More Teeth, More Brain Power? A Big 10-Year Study Says Yes

A large study in Japan looked at 44,083 older adults to see if people with more natural teeth live more years without dementia. The short answer: yes—keeping more teeth was tied to longer dementia-free life and longer life overall.

Snippet: “Having more teeth was associated with longer dementia-free and total life expectancies.” (read the study). 

The team followed people ages 65+ for 10 years. They grouped participants by how many natural teeth they had: 20+, 10–19, 1–9, or 0. Then they tracked who developed dementia and who passed away. Using those data, they estimated how many years people could expect to live without dementia.

• With 20+ teeth, people were expected to live about 16.4 dementia-free years (men) and 18.9 dementia-free years (women). Total life was ~17.8 years (men) and ~22.0 years (women).
  
  
• With 0 teeth, dementia-free life dropped to ~14.4 years (men) and ~17.1 years (women). Total life was ~15.4 years (men) and ~19.8 years (women) 
  

The authors discuss a few simple, common-sense reasons:

• Nutrition: More teeth make chewing easier, so people can enjoy a wider range of foods that support brain health.
  
  
• Social life: Tooth loss can make people avoid talking or going out, which raises dementia risk.
  
  
• Inflammation & stimulation: Gum disease and fewer teeth may reduce chewing-related brain stimulation and raise inflammation—both linked to cognitive decline.
  

• Brush and floss daily.
  
  
• See your dentist for routine cleanings and gum checks.
  
  
• Treat gum disease early.
  
  
• Limit sugary drinks to protect teeth.
  
  
• If you’ve lost teeth, ask about dentures or implants to improve chewing and confidence (the study focused on natural teeth, but better function can still help daily life).
  

This research shows a strong link, but it doesn’t prove that teeth cause longer dementia-free life. Still, caring for your mouth is a smart move for healthy aging. For the exact statistics and methods, check the ScienceDirect page.