Physical Evaluation Polysomnographic analysis of bruxism Marilene de Oliveira Trindade, PhD, MS n Antonio Gomez Rodriguez, MD, MS The American Academy of Sleep Medicine (AASM) defines sleep bruxism were analyzed clinically and underwent PSG. The descriptive analysis as a stereotyped movement disorder characterized by clenching and correlated apnea, arousals, and limb movements in the 12 patients who grinding of the teeth during sleep. Bruxism is found in 14%-20% of exhibited signs and symptoms of sleep bruxism. Of these patients, 4 were children, 8% of adults <60 years old, and 3% of adults >60 years old. confirmed through PSG to have bruxism. The mandibular movements of bruxism can be confused with rhythmic In a comparison between the 4 patients with confirmed bruxism (PSGB mandibular movements associated with other sleep disorders, such as group) and the 8 patients confirmed not to have bruxism (NPSGB group), arousals/microarousals, limb movement disorder, and obstructive sleep the respiratory event index was lower in the PSGB group (13.17 and 17.95, apnea/hypopnea syndrome. Polysomnography (PSG) is the study of sleep respectively). The mean leg movement index was higher in the PSGB group disorders based on the recording of physiological events throughout than the NPSGB group in total sleep time (21.36 and 8.42, respectively) an entire night of sleep. This system involves electroencephalography, and in rapid eye movement sleep time (34.54 and 10.30, respectively). electrooculography, and electromyography of the submental/suprahyoid, Received: June 12, 2012 tibialis anterior, mentalis, masseter, and temporal muscles, through which Accepted: December 6, 2012 signs of sleep bruxism can be identified. The aim of the present study was to identify bruxism during a night of sleep in a laboratory. Thirty patients Key words: bruxism, polysomnography ccording to Silber, sleep is a complex are needed.4,5 There is no consensus regard- involves electroencephalography (EEG), and highly organized physiological ing a specific etiology for bruxism, thus electrooculography (EOG), and electro- state.1 In humans, the sleep-wakeful- multifactor etiology is the term that is most myography (EMG) tests to determine the A 6,7 ness cycle corresponds to 3 major phases: commonly employed. electrical activity in the brain, eyes, and wakefulness, slow-wave sleep with no rapid In the clinical evaluation for the diag- muscles, respectively. Audiovisual monitor- eye movement (NREM), and sleep with nosis of sleep bruxism, a combination ing is also involved. The EMG measures rapid eye movement (REM). REM sleep of at least 2 of the criteria suggested by the electrical activity of the submental/ accounts for approximately 20% to 25% Lavigne & Manzini in Table 1 should suprahyoid regions, thoracic-abdominal of sleep. Stages 1 and 2 NREM account be considered.8 The incidence of sleep movements, oximetry, heart rate, nasal for over half of overall sleep time, whereas bruxism is 1.9-fold higher among smokers flow pressure, as well as the tibialis anterior, stage 3 NREM, which appears mainly in and individuals who use caffeine, alcohol, mentalis, masseter, and temporal muscles. the first half of the sleep period, accounts drugs, or other substances that affect the With this system, signs of sleep disorders for 15%.1,2 central nervous system.9-14 can been identified concomitantly, and epi- Repetitive movements with contact of Individuals with sleep bruxism may sodes of sleep bruxism can be recognized.19 the teeth beyond the normal functions of have other concomitant sleep disorders, chewing and swallowing represents a para- such as obstructive sleep apnea/hypopnea functional behavior known as bruxism or (OSAH), restless leg syndrome, REM sleep parasomnia movement. Motor activity in behavior disorder, insomnia, and other Table 1. Criteria used for the clinical sleep bruxism was included in the AASM parasomnia and dopamine disorders.9,15,16 diagnosis of sleep bruxism.8 2005 International Classification of Sleep Sleep bruxism may be accompanied by 2 Disorders: Diagnostic and Coding Manual. secondary risk factors, such as tooth decay, • History of teeth grinding noises reported Bruxism can be a conscious or unconscious tooth marks on the sides of the tongue, by bedroom partner or family member habit, diurnal and/or nocturnal—all of bilateral masseter hypertrophy, occlusal which are seen as separate disorders with trauma, iatrogenic problems, chronic pain • Presence of worn facets on the surface 3 of teeth not compatible with age or different etiologies. The facial muscle in the mandibular musculature or region function contractions of sleep bruxism are associ- of the temporomandibular joint, and lim- ated with the sound of teeth grinding, ited mandibular movement.5,17,18 • Headaches in temporal region which varies in frequency throughout the Polysomnography (PSG) is used for the • Fatigued mandibular musculature at night. Sleep bruxism is found in 14%-20% diagnosis and study of different sleep disor- night or while awake of children, 8% of adults under age 60, ders based on the recording of physiologi- • Lockjaw, or difficulty opening the mouth and 3% of adults over 60. More in-depth cal events throughout an entire night of in the morning investigations, addressing the fact that sleep using electrodes and sensors in a labo- • Dental hypersensitivity sleep bruxism occurs concomitantly with ratory setting. One clinical routine is the teeth clenching during waking hours in the determination of the frequency of rhyth- • Hypertrophy of the masseter muscles presence of oral motor control alterations, mic mandibular movements. This system 56 January/February 2014 General Dentistry www.agd.org Prior to initiating the exam, calibration with bruxism than individuals without this Sleep Unit of the Vigo General University of the muscles is performed based on disorder.28 The increase in motor activity Hospital in Spain. Of the 30 patients the maximal voluntary clenching of the in individuals with bruxism is understand- evaluated through PSG, a questionnaire teeth for 15 seconds. A 10% increase in able, as microarousals are associated with specifically addressing bruxism, and the amplitude in relation to maximal voluntary intrinsic differences in cortical autonomic reports of bedroom partners, 12 exhib- clenching, whether or not accompanied recruitment and motor activation of the ited signs and symptoms of bruxism; 4 by body movement, is considered to char- muscles of the body and mandible.29 had the diagnosis confirmed by PSG. acterize a bruxism episode during sleep.20 The pathophysiology of bruxism is not All participants signed a statement of Conditions associated with aging and pain yet fully understood. Oral somatosen- informed consent agreeing to participate are important factors influencing sleep sory stimuli in the presence of occlusal in the study, in compliance with the organization, and the prevalence of some abnormalities may trigger the synthesis of norms established by the Vigo General sleep disorders (such as sleep apnea) is catecholamines, thereby enhancing sym- University Hospital. higher in an older population. Older sub- pathetic tonus (a partial constriction of Besides the conventional PSG instru- jects (>60 years) present fewer sleep brux- blood vessels instigated by the sympathetic ments, electrodes were also placed on ism episodes per hour of sleep than younger nervous system), thus increasing muscle the right and left masseter muscles. sleep bruxers.21 Age may also influence the reflex. Muscle symptoms in the face and Calibration of the PSG apparatus was occurrence of rhythmic masticatory muscle head reported by individuals with bruxism performed based on the contraction of activity in the elderly population. should be distinguished from those indica- the masseter muscles corresponding to Bruxism has been associated with poor tive of other sleep disorders. Orofacial 10% greater amplitude in relation to sleep quality in patients with chronic pain symptoms associated with temporoman- maximal voluntary teeth clenching for 15 or OSAH. The association between oro- dibular disorder, such as limited mouth seconds. The mean number and duration facial pain symptoms and sleep bruxism opening, joint noises, and facial muscle of total facial contraction movements is probaby not independent of the interac- pain, may also be associated with sleep were calculated for the respective episodes tion between pain and poor sleep. Sleep bruxism. Recent studies have strength- in different NREM and REM phases apnea, like insomnia, has been associated ened the association between bruxism during a night of sleep in the PSGB with increased pain sensivity (decreased and apnea, but others have not found a group (n = 4). The index of total facial pain threshold).22,23 significant number of respiratory disor- contraction movements in both duration Sleep bruxism predominantly occurs ders or oxygen desaturation cases among and number was then calculated. The in NREM Stage 2 (60%-80% of cases), individuals with bruxism.29 In some PSG index and mean number of contractions although it is important to note that some studies, teeth clenching and RMM were of the mentalis muscle and the masseters authors have suggested that grinding in found in 40%-60% of adult patients with were obtained by measuring the total the REM phase has a greater destructive OSAH.22 However, these studies sought number of events when these muscles potential for teeth.20,24,25 To facilitate the to demonstrate a temporal