Sleep bruxism is characterized by involuntary movements of the Rhythmic Masticatory Muscular Activity (RMMA). Some symptoms are: pain on palpation of the masticatory musculature, tooth wear associated with tooth grinding, pain in the temporomandibular joints or headaches. Accurate diagnosis and adequate treatment are very useful in order to rule out derived problems.
Sleep bruxism: what is it?
Sleep bruxism is a sleep-related movement disorder characterized by the presence of involuntary Rhythmic Masticatory Muscle Activity (RMMA) movements associated with micro-awakening phenomena and, occasionally, the presence of tooth grinding noises.
It is important to highlight that for many years bruxism was considered a parafunctional chewing activity, related to dental wear and pain in the masticatory muscles. However, at present, the etiology of nocturnal bruxism can be considered multifactorial.
In this aspect, the major advance has been the recognition that the etiopathogenic mechanisms involved in waking bruxism (daytime clenching) and sleep bruxism appear to be quite distinct. This has led to a change in diagnostic criteria, the design and orientation of research studies, and the therapeutic management thereof.
Prevalence of sleep bruxism and waking bruxism in society
Sleep bruxism is a common disorder, occurring with an average prevalence of 8% in the general population. However, waking bruxism is mainly characterized by the presence of tooth clenching rather than grinding episodes and tends to increase with age, with an estimated prevalence of 12% in children and up to 20% in the adult population.
It is important to note that sleep bruxism is often coexistent with waking bruxism. Thus almost 1/3 of patients who report sleep bruxism are also aware of the presence of this habit during wakefulness.
Signs and Symptoms of Sleep Bruxism
Patients presenting with sleep bruxism usually report some of the following signs and symptoms:
– hypertrophy (increase in volume) and pain on palpation of the masticatory musculature (maseterine and temporal).
– indentations on the lateral edges of the tongue
– presence of dental wear, associated with tooth grinding.
– preauricular pain at the level of the tempomandibular joints (TMJ)
– presence of morning headaches
Diagnosis, therapy and treatment of sleep bruxism
In cases of sleep bruxism associated with morning pain in the masticatory musculature or when signs of dental overload are observed (dental wear, dental sensitivity, etc.), the nocturnal use of a rigid full-arch occlusal splint may be indicated to control the harmful effects of sleep bruxism on the masticatory apparatus. However, the grinding associated with sleep bruxism may persist even when wearing the splint, as the patient continues to show progressive wear of the splint.
If there are other related risk factors such as OSAHS (Sleep Apnea-Hypopnea Syndrome), the use of Mandibular Advancement Devices (MAD) would be more indicated.
In cases of sleep bruxism associated with anxiety, high levels of daytime stress or psychophysiological insomnia, in addition to cognitive-behavioral therapy, pharmacotherapy with anxiolytics (clonazepam) or beta-blockers (propanolol) may be indicated, always for short periods of time. Likewise, in those cases in which sleep bruxism is associated with daytime bruxism with significant contracture and hypertrophy of the maseterine and temporal muscles, infiltration with botulinum toxin may be indicated.
In the case of waking bruxism, the patient usually goes to the dental and stomatology expert, who will be in charge of the clinical management. However, the odontostomatologist who is faced with a patient with waking bruxism should not lose sight of two aspects:
1) It is important to rule out that the bruxism presented by the patient is a sign of an underlying disease or process (neurological or psychiatric disease, regular intake of medication or drugs, etc.). In such cases, referral to the appropriate specialist for treatment would be most advisable.
2) There is a high degree of concordance between the presence of waking bruxism and sleep bruxism, the latter being also important for future diagnostic and therapeutic interventions. Of particular importance in this case are sleep-related breathing disorders (OSAHS), since, due to their high morbidity-mortality rate, they should be diagnosed as soon as possible.
Finally, it is important to point out that the systematic use of occlusal splints for the treatment of sleep bruxism should be questioned, since some of them, in certain situations, can aggravate episodes of bruxism if there is coexistence with sleep-related respiratory disorders. It is also important that the odontostomatologist in charge of treatment has specific training in craniomandibular dysfunction and orofacial pain, since these patients are often detected not only by the presence of dental wear but also by the presence of symptoms at the level of the masticatory apparatus (pain in the musculature, arthralgia, headaches, joint blockages of the TMJs, etc.), which should be correctly diagnosed and treated.