Many patients ask their dentists, “Is dental health really that important as we grow older?”
While we often associate teeth with chewing or appearance, studies now show that oral health reflects how well the body functions as we age.
The study is part of the Oral Health Screening to Assess Keys of Aging Well, known as the OHSAKA study 1. It was conducted by researchers from Osaka University and Osaka Metropolitan University in Japan. This was a large population-based study using dental examination data linked with national health insurance records in Japan.
The researchers aimed to answer a simple but important question: is counting teeth enough to under health risks in older adults, or does the condition of those teeth matter more?
190,282 adults participated
All participants were 75 years of age or older
Dental examinations were performed by dentists
Wisdom teeth were excluded
Teeth were classified as:
Healthy teeth
Filled or treated teeth
Untreated decayed teeth
Participants were followed up for an average of 3.4 years
The main outcome measured was all-cause mortality, meaning death from any cause
The researchers adjusted for many health-related factors such as age, sex, body weight, smoking, medical history, hospital visits, and need for long-term care. This helped ensure findings were not explained by these factors alone.
Earlier studies have often focused only on the number of remaining teeth. Many relied on self-reported information and did not consider whether the teeth were healthy, treated, or decayed.
This study is different because:
It used clinical recorded dental examinations
It included a very large number of older adults
It compared different ways of counting teeth based on their condition
This allowed the researchers to better understand which dental measures reflect overall health more accurately.
The study found that counting healthy teeth together with filled or treated teeth was the most reliable way to predict overall outcomes. Older adults with a higher number of healthy and treated teeth had lower mortality rates during the follow-up period compared to those with fewer functional teeth. This suggests that teeth which are healthy or properly restored support daily activities such as chewing, nutrition, and comfort, which are important for general health in older age.
When untreated decayed teeth were included in the tooth count, the ability to predict mortality became weaker.
This indicates that untreated dental decay may reflect:
Ongoing oral infection or inflammation
Reduced chewing ability
Difficulty challenges in health or access to care
In contrast, teeth that had been treated and restored behaved more similarly to naturally healthy teeth in terms of health outcomes.
During the follow-up period, approximately 12% of men and5.7% of women passed away due to various causes.
These rates differed across groups based on the number of healthy and treated teeth. Participants with fewer functional teeth showed higher mortality rates than those with more healthy or restored teeth.
It is important to note that mortality at this age is influenced by many factors. Dental health is one of the several indicators rather than a single cause.
Based on the OHSAKA study, counting healthy and treated teeth together provides a more accurate reflection of overall health risk in adults aged 75 years and older than counting all remaining teeth. In simple terms, this study reinforces an important clinical message: caring for teeth and treating problems when they arise is an essential part of maintaining health and quality of life in older age.
For patients, the message is reassuring and practical. Regular dental visits remain important at every stage of life.
This study does not claim that teeth alone determine how long someone lives. However, it reinforces an important point. Oral health reflects how well we care for our body over time. Looking after your teeth is one of the many ways to support a healthier and more comfortable life as you age.
Does oral health really affect overall health?
Yes. Poor oral health can lead to infections and inflammation that may affect the rest of the body. Maintaining healthy teeth and gums supports overall well-being.
Is it better to save a tooth or remove it?
Whenever possible, saving and restoring a tooth is usually better for chewing, jaw health, and overall comfort.
Is dental treatment still important in older age?
Absolutely. Treating cavities, gum disease, or damaged teeth helps maintain comfort, nutrition, and quality of life at any age.e
How often should older adults visit the dentist?
Most patients benefit from a dental checkup every six months, or as advised by their dentist based on individual needs.
Reference
Otsuki, Naoko, Ryohei Yamamoto, Tomoaki Mameno, Satoko Takeuchi, Maki Shinzawa, Ayumi Kono, and Kazunori Ikebe. “Assessing the Effectivity of Counting the Number of Teeth With Their Conditions to Predict Mortality: The OHSAKA Study.” BMC Oral Health (2025). https://doi.org/10.1186/s12903-025-07275-6.
