Study finds gum infections and tooth loss can shrink your brain

Every time you suffer from a gum infection or lose a tooth, the part of your brain that controls memory shrinks. Here is how you can prevent your brain from shrinking further.
Rupendra Brahambhatt
Dental technician doing partial dentures
Dental technician doing partial dentures


A new study from Japan’s Tohoku University suggests that dental problems may cause the shrinking of the hippocampus, the part of the brain that controls your memory and learning ability. 

So if you don’t take good care of your gums and teeth, you may develop dementia and may even suffer from Alzheimer’s disease when you reach middle or old age. 

“This study aimed to clarify a longitudinal association between the number of teeth present (NTP) and hippocampal atrophy dependent on the severity of periodontitis (a disease that damages the tissues that hold your teeth) in a late middle-aged and older adult population,” the researchers note.

These findings are based on an experiment that continued for more than four years and involved 172 participants with a median age of 67.

Finding the link between dental health and brain function

A study published in 2021 suggested that as old-age individuals lose their teeth with age, their risk of developing cognitive impairments like dementia increases. Another study in 2022 that took into account animal models also hinted that tooth loss leads to neurodegeneration.

So clearly, the Tohoku University team is not the first to highlight the connection between tooth loss and dementia. However, thanks to the current study, we know how a particular part of the brain i.e., the hippocampus, is affected due to gum diseases and tooth loss.

The researchers performed an interesting experiment to demonstrate this connection. They compared the number of teeth, periodontal probing depth (a parameter for measuring gum tissues, it should range between one to three millimeters), and volume of the hippocampus of 172 participants before and after four years. 

All these participants underwent a series of dental and brain checkups before the study began, and none had dementia. 

However, after four years, the researchers noticed some participants developed mild gum infections, and others were facing severe gum diseases. The hippocampus volume was also found to be reduced in both such participants.

What’s more interesting is that participants with mild infections but fewer teeth and those with severe gum damage but more teeth experienced the fastest shrinking of the left hippocampus region. 

“The findings suggest that retaining teeth with severe gum disease is associated with brain atrophy. Controlling the progression of gum disease through regular dental visits is crucial, and teeth with severe gum disease may need to be extracted and replaced with appropriate prosthetic devices,” explained Satoshi Yamaguchi, one of the study authors and a researcher from Tohoku University.

The loss of one tooth in mild category participants shrunk the hippocampus to the same extent caused by one year of aging. The similar loss led to hippocampus shrinkage equal to 1.3 years of brain aging in participants with severe gum infection.

The researchers further suggest that although their study shows a possible connection between tooth loss and hippocampus volume, their findings must be further verified. 

Yamaguchi added, “Future studies are needed with larger groups of people.” The current experiment involved only a small group of people, and that too from one particular region of the world. 

Scientists may take some time to prove these findings, but now you have one more solid reason to take good care of your teeth.

The study is published in the journal Neurology.

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