Why Do Dementia Patients Grind Their Teeth?

Teeth grinding in dementia patients traces back to the progressive loss of brain tissue that normally keeps jaw muscles under coordinated, voluntary control. As dementia damages regions involved in motor regulation and disrupts key chemical-signaling pathways, repetitive jaw clenching and grinding can emerge as an involuntary behavior. A systematic review and meta-analysis found that people with neurodegenerative disorders are roughly one and a half times more likely to exhibit bruxism than age-matched controls, and the connection runs deeper than simple habit or stress.¹ The causes involve overlapping neurological, chemical, and behavioral factors that vary from one person to the next.

What Is Actually Happening in the Brain

In a healthy brain, the muscles that open and close the jaw are governed by a finely tuned circuit that includes the motor cortex, the basal ganglia, the brainstem, and the cerebellum. These structures work together to let you chew when you want to and keep your jaw relaxed when you don’t. Dementia erodes that circuitry. As neurons degenerate in the cortex and deeper brain structures, the normal inhibitory signals that prevent purposeless jaw activity weaken or disappear altogether.

Two neurotransmitter systems appear especially relevant. Dopamine, which plays a central role in movement control, becomes dysregulated in several forms of dementia. The basal ganglia rely heavily on dopamine signaling to suppress unwanted movements, so when dopamine pathways deteriorate, repetitive motor behaviors like grinding can slip through. Serotonin pathways also factor in; serotonin helps modulate muscle tone and arousal states, and disruptions in serotonergic signaling have been linked to bruxism in the broader population. A meta-analysis exploring the neurobiological mechanisms behind bruxism in neurodegenerative diseases specifically highlighted the roles of both dopaminergic and serotonergic pathways.¹

This means the grinding is not a conscious behavior the person can simply decide to stop. It is driven by structural and chemical changes in the brain, which is why asking a dementia patient to “just relax your jaw” is about as effective as asking someone with Parkinson’s to stop trembling. The voluntary control mechanisms that would make that possible are the very ones being dismantled by the disease.

The Medication Connection

Many of the drugs commonly prescribed to dementia patients can independently trigger or worsen bruxism. Selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), frequently used to manage depression and anxiety in people with dementia, are well-known culprits. By altering serotonin levels in the brain, these medications can increase jaw muscle activity, especially during sleep. Antipsychotic drugs used to manage agitation and behavioral symptoms also affect dopamine signaling and can produce involuntary movement side effects that include teeth grinding.

This creates a frustrating clinical dilemma. The very medications that help manage some of dementia’s most disruptive behavioral symptoms may be fueling another distressing one. Clinicians sometimes need to weigh whether the grinding started before or after a medication was introduced, and whether adjusting the dose or switching to a different drug might help. In one documented case, a 66-year-old man with severe vascular dementia and persistent awake bruxism responded well when trazodone was introduced, with a noticeable reduction in grinding and no problematic sedation or other side effects.² That said, a single case report is far from a proven treatment, and what worked for one patient may not generalize. It does, however, point to the idea that medication adjustments are worth exploring rather than simply accepting the grinding as untreatable.

Primitive Reflexes and Loss of Higher Control

One underappreciated explanation involves the re-emergence of primitive oral reflexes. In infancy, humans have strong rooting and sucking reflexes that gradually come under cortical control as the brain matures. When dementia strips away higher cortical function, some of these early reflexes resurface. Repetitive jaw movements, including grinding and clenching, may represent a version of these archaic motor patterns breaking free from inhibition.

This is particularly visible in advanced-stage dementia, where patients may also exhibit other primitive reflexes like grasping or sucking motions. The grinding at this stage often happens during waking hours, not just during sleep, and can be nearly continuous. It differs from the sleep bruxism that is common in the general population; awake bruxism in dementia tends to be more forceful, more persistent, and more resistant to intervention because the person lacks the cognitive capacity to become aware of it or to respond to behavioral cues.

Why It Distresses Caregivers So Much

Teeth grinding in dementia is frequently described in the clinical literature as “under-recognized,” not because it is subtle but because clinicians sometimes dismiss it as a minor issue compared to the disease’s other devastating symptoms. For the people actually living with a grinding patient day after day, however, the experience can be deeply upsetting. The sound itself is one factor: constant, audible grinding produces a grating noise that many caregivers find viscerally difficult to tolerate for hours at a time. But beyond the sound, caregivers often worry that the person is in pain, is damaging their teeth irreparably, or is exhibiting a sign that the disease has entered a new, worse phase.³

A case series involving two Alzheimer’s patients, one in the early stage and one in an advanced stage, found that bruxism caused significant distress for both patients’ caregivers.³ That distress can compound an already overwhelming caregiving burden, and the fact that the behavior seems impossible to redirect through normal means (verbal instruction, distraction) adds to the sense of helplessness. Caregivers sometimes interpret the grinding as a sign of suffering, which in advanced dementia is genuinely difficult to assess since the patient cannot articulate what they are feeling.

Physical Consequences for the Patient

Bruxism in dementia is not just a noise problem. The forces generated during sustained teeth grinding are substantial, and over weeks or months, they can crack or fracture teeth, wear down enamel to the dentin layer, damage dental restorations, and contribute to temporomandibular joint pain. For a dementia patient who may already struggle with dental care and oral hygiene, this accelerates an existing decline in oral health.

The nutritional implications are worth flagging. Severe tooth damage from bruxism can make chewing painful or mechanically difficult. Dementia patients are already at elevated risk for malnutrition because of swallowing difficulties, loss of appetite, and the inability to prepare food independently. When bruxism-related dental damage is layered on top of these challenges, it can push a person toward softer, less nutritious foods or reduce their willingness to eat at all. In the case of the man with severe vascular dementia treated with trazodone, clinical concern about nutritional compromise was explicitly noted as a motivation for treating the bruxism.² Dental procedures are also poorly tolerated by many people with advanced cognitive impairment, meaning the damage from grinding is harder to repair once it occurs.

The Mouthguard Safety Problem

For most people with bruxism, a mouthguard or occlusal splint is the go-to recommendation. In patients without cognitive impairment, splints can reduce the mechanical stress on teeth and jaw joints. One engineering analysis showed that jaw bone stress dropped by roughly 70% after six months of splint use, with the greatest benefit around the molar teeth.⁴

In dementia patients, however, mouthguards carry a serious and sometimes fatal risk. A person with advanced cognitive impairment may not understand what the device is, may try to chew or swallow it, or may dislodge it during unsupervised moments. A case report published in a major geriatrics journal documented a fatal asphyxiation when a mouthguard used for awake bruxism in a patient with frontotemporal dementia became lodged in the airway.⁵ Beyond that extreme outcome, systematic reviews have found surprisingly weak evidence that mouthguards actually improve pain, jaw clicking, restricted mouth opening, or quality of life in bruxism patients generally.⁵

The upshot for dementia care is that the most intuitive-seeming solution, putting something between the teeth, is often the wrong one. If a mouthguard is considered at all, it should only be used under continuous supervision and after careful assessment of the person’s ability to keep the device safely in place. Many clinicians working with advanced dementia patients have moved away from recommending them entirely.

Treatment Approaches That May Help

With mouthguards largely off the table for many patients, what options remain? Treatment tends to be individualized and involves a combination of strategies rather than any single fix.

Medication review: The first step is usually to look at whether any current medications could be causing or worsening the bruxism. SSRIs, antipsychotics, and stimulants are common offenders. Adjusting doses, switching agents, or in some cases discontinuing a drug under medical guidance can reduce grinding.
Botulinum toxin injections: Injecting botulinum toxin into the masseter muscles, the large jaw-closing muscles on either side of the face, weakens their contraction force and can substantially reduce grinding. In one of the reported Alzheimer’s cases, botulinum toxin provided complete relief of the symptom.³ The effect is temporary, typically lasting three to four months, so repeat injections are needed. For patients who tolerate the procedure, this is one of the more reliable interventions currently available.
Trazodone: As noted in the vascular dementia case report, trazodone has shown promise in at least one patient, though evidence remains limited to isolated reports.² Trazodone is already used in dementia care for sleep disturbances, which makes it a practical option when bruxism coexists with insomnia or nighttime agitation.
Environmental and behavioral strategies: Reducing environmental stressors, maintaining consistent routines, addressing pain or discomfort that the patient cannot verbalize, and ensuring adequate sensory stimulation may reduce agitation-driven grinding. These strategies are harder to study formally, but they align with general best practices for managing behavioral symptoms in dementia.

The honest reality is that none of these approaches has been tested in large-scale trials for bruxism specifically in dementia populations. The evidence base consists mostly of case reports and small series, supplemented by what is known about bruxism treatment in people without cognitive impairment. Clinicians are largely working from first principles and clinical experience rather than established protocols.

Sleep Bruxism Versus Awake Bruxism in Dementia

It is worth distinguishing between grinding that happens during sleep and grinding that happens while the person is awake, because the two forms may have different underlying drivers and require different management approaches. Sleep bruxism is linked to arousal events during sleep, brief moments when the brain partially wakes up, and it occurs across the general population regardless of cognitive status. Dementia patients have notoriously disrupted sleep architecture, with fragmented sleep cycles and altered time spent in different sleep stages, which may increase the frequency of these arousal-related grinding episodes.

Awake bruxism, on the other hand, is more closely tied to the cortical and subcortical damage caused by the dementia itself. It tends to appear in more advanced stages and can persist for hours during the day. Awake bruxism is generally considered harder to manage because it occurs during the patient’s active hours, when caregivers are present and exposed to the sound and when the cumulative mechanical forces on the teeth are greater. It is also the form most associated with the choking risk from mouthguards, since the patient is moving, swallowing, and potentially manipulating objects in their mouth during waking activity.

Does Bruxism Signal Disease Progression?

Caregivers sometimes wonder whether the onset of teeth grinding means the dementia has entered a new stage. The answer is complicated. Bruxism has been reported in patients at various points along the disease trajectory, from relatively early stages to very advanced ones. However, there is a general pattern in clinical reports: awake bruxism, especially when it is persistent and forceful, tends to show up more frequently in moderate to advanced dementia, when cortical control over motor function has deteriorated substantially.

Whether bruxism independently predicts faster cognitive decline is an open question that the current research has not answered. The meta-analysis confirming higher bruxism prevalence in neurodegenerative disorders noted significant variability between studies and no statistically significant overall effect when heterogeneity was accounted for, which reflects how thin the evidence base still is.¹ So while the appearance of grinding may coincide with disease progression, treating it as a reliable staging marker would go beyond what the data currently support.

Why This Problem Gets So Little Research Attention

Given how distressing bruxism is for caregivers and how damaging it can be for patients, you might expect a robust body of research on the topic. Instead, the literature is sparse. The meta-analysis that pooled data on bruxism prevalence in neurodegenerative disorders included only three studies, a remarkably small number for a condition affecting an aging population in the tens of millions worldwide.¹ Treatment evidence comes almost entirely from case reports rather than controlled trials.

Several factors contribute to this gap. Dementia patients are difficult to enroll in clinical trials because of consent challenges and the unpredictability of their behavior. Bruxism, while unpleasant, is rarely life-threatening on its own and tends to rank lower on the priority list than cognitive decline, wandering, aggression, or falls. And the symptom falls into an awkward gap between neurology and dentistry, two fields that do not always communicate effectively about shared patients. The result is that caregivers dealing with persistent teeth grinding often find themselves navigating a problem for which their loved one’s medical team has few evidence-backed answers.

Researchers have flagged this explicitly, calling bruxism in Alzheimer’s disease an “under-recognized” problem despite its clear impact on both patients and the people caring for them.³ Until larger studies are conducted, management will continue to rely on individualized clinical judgment, careful medication review, and the occasional use of interventions like botulinum toxin that have shown promise in isolated cases but lack the stamp of rigorous trial data.

1
PubMed Central. Prevalence of bruxism in neurodegenerative disorders in the elderly: A systematic review and meta-analysis
2
PubMed. Trazodone Treatment of Bruxism in a Patient With Severe Dementia
3
PubMed. The approach and management of bruxism in Alzheimer’s disease: An under-recognized habit that concerns caregivers
4
PubMed Central. Finite element analysis of occlusal splint therapy in patients with bruxism
5
Journal of the American Medical Directors Association. Fatal Asphyxiation From a Mouthguard Used for Awake Bruxism in Frontotemporal Dementia: A Case Report and Review of the Literature