RESEARCHERS are beginning to discover a connection between oral health and brain health as populations around the world age.
There has been growing evidence that missing teeth in older adults, commonly dismissed as cosmetic or dental issues, is in fact a big driver of cognitive decline and even dementia.
This process, in some cases referred to metaphorically as “architectural erosion”, shows how the loss of dental structure can impact mental health.
The hidden link between teeth and the brain
Teeth are more than just tools for chewing; they are crucial to the structural and functional health of the mouth, jaw and even the brain.
When chewing, we have neural circuits and cognitive processes in the brain and chewing stimulates the brain.
If teeth are lost, this constant stimulation is lost and this can lead to a change in the brain’s architecture.
Recent studies have found a strong connection between tooth loss and decreased cognitive function.
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Older individuals with serious tooth loss tend to have faster memory loss, less attention and worse executive function than older people who have more of their natural teeth.
Understanding architectural erosion
The term “architectural erosion” describes the breakdown of oral and neurological structures caused by missing teeth.
The loss of key components in a building breaks its overall stability and tooth loss can destabilise the delicate balance of neural connections in the brain.
Loss of teeth leads to bone resorption in the jaw a physiological process where the bone tissue deteriorates due to lack of stimulation.
This structural deterioration of the jawbone not only diminishes facial aesthetics, but also reduces the sensory input that the brain receives from oral mechanoreceptors.
This reduction in sensory feedback can trigger a cascade of neural changes affecting areas of the brain that are responsible for cognition.
The science behind the connection
Researchers have proposed several mechanisms that could explain why tooth loss accelerates cognitive decline:
Reduced masticatory function: Chewing requires careful motor and sensory co-ordination between the muscles of the jaw and oral cavity, which are very large and complex.
This increases the blood flow in the brain to memory and learning regions (hippocampus).
A lack of teeth can decrease chewing efficiency and, therefore, blood flow in the brain and nutrition.
Inflammatory pathways: Poor oral health and periodontal disease can be associated with tooth loss.
Chronic inflammation that occurs with gum disease may have systemic effects, such as the release of pro-inflammatory cytokines that are associated with neuroinflammation and Alzheimer’s disease progression.
Nutritional deficiencies: Poor nutrition can limit diet variety as missing teeth can limit the variety of diet options by making it difficult to eat some fruits, vegetables and protein sources.
If the health of the brain is not as good as it needs to be, cognitive decline and age-related health problems occur.
Social and psychological impact: Tooth loss can affect self-esteem and social engagement, and when one does, they can lead to isolation and depression both known risk factors for cognitive decline.
Evidence from epidemiological studies
Several large-scale studies have reinforced the link between tooth loss and dementia:
A 2019 study in the Journal of the American Geriatrics Society followed more than 10 000 elderly people and found that individuals with fewer than 20 natural teeth had a 28% higher risk of developing dementia compared to those with more teeth.
Japan-based research shows elderly people with more natural teeth scored better on cognitive tests even after other health factors were taken into account.
Animal studies showed that removal of molars in animals led to a decrease in memory task performance and decreased hippocampal neuron density.
Although cause and effect are complex and multifaceted, these results highlight the importance of oral health as a modifiable factor in cognitive ageing.
What this means for elderly care
The recognition of oral health as important to cognitive wellness needs to be made more visible to healthcare practitioners, caregivers and the elderly.
Dental care has historically been separated from general healthcare, especially for seniors on fixed incomes or in long-term care facilities.
But integrative approaches that focus on dental preservation and rehabilitation could be useful in dementia prevention strategies.
Preserving natural teeth: The most effective preventative treatment we can take from a young age is regular dental check-ups, fluoride treatment and good oral hygiene.
Rehabilitation with dentures and implants: Dental prosthetics and implants can restore masticatory function and nutrition for those who have lost teeth.
Increasing evidence suggests that restoring chewing ability with implants or well-fitted dentures may slow cognitive decline.
Nutritional support: Dieticians and caregivers should provide healthy foods for older people that are appropriate for their dental abilities.
Holistic healthcare models: Dental assessments should be included in routine geriatric evaluations to identify those at risk early and initiate early interventions.
Challenges and future directions
Despite this strong evidence, clinical guidelines for oral health and cognitive decline remain to be established.
Most studies so far have been observational.
We shall need longitudinal and interventional research to understand why and how this occurs.
These inequalities and disparities in access to dental care especially for poor and minority elderly people pose public health challenges.
This is a matter of importance to ensure that the benefits of good oral health are widespread and potentially help to reduce the global dementia burden.
The metaphor “architectural erosion” serves as a powerful reminder that the mouth is not just a route to nutrition but a key component of overall health.
Missing teeth do more than alter a smile they may accelerate the wear and tear on the brain.
As science continues to unravel the intertwined fates of teeth and cognition, society needs to recognise and act on these insights.
By preserving the architecture of the mouth, we lay the foundation for healthier brains and more vibrant golden years.
