Good dental health can have benefits that reach well beyond just a person’s teeth. For example, it’s been suggested that good brushing and flossing habits could be reducing your risk of having a stroke. Some research also indicates that gum disease and cavities could serve as predictors of heart disease.

According to a new study by European researchers, keeping your teeth may be also be important for keeping a strong and accurate memory. Though the study was relatively small in size at 273 participants, it found that memory score tests are linked with the number of remaining teeth in older adults. All of the participants were at least 55 years of age at the time of the study, which accounted for age in order to eliminate the notion that tooth loss and memory loss are only natural results of aging that occur together synchronously.

Human and Animal Studies Agree

Previous studies on both humans and animals have also come to the conclusion that thinking and memory correlate with a person’s number of remaining teeth. The researchers concluded that elderly adults with very few remaining teeth should be considered at high risk for memory loss.

In a previous study, a different group of researchers removed teeth from rats and found that these rats had significant learning and memory problems in comparison to rats whose teeth had been left intact. Specifically, the rats whose teeth had been removed exhibited damage to the part of the brain known as the hippocampus, which is responsible for forming memories. These rats also lost more brain neurons overall than the rats whose teeth were left untouched.

As mentioned, the new study was relatively small, but a previous study on humans – over 4,000 of them, in fact – came to the conclusion that people with no teeth or very few teeth were more likely to suffer memory loss. This study accounted for various lifestyle aspects that could have affected the conclusions, including alcohol and tobacco use as well as age.

The Link Between Teeth and Cognition

Although the researchers are still unsure of why tooth loss is linked to memory loss, they theorize that since teeth send sensory signals to the brain, the brain receives fewer sensory signals overall once natural teeth are lost. The nerves that send these signals are responsible for creating tactile sensation in the face, and for facial motor functions like smiling, frowning and chewing. Prosthetic teeth don’t send these same types of signals to the brain because they’re not attached by ligaments and nerves to the jaw in the way natural teeth are.

Another theory is that tooth loss and memory loss are caused by the same common factor. The researchers say that gum infections, for example, could cause inflammation as well as tooth loss, and that inflammation is the reason why brain neurons die and memory is weakened.

One final theory posed by the researchers has to do with nutrition. They suggested that since the average participant in the study only had 22 teeth, about 30% less than a full set, they may also avoid foods that are more difficult to chew. These foods, such as raw vegetables, contain nutrients important to cognition and memory.

The Bottom Line

Tooth loss is linked with memory loss for older adults, according to a new European study, though researchers still aren’t sure of the reason behind the link. Since this most recent study had a small participant pool, future studies will likely use a broader range of subjects in order to hone in on the exact nature of the link.

The full text of the study is available online in the European Journal of Oral Sciences.