Missing teeth increase the risk of dementia? It's true

Note that missing teeth are no longer just a matter of aesthetics and chewing function. Epidemiological studies have shown that missing teeth also increase the risk of dementia. Although the exact mechanism by which missing teeth increases the risk of dementia is not clear, it can still be combed through various literature to find clues that missing teeth increase the risk of dementia.

Obstructed chewing exercise affects cerebral blood flow

People have different rates of cerebral blood flow and blood flow before and after chewing. After chewing exercise, the blood flow rate of the middle cerebral artery is significantly increased, and the blood supply to the corresponding brain area is also increased.

　Teeth can increase the burden of bite on surrounding teeth, and long-term loss can cause the jaw teeth to elongate and the teeth on both sides to tilt, resulting in chewing dysfunction. Therefore, when the elderly lack teeth, normal chewing exercises cannot be successfully completed.

Compared with people with sound dentition, the brain blood flow rate of people with toothless teeth is significantly slowed down, and the blood supply volume of the brain is also significantly reduced. This promotes corresponding degeneration of neural tissue structure and function.

The study found that there were abnormal changes in cerebral blood flow in elderly patients with dementia, and the blood flow rate and blood volume of the bilateral frontal lobe, hippocampus, temporal cortex and basal nucleus brain were significantly lower than those of healthy elderly people.

Missing teeth affect brain neuromediators

Two months after the extraction of unilateral molars in the elderly mice, the researchers found that the lack of teeth caused a reduction in the prefrontal cortex and cholinergic fibers in the hippocampus of the elderly mice.

Tooth loss induces memory impairment through a pathway unrelated to amyloid myolin and reduces neuronal activity, presynaptic and post-synaptic protein levels in the cortex and hippocampus. Tooth loss induces glial cell activation, which in turn leads to an upregulation of expression levels of neuroinflammation cytokine tumor necrosis factor and interleukin in the hippocampus. Tooth loss activates the stress-activating protein kinase JNK and increases the level of heat shock protein 90 (HSP90) in the hippocampus, which can lead to the activation of glial cells.

The release of hippocampal glutamate after tooth deficiency will also decrease, resulting in a decrease in neuronal excitability, further aggravating the occurrence of dementia and cognitive impairment.

Inflammation can affect the brain through neural pathways

Seeing this reason, everyone may also be puzzled. We're talking about tooth loss and dementia, what does it have to do with periodontitis? In fact, the main reason for tooth loss in the elderly is chronic periodontitis.

Periodontitis is when microorganisms in dental plaque cause chronic infection of periodontal support tissue, resulting in the destruction of periodontal support tissue and eventually loosening and extraction of teeth.

High levels of pathogenic bacteria and mediators of inflammation can be detected in the components of the gingival sulcus in patients with periodontitis. Patients with periodontitis also have higher levels of C-reactive protein and leptin in their serum.

These inflammatory factors and oral microbiota may influence the brain through circulation or neural pathways to promote dementia. Case-control studies have shown a correlation between inflammatory cytokine levels and periodontitis in patients with Alzheimer's disease and mild cognitive impairment.

Source: Beijing Youth Daily