Wear, fractures, dental cracks or even deterioration of chewing… Such are the ravages of bruxism. Teeth clenching symptomatic of stress during the day. Chattering teeth that interfere with sleep. It is this last nocturnal bruxism that would do the most damage … Explanations.

The definition of bruxism has changed a lot over the last century. We owe the first description of this pathology to Marie Pietkewicz in 1907. The latter then spoke of “bruxomania” which she defined as “activities of teeth clenching and dental friction without a functional goal”. In common parlance we speak of “teeth grinding” in reference to the auditory perception of bruxism.

In 2005, the ASDA (American Sleep Disorders Association) describes “stereotypical and periodic, rhythmic or spasmodic” movements and evokes in the very definition of bruxism, the 3 main usual consequences of the latter:

• tooth wear;
• dental noises;
• discomfort in the muscles of the jaw.

In 2008, the AAOP (American Academy of Orofacial Pain) added that bruxism can be diagnosed by “the presence of wear facets outside the physiological areas of masticatory functions”. The GTP (American Glossary of Prosthetic Terms) prefers to speak of “occlusal trauma”.

In 2013, an international consensus (established by Lobbezzo and.al) emphasizes repetitive activity and muscle tension in the jaw.

People at risk

Bruxism is a widespread affection: it affects around 8% of the adult population. Night bruxism is more common in children (diagnosed in 10 to 20% of the pediatric population against only 5 to 8% of the adult population). Conversely, daytime bruxism sets in with age, since it affects more than 20% of the adult population (against 12% of children). The latter would affect women more.

In 1990, the ICSD (International Classification of Sleep Disorders) classified bruxism in the category of sleeping troubles and more precisely parasomnies. However, in 2008, the AAOP (American Academy of Orofacial Pain) defined bruxism as a “diurnal or nocturnal parafunctional activity”. Indeed, the scientist Lobezzo confirms this distinction and adds that daytime bruxism and nighttime bruxism have different physiological causes and mechanisms.

It is classified as a behavioral disorder according to the American Psychiatric Association (AAP). It manifests as “sustained muscle contractions for more than 2 seconds”. It intervenes in reaction to a stressful situation or to an anxiety experienced by the subject. It usually gets worse over the course of the day.

Night bruxism

It is the most destructive form for the teeth and jaw. It manifests itself during sleep. It is sometimes still present in the morning but gradually disappears over the day. Night bruxism is usually phasic, characterized by “brief and repeated contractions of the masticatory muscles with at least three consecutive bursts of electromyographic activity that last between 0,25 and 2 seconds each”.

During the day, bruxism is more manifested by tooth clenching, while at night, it is characterized by grinding and friction movements. Note that bruxism can be unrelated to any pathology or medical treatment. On the other hand, it is sometimes secondary to another pathology (sleep, neurological or psychiatric disorders) or even to the taking of certain medications.

The causes of bruxism are not always clear. Recent research has concluded that neither occlusal interference nor factors related to the oral facial skeleton play a role in the etiology of bruxism1. However, certain risk factors associated with bruxism have been observed.

Sleep disorders

Bruxism is more common in people who suffer from a sleep disorder such as snoring, breathing pauses during sleep, and obstructive sleep apnea (OSA). Other parasomnias such as violent or harmful behavior during sleep, sleep paralysis, hypnagogic / hypnopompic hallucinations (semi-consciousness between sleep and awakening) are also more frequently reported by bruxomaniacs.

Lifestyle factors

Demographic and lifestyle factors such as young age, higher education level, smoking, caffeine consumption, and heavy alcohol consumption are co-factors associated with bruxism.

Stress, anxiety and other psychological components

Mental disorders, anxiety, stress and adverse psychosocial factors are significantly related to teeth grinding during sleep and almost 70% of bruxism has been found to result from stress or anxiety. It is well documented that work-related stress interferes with good sleep and, therefore, may be responsible for daytime sleepiness. But, it is also the most important factor associated with bruxism.

Manifestations of periodontals

The fact of bruxing teeth causes certain periodontal manifestations:

• periodontal enlargementswhich can be observed radiographically. They appear as a dark space between the tooth and the bone that is larger than usual. Clinically, it results in increased mobility of the tooth;
• bone melting around the tooth which causes mobility or even dental and implant exclusions.

Symptoms in the jaw and mouth

Bruxism causes a large number of symptoms in the jaw and mouth:

• bone signs (compensatory bone remodeling, exostosis, mandibular tori, concave bone lyses, etc.);
• mucous signs (biting causing lesions on the lips, tongue and inside of the cheeks, a hyperkeratinized white line on the inside of the cheek, etc.);
• dental occlusion disorders (the way in which the mandibular teeth mesh with the maxillary teeth) which can interfere with chewing, swallowing and phonation;
• muscle signs (pain, hypertrophy, hypertonicity, contracture, muscle trismus of the jaw, etc.);
• articular signs (pain in the temporomandibular joints, remodeling of the condyles, temporomandibular osteoarthritis, displacement of the articular discs, etc.);
• dental ankylosis, that is to say the fusion of the tooth with the bone. Indeed, the micro stresses cause microcracks in the bone. In response, hypercementosis can be created and cracks filled with fibrous tissue, which can lead to the disappearance of the alveolar-dental ligament and the fusion between the root of the tooth and the alveolar bone.

Dental wear veneers

Generally, the wear veneers pose an aesthetic problem for the patient which prompts them to consult. Indeed, bruxism gives the impression of shorter teeth, widened and whose edges align:

• the occlusal surfaces flatten and the teeth lose height. But bruxism being a slow phenomenon, the bone has time to compensate for this loss of height which makes it possible to maintain the appearance of the underside of the face;
• the alveolar bone (that is, the bone that surrounds and maintains the tooth on the maxillary arch) located under the tooth may widen;
• teeth can move sideways;
• the cervical part (body of the tooth) can also be weakened due to the pressure on the occlusal surface of the tooth. However, while wear and tear is a symptom of bruxism, it alone cannot diagnose bruxism. Indeed, a study shows that wear is found in 40% of asymptomatic patients with bruxism.

Wear is a natural phenomenon caused by various spontaneous mechanisms such as:

• erosion;
• l’abfraction ;
• abrasion;
• or dental attrition.

Stages of severity of tooth wear (according to the classification of Rozencweig et al. 1994)

• Stage 1: wear on dental enamel (surface layer of the tooth) on less than 3 pairs of teeth
• Stage 2: wear of the enamel and dentin (layer located below the enamel) on less than 6 pairs of teeth
• Stage 3: wear of enamel and dentin on more than 6 pairs of teeth
• Stage 3 and 4: wear of more than half of the dental crown.

Altered chewing

The measurement of the functional masticatory angle of planas * (at the level of the incisors) makes it possible to diagnose but also to assess bruxism. Indeed, bruxism causes a decrease in the latter compromising the quality of chewing. * The functional angle of planas is the angle formed in the frontal plane by the horizontal passing through the free edge of the upper incisors and the oblique materializing the displacement of the mandibular interincisal center from the position of maximum intercuspidation to a laterality end-to-end position.

Dental cracks and fractures

Bruxism causes pressure on the occlusal face of the teeth which predisposes to dental fractures and cracks (more or less deep ranging from a lesion of the enamel to the dental pulp for the most serious cases). Wearing prostheses or implants does not remove this risk: this material can be damaged and must be totally or partially replaced. Bruxism causes more vertical fractures. Complications to these fractures or cracks are possible when the pulp and dentin are exposed. The passage of bacteria is then possible and can lead to inflammation (pulpitis) or even necrosis.

Finally, bruxism is often associated with other ailments and pathologies:

• headache;
• tinnitus;
• sleeping troubles
• Sleep Apnea ;
• gastroesophageal reflux,
• etc.

There is no treatment that can completely eliminate bruxism. On the other hand, there are several types of treatments that limit the sequelae of bruxism.

The occlusal plaque

Also called occlusal splint is a thermoplastic dental appliance designed to measure for the patient’s jaw and from the latter’s dental impressions. It aims to prevent the lower jaw from touching the upper jaw in case of snapping, squeaking, squeezing, etc. This device is worn at night.

Dental balancing

The dental balancing allows a better “interlocking” of the teeth. The dentist performs a micro-grinding (filing) on ​​the surface of the teeth in order to stabilize them.

Psychotherapy and relaxation methods

If your bruxism is stress related, it is recommended that you treat it. You have to find the method that suits you: psychotherapy, meditation, relaxation, yoga, sophrology, hypnotherapy, massage therapy, etc. Meditation / breathing exercises before sleep are recommended to treat nighttime bruxism.

A change in lifestyle

The reduction in exposure to stress, the avoidance of overwork and also psychoactive substances (tea, coffee, energy drinks, etc.) as well as alcohol and tobacco make it possible to reduce the symptoms of bruxism.

In the event of suggestive symptoms (such as nocturnal teeth chattering (most often heard by the spouse), pain or tension in the jaw, wear or even destruction of the teeth, etc.), it is recommended to consult a doctor. Dentiste. If your bruxism is linked to stress, the latter will direct you to specific therapy (psychotherapy, sophrology, massage therapy, etc.).