DOI: 10.1051/odfen/2018046 J Dentofacial Anom Orthod 2018;21:108 © The authors Sleep bruxism and sleep disorders in adolescents M. C. Carra Odontology Department, Diderot University – Paris 7, France PU-PH, Odontology Department (Periodontology), Rothschild Hospital, AP-HP, Paris, France ABSTRACT Sleep Bruxism, the sleep-related movement disorder of tooth grinding and clenching, is highly reported in pediatrics with a prevalence of up to 40 % during childhood and adolescence. The precise etiology of sleep bruxism remains unknown, but it may involve genetic and psychosocial components (such as anxiety and stress). Clinicians should be aware that quite often sleep bruxism is associated with other disorders, such as snoring, sleep-disordered breathing, sleep complaints, and behavioral problems. These comorbidities should be investigated, because they may be severe and prolonged if they are not treated. SB may lead to morning jaw muscle soreness or pain, headache, masticatory muscle hypertrophy, temporomandibular disorders, and tooth wear. Especially in pediatrics, sleep bruxism is usually man- aged with conservative therapies, such as sleep hygiene, behavioral modifications, biofeedback, familial counseling and, only in cases of severe tooth wear or other serious possible consequences of SB, soft occlusal splints. KEY WORDS Sleep bruxism, sleep disorders, sleep-disordered breathing, sleep quality, oral parafunction SLEEP DURING ADOLESCENCE It is estimated that humans spend more changes, especially a decrease in deep than a third of their lives asleep. Sleep is slow-wave sleep, the recuperative phase in fact an essential component for physical of sleep, and a change in circadian rhythm. and mental health, and especially during These changes are associated with major childhood and adolescence when it plays a changes in the adolescent’s lifestyle that key role in growth and development. are linked to academic constraints, the The structure and need for sleep changes multiplicity of extracurricular activities, and with age—newborns sleep 12–18 h a day, freedom from family supervision. In addi- whereas 12–17-year-old adolescents need tion, the appearance of new behaviors, at least 8–9 h of sleep a night. However, such as the overuse of cell phones or com- adolescence is marked by profound sleep puters, can alter an adolescent’s bedtime Address for correspondence: Maria Clotilde Carra – 5, rue de Garancière 75006 Paris Article received: 26-6-2017. E-mali: [email protected] Accepted for publication: 28-7-2017. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1 Article available at https://www.jdao-journal.org or https://doi.org/10.1051/odfen/2018046 M. C. CARRA and sleeping patterns, delaying their cognitive function, and quality of life. In falling asleep, interrupting their sleep, sleep deprivation, adolescents tend to and compromising sleep quality. be sleepy during the day and this can Insufficient sleep and sleep disor- have many cognitive, behavioral, and ders are unfortunately very common metabolic consequences. Unsatisfac- in children and adolescents. Some tory school performance, mood dis- epidemiological surveys report that turbances, and drug and alcohol abuse 25%–50% of young people are affected can also be a consequence of sleep by some type of sleep disorder during disorders3. The most common sleep their childhood or adolescence, but it disorders among adolescents include is recognized that sleep disorders are insomnia (with an average prevalence of generally underdiagnosed and under- 9%–13%), habitual snoring (8%–15%), treated in the pediatric population. In obstructive sleep apnea (1%–4%), and addition, the presence of medical con- sleep bruxism (14%–25%). ditions, such as neurological and psy- In the following sections, we will de- chiatric disorders is associated with an tail the main features of sleep bruxism increased risk of concomitant sleep to provide clinicians with an epidemi- disorders34. ological, diagnostic, and therapeutic Inadequate sleep has a negative im- overview of this disorder, which is so pact on the adolescent’s overall health, common in adolescents. SLEEP BRUXISM Sleep bruxism (SB) is the involuntary, to become aware of the activity and repetitive, and rhythmic activity of the to stop it. In fact, although both repre- masticatory muscles that occurs dur- sent involuntary behavior, DB can be ing sleep, such as clenching or grind- controlled and prevented during wak- ing of the teeth, often associated with ing hours, whereas SB is subject to typical noises produced by contact be- the complex mechanisms that regulate tween teeth30. SB is classified among sleep physiology and is very difficult movement disorders related to sleep in to modify5,38. The consequences of the International Classification of Sleep DB and SB would seem to be different Disorders (ICSD-III)1, and it is one of as well; this would seem to be mainly the oral parafunctions most frequently related to the force exerted and the seen in children and adolescents6. The duration of the contractions of the mas- grinding and especially clenching of ticatory muscles involved in the clench- the teeth can also occur during the day ing and grinding activity of the teeth. and this is often referred to as daytime bruxism (DB). The two circadian forms Epidemiology of bruxism share several risk factors and often coexist in the same individ- According to the most recent stud- ual, but they are distinguished by one ies, the prevalence of SB does not vary fundamental characteristic: The ability by sex but by age. A peak prevalence of 2 Carra M.C., Sleep bruxism and sleep disorders in adolescents SLEEP bruXISM AND SLEEP disorders IN ­adoLESCENTS up to 40% is observed between 9 and prevalence of DB increases with age, 11 years, falling to 10%–14% during estimated at 12% in children aged adolescence and stabilizing at approx- 7–17 years and at >20% in adults6. imately 7%–8% in adulthood7,9,15,31,32. SB prevalence increases in some Physiopathology populations: it is 3–4 times higher in children and adolescents with a con- The pathophysiology of SB has been comitant psychological disorder and extensively studied in experimental 1–2 times higher in adolescents with studies using polysomnography stud- other sleep disorders (e.g., for exam- ies to assess the brain, muscle, and ple, sleepwalking, obstructive sleep respiratory functions of the sleeping apnea). SB is therefore a very common subject29. These studies have de- sleep disorder. Nevertheless, it must scribed sporadic rhythmic activity of be considered that most of the epide- the masseter and temporal muscles in miological studies reported are popu- almost 60% of the general adult pop- lation-based surveys based solely on ulation, but in SB patients, episodes questionnaires (self-evaluation of brux- of tightness/grinding are much more ism), whose validity as diagnostic tools frequent (at least two episodes/hour of remains debated because of the many sleep) and are associated with more in- confounding factors. For example, the tense muscle contractions28,29. SB ep- typical noise of SB produced by the isodes occur during specific periods of grinding of the teeth does not occur in sleep: They occur mainly in light sleep all bruxism sufferers, nor necessarily in and in association with microarousals all episodes of bruxism (it is estimat- or other orofacial or body movements. ed that only 50%–60% of SB episodes SB episodes are associated with in- produce any kind of noise). In addition, creased sympathetic nervous system the absence of grinding noise or a sit- tone, cardiac activity, and blood pres- uation when the affected individual is sure. It may also be associated with sleeping alone can influence the ability transient hypoxia (a reduction in oxy- to notice and report bruxism activity gen levels), which normally recovers during sleep. In general, regarding the within 7–9 s but supports the hypoth- pediatric population, it is often the par- esis of a relationship between SB and ents who report and consult for their ventilation (or respiratory disorders) child’s SB, but it has been observed during sleep12,25. that the reliability of the parents’ re- Although the precise etiology of SB port and their knowledge of the prob- remains unknown, a genetic compo- lem are not good44. It should also be nent is strongly suspected. Although a considered that the SB is concomitant gene or genetic polymorphism specific with DB in approximately one-third of to bruxism has not yet been identified, adolescents, and these two activities the data show that there is family may be confused by the young patient aggregation and strong link between or their parents. Conversely to SB, the monozygotic twins23,24,36. J Dentofacial Anom Orthod 2018;21:108 3 M. C. CARRA Table I: Clinical consequences of sleep bruxism in adolescents. Clinical signs Associated symptoms Abnormal wear on teeth and restorations Masticatory muscle pain and fatigue Linea alba (white line on the cheek along the occlusal plane) Headache (frequent upon waking) Imprints of teeth on the tongue TMJ Clicking Hypertrophy of the manducator muscles Dry mouth upon waking Oral respiration Occlusal discomfort SB is therefore very likely to have Clinical consequences a central origin, but some peripher- al influences may play a role. Stress, Bruxism is a well-known problem for anxiety, and other psychosocial com- dentists who must manage its con- ponents are now considered as risk sequences on the oral cavity on a dai- factors for bruxism. In particular, com- ly basis, including abnormal wear on pared to adolescents without SB, teeth, restorations, and prostheses. The those with SB are more stressed, association between SB and wear has less able to handle stress, often per- been demonstrated in several studies. fectionist and more aggressive, and Although tooth wear cannot be consid- have a higher rate of psychosocial ered as an absolute diagnostic criterion, and behavioral disorders9,10,15,39,46.