(Not) total recall: What dental hygienists need to know about Alzheimer’s disease and its treatment

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If you are an avid reader of this column or have heard me present continuing education seminars and webinars, you know that I always stress the importance of dental hygienists encouraging their patients to maintain good oral and systemic health. Recent research is extending our understanding of the connection between oral health and Alzheimer’s disease and dementia. It is important to be aware of the dental hygiene implications of disorders such as Alzheimer’s disease and the role dental hygienists serve in promoting good oral hygiene, prophylaxis, and prompt treatment for these patients.

What is Alzheimer’s disease?

Alzheimer’s disease is neurodegenerative disorder characterized by the loss of memory, language, visuospatial skills, problem-solving ability, and abstract reasoning. It is also frequently associated with behavioral abnormalities.¹ Alzheimer’s disease is a progressive disease, where dementia symptoms gradually worsen over a number of years. In its early stages, memory loss is mild, but with late-stage Alzheimer’s disease, individuals lose the ability to carry on a conversation and respond to their environment.²

Causes and clinical effects

The cause of Alzheimer’s disease is unknown, but it appears to involve the loss of cortical and cholinergic neurons. Deposits of beta-amyloid plaques initiate inflammation, neurofibrillary tangles, and oxidative damage that result in a decrease of neurotransmitters necessary for normal cognition, memory, and behavior.³ The synaptic dysfunction and death of nerve cells that use acetylcholine, which is necessary for attention and learning processes, may lead to the memory decline seen in Alzheimer’s disease. The synaptic dysfunction and death of nerve cells that use serotonin and dopamine, which are involved in mood and emotional balance, may lead to the behavioral and psychiatric symptoms sometimes seen in patients with Alzheimer’s disease.³

The resulting cognitive defects and memory loss that are the hallmarks of Alzheimer’s disease cause significant reduction in quality of life and social isolation. Risk factors for Alzheimer’s disease include age, positive family history of dementia, and the presence of certain genetic markers.³ Physicians usually arrive at the clinical diagnosis of Alzheimer’s disease by identifying the patient’s clinical symptoms and comparing them with a set of known criteria. However, it is important to rule out other, more treatable illnesses, such as depression, hypothyroidism, electrolyte imbalance, stroke, and central nervous system (CNS) infection.¹

The onset of Alzheimer’s disease is typically insidious. Usually, the first symptom is loss of recent memory, followed by issues with cognition that interfere with job functions and daily life activities.³ As symptoms progress, patients are often unable to work and may become disoriented in their surroundings. Loss of language, motor skills, and inhibitions may lead to anxiety, depression, and behavioral problems, sometimes manifesting as physical and verbal aggression.⁴

Prescription drugs for treatment

There is no cure for Alzheimer’s disease. Prescription drugs currently used in the treatment of its symptoms include cholinesterase inhibitors such as donepezil (Aricept), rivastigmine (Exelon), and galantamine (Razadyne).^5-7 While their exact mechanism of action is unknown, these drugs are believed to boost cholinergic neurotransmission at remaining functional synapses by inhibiting acetylcholinesterase, an enzyme involved in the breakdown of acetylcholine. Administration of these agents has resulted in cognitive improvement and improvement in daily function in patients with mild-to-moderate Alzheimer’s disease.^5-7 Common adverse effects of the drugs include gastrointestinal upset, hypersalivation, fatigue, syncope, and headache.^5-7

Memantine (Namenda), is an N-methyl-D-aspartate (NMDA) receptor antagonist that has been approved for use in the treatment of moderate-to-severe Alzheimer’s disease.⁸ Its mechanism of action involves preventing elevated concentrations of glutamate (an excitatory neurotransmitter in the CNS) from destroying cholinergic neurons.⁸ Memantine is effective in delaying the progression of some symptoms to improve daily function. Common adverse effects of memantine include hypertension, dizziness, confusion, tinnitus, blurred vision, and headache.⁸

Lecanemab (Leqembi) is an FDA-approved immunotherapy to treat early Alzheimer’s disease. It targets the protein beta-amyloid to help reduce amyloid plaques, one of the hallmark brain changes in Alzheimer’s disease.⁹ Clinical studies to determine the effectiveness of lecanemab were conducted only in people with early-stage Alzheimer’s disease or mild cognitive impairment due to the disease. Study results showed lecanemab slowed the rate of cognitive decline among study participants over the course of 18 months and reduced the levels of amyloid in the brain.⁹ Currently, insurance may cover this medication only in specific situations due to its high cost. Adverse effects of lecanemab include localized brain swelling, bleeding in the brain, or both, as well as headache and infusion-related reactions.⁹

Oral implications of Alzheimer’s disease

Patients with Alzheimer’s disease have a greater incidence of xerostomia, oral lesions, candidiasis, periodontal disease, and root caries. In addition, these patients often sustain oral injuries from falls as well as lacerations of the tongue and cheeks (due to impaired mastication), and they are at an increased risk for aspiration pneumonia (due to dysphagia).^10,11 Patients with Alzheimer’s disease generally can receive routine dental hygiene treatment. Treatment programs should emphasize frequent recalls and examinations, fluoride applications, and oral hygiene education.^10,11

How Alzheimer’s affects dental treatment

Patients with advanced dementia may be anxious, hostile, uncooperative, and difficult to treat.⁴ Because of the progressive nature of the disease, procedures aimed at restoring oral health should be performed early on. Subsequent care should focus on prophylaxis and minimizing deterioration, utilizing short appointments whenever possible.^10,11

The dental hygienist is invaluable in promoting good oral hygiene, prophylaxis, and prompt treatment with communication to patients with Alzheimer’s disease. These patients may not have an interest in caring for themselves and/or may lack the ability to do so.^9,10 Thus, their ability to maintain proper daily oral hygiene can become severely compromised.

The dental hygienist should maintain a positive, empathetic attitude with the patient and communicate all instructions regarding maintenance of the patient’s oral health to the patient and family members, when necessary. All communication should be in short, easy-to-understand language since patients may experience difficulty understanding instructions and may easily become anxious or stressed.^9,10

Editor's note: This article appeared in the June 2024 print edition of RDH magazine. Dental hygienists in North America are eligible for a complimentary print subscription. Sign up here.

References

1. Friedlander AH, Norman DC, Mahler ME, Norman KM, Yagiela JA. Alzheimer’s disease: psychopathology, medical management and dental implications. J Am Dent Assoc. 2006;137(9):1240-1251. doi:10.14219/jada.archive.2006.0381
2. What is Alzheimer’s disease? Alzheimer’s Association. Accessed February 15, 2024. https://www.alz.org/alzheimers-dementia/what-is-alzheimers
3. Knopman DS. Alzheimer’s disease and other dementias. In: Goldman L, Ausiello D, eds. Cecil Textbook of Medicine. 23rd ed. Elsevier Health Sciences; 2007:2667-2676.
4. Mintzer JE. Underlying mechanisms of psychosis and aggression in patients with Alzheimer’s disease. J Clin Psychiatry. 2001;62(Suppl 21):23-25.
5. Courtney C, Farrell D, Gray R, et al. Long-term donepezil treatment in 565 patients with Alzheimer’s disease (AD2000): randomised double-blind trial. Lancet. 2004;363(9427):2105-2115.
   doi:10.1016/S0140-6736(04)16499-4
6. Pirttilä T, Wilcock G, Truyen L, Damaraju CV. Long-term efficacy and safety of galantamine in patients with mild-to-moderate Alzheimer’s disease: multicenter trial. Eur J Neurol. 2004;11(11):734-741. doi:10.1111/j.1468-1331.2004.00885.x
7. Colombres M, Sagal JP, Inestrosa NC. An overview of the current and novel drugs for Alzheimer’s disease with particular reference to anti-cholinesterase compounds. Curr Pharm Des. 2004;10(25):3121-3130. doi:10.2174/1381612043383359
8. Miguel-Hidalgo JJ, Alvarez XA, Cacabelos R, Quack G. Neuroprotection by memantine against neurodegeneration. Brain Res. 2002;958(1):210-221. doi:10.1016/s0006-8993(02)03731-9
9. Chowdhury S, Chowdhury NS. Novel anti-amyloid-beta (A) monoclonal antibody lecanemab for Alzheimer’s disease: a systematic review. Int J Immunopathol Pharmacol. 2023;37:3946320231209839. doi:10.1177/03946320231209839
10. Henry RG, Smith BJ. Managing older patients who have neurologic disease: Alzheimer disease and cerebrovascular accident. Dent Clin North Am. 2009;53(2):269-294. doi:10.1016/j.cden.2008.12.011
11. Sacco D, Frost DE. Dental management of patients with stroke or Alzheimer’s disease. Dent Clin North Am. 2006;50(4):625-633. doi:10.1016/j.cden.2006.08.001