tal plaque are a major cause of respiratory infections in older adults, especially those in institutions.^99-102 Up to 48% of infections seen in nursing homes result from aspiration pneumonia, and the cost to treat patients developing pneumonia in these institutions has increased dramatically.⁹⁹ Aspiration pneumonia is a significant cause of morbidity, hospitalization, and mortality in the nursing home population.¹⁰⁰

 

When host defense mechanisms are compromised because of disease, aging, poor nutrition, or other conditions associated with elderly patients in nursing homes, the aspiration of a large pathogenic inoculum from periodontally involved teeth overwhelms normal flora and significantly increases the risk of respiratory infection.¹⁰³ Bacteria constitute approximately 70% to 80% of solid plaque material and 1 mm³ of plaque contains more than 106 bacteria of 300 different aerobic and anaerobic species.⁹⁹ Aspiration of plaque bacteria by older patients often leads to lower respiratory tract infections, such as aspiration pneumonia or pneumonitis, and recent evidence links anaerobic bacteria from periodontopathic biofilms with aspiration pneumonia in elderly persons.^103,104 Thus, poor periodontal health and accumulation of dental plaque is a major contributory factor in respiratory infections.^99,100,105 Furthermore, addressing periodontal health in nursing home patients is critical not only because older adults are now more likely to retain their teeth but because younger

persons are being admitted to such facilities.^101,102

 

Effect of Aging on the Periodontal-Systemic Connection Age may also predispose individuals to the periodontal-systemic connection. It is well known that the incidence of periodontitis and the severity of untreated periodontal disease increase with age.^106-108 Secretion of pro-inflammatory cytokines from monocytes/macrophages and levels of soluble TNF-α receptor normally increase with age.^109,110 Thus, further increases in serum cytokines induced by periodontitis would not only be cumulative but could create a more destructive scenario through enhanced receptor interactions. Serum lipid levels also increase with age, particularly LDL.^111,112 Similar to the pro-inflammatory cytokines, periodontitis-induced LDL/TRG elevation could be more damaging in this context and further increase pathological lipid levels.

 

Aging is associated with increased insulin resistance.^113,114 Likewise, the incidence and severity of diabetes also increases with age.^115,116 These conditions may result from loss of an individual’s capacity to respond to environmental challenges.¹¹⁵ Some investigators attribute this association to an imbalance of important intracellular divalent cations such as calcium and magnesium that make cells vulnerable to ionic disturbances.¹¹⁶ Many other systemic diseases/conditions associated with chronic inflammation also demonstrate increased incidence and severity with

Fig. 1: Linkage between periodontitis and systemic diseases/conditions predominantly affecting the elderly

Respiratory Infection

Dementia

Aspiration

Microglia activation

Atherosclerosis

Bacteremia

Elevated Serum
Pro-Inflammatory Cytokines

Altered Lipid Metabolism

Periodontitis

Hyperlipidemia

Endotoxemia

Rheumatoid factor

Arthritis

Vascular endothelium

Synovial
inflammation

Insulin resistance

sz-Cell
destruction

Diabetes

Atherosclerosis

Cardiovascular/
Cerebrovascular
Disease