Why Does My Child Grind Their Teeth in Their Sleep? The Role of Iron and the Brain

By Dr Tom Shumack, BSci (Syd. Uni), BDent (Hons) (Syd. Uni)Grad Dip Clin Dent (Oral Implants) (Syd.Uni) MRAACDS (PDS)

Many parents are surprised to learn that night-time teeth grinding—known as sleep bruxism—isn’t just a bad habit. At Shumack Dental & Implants here in Wagga Wagga, we often explain to families that bruxism in children is now understood as a neurologically driven movement disorder, not simply a response to stress or misaligned teeth.

Understanding Sleep Bruxism in Children

Sleep bruxism is characterised by involuntary, rhythmic jaw movements during sleep. It can involve clenching, grinding, or even chewing motions—often loud enough to be heard from another room. While it may appear harmless, persistent bruxism can wear down teeth, disrupt sleep, and even signal deeper neurochemical imbalances.

The Brain, Sleep and Iron

Modern research links paediatric sleep bruxism to disrupted dopaminergic signalling—a brain system that relies on the neurotransmitter dopamine. Dopamine plays a crucial role in regulating movement, attention, arousal, and sleep stability. But here’s the twist: iron is essential for dopamine function, and many children with sleep bruxism have low iron stores, even when their overall blood tests appear normal.

Iron acts like fuel in the brain’s dopamine factory. Specifically, it:
- Helps produce dopamine (by activating the enzyme tyrosine hydroxylase)
- Regulates how quickly dopamine is reabsorbed after it’s released
- Affects how well children move through sleep stages and avoid frequent arousals

When ferritin (the protein that stores iron) is low, the dopamine system can’t function properly—leading to increased movement during sleep, including grinding.

What the Research Shows

Several studies from around the world back this up:

- Serra-Negra et al. (2014) found that children with parent-reported bruxism had significantly lower ferritin levels, often below 50 ng/mL.
- Teixeira et al. (2015) showed that even without anaemia, children with low ferritin were more likely to grind their teeth at night.
- Studies on restless legs syndrome (which also involves dopamine dysfunction) have linked low brain iron levels to increased movement during sleep.
- A 2022 meta-analysis in Sleep Medicine Reviews found children with sleep bruxism were also more likely to have ADHD symptoms, disturbed sleep, and internalising behaviours—again pointing to a common neurological root.

What Does Low Ferritin Do?

Step-by-step, the process looks something like this:

1. Low iron → reduced ferritin stores in the brain
2. Reduced ferritin → less dopamine produced
3. Less dopamine → more involuntary motor activity during sleep
4. More movement + lighter sleep → increased likelihood of grinding

In other words, the brain is “overactive” during non-REM sleep, triggering the jaw muscles to contract and grind.

When Should You Investigate Further?

At Shumack Dental & Implants, we don’t rush to test every child who grinds their teeth. But if a child presents with persistent bruxism, especially alongside:

- Poor sleep quality or frequent waking
- Daytime tiredness or attention issues
- Behavioural signs resembling ADHD
- Restless legs or frequent leg movement at night
- Enlarged tonsils or snoring (which could suggest sleep-disordered breathing)

…it may be worth asking their GP or paediatrician to check ferritin levels. Research suggests a ferritin level below 50 ng/mL could contribute to bruxism, even if haemoglobin levels are still normal.

What’s the Benefit?

Ferritin is easy to measure with a simple blood test, and treatment may involve something as low-risk as increasing dietary iron or adding a short course of supplements. This could improve sleep quality, reduce grinding, and even support better daytime concentration.

Final Thoughts

Tooth grinding in kids isn’t just a nuisance—it might be a window into how their brains are sleeping, growing, and regulating movement.

At Shumack Dental & Implants in Wagga Wagga, we take a whole-child approach. If your child is grinding their teeth at night, we’re happy to assess their dental development and collaborate with your family doctor to explore deeper causes—like iron deficiency—that might be impacting their sleep and wellbeing.

Written by the Shumack Dental & Implants Team
With insights from Dr Emily Grant and Dr Josh Dunn
References available on request.