Why is a night guard prescribed as a first-line treatment?

The logic is simple and defensible: a patient grinds their teeth, their teeth get damaged, so a barrier must be interposed to stop the damage. The night guard fulfills this role of a mechanical shield.

It is also easy to prescribe (impression, laboratory fabrication, in-office adjustment), partially reimbursed by health insurance, and requires no change in patient behavior. It's passive: you put it on, you sleep, it's done.

This model has a real advantage: immediate protection. For a patient with advanced wear or ongoing fractures, waiting for a long-term treatment to take effect while their teeth continue to degrade is not reasonable.

The problem begins when the night guard becomes the only treatment, without considering the underlying cause.

The 6 Documented Side Effects

1. Progressive Tooth Movement

This is the most documented side effect in orthodontic literature. Prolonged nocturnal wear of a rigid night guard exerts forces on the teeth, and these forces, even minimal, can cause displacements over months.

Specifically: patients report that their occlusion (how the upper and lower teeth fit together) gradually changes. Teeth no longer "close" in the same way in the morning after removing the night guard. For some, this shift persists and may require corrective orthodontic treatment.

This phenomenon is particularly pronounced with thermoformed night guards purchased from pharmacies or online, whose fit precision is inferior to custom-made night guards. But even custom-made night guards are not entirely free from this risk, especially after several years of wear.

The mechanism is known: it's the same principle as orthodontics. A constant force, even weak, applied to a tooth eventually moves it. The night guard unintentionally applies this type of force if it's not perfectly adjusted, and no night guard remains perfectly adjusted indefinitely.

2. Potential Worsening of Sleep Apnea

This side effect is more recent in the literature but sufficiently documented to warrant serious attention.

Several studies published in Sleep Medicine and Journal of Clinical Sleep Medicine have shown that wearing a maxillary occlusal guard (on the upper teeth) can alter the position of the mandible during sleep, reduce pharyngeal space, and worsen obstructive apnea episodes in predisposed patients.

The problem: many bruxers also have undiagnosed sleep apnea. Nocturnal bruxism is often a symptom associated with OSA (obstructive sleep apnea). Prescribing a night guard without ruling out apnea potentially aggravates the underlying problem.

The current recommendation from several learned sleep societies is clear: before prescribing a bruxism night guard, screening for sleep apnea should be performed in patients with risk factors (snoring, drowsiness, high BMI, large neck circumference).

In practice, this screening is rarely done. The night guard is prescribed based on bruxism alone, without questioning about sleep.

3. Dependence and Atrophy of the Natural Reflex

This is a rarely discussed but logical point: if the masticatory muscles continue to contract every night for years despite the night guard, nothing is done to modify the reflex itself.

Several practitioners report a phenomenon of "night guard dependence": patients who have worn a night guard for a long time can no longer sleep without it. Not because bruxism has increased, but because the muscles have adapted to the presence of the night guard. Its removal produces a sensation of discomfort, tension, or even joint pain.

In other words, the night guard can become a permanent crutch. It does not treat bruxism; it accompanies it. And since bruxism is not corrected, there is no reason for it to become useless one day.

Some studies even note an increase in EMG activity (muscle tension) in long-term wearers, with the jaw "forcing" more to regain contact through the thickness of the night guard.

4. Discomfort and Sleep Disturbance

Anyone who has worn a night guard knows: it's not pleasant. The sensation of plastic in the mouth, excessive salivation in the first few nights, the feeling of bulk.

For some patients, this discomfort never completely disappears. And it results in a measurable degradation of sleep: prolonged sleep onset time, more frequent nocturnal awakenings, a feeling of non-restorative sleep.

It's paradoxical: a treatment supposed to protect against the consequences of bruxism (including sleep degradation) can itself impair sleep. For patients whose bruxism is strongly linked to stress and poor sleep, this is a potential vicious cycle.

The abandonment rate is revealing. According to available data, 20-30% of patients stop wearing their night guard within the first 6 months, primarily due to discomfort. Among those who continue, actual compliance (wearing it every night) is often much lower than what patients report in consultations.

5. Hygiene and Bacterial Risks

A night guard is an object in direct contact with the oral mucosa for 6 to 8 hours each night. It creates a humid, warm, and confined environment, ideal for bacterial and fungal proliferation.

Without rigorous daily cleaning, the night guard can become a reservoir for bacteria, promoting gingivitis, bad breath, and potentially oral candidiasis (fungal infections).

The recommended cleaning is simple (soft brush + neutral soap, never abrasive toothpaste) but must be daily. In practice, many patients simply rinse it quickly with water.

Soft resin (thermoformed) night guards are more porous and harder to clean than custom-made rigid night guards. Their replacement is recommended every 6 to 12 months, which few patients adhere to.

6. Recurring Cost and Rapid Wear

A night guard is not a one-time purchase. Depending on the intensity of bruxism, it wears out and must be replaced:

Thermoformed night guard (pharmacy/online): €15 to €50, lifespan 3 to 6 months for a moderate bruxer, sometimes a few weeks for a severe bruxer.

Custom-made night guard (dental office): €150 to €400, average lifespan 2 to 3 years.

A severe bruxer who wears a custom-made night guard for 10 years will replace it 3 to 5 times, totaling €600 to €2,000, without their bruxism having decreased at all.

Thermoformed night guards, cheaper per unit, often end up costing more over time due to their rapid wear and lower protective effectiveness.

What the Research Says

The side effects listed above are not opinions; they are observations documented in scientific literature. Some key references:

Tooth movements linked to night guard wear are documented notably in the American Journal of Orthodontics and the Journal of Prosthetic Dentistry.

The worsening of sleep apnea has been highlighted in several studies published in Sleep Medicine Reviews and the Journal of Clinical Sleep Medicine, with recommendations for systematic screening before prescription.

The absence of bruxism reduction by the night guard (purely protective effect) is a consensus in systematic reviews published in the Journal of Oral Rehabilitation.

This does not mean that the night guard is "bad"; it means it has limitations and side effects that every patient should be aware of before committing to long-term daily wear.

Does the Night Guard Treat the Cause?

This is the fundamental question, and the answer is no.

The night guard protects the teeth. It does not alter the frequency or intensity of bruxism. The muscles continue to contract, cortisol continues to rise, sleep continues to be fragmented. Only the tooth surface is spared.

It's a bit like putting a screen protector on a phone that you drop every day: the screen is protected, but you keep dropping the phone.

To address the cause, one must tackle the neuromuscular reflex itself.

Alternatives to Consider

If you already wear a night guard and it works for you, there's no need to stop it overnight. But it's relevant to add a fundamental approach in parallel.

Proprioceptive approaches (like the FPS used by Bruxless) aim to reduce the muscle activity itself, with the goal of progressively decreasing the need for mechanical protection.

Stress management (CBT, heart coherence, meditation, therapy) acts on one of the main triggering factors.

Maxillofacial physiotherapy directly addresses muscle tension and associated TMD.

Sleep hygiene (regular hours, reduced screen time, bedroom environment) improves the quality of sleep and indirectly reduces the frequency of bruxism.

The Importance: Acting at the Source of the Reflex
Bruxless uses Functional Proprioceptive Stimulations to reduce nocturnal muscle activity, whereas the night guard merely protects the teeth. 

Discover an approach that goes beyond mechanical protection →

Frequently Asked Questions

My night guard hurts, is that normal?

Slight discomfort during the first few nights is common. Persistent pain, painful pressure points, or a change in occlusion upon waking are not normal; return to your dentist for an adjustment.

Hard or soft night guard, which is better?

For bruxism, a hard night guard (hard resin) is generally preferred by practitioners. Soft night guards encourage some patients to chew, which can increase muscle activity. Commercial thermoformed soft night guards are an economical compromise, not a therapeutic optimum.

Can a night guard be worn for life?

Technically, yes. But it's a sign that the cause of bruxism is not being treated. The goal should be to no longer need it, not to wear it indefinitely.

Does a night guard prevent bruxism?

No. It prevents teeth from getting damaged. The muscles continue to contract. The distinction is fundamental: protection vs. treatment.