Risk factors for sleep bruxism in the general population

Occlusal splints for treating sleep bruxism (tooth grinding)

BACKGROUND

Sleep bruxism is an oral activity characterised by teeth grinding or clenching during sleep. Several treatments for sleep bruxism have been proposed such as pharmacological, psychological, and dental.

OBJECTIVES

To evaluate the effectiveness of occlusal splints for the treatment of sleep bruxism with alternative interventions, placebo or no treatment.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group's Trials Register (to May 2007); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 1); MEDLINE (1966 to May 2007); EMBASE (1980 to May 2007); LILACS (1982 to May 2007); Biblioteca Brasileira de Odontologia (1982 to May 2007); Dissertation, Theses and Abstracts (1981 to May 2007); and handsearched abstracts of particular importance to this review. Additional reports were identified from the reference lists of retrieved reports and from article reviews about treating sleep bruxism. There were no language restrictions.

SELECTION CRITERIA

We selected randomised or quasi-randomised controlled trials (RCTs), in which splint therapy was compared concurrently to no treatment, other occlusal appliances, or any other intervention in participants with sleep bruxism.

DATA COLLECTION AND ANALYSIS

Data extraction was carried out independently and in duplicate. Validity assessment of the included trials was carried out at the same time as data extraction. Discrepancies were discussed and a third review author consulted. The author of the primary study was contacted when necessary.

MAIN RESULTS

Thirty-two potentially relevant RCTs were identified. Twenty-four trials were excluded. Five RCTs were included. Occlusal splint was compared to: palatal splint, mandibular advancement device, transcutaneous electric nerve stimulation, and no treatment. There was just one common outcome (arousal index) which was combined in a meta-analysis. No statistically significant differences between the occlusal splint and control groups were found in the meta-analyses.

AUTHORS' CONCLUSIONS

There is not sufficient evidence to state that the occlusal splint is effective for treating sleep bruxism. Indication of its use is questionable with regard to sleep outcomes, but it may be that there is some benefit with regard to tooth wear. This systematic review suggests the need for further investigation in more controlled RCTs that pay attention to method of allocation, outcome assessment, large sample size, and sufficient duration of follow up. The study design must be parallel, in order to eliminate the bias provided by studies of cross-over type. A standardisation of the outcomes of the treatment of sleep bruxism should be established in the RCTs.

Validation of the BiteStrip screener for sleep bruxism

OBJECTIVE

The aim of this study was to validate a small electronic electromyographic device (BiteStrip) designed to screen masseter electromyographic events that indicate sleep bruxism (SB) against traditional masseter electromyographic events (MEMG).

STUDY DESIGN

Six SB treatment-seeking patients, 4 obstructive sleep apnea (OSA) patients and 8 symptom-free controls, underwent overnight polysomnography, including MEMG and BiteStrip recordings. Total BiteStrip and MEMG scores and indices (events per hour) based on total recording time (TRT) and total sleep time (TST) were computed. Measures of accuracy, Spearman's rho correlations, and nonparametric group comparisons were performed.

RESULTS

BiteStrip average sensitivity was 0.72, average positive predictive value was 0.75. Correlations between left BiteStrip and MEMG total scores, TRT, and TST indices were r = 0.81, r = 0.79, and r = 0.79, respectively. Bland-Altman plots showed good agreement between indices. Significant group differences were observed for total scores and indices.

CONCLUSIONS

BiteStrip and MEMG scores showed strong relationships. Sensitivity and positive predictive value were acceptable. The BiteStrip is a viable screener for identifying masseter electromyographic events that indicate SB.

Effects of pergolide on severe sleep bruxism in a patient experiencing oral implant failure

In the patient described in this study, oral implants failed as a probable consequence of severe, polysomnographically confirmed sleep bruxism. As this patient had the wish to be re-implanted after this failure, we decided to try diminishing the frequency of bruxism and duration first. To that end, two management strategies were used. Their efficacy was evaluated polysomnographically, yielding a total of six overnight recordings. Of the selected management strategies, the administration of low doses of the dopamine D1/D2 receptor agonist pergolide finally resulted in a substantial and lasting reduction in the bruxism outcome measures under study. This result supports the previous suggestion that central neurochemicals like dopamine may be involved in the modulation of sleep bruxism. The case report also illustrates the importance of an extensive history taking (questionnaires as well as oral) and clinical examination of oral implant patients for the presence of severe bruxism before the implant procedure is started. In case of doubt, polysomnography may be considered to definitively confirm or rule out the presence of severe sleep bruxism.

Genesis of sleep bruxism: Motor and autonomic-cardiac interactions

This is a short review paper presenting hypothesis to explain the mechanism that may be involved in the genesis of sleep bruxism (SB). In humans, SB is a repetitive sleep movement disorder mainly characterized by rhythmic masticatory muscle activity (RMMA) at a frequency of 1Hz and by occasional tooth grinding. Until recently, the mechanism by which RMMA and SB episodes are triggered has been poorly understood. It is reported that during light sleep, most SB episodes are observed in relation to brief cardiac and brain reactivations (3-15s) termed "micro-arousals". We showed that RMMA are secondary to a sequence of events in relation to sleep micro-arousals: the heart (increase in autonomic sympathetic activity) and brain are activated in the minutes and seconds, respectively, before the onset of activity in suprahyoid muscles and finally by RMMA in jaw closing masseter or temporalis muscles. In non-human primate study, we have shown that the excitability of cortico-bulbar pathways is depressed during sleep; no rhythmic jaw movements (RJM) are observed following intracortical microstimulation (ICMS) of cortical masticatory area (CMA) during sleep compared to the quiet awake state. The above results suggest that the onset of RMMA and SB episodes during sleep are under the influences of brief and transient activity of the brainstem arousal-reticular ascending system contributing to the increase of activity in autonomic-cardiac and motor modulatory networks.

Clinical Identification of the Simple Sleep-Related Movement Disorders

Simple sleep-related movement disorders must be distinguished from daytime movement disorders that persist during sleep, sleep-related epilepsy, and parasomnias, which are generally characterized by activity that appears to be simultaneously complex, goal-directed, and purposeful but is outside the conscious awareness of the patient and, therefore, inappropriate. Once it is determined that the patient has a simple sleep-related movement disorder, the part of the body affected by the movement and the age of the patient give clues as to which sleep-related movement disorder is present. In some cases, all-night polysomnography with accompanying video may be necessary to make the diagnosis. Hypnic jerks (ie, sleep starts), bruxism, rhythmic movement disorder (ie, head banging/body rocking), and nocturnal leg cramps are discussed in addition to less well-appreciated disorders such as benign sleep myoclonus of infancy, excessive fragmentary myoclonus, and hypnagogic foot tremor/alternating leg muscle activation.

Effects of an occlusal splint compared with cognitive-behavioral treatment on sleep bruxism activity

The impact of an occlusal splint (OS) compared with cognitive-behavioral treatment (CBT) on the management of sleep bruxism (SB) has been poorly investigated. The aim of this study was to evaluate the efficacy of an OS with CBT in SB patients. Following a randomized assignment, the OS group consisted of 29, and the CBT group of 28, SB patients. The CBT comprised problem-solving, progressive muscle relaxation, nocturnal biofeedback, and training of recreation and enjoyment. The treatment took place over a period of 12 wk, and the OS group received an OS over the same time period. Both groups were examined pretreatment, post-treatment, and at 6 months of follow-up for SB activity, self-assessment of SB activity and associated symptoms, psychological impairment, and individual stress-coping strategies. The analyses demonstrated a significant reduction in SB activity, self-assessment of SB activity, and psychological impairment, as well as an increase of positive stress-coping strategies in both groups. However, the effects were small and no group-specific differences were seen in any dependent variable. This is an initial attempt to compare CBT and OS in SB patients, and the data collected substantiate the need for further controlled evaluations, using a three-group randomized design with repeated measures to verify treatment effects.

A psychological study on patients with masticatory muscle disorder and sleep bruxism

Sleep bruxism (SB) has been believed to be related to stress and psychosocial factors, however their implicit relationship has remained unclear. This study was conducted on patients visiting our clinic with SB and masticatory muscle disorders (MMD) for the purpose of clarifying personality and behavioral traits. This study was conducted on patients of MMD visiting our clinic. The Rosenzweig Picture-Frustration study was performed on each patient. Twenty-seven (27) patients were divided into two groups: 17 patients with SB and 10 patients without. The SB group showed a significantly lower level of E (extrapunitive) reaction than the nonSB group. SB patients showed a significantly higher level of M (impunitive) reaction than those without SB. Concerning the directions of aggression, the percentage of E-A (extraaggression) was significantly lower in SB patients than in those without. On the other hand, the percentage of I-A (intraaggression) was significantly higher in patients with SB than those without. Our study found a new aspect of the patients with MMD and SB: they are not only intraaggressive, but are also unable to be extrapunitive and extraaggressive. Consequently, they are unable to demonstrate adequate self-assertiveness in stressful situations.

A Review of Pediatric Nonrespiratory Sleep Disorders

Sleep problems are extremely common during childhood, from infancy to adolescence. Despite the prevalence of sleep problems, childhood sleep disorders are often underrecognized and undiagnosed, despite being either preventable or treatable. Sleep impacts almost all aspects of a child's functioning, and thus the increased recognition and treatment of sleep disorders will positively affect a child's well-being. Children experience the same broad range of sleep disturbances encountered in adults, including sleep apnea, insomnia, parasomnia, delayed sleep phase, narcolepsy, and restless legs, but their clinical presentation, evaluation, and management may differ. Although snoring and sleep apnea may be the most common indication for an overnight sleep study in a child, one quarter of children presenting to a sleep clinic for evaluation will have a second sleep diagnosis, which is often nonrespiratory in nature. Especially in children, ruling out sleep apnea is rarely the end point of the sleep evaluation. Clinicians involved in sleep medicine must be prepared to recognize, evaluate, and manage plans for sleep disorders across the lifespan of the patient. This article will provide an updated review of nonrespiratory pediatric sleep disorders within a developmental framework.

[Computerized occlusal analysis in bruxism]

INTRODUCTION

Sleep bruxism as nocturnal parafunction, also known as tooth grinding, is the most common parasomnia (sleep disorder). Most tooth grinding occurs during rapid eye movement - REM sleep. Sleep bruxism is an oral habit characterized by rhythmic activity of the masticatory muscles (m. masseter) that causes forced contact between dental surfaces during sleep. Sleep bruxism has been associated with craniomandibular disorders including temporomandibular joint discomfort, pulpalgia, premature loss of teeth due to excessive attrition and mobility, headache, muscle ache, sleep interruption of an individual and problems with removable and fixed denture. Basically, two groups of etiological factors can be distinguished, viz., peripheral (occlusal) factors and central (pathophysiological and psychological) factors. The role of occlusion (occlusal discrepancies) as the causative factor is not enough mentioned in relation to bruxism.

OBJECTIVE

The main objective of this paper was to evaluate the connection between occlusal factors and nocturnal parafunctional activities (occlusal disharmonies and bruxism).

METHOD

Two groups were formed- experimental of 15 persons with signs and symptoms of nocturnal parafunctional activity of mandible (mean age 26.6 years) and control of 42 persons with no signs and symptoms of bruxism (mean age 26.3 yrs.). The computerized occlusal analyses were performed using the T-Scan II system (Tekscan, Boston, USA). 2D occlusograms were analyzed showing the occlusal force, the center of the occlusal force with the trajectory and the number of antagonistic tooth contacts.

RESULTS

Statistically significant difference of force distribution was found between the left and the right side of the arch (L%-R%) (t=2.773; p<0.02) in the group with bruxism. The difference of the centre of occlusal force - COF trajectory between the experimental and control group was not significant, but the trajectory of COF was longer in the group of bruxists (67.3+24.4mm). In addition, the significant difference of COF position in relation to the center of the elliptic fields was not found in bruxists (chi-squared=1.63; p> 0.05), but obtained results directly revealed uneven distribution of the occlusal forces which caused the excessive attrition and mobility of tooth.

CONCLUSION

Our study failed to find direct correlation between occlusal factors and bruxism, so they are basically contributing factors.

Bruxism: its multiple causes and its effects on dental implants - an updated review*

There is a growing interest in bruxism, as evidenced by the rapidly increasing number of papers about this subject during the past 5 years. The aim of the present review was to provide an update of two previous reviews from our department (one about the aetiology of bruxism and the other about the possible role of this movement disorder in the failure of dental implants) and to describe the details of the literature search strategies used, thus enabling the readers to judge the completeness of the review. Most studies that were published about the etiology during the past 5 years corroborate the previously drawn conclusions. Similarly, the update of the review about the possible causal relationship between bruxism and implant failure reveals no new points of view. Thus, there is no reason to assume otherwise than that bruxism is mainly regulated centrally, not peripherally, and that there is still insufficient evidence to support or refute a causal relationship between bruxism and implant failure. This illustrates that there is a vast need for well-designed studies to study both the aetiology of bruxism and its purported relationship with implant failure.

Finite element analysis of the temporomandibular joint during lateral excursions of the mandible

One of the most significant characteristics of the temporomandibular joint (TMJ) is that it is in fact composed of two joints. Several finite element simulations of the TMJ have been developed but none of them analysed the different responses of its two sides during nonsymmetrical movement. In this paper, a lateral excursion of the mandible was introduced and the biomechanical behaviour of both sides was studied. A three-dimensional finite element model of the joint comprising the bone components, both articular discs, and the temporomandibular ligaments was used. A fibre-reinforced porohyperelastic model was introduced to simulate the behaviour of the articular discs, taking into account the orientation of the fibres in each zone of these cartilage components. The mandible movement during its lateral excursion was introduced as the loading condition in the analysis. As a consequence of the movement asymmetry, the discs were subjected to different load distributions. It was observed that the maximal shear stresses were located in the lateral zone of both discs and that the lateral attachment of the ipsilateral condyle-disc complex suffered a large distortion, due to the compression of this disc against the inferior surface of the temporal bone. These results may be related with possible consequences of a common disorder called bruxism. Although it would be necessary to perform an exhaustive analysis of this disorder, including the contact forces between the teeth during grinding, it could be suggested that a continuous lateral movement of the jaw may lead to perforations of both discs in their lateral part and may damage the lateral attachments of the disc to the condyle.

Clinical evaluation of tinnitus in patients with sleep bruxism: prevalence and characteristics

Evaluation of the prevalence and characteristics of tinnitus in a Brazilian series of sleep bruxism patients. In this descriptive study, 100 patients (80 women and 20 men) were selected through the self-report of grinding teeth during sleep, confirmed by room mate or family member. They were evaluated according to a systematized approach: a questionnaire for orofacial pain and the Portuguese version of the Research Diagnostic Criteria for Temporomandibular Disorders. The patients were divided into two groups: group A, 54 patients with complaint of tinnitus and group B, 46 patients without tinnitus complaint. The mean age was 37.85 (13-66 years) and 34.02 years (20-59 years), respectively, for groups A and B (P = 0.1164). There was statistically significant difference between the two groups, with higher prevalence for the group A, in relation to: presence of chronic facial pain (P = 0.0007); number of areas painful to palpation in the masticatory and cervical muscles (P = 0.0032); myofascial pain in the masticatory muscles (P = 0.0003); absence of teeth without prosthetic replacement (P = 0.0145) and indices of depression (P = 0.0234). Structural alterations of the TMJ, like disc displacement and vertical dimension loss did not differ for the two groups. Tinnitus frequency was higher in patients with sleep bruxism and chronic facial pain. Myofascial pain, number of areas painful to palpation in the masticatory and cervical muscles, higher levels of depression and tooth absence without prosthetic replacement were more frequent in the group with tinnitus.

Adaptations of Mouthguards for Patients with Special Needs

The adaptations and applications of mouthguard appliances are many and varied, with uses ranging from protective to therapeutic. These modifications serve the individual needs of patients. This requires problem-solving based on combining form and function with the skills of the dentist.

Anxiety symptoms in clinically diagnosed bruxers

The present work was an attempt to investigate for the existence of an association between anxiety psychopathology and bruxism. The presence of bruxism was investigated according to validated clinical criteria in 98 subjects, who also filled out a self-report questionnaire (PAS-SR) for the assessment of panic-agoraphobic spectrum. 34.7% (n = 34) of participants were diagnosed as bruxers. The prevalence of anxiety psychopathology was similar between bruxers and non-bruxers, but Mann-Whitney U-test revealed significant differences in total PAS-SR (P = 0.026) score, indicating that subclinical symptoms of the anxiety spectrum might differentiate bruxers from controls. In particular, significant differences emerged in scores of domains evaluating panic (P = 0.039), stress sensitivity (P = 0.006) and reassurance sensitivity symptoms (P = 0.005) of panic-agoraphobic spectrum. Support to the existence of an association between bruxism and certain psychopathological symptoms has been provided.

On the pharmacotherapy of sleep bruxism: placebo-controlled polysomnographic and psychometric studies with clonazepam

OBJECTIVES

Sleep bruxism (SB) is a parasomnia defined as a stereotyped movement disorder characterized by grinding or clenching of the teeth during sleep. Pathophysiologically, SB is the result of biological and psychosocial influences. Treatment comprises behavioral, orthodontic and pharmacological interventions. While benzodiazepines and muscle relaxants have been reported by clinicians to reduce bruxism-related motor activity, placebo-controlled studies are lacking. Thus, the aim of the present study was to investigate the acute effects of clonazepam (Rivotril) as compared with placebo, utilizing polysomnography and psychometry.

METHOD

Ten drug-free outpatients (6 females, 4 males), aged 46.5 +/- 13.1 years, suffering from SB (ICD-10: F45.8; ICSD: 306.8) and having been treated by bite splints were included in the trial. Comorbidity was high: 7 patients presented nonorganic insomnia related to adjustment or anxiety disorders (5 patients) or depression (2 patients); all patients had a concomitant movement disorder (6 restless legs syndrome, 4 periodic leg movement disorder). After one adaptation night, patients received placebo and 1 mg clonazepam 1/2 hour before lights out in a single-blind, nonrandomized study design. Objective sleep quality was determined by polysomnography, subjective sleep and awakening quality by rating scales, objective awakening quality by psychometric tests. Clinical evaluation was based on the Pittsburgh Sleep Quality Index (PSQI), the Zung Depression (SDS) and Anxiety (SAS) Scales, the Quality of Life Index, the Epworth Sleepiness Scale and the International Restless Legs Syndrome Study Group (IRLSSG) Scale.

RESULTS

On admission, SB patients exhibited deteriorated PSQI, SAS, SDS and IRLSSG measures. As compared with placebo, 1 mg clonazepam significantly improved the mean bruxism index from 9.3 to 6.3/h of sleep. Furthermore, it significantly improved the total sleep period, total sleep time, sleep efficiency, sleep latency and time awake during the total sleep period, and increased stage 2 sleep and movement time. Periodic leg movements decreased significantly, while the apnea index and apnea-hypopnea index increased marginally, but remained within normal limits. Subjective sleep quality improved as well, while in mood, performance and psychophysiology no changes were observed.

CONCLUSION

Acute clonazepam therapy significantly improved not only the bruxism index but also objective and subjective sleep quality, with unchanged mood, performance and psychophysiological measures upon awakening, suggesting good tolerability of the drug.

The clenching-grinding spectrum and fear circuitry disorders: clinical insights from the neuroscience/paleoanthropology interface

This review discusses the clenching-grinding spectrum from the neuropsychiatric/neuroevolutionary perspective. In neuropsychiatry, signs of jaw clenching may be a useful objective marker for detecting or substantiating a self-report of current subjective emotional distress. Similarly, accelerated tooth wear may be an objective clinical sign for detecting, or substantiating, long-lasting anxiety. Clenching-grinding behaviors affect at least 8 percent of the population. We argue that during the early paleolithic environment of evolutionary adaptedness, jaw clenching was an adaptive trait because it rapidly strengthened the masseter and temporalis muscles, enabling a stronger, deeper and therefore more lethal bite in expectation of conflict (warfare) with conspecifics. Similarly, sharper incisors produced by teeth grinding may have served as weaponry during early human combat. We posit that alleles predisposing to fear-induced clenching-grinding were evolutionarily conserved in the human clade (lineage) since they remained adaptive for anatomically and mitochondrially modern humans (Homo sapiens) well into the mid-paleolithic. Clenching-grinding, sleep bruxism, myofacial pain, craniomaxillofacial musculoskeletal pain, temporomandibular disorders, oro-facial pain, and the fibromyalgia/chronic fatigue spectrum disorders are linked. A 2003 Cochrane meta-analysis concluded that dental procedures for the above spectrum disorders are not evidence based. There is a need for early detection of clenching-grinding in anxiety disorder clinics and for research into science-based interventions. Finally, research needs to examine the possible utility of incorporating physical signs into Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition posttraumatic stress disorder diagnostic criteria. One of the diagnostic criterion that may need to undergo a revision in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition is Criterion D (persistent fear-circuitry activation not present before the trauma). Grinding-induced incisor wear, and clenching-induced palpable masseter tenderness may be examples of such objective physical signs of persistent fear-circuitry activation (posttraumatic stress disorder Criterion D).

The Primary Parasomnias

BACKGROUND

Primary parasomnias are undesirable motor or verbal phenomena which occur during sleep and result in abnormal arousals. They occur out of all sleep stages or during transitions between sleep and awake. Secondary parasomnias are sleep disturbances that are caused by disorders of other organ systems. This review addresses only primary parasomnias. Arousal disorders and the parasomnias associated with REM sleep are the primary parasomnias most likely to be seen in a neurology practice. Sleep-wake transition disorders are also discussed with nocturnal leg cramps, probably the most common in this group.

REVIEW SUMMARY

The salient clinical features of the primary parasomnias are discussed. Emphasis is placed on the differential diagnosis of the different conditions and the best management strategies. Parasomnias encountered in infancy, such as infant sleep apnea, are not discussed in this review.

CONCLUSIONS

Parasomnias are common disturbances of sleep that may significantly affect the patient's quality of life and that of the bed partner. Most parasomnias can be diagnosed with careful history taking and polysomnography, and management is usually safe and effective.

Mood disorders in subjects with bruxing behavior

OBJECTIVE

An investigation was conducted on 105 subjects to assess the existence of an association between mood psychopathology and bruxism.

METHODS

Validated clinical criteria were used to diagnose bruxism and a self-report validated questionnaire (MOODS-SR) was filled out by each patient for an evaluation of depression and mania symptoms of mood spectrum.

RESULTS

Prevalence of mood psychopathology, as identified by MOODS-SR score> or =60, was significantly higher in bruxers (11/38, 28.9% vs. 6/67, 8.9%; P=0.007). Significant differences between bruxers and non-bruxers also emerged in total MOODS-SR (P=0.001) scores and in total scores of domains evaluating manic (P=0.001) and depressive symptoms (P=0.007).

CONCLUSIONS

Support to the existence of an association between bruxism and mood disorders has been provided. Further studies are strongly needed to clarify mechanisms underlying the described association.

Psychic and occlusal factors in bruxers

BACKGROUND

The aim of this study was to investigate the existence of associations between bruxism and psychic and occlusal factors.

METHODS

Participants in this study (n=85) were recruited from the Section of Odontostomatology, Deparent of Neuroscience, University of Pisa, Italy. They were split into two groups, bruxers (n=34) and non-bruxers (n=51), on the basis of the presence of both clinical and anamnestical indicators of bruxim. All participants were administered two self-reported validated questionnaires to evaluate (MOODS-SR) and panic-agoraphobic (PAS-SR) spetra. A number of occlusal variables (deep-bite: cross-bite, open-bite, mediotrusive and laterotrusive interferences, slide RCP-ICP, laterotrutsive guides, canine and molar classes) were also recorded.

RESULTS

With regards to occlusal factors, the only association was revealed between bruxism mediotrusive interferences (p < 0.05). As for psychiatric investigation, significant differences between bruxers and controls emerged for the presence of both depressive (p < 0.01) and manic symptoms (p < 0.01) in MOODS-SR, and for stress sensitivity (p < 0.01), anxious expectation (p < 0.05), and reassurance sensitivity symptoms (p < 0.05) in PAS-SR. In particular, both mood (p < 0.01) and panic-agoraphobic (p < 0.05) spectra symptoms seem to differentiate bruxers from controls in males, while in females strong differences emerged for stress sensitivity symptoms (p < 0.05).

CONCLUSIONS

It can be confirmed that certain psychic traits are present in bruxers, while occlusal factors are not useful parameters to discern bruxers from non-bruxers.

Non-rapid eye movement parasomnias

Non-rapid eye movement parasomnias are unique physical or experiential phenomena that disrupt sleep. Non-rapid eye movement parasomnias are common in children, but they typically outgrow them. Sleep-stage shifts caused by sleep-disordered breathing and associated arousals may be precipitating events for episodes of parasomnia. Seizure disorders should always be considered in the differential diagnosis for the evaluation of parasomnias. Violent or injurious sleepwalking should be rapidly evaluated and treated.

Quantitative polygraphic controlled study on efficacy and safety of oral splint devices in tooth-grinding subjects

The efficacy of occlusal splints in diminishing muscle activity and tooth-grinding damage remains controversial. The objective of this study was to compare the efficacy and safety of an occlusal splint (OS) vs. a palatal control device (PCD). Nine subjects with sleep bruxism (SB) participated in this randomized study. Sleep laboratory recordings were made on the second night to establish baseline data. Patients then wore each of the splints in the sleep laboratory for recording nights three and four, two weeks apart, according to a crossover design. A statistically significant reduction in the number of SB episodes per hour (decrease of 41%, p = 0.05) and SB bursts per hour (decrease of 40%, p < 0.05) was observed with the two devices. Both oral devices also showed 50% fewer episodes with grinding noise (p = 0.06). No difference was observed between the devices. Moreover, no changes in respiratory variables were observed. Both devices reduced muscle activity associated with SB.

Improvement of bruxism after T & A surgery

Bruxism or tooth grinding is an oral habit that frequently occurs during sleep. Some authors suggest it is associated to sleep apnea.

OBJECTIVES

The main goal of this study is compare the incidence of bruxism before and after adenotonsillectomy (T & A surgery) in children with sleep-disordered breathing.

METHODS

This is a prospective study in which we evaluated 69 consecutive children from the Otolaryngology Department of the University of São Paulo Medical School in pre- and post-surgical periods of adenotonsillectomy. Before and after surgery parents answered a questionnaire about sleep-disturbed breathing and bruxism. Children were submitted to E.N.T. examination and speech pathologist evaluation. The orthodontist inspected malocclusion. Before surgery all the 69 children presented sleep apnea and 45.6% presented bruxism. Malocclusion could be found in 60.71%. Three months after surgery none of the children presented breathing problems and only 11.8% presented bruxism. There was no difference in malocclusion.

CONCLUSIONS

This study suggests that there is a positive correlation between sleep-disordered breathing and bruxism. There was an important improvement of bruxism after T & A surgery. Otolaryngologists must be aware that this pernicious sleep disorder is associated to airway obstruction and so, it must be considered when evaluating T & A hyperplasia.

Restoration of canine guidance on an occlusal splint using amalgam: a clinical report

A primary consequence of sleep bruxism is severe tooth wear. Although an occlusal splint is able to protect teeth, grinding may continue on its surface. This clinical report describes an approach to restore canine guidance on an occlusal splint, with amalgam, for a patient with sleep bruxism. This procedure allowed maintenance of the canine guidance for a period of time longer than 3 months, postponing the fabrication of a new splint.

Posttraumatic stress disorder: psychopathology, medical management, and dental implications

PTSD is a chronic mental illness that may arise after an individual experiences or witnesses a life-threatening event. Symptoms consist of persistent reexperiencing of the event, avoidance of reminders of the event, a numbing of positive emotions, and social withdrawal. A depressed mood and excessive use of alcohol and tobacco may accompany the disorder. PTSD afflicts approximately 5% of men and 11% of women. Dental disease may be extensive because of neglect of oral hygiene compounded by cigarette smoking. Dental treatment includes preventive education, oral cancer screening, and prescribing saliva substitutes or stimulants and anticaries agents to combat medication-induced xerostomia. Precautions must be taken when prescribing or administering certain analgesics, antibiotics, or sedative agents that may adversely interact with the psychiatric medications or when performing surgery because of the long-term effects of alcohol abuse.

Neurobiological mechanisms involved in sleep bruxism

Sleep bruxism (SB) is reported by 8% of the adult population and is mainly associated with rhythmic masticatory muscle activity (RMMA) characterized by repetitive jaw muscle contractions (3 bursts or more at a frequency of 1 Hz). The consequences of SB may include tooth destruction, jaw pain, headaches, or the limitation of mandibular movement, as well as tooth-grinding sounds that disrupt the sleep of bed partners. SB is probably an extreme manifestation of a masticatory muscle activity occurring during the sleep of most normal subjects, since RMMA is observed in 60% of normal sleepers in the absence of grinding sounds. The pathophysiology of SB is becoming clearer, and there is an abundance of evidence outlining the neurophysiology and neurochemistry of rhythmic jaw movements (RJM) in relation to chewing, swallowing, and breathing. The sleep literature provides much evidence describing the mechanisms involved in the reduction of muscle tone, from sleep onset to the atonia that characterizes rapid eye movement (REM) sleep. Several brainstem structures (e.g., reticular pontis oralis, pontis caudalis, parvocellularis) and neurochemicals (e.g., serotonin, dopamine, gamma aminobutyric acid [GABA], noradrenaline) are involved in both the genesis of RJM and the modulation of muscle tone during sleep. It remains unknown why a high percentage of normal subjects present RMMA during sleep and why this activity is three times more frequent and higher in amplitude in SB patients. It is also unclear why RMMA during sleep is characterized by co-activation of both jaw-opening and jaw-closing muscles instead of the alternating jaw-opening and jaw-closing muscle activity pattern typical of chewing. The final section of this review proposes that RMMA during sleep has a role in lubricating the upper alimentary tract and increasing airway patency. The review concludes with an outline of questions for future research.

Parasomnias: epidemiology and management

The category of common sleep disorders known as parasomnias includes disorders of arousal, rapid eye movement (REM) sleep behaviour disorder (RBD), nocturnal seizures, rhythmic movement disorder, and tooth grinding or 'bruxism'. Parasomnias are all characterised as undesirable physical or behavioural phenomena occurring during the sleep period. Although these conditions can be distressing and, in some cases, hazardous to the sleeper and his or her bed partner, it is important to recognise that parasomnias are diagnosable and treatable in the vast majority of patients. Evaluation begins with a careful clinical interview with the sleeper and a family member to elucidate the frequency, duration, description and timing after sleep onset of these behavioural events. Disorders of arousal are the most common type of parasomnia and cover a spectrum from calm sleepwalking to emotionally agitated or complex behaviours, such as dressing or driving, for which the patient usually has no memory upon awaking. 'Sleep terrors' are quite common in young children and are often outgrown. Disorders of arousal represent a partial, as opposed to a full, awakening from deep non-REM sleep, typically occurring within the first 60 to 90 minutes after sleep onset. RBD is characterised clinically by a history of dream-enacting behaviour, and the patient may recall dream content. REM sleep periods typically occur in the latter half of the night. Physiologically, RBD results from a lack of the normal muscle atonia that is associated with REM sleep. RBD has been linked to a number of other neurological conditions; thus, a careful review of systems and a physical examination are crucial. A formal laboratory sleep study or polysomnogram with an expanded electroencephalographic montage can help distinguish among non-REM and REM parasomnias and nocturnal seizures. The latter may manifest clinically as arousals from sleep associated with vocalisation and/or complex behaviours. Rhythmic movement disorder can include head banging or body rocking at sleep onset or during the night. Tooth grinding is a common sleep-related behaviour that, when severe, can result in dental injury. Hypnagogic hallucinations (experience of dream imagery at sleep onset) and sleep-onset paralysis (experience of muscle/body paralysis as one is falling asleep) are symptoms rather than diagnostic categories. These phenomena classically occur in many individuals with narcolepsy, but also may occur in healthy sleep-deprived individuals. Safety precautions and good general sleep hygiene measures are recommended for individuals with a parasomnia, as the disorder can be exacerbated by sleep deprivation and various other factors. When the events are frequent or particularly dramatic, medication with a long- or medium-acting benzodiazepine, such as clonazepam, at bedtime is effective therapy in most cases of non-REM disorders of arousal and RBD. A dental guard may be helpful in tooth grinders. Relaxation training and guided imagery may be helpful strategies for some patients, especially those with disorders of arousal or rhythm movement disorders. There is no evidence of any association between parasomnias and psychiatric illness. Demystification of these conditions and reassurance, particularly for parents of paediatric patients, is an important aspect of clinical intervention.

Sleep bruxism related to obstructive sleep apnea: the effect of continuous positive airway pressure

Several studies have reported that sleep bruxism rarely occurs in isolation. Recently, in an epidemiological study of sleep bruxism and risk factors in the general population, it was found that among the associated sleep symptoms and disorders obstructive sleep apnea (OSA) was the highest risk factor for tooth grinding during sleep. The purpose of this report was to evaluate the effect of continuous positive airway pressure (CPAP) on sleep bruxism in a patient with both severe OSA and sleep tooth grinding. Two polysomnographic (PSG) recordings were carried out. The first showed 67 events of sounded tooth grinding, most of them appearing as an arousal response at the end of apnea/hypopnea events in both the supine and lateral postures. During the CPAP titration night most breathing abnormalities were eliminated and a complete eradication of the tooth grinding events was observed. The results of this study suggest that when sleep bruxism is related to apnea/hypopneas, the successful treatment of these breathing abnormalities may eliminate bruxism during sleep.

The significance of saliva during sleep and the relevance of oromotor movements

Saliva is an essential component of the oroesophageal milieu and allows for normal speech, taste, mastication, food bolus formation and swallowing. Saliva has important functions in protecting the hard and soft tissues of the oral cavity from acids and pathogenic microbes. A large number of people suffer either subjective or objective alterations in quantity and/or quality of their saliva that may be secondary to disease, medications, medical treatments or emotional events. Sleep-related xerostomia is a sensation of dry mouth associated with a report of either mouth and/or throat discomfort that induces awakenings for water intake. The prevalence of self-reported dry mouth complaint during sleep (associated with awakening and water intake) in a Canadian survey was estimated at 23%. The biological significance of decreased saliva during sleep is unknown and it is unclear how the oral cavity compensates for this period of relative dryness. The amount of saliva produced is greatest during the waking hours of the day and diminishes dramatically during sleep and may represent another process in the human body that displays a circadian rhythmicity. Salivary secretion during wakefulness is, in part, associated with oromotor activity involving the masticatory muscles. Rhythmic masticatory muscle activity and swallowing are non-disruptive events that occur during normal sleep. We hypothesize herein that lubrication from saliva is necessary during sleep to protect tissue integrity and health of oroesophageal structures.

Lower number of K-complexes and K-alphas in sleep bruxism: a controlled quantitative study

OBJECTIVES

Although patients with sleep bruxism (SB) show a higher incidence of rhythmic masticatory muscle activity (RMMA) during sleep than matched normal controls, they are good sleepers. Sleep macrostructure (e.g. total sleep time, sleep latency, number of awakenings or sleep stage shifts and sleep stage duration) is similar between groups. Differences in sleep microstructure between SB patients and normals have been investigated only in few studies. The aim of the present study was to quantify number of microarousals, K-complexes, K-alphas, EEG spindles, and the density of slow wave activity, in both groups, in order to better understand the pathophysiology of SB.

METHODS

Ten normal sleepers were matched for age and gender with 10 patients who exhibited frequent tooth-grinding during sleep. Using quantitative polysomnographic measures, we compared the above-mentioned sleep variables in both groups. Data are presented as indices for total sleep and for consecutive non-rapid eye movement (non-REM) episodes over non-REM to rapid eye movement (REM) cycles and per hour of sleep.

RESULTS

SB patients showed 6 times more RMMA episodes per hour of sleep than normals (P<0.001), with a higher frequency in the second and third non-REM to REM cycles. SB patients presented 42.7% fewer K-complexes per hour of stage 2 sleep, but only normals showed a decline from the first to fourth non-REM episode. Only 24% of SB-RMMA episodes were associated with K-complexes in 60 s. The number of K-alphas was 61% lower in SB patients, no change across non-REM episodes was noted. While no difference in electroencephalographic (EEG) spindles or slow wave activity (SWA) was observed between groups, EEG spindles increased and SWA decreased linearly over consecutive non-REM to REM cycles.

CONCLUSIONS

According to our observations, good sleep in SB patients is characterized by a low incidence of K-complexes or K-alphas and by the absence of any difference in other sleep microstructure variables or SWA.

Symptoms of sleep disturbances among children at two general pediatric clinics

OBJECTIVE

We assessed the frequency of childhood sleep problems at 2 general pediatric clinics.

STUDY DESIGN

Parents of 1038 unselected children (554 boys) aged 2.0 to 13.9 years completed a validated Pediatric Sleep Questionnaire while waiting for appointments.

RESULTS

Habitual snoring was reported in 176 (17%) of the children. Criterion scores suggestive of sleep-disordered breathing were found in 115 (11%) of the children, in 29% of children at the clinic for neurologic indications, and in 21% of children at the clinic for noninfectious respiratory indications. Insomnia (ie, unrefreshing sleep or difficulty with sleep onset, sleep maintenance, or early morning awakening from sleep) was reported in 430 (41%) of the children; > or =2 symptoms were present in 191 (18%) of the children. Excessive daytime sleepiness was suggested in 148 (14%) of the children, and 390 (38%) had symptoms of sleep terrors, sleepwalking, or nocturnal bruxism.

CONCLUSIONS

Sleep problems such as sleep-disordered breathing, insomnia, excessive sleepiness, and parasomnias are frequent among children seen at general pediatric practices.