence of TMJ pain and some features of craniofacial morphology. Individuals with TMJ pain have a lower condylar volume and a tendency towards hyperdivergent growth.

The aim of the present study was to assess the potential role of some biological, psychological, and social factors to predict the presence of painful temporomandibular disorders (TMDs) in a TMD-patient population. The study sample consisted of 109 consecutive adult patients (81.7% females, mean age 33.2 &plusmn, 14.7 years) who were split into two groups based on Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) diagnoses: painful TMD and non-painful TMD. The presence of pain was adopted as the depended variable to be identified by the following independent variables (i.e., predictors): age, gender, bruxism, tooth wear, chewing gum, nail biting, perceived stress level, chronic pain-related impairment (GCPS), depression (DEP), and somatization (SOM). Single-variable logistic regression analysis showed a significant relationship between TMD pain and DEP with an odds ratio of 2.9. Building up a multiple variable model did not contribute to increase the predictive value of a TMD pain model related to the presence of depression. Findings from the present study supported the existence of a relationship between pain and depression in painful TMD patients. In the future, study designs should be improved by the adoption of the best available assessment approaches for each factor.

PURPOSE To assess the correlation between RDC/TMD Axis I and Axis II diagnoses and whether pain could mediate a possible correlation between these two variables. MATERIALS AND METHODS Data of both RDC/TMD axes were collected from 737 consecutive patients who sought TMD advice at the University of Padova, Italy. A descriptive analysis was used to report the frequencies of Axis I and II diagnoses, and Spearman test was performed to assess the correlation between the axes. Subsequently, the sample was divided into two groups (painful vs nonpainful TMD). Frequencies were reported using descriptive analysis, and chi-square test was used to compare groups. The painful TMD group was then divided based on the level of pain-related impairment (low = Groups I and II; high = Groups III and IV). Then, frequencies of depression and somatization were reported using descriptive analysis for each disability group, and chi-square test was used to compare groups. RESULTS No correlation levels were found between Axis I and any of the Axis II findings (Graded Chronic Pain Scale, depression, and somatization). The painful TMD group presented higher levels of depression and somatization (P < .05). Comparisons of depression and somatization frequencies between pain-impairment groups showed a significantly higher prevalence of abnormal scores for the severe pain-impairment group. CONCLUSION There is no correlation between specific Axis I and Axis II findings. The presence of pain, independent of the muscle or joint location, is correlated with Axis II findings, and higher levels of pain-related impairment are associated with the most severe scores of depression and somatization.

This study aims to assess the correlation between indexes of jaw muscle function and dento‐skeletal morphology. A sample of 35 temporomandibular disorders‐free healthy individuals (10 males, mean age 26.7 ± 9.8 years) underwent surface electromyographic (sEMG) assessment of bilateral masseter and temporalis muscles, to evaluate sEMG activity during maximum voluntary clenching (MVC) with a dedicated device (Easymyo®, T.F.R. Technology, Udine, Italy). Four outcome parameters were assessed for each individual: MCV on cotton rolls; MVC on teeth; chewing on right and left sides; clench/relax test. Electromyographic recordings were assessed based on five standardized indexes of muscle function, to evaluate the degree of muscle asymmetry during static and dynamic function (i.e., percentage overlapping coefficient [POC], Impact, Asymmetry, Activation, and Torque). For each individual, the presence of a number of occlusal and skeletal features was assessed: asymmetry of molar class; deviated incisor midline; deep bite; open bite; and crossbite. Skeletal class and vertical dimension of occlusion were also evaluated. Based on normality distribution of data, t test and analysis of variance, when needed, were used to compare muscle function indexes between individuals with and without the different dento‐skeletal features. None of the muscle function indexes (POC, Impact, Asymmetry, Activation, and Torque) was significantly different between individuals with or without the various dental and skeletal features. Gender differences were also not significant (p > 0.05). Despite some minor differences were observed, none of them was significant. Thus, the interaction between form and function is too complex for hypothesizing a simple one‐to‐one relationship between interarch tooth relationship and muscle function patterns.

The concept of equilibrating the occlusion to treat and/or to prevent temporomandibular disorders found its background in the old precepts of gnathology, but an assessment of the available literature as well as an appraisal of its biological rationale suggests that it is not recommended for routine use.

The aim of this study was to assess awake bruxism (AB) behaviours in a sample of healthy young adults using a smartphone-based application for a real-time report (ie, ecological momentary assessment [EMA], also called experience sampling method [ESM]). Forty-six dental students used a smartphone application that sent 15 alerts at random intervals during the day for 1 week to collect AB self-reports. They had to answer on time by tapping on the display icon that refers to their current condition of jaw muscles: relaxed; teeth contact; teeth clenching; teeth grinding; jaw clenching without teeth contact (ie, bracing). The average frequency of relaxed jaw muscles, as a percentage of answers over the 7 days, was 71.7%. Teeth contact (14.5%) and jaw clenching (10.0%) were the most frequent AB behaviours. No significant gender differences were detected. Interindividual differences were quite relevant, but the overall frequency was in general only moderately variable from day-to-day. Coefficient of variation (CV) was low for the condition "relaxed jaw muscles" (0.44). At the individual level, teeth contact was the most prevalent behaviour, with a 39.1%-52.2% proportion of subjects reporting it at least once a day. During a 7-day observation period, the frequency of real-time report of AB behaviours in a sample of healthy young adults was 28.3%. The low daily variability in the average frequency value for the relaxed jaw muscles condition suggests that EMA may be a reliable strategy to get deeper into the epidemiology of oral behaviours. This investigation introduced EMA principles to the study of AB and provided data on the frequency of AB behaviours in young adults that could be compared to populations with risk/associated factors and possible clinical consequences.

Sleep bruxism (SB) in children has been associated with several sleep characteristics, which may alter their sleep pattern. This change affects the internal biological clock and consequently the chronotype profile. The aim of this study was to evaluate the existence of an association between possible SB in children with specific chronotype profiles and sleep characteristics. The study included 207 parents/guardians of children aged between 3 and 12 years who were waiting for their children's dental treatment at the Pediatric Dentistry Clinic of the Federal University of Rio de Janeiro, Brazil. A questionnaire on the socio-demographic characteristics of parents and children as well as on the features of the children's sleep was applied. In addition, the CIRENS scale (Circadian Energy Scale) was completed by the parents to identify the children's chronotype. A chi-squared test was used to determine the association between possible SB, the chronotype, and sleep characteristics. A multiple logistic regression model was implemented to observe the influence of chronotype, age, and other independent variables on the possible SB. The logistic regression model demonstrated that nocturnal agitation (p = 0.009; OR = 3.42) and nightmares (p = 0.045; OR = 3.24) were associated with possible SB in children. Although no significant association (p = 0 .089) between the chronotype profile and possible SB was observed in the 3 to 5 years age group, a proportional difference was observed between the chronotype categories in this age group-12.5% of children with SB had a morning type, while 26.4% had an intermediate type and 47.8% an evening type compared to those without possible SB. Nocturnal agitation and nightmares were associated with possible SB. In addition, young children with an evening chronotype had a tendency toward possible SB.

Objective: To assess the frequency and age distribution of Axis I and Axis II diagnoses among Polish patients with temporomandibular disorders (TMD).Method: One hundred sixty-three (n = 163) consecutive adult patients seeking TMD treatment were assessed based on the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) guidelines. Descriptive statistics on the frequency of diagnoses and mean age of the diagnostic groups was performed. Result: Frequency of muscle disorders, disc displacements, and other joint disorders was 56.9, 48.9, and 31%, respectively. Disc displacement was the most common diagnosis in younger patients. Severe somatization and depression were shown in 11.9 and 15.8% of patients, respectively. Only 10.5% of the patients showed severe pain-related impairment. Females tended to have higher psychosocial scores than males. Discussion: The frequency of Axis I TMD diagnoses in Polish patients is similar to other populations, whereas Axis II findings slightly differ from previous reports from other countries.

Zusammenfassung Zielsetzung Untersuchung, ob Patienten mit diagnostizierten Kiefergelenkstörungen (TMDs) vergleichbar häufig eine kieferorthopädische Behandlung in der Anamnese haben, wie Personen ohne TMDs und Untersuchung, ob Patienten mit idealer kieferorthopädischer Behandlung in der Vorgeschichte weniger häufig Symptome zeigen als Patienten mit einer nicht idealen Therapie. Material und Methoden Es wurden 2 Gruppen zusammengestellt, eine Studien- bzw. TMD-Gruppe und eine Kontrollgruppe, mit gleicher Alters- und Geschlechtszusammensetzung. Bei den Patienten mit einer kieferorthopädischen Behandlung in der Anamnese wurde anhand normaler Werte bei 5 Okklusionsparametern zwischen einer idealen und einer nicht idealen kieferorthopädischen Behandlung unterschieden. Ergebnisse In Bezug auf eine kieferorthopädische Behandlung in der Anamnese ergab sich keine klinisch signifikante Korrelation mit den einzelnen Kiefergelenkstörungen (Muskelschmerzen, Gelenkschmerzen, Diskusverlagerung, Arthrosen), wobei der Wert für den Koeffizienten Phi (Θ) zwischen 0,120 und 0,058 lag. Bei den Patienten mit einer kieferorthopädischen Behandlung in der Anamnese war die Korrelation mit ideal oder nicht ideal verlaufener Behandlung im Allgemeinen klinisch nicht oder nur sehr schwach relevant. Schlussfolgerungen Die Ergebnisse der vorliegenden Studie bestätigen, dass kieferorthopädische Maßnahmen keine klinisch signifikanten Auswirkungen auf Kiefergelenkstörungen haben. Die sehr niedrigen Werte für eine Korrelation zwischen einer oder keiner kieferorthopädischen Behandlung in der Anamnese mit idealen oder nicht idealen Ergebnissen und den unterschiedlichen Kiefergelenkstörungen lassen darauf schließen, dass eine kieferorthopädische Behandlung bei der Entstehung von Kiefergelenkstörungen keine Rolle spielen kann.

Background: Polysomnography (PSG) is the gold standard for sleep bruxism (SB) diagnosis. PSG/SB children's criteria are not available; thus, parental-report SB is widely used. Aim: Assessing the diagnostic accuracy of parental report of sleep tooth grinding (STG) with a PSG/SB diagnosis in children, adopting adult criteria. Design: Thirty-seven children from clinics of Universidad CES were included. Parents filled the Children's Sleep Habits Questionnaire (CSHQ) assessing the single-observation report – CSHQ – of STG with a No/Yes answer and five ordinal answers. A 5-day diary reporting the presence/absence of STG (multiple-observation report) was also completed. Each child underwent a single-night PSG study. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, likelihood ratios, Spearman correlation coefficient, and Cohen's kappa coefficient were used to analyze data. Results: Single observation, using No/Yes answer, showed acceptable specificity and NPV, while low PPV and sensitivity. Accuracy and likelihood ratios were low. When using the five ordinal answers, weak correlation and fair agreement (r = 0.34 and κ = 0.40) with PSG/SB adult criteria were found. Multiple-observation evaluation of STG presented moderate correlation and agreement (r = 0.50 and κ = 0.48). Conclusions: Although multiple-observation report achieved better agreement than single-observation report, our results failed supporting the validity of report strategies for the diagnosis of SB in children, as an equivalent of PSG/SB adult criteria.

In this second part of a diptych on bruxism, the focus is on the associations of this masticatory muscle activity with other sleep-related conditions. Its association with the obstructive sleep apnoea syndrome (OSAS) has been a particular object of study. Bruxism seems to play a protective role in OSAS, although the evidence for this is not yet conclusive. Apart from this possible positive consequence, bruxism also has several negative consequences, for which evidence is available to a greater or lesser extent. For example, bruxism has been associated with temporomandibular pain and dysfunction, periodontal and endodontic problems, failures of restorations and implants, and tooth wear. In some cases, these consequences are severe enough to justify treatment of bruxism. In all other cases, there is no indication for diagnostics and treatment, given the possible positive consequences. If treatment is indicated, modalities should be conservative, like stabilisation appliances, counselling, medication, psychology, and physiotherapy.In dit deel van het tweeluik over bruxisme wordt ingegaan op de associaties van deze kauwspieractiviteit met andere aandoeningen. Vooral de associaties met het obstructief slaapapneusyndroom zijn onderzocht. Bruxisme lijkt een beschermende functie bij deze aandoening te hebben, hoewel de bewijslast daarvoor nog niet sluitend is. Naast dit mogelijke positieve gevolg heeft bruxisme ook een aantal nadelige gevolgen waarvoor in meer of mindere mate bewijslast voorhanden is. Zo wordt de kauwspieractiviteit in verband gebracht met temporomandibulaire pijn en disfunctie, parodontale en endodontische problemen, het falen van restauraties en implantaten, en gebitsslijtage. In een aantal gevallen zijn deze gevolgen ernstig genoeg om een behandeling van bruxisme te rechtvaardigen. In alle andere gevallen bestaat er voor de behandeling van bruxisme geen indicatie, gelet op de mogelijke positieve gevolgen. Indien behandeling is geïndiceerd, dan dient er conservatief te worden gehandeld met modaliteiten als stabilisatieopbeetplaten, voorlichtingsgesprekken, medicatie, psychologie en fysiotherapie.

To answer a clinical research question: 'is there any association between features of dental occlusion and temporomandibular disorders (TMD)?' A systematic literature review was performed. Inclusion was based on: (i) the type of study, viz., clinical studies on adults assessing the association between TMD (e.g., signs, symptoms, specific diagnoses) and features of dental occlusion by means of single or multiple variable analysis, and (ii) their internal validity, viz., use of clinical assessment approaches to TMD diagnosis. The search accounted for 25 papers included in the review, 10 of which with multiple variable analysis. Quality assessment showed some possible shortcomings, mainly related with the unspecified representativeness of study populations. Seventeen (N = 17) articles compared TMD patients with non-TMD individuals, whilst eight papers compared the features of dental occlusion in individuals with TMD signs/symptoms and healthy subjects in non-patient populations. Findings are quite consistent towards a lack of clinically relevant association between TMD and dental occlusion. Only two (i.e., centric relation [CR]-maximum intercuspation [MI] slide and mediotrusive interferences) of the almost forty occlusion features evaluated in the various studies were associated with TMD in the majority (e.g., at least 50%) of single variable analyses in patient populations. Only mediotrusive interferences are associated with TMD in the majority of multiple variable analyses. Such association does not imply a causal relationship and may even have opposite implications than commonly believed (i.e., interferences being the result, and not the cause, of TMD). Findings support the absence of a disease-specific association. Based on that, there seems to lack ground to further hypothesise a role for dental occlusion in the pathophysiology of TMD. Clinicians are encouraged to abandon the old gnathological paradigm in TMD practice.

Since the publication of a special issue on bruxism of the NTvT in July 2000, consensus has been reached on bruxism's definition as a repetitive masticatory muscle activity that is characterised by clenching and/or grinding while awake (awake bruxism) or during sleep (sleep bruxism). As yet, however, no consensus exists about the diagnosis of bruxism: sufficient evidence to establish the reliability and validity of the commonly used techniques (self-report, clinical examination, imaging, electromyography, polysomnography) has not yet been produced. Morphological factors are no longer considered important aetiological factors, while increasing evidence suggests aetiological roles for psychosocial, physiological, biological, and exogenous factors. This review paper is the first part of a diptych and is concerned with the definition, diagnostics, epidemiology and possible causes of this disorder. In the second part, that will be published in the next issue, associations of bruxism with other conditions will be discussed, along with its (purported) consequences and its management.Sinds het verschijnen van een themanummer van het Nederlands Tijdschrift voor Tandheelkunde in juli 2000 over bruxisme is er consensus bereikt over de definitie van bruxisme als een repetitieve kauwspieractiviteit die wordt gekarakteriseerd door klemmen en/of knarsen tijdens waken (waakbruxisme) en/of slapen (slaapbruxisme). Over de diagnostiek van bruxisme bestaat nog geen consensus: voor geen van de gebruikte technieken (zelfrapportage, klinisch onderzoek, beeldvorming, elektromyografie, polysomnografie) is aangetoond dat deze betrouwbaar en valide is. Oorzaken worden niet meer gezocht onder de morfologische factoren, maar in toenemende mate onder de psychosociale, fysiologische, biologische en exogene factoren. Dit literatuuroverzicht betreft het eerste deel van een tweeluik en gaat in op de definitie, de diagnostiek, de epidemiologie en de mogelijke oorzaken van deze aandoening. In het tweede deel, in de volgende editie, zal worden ingegaan op de associaties van bruxisme met andere slaapgerelateerde aandoeningen, op de (vermeende) gevolgen van bruxisme en op de behandeling ervan.

This systematic review and meta-analysis (MA) aimed to evaluate the diagnostic validity of questionnaires, clinical assessment and portable diagnostic devices compared to the reference standard method polysomnography (PSG) in assessing sleep bruxism (SB). Two reviewers searched electronic databases for diagnostic test accuracy studies that compared questionnaires, clinical assessment or portable diagnostic devices for SB, with the reference standard method PSG, comprising previous studies from all languages and with no restrictions regarding age, gender or time of publication. Of the 351 articles, eight met the inclusion criteria for qualitative, and seven for quantitative analysis. The methodology of selected studies was evaluated using the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2). The studies were divided and analysed over three groups: three studies evaluating questionnaires, two regarding the clinical assessment of tooth wear and three covering portable diagnostic devices. The MA indicated that portable diagnostic devices showed the best validity of all evaluated methods, especially as far as a four-channel EMG/ECG recording is concerned. Questionnaires and the clinical assessment can be used as screening methods to identify non-SB individuals, although it is not that good in identifying subjects with SB. The quality of evidence identified through GRADEpro, was from very low-to-moderate, due to statistical heterogeneity between studies.

Statement of problem The presence of temporomandibular disorders (TMDs) and/or bruxism signs and symptoms may present multifaceted concerns for the prosthodontist. Purpose The purpose of this systematic review was to evaluate the relationship between prosthetic rehabilitation and TMDs and bruxism. Material and methods Three research questions were identified based on different clinical scenarios. Should prosthodontics be used to treat TMD and/or bruxism? Can prosthodontics cause TMDs and/or bruxism? How can prosthodontics be performed (for prosthetic reasons) in patients with TMDs and/or bruxism? A systematic search in the PubMed database was performed to identify all randomized clinical trials (RCTs) comparing the effectiveness of prosthodontics with that of other treatments in the management of TMDs and/or bruxism (question 1); clinical trials reporting the onset of TMDs and/or bruxism after the execution of prosthetic treatments in healthy individuals (question 2); and RCTs comparing the effectiveness of different prosthodontics strategies in the management of the prosthetic needs in patients with TMDs and/or bruxism (question 3). Results No clinical trials of the reviewed topics were found, and a comprehensive review relying on the best available evidence was provided. Bruxism is not linearly related to TMDs, and both of these conditions are multifaceted. Based on the diminished causal role of dental occlusion, prosthetic rehabilitation cannot be recommended as a treatment for the 2 conditions. In theory, they may increase the demand for adaptation beyond the stomatognathic system's tolerability. No evidence-based guidelines were available for the best strategy for managing prosthetic needs in patients with TMDs and/or bruxism. Conclusions This systematic review of publications revealed an absence of RCTs on the various topics concerning the relationship between TMD and bruxism and prosthodontics. Based on the best available evidence, prosthetic changes in dental occlusion are not yet acceptable as strategies for solving TMD symptoms or helping an individual stop bruxism. Clinicians should take care when performing irreversible occlusal changes in healthy individuals and in patients with TMD and/or bruxism.

The objective of the study was to conduct a systematic review of the literature assessing the effects of botulinum toxin (BoNT-A) injections in the management of bruxism. Search for articles involved the PubMed, Scopus, Web of Science, Embase, Cochrane, Scielo and Lilacs databases. Specific terms were used and the search carried out from 1980 to March 2016 by three independent researchers. Randomized controlled studies (RCTs), prospective and before–after studies that applied BoNT-A at the masseter and/or temporalis muscles were included. Three RCTs and two uncontrolled before–after studies out of 904 identified citations were included in this review. All five articles dealt with sleep bruxism and featured a small sample size. None of them was about awake bruxism. Two randomized clinical trials were double-blinded, with a control group using saline solution. Two studies used polysomnography/electromyography for sleep bruxism diagnosis, whilst others were based on history taking and clinical examination. All studies using subjective evaluations for pain and jaw stiffness showed positive results for the BoNT-A treatment. In contrast, the two studies using objective evaluations did not demonstrate any reduction in bruxism episodes, but a decrease in the intensity of muscles contractions. Despite the paucity of works on the topic, BoNT-A seems to be a possible management option for sleep bruxism, minimizing symptoms and reducing the intensity of muscle contractions, although further studies are necessary especially as far as the treatment indications for bruxism itself is concerned. BoNT-A has been increasingly diffused in dentistry over recent years, being also used for pain management in patients with bruxism. Nonetheless, there is no consensus about its effects in this disorder.

The presence of body posture changes among patients with temporomandibular disorders (TMD) has been a controversial topic in dentistry. Based on that, the aim of this study was to assess postural features of pain-free subjects with internal derangement of the temporomandibular joint (TMJ), viz. disc displacement, when compared to subjects with normal disc position. A total of 21 subjects with unilateral, pain-free TMJ disc displacement (DD) and 21 subjects without any TMD signs of symptoms were assessed for body posture changes by means of posturographic evaluation of several body segments and postural balance reactions through the centre of mass during jaw movements using a balance platform. Posturographic measurements showed the absence of any significant differences between the two groups in any of the outcome parameters. Similarly, all balance platform responses to mandibular movements were not different between groups. There are no significant differences in body posture between subjects with and without unilateral disc displacement in the temporomandibular joint. Such observations, indicating a well-preserved postural balance in the presence of TMJ internal derangement, put into serious question the potential influence of TMJ disorders on whole body posture and viceversa.