Teeth grinding at night, medically known as nocturnal bruxism, is a widespread yet often misunderstood condition characterized by the involuntary clenching or grinding of teeth during sleep.

Although many may shrug off occasional teeth grinding, persistent episodes can lead to significant dental damage, jaw pain, and disrupted sleep quality.

The Nature of Nocturnal Bruxism

Nocturnal teeth grinding is classified as a sleep-related movement disorder. Unlike awake bruxism, which happens consciously often due to stress or tension, nocturnal bruxism occurs involuntarily during various sleep stages. The activities involve rhythmic or sustained jaw muscle contractions that can exert excessive pressure on teeth—often surpassing 250 pounds of force—much higher than during normal chewing. This mechanical stress can wear down tooth enamel, lead to sensitivity, and strain the temporomandibular joint, causing pain and dysfunction.

Psychological and Emotional Triggers

Stress and anxiety are among the most commonly linked causes of nocturnal teeth grinding. Mental and emotional tension experienced during waking hours may translate to increased muscle activity during sleep. Elevated stress hormones, heightened autonomic nervous system activity, and disrupted sleep architecture contribute to these involuntary jaw movements. Sleep bruxism can thus be a somatic manifestation of psychological pressures.

People under chronic stress or anxiety conditions often report more frequent and intense teeth grinding while asleep. The condition can be exacerbated during periods of life changes, exams, work pressure, or emotional turmoil.

Sleep Disorders and Neurological Factors

Significant correlations exist between nocturnal bruxism and sleep-related disorders such as obstructive sleep apnea (OSA). In OSA, interrupted breathing triggers sudden arousals that activate jaw muscles, sometimes causing episodes of teeth grinding. These micro-awakenings and irregular breathing promote muscle contractions as the body tries to maintain airway patency.

Additionally, nocturnal bruxism has associations with neurological conditions including Parkinson’s disease and attention deficit hyperactivity disorder (ADHD). Disruptions in central nervous system regulation likely influence motor control during sleep, increasing bruxism susceptibility.

Influence of Lifestyle and Substances

Certain lifestyle habits can exacerbate teeth grinding frequency and severity. Excessive caffeine intake stimulates the central nervous system and may increase nocturnal muscle activity. Fragmenting restorative phases and promoting bruxism episodes.

Medications, particularly some antidepressants and stimulants, have been linked to increased chances of nocturnal grinding by affecting neurotransmitter balance and muscle control.

Dental and Genetic Factors

Dental misalignment (malocclusion) or irregular tooth‑contact patterns can increase the risk of compensatory jaw muscle activity during sleep. While these mechanical factors may contribute to Bruxism, they are seldom the sole cause. At the same time, research shows familial clustering of bruxism, suggesting that genetic or neuro‑physiological predisposition (such as heightened nervous‑system excitability) plays a role.

Dr. Amanda Phoon Nguyen, an dental medicine and dental‑sleep specialist, emphasizes that while bruxism (teeth grinding) and temporomandibular disorder (TMD) may present in similar ways — such as jaw pain or headaches — they are distinct conditions that require different treatment approaches. She further notes that in certain cases, an underlying sleep disorder (for example, sleep apnoea) may complicate the diagnosis or management of bruxism.

Nocturnal teeth grinding arises from intricate connections between psychological stress, neurological regulation, sleep disruptions, lifestyle influences, and dental irregularities. Its manifestation during sleep reflects heightened muscle activity often triggered by emotional strain or conditions like sleep apnea. Dietary and substance factors further modulate the risk, while genetic predisposition influences susceptibility. Mechanical dental factors may exacerbate but seldom solely cause the habit.