Tooth loss, dementia

(By Dr. Joseph D. Lim and Dr. Kenneth Lester Lim, BS-MMG, DDM, MSc-OI)

TOOTH loss means a higher risk of cognitive impairment and dementia among older adults.

The risk increases with each missing tooth, according to a new study published in the Journal of the American Medical Directors Association.

Compared to other age groups, poor oral hygiene, tooth cavities, gum disease, and tooth loss, are more common in older adults.

Recent studies have shown that there is a link between older adults and poor oral health and cognitive impairment or dementia.

In a study supported by the National Institute on Aging, U.S. National Institutes of Health, a research team at New York University looked closely at this link to get a more comprehensive picture.

The study analyzed six major databases of biomedical science publications and identified 14 relevant studies. The   studies used questionnaires, assessments, medical records, and information from death certificates to identify participants with cognitive impairment or dementia.

Out of a total of 34,074 participants, 4,689 had cognitive impairment or dementia.

Mild cognitive impairment and mild dementia are common among senior citizens. According to the Mayo Clinic, “the main distinctions between mild cognitive impairment and mild dementia are that in the latter, substantial interference with daily life is evident.” The key phrase here is “substantial interference” in daily activities.

The study then used medical examinations and self-reported records to assess tooth loss and classified participants as having more or fewer missing teeth.

It found that participants with more missing teeth had, on average, a 48 percent higher risk of cognitive impairment and a 28 percent higher risk of dementia.

The relationship between tooth loss and cognitive decline was “dose-dependent”: that is, each lost tooth was associated with a 1.4 percent increase in the risk of cognitive impairment and a 1.1 percent increase in the risk of dementia.

Participants who were missing 20 or more teeth had a 31 percent higher risk of cognitive impairment.

Participants who had lost all their teeth had a 54 percent higher risk of cognitive impairment and a 40 percent higher risk of dementia.

Interestingly, participants who had missing teeth but used dentures did not have a significantly higher risk of dementia than participants without missing teeth.

It wasn’t clear what the association between tooth loss and the risk of cognitive decline is. It could be that tooth loss means difficulty in chewing and may lead to poor nutrition, chemical imbalances, or changes to the brain that affect brain function.

Poor oral hygiene may lead to increased bacteria in the mouth, resulting in gum disease. Gum disease can cause inflammation and raise the risk of dementia.

It could be that people with cognitive decline might be less likely to keep up with oral hygiene, leading to tooth loss.

As for tooth loss without using dentures, it could mean lower socioeconomic status and lower education; both have been associated with an increased risk of dementia.

The study does suggest that timely interventions such as the use of dentures could help prevent or slow down cognitive decline linked to tooth loss.

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Dr. Joseph D. Lim is the former Associate Dean of the College of Dentistry, University of the East; former Dean, College of Dentistry, National University; Past President and Honorary Fellow of the Asian Oral Implant Academy; Honorary Fellow of the Japan College of Oral Implantologists; and Honorary Life Member of the Thai Association of Dental Implantology. For questions on dental health, e-mail jdlim2008@gmail.com or text 0917-8591515.

Dr. Kenneth Lester Lim, BS-MMG, DDM, MSc-OI, graduated Doctor of Dental Medicine, University of the Philippines College of Dentistry, Manila, 2011; Bachelor of Science in Marketing Management, De la Salle University, Manila, 2002; and Master of Science (MSc.) in Oral Implantology, Goethe University, Frankfurt, Germany, 2019. He was Assistant Professor at the National University, 2018; and Associate Professor, University of Makati, 2018. For questions on dental health, e-mail limdentalcenter@gmail.com.)/PN