Now a new study has highlighted the link between tooth loss and one of the most frightening risks of growing old: dementia, including Alzheimer’s disease.
The Fewer the Teeth, the Greater the Risk
For this study, published in the Journal of the American Geriatrics Society, researchers in Japan observed over 1500 people age 60 and over who initially had no dementia. They were given dental exams, and were observed for five years, during which time researchers tracked the development of dementia among the population.
During this five year period, 180 individuals (15%) developed dementia. Most of the cases (127) were Alzheimer’s disease, while the remainder were categorized as vascular dementia. The symptoms of vascular dementia may be similar to Alzheimer’s disease, but the onset is often more sudden. It is more likely in people who have elevated stroke risk, and it shares some similarity with a stroke.
For the purposes of data analysis, the population was divided into four groups on the basis of their number of remaining teeth: 20 or more teeth, 10-19 teeth, 1-9 teeth, or no teeth remaining. Looking at the data, researchers found that people with 20 or more teeth had the lowest risk of dementia, while the other groups had elevated dementia risk:
- 10-19 teeth: 62% higher risk
- 1-9 teeth: 81% higher risk
- No remaining teeth: 63% higher risk
Researchers also found that the risk of Alzheimer’s disease was inversely related to the number of teeth a person had remaining.
How Teeth Benefit the Brain
Although the association shown in this study is important, just as important is understanding how our number of teeth might be linked to the health of our brain. That is a harder question to answer, but there are some strong candidates for the link.
The leading theory is that the link is actually systemic inflammation. This theory focuses on the role of gum disease in both tooth loss and Alzheimer’s disease. Gum disease is a chronic infection, and when you have gum disease your body maintains an elevated immune response. This inflammatory response has been shown to be damaging to the brain and has also been associated with Alzheimer’s disease.
But a newer theory explicitly links teeth with brain function. In this theory, supported by a recent study, the presence of teeth and active chewing directly stimulates the brain via the trigeminal nerve (the same nerve that links TMJ and migraines). As a result, people who maintain their teeth–or replace their teeth with dental implants–experience more brain stimulation, helping the brain to stay more active despite its age.
Keep Your Teeth to Keep Your Wits
No matter which theory is true (or both or neither), the effect is the same: keeping your teeth can help your brain stay sharp as you get older. And if you want to maintain your teeth for a lifetime, it’s important to see your dentist regularly.