Colloquially known as gnashing or grinding of teeth, sleep bruxism is mainly characterized by “rhythmic masticatory muscle activity” (RMMA) at a frequency of about once per second, and also with occasional tooth grinding.¹

The chewing movement of our jaws can be executed both conscious and unconsciously. People don’t normally gnash or grind their teeth when awake, but keep the jaw relaxed with a slight gap between the upper and lower teeth. Actual contact between all teeth happens when we’re chewing food, speaking, swallowing, or doing any conscious movement that requires to close the mouth, and these sum up to only 20 minutes daily.²

The dopamine hypothesis

During sleep, our mouth rests open due to the phenomena called “physiologic motor paralysis”, which is the complete loss of voluntary motor control. Disturbance of the dopaminergic system in the central nervous system has been suggested to be involved in the etiology of bruxism³. Evidence for this comes from observations of the modifying effect of medications which alter dopamine release on bruxing activity, such as levodopa, amphetamines or nicotine. Nicotine stimulates release of dopamine, which is postulated to explain why bruxism is twice as common in smokers compared to non-smokers ⁴. Underlying this factor may be psychosocial factors including daytime stress which is disrupting peaceful sleep.

The GABA and glycine hypothesis

More recently, a study from 2012 with rats suggests that the neurotransmitters gamma-aminobutyric (GABA) and glycine together inhibit brain cells responsible for voluntary movements. Therefore, paralysis may not occur if these neurotransmitters are prevented from reaching their receptors. Disregulation of this mechanism can possibly hint at Parkinson’s or other neurodegenerative disease in the future.

Rosmarinic acid is believed to increase GABA levels by inhibiting the enzyme (4-aminobutyrate transaminase) that converts GABA to L-glutamate.

The greatest sources of rosmaric acid is Lemon balm (Melissa officinalis).

Lemon balm can be taken in its extract form. Its properties improved sleep quality in 20 volunteers who suffered from sleep disturbances and anxiety disorders ⁵.