Good ‘Mental-Dental’ Health Important in Preventing, Slowing Dementia

Age-related conditions are increasingly of interest to psychiatrists and other health care professionals given demographic shifts in the population. Cognitive disorders, such as Alzheimer’s disease, are progressive conditions that can influence activities of daily living. Decreased engagement in comprehensive oral health care can lead to an increased risk for dental conditions, compromised oral functioning, decreased quality of life, and ultimately accelerated physical and mental decline.

Poor oral health is more common in patients with psychiatric disorders, including dementias. Psychiatric conditions and medications used to treat them may lead to tooth decay, gum diseases, tooth grinding, and clenching that can fracture teeth, damage the temporomandibular joints, and cause pain. Further, some individuals may neglect their oral health as a result of impaired cognition, poor self-concept, fear of judgment, financial factors, limited social support, or procedure-related anxiety.

Many patients with psychiatric illness are also coping with other medical ailments, and some may have substance use disorders as well. Comorbid substance use and medical conditions can further accelerate oral decline due to drug side effects, carcinogenesis, and alterations to the body’s immune response. This last point is particularly noteworthy for individuals with diabetes given the bidirectional relationship between this condition and periodontitis (advanced gum disease). Diabetics often experience accelerated periodontitis progression secondary to alterations in the body’s immune response to periodontal bacteria and microvascular disease. Treatment of periodontitis not only prevents premature loss of teeth, but may also improve glycemic control and prevent diabetes complications.

Periodontal pathogens and tooth loss have recently been associated with a higher risk for dementia. A large retrospective cohort study by May Beydoun, Ph.D., and colleagues published in the February 2020 Journal of Alzheimer’s Disease found evidence for an association between periodontal pathogens and Alzheimer’s disease. Another recent report, a large meta-analysis by Xiang Qi and colleagues published in 2021 in the Journal of the American Medical Directors Association, suggested that tooth loss was independently associated with cognitive impairment and dementia. This study also suggested that the risk of diminished cognitive function increases with the incremental numbers of teeth lost.

While these findings provide an opportunity to address factors that may potentially increase the risk for dementia, it is important to note that periodontitis, tooth loss, and neurodegenerative disorders are multifactorial phenomena, and it is unclear how they may relate to the development of cognitive disorders. Although these disorders may share some common contributory factors, such as genetics, substance use, and microvascular diseases, precise mechanisms have not been elucidated in humans. Ultimately, cohort studies are needed to identify both causative and protective factors regarding the association between oral diseases and neurodegenerative disorders.

How should psychiatrists, patients, and the public approach these findings? Individuals who are at risk for neurodegenerative disorders should strive to maintain good oral hygiene and seek regular comprehensive oral care, including preventive dental visits. Dental checkups are particularly important for individuals with inflammatory diseases—such as diabetes—which are also associated with cognitive changes. Further, individuals who are missing teeth should replace them through prosthodontic treatment, such as dental implants or dentures. While the precise mechanisms are not clear, missing teeth can impair nutrition and contribute to other physiologic changes that increase the risk of dementia. Replacing missing teeth aids in mastication of food, digestion, speech, appearance, and other factors that enhance quality of life and reduce the risk for physical and mental decline.

For individuals who are already experiencing neurodegenerative conditions, it is important to establish an appropriate “dental home” for comprehensive oral care and to discuss both short- and long-term treatment planning. Treatment plans are typically orchestrated using guidance from the Seattle Care Pathways and take into consideration both oral and overall health prognoses. Individuals who are expected to experience physical and mental decline within a short time should be provided treatment that strives to resolve acute oral concerns, reduce oral inflammation, maintain teeth with acceptable prognoses, and replace missing teeth in a manner that maintains the individual’s comfort and quality of life. Individuals with more advanced neurodegenerative disorders often benefit from focused approaches that maintain oral comfort and prevent acute oral conditions.

Interprofessional collaborations between dentists, physicians, social workers, and other health care team members are integral to supporting the delivery of individualized care to individuals who are at risk for or experiencing neurodegenerative disorders. ■