Trisha E. O`Hehir, RDH, BS
The possibility of a link between periodontal disease and systemic conditions has received a great deal of interest in the research community, as well as in many consumer publications. We are learning more each day in this area. Many research studies will be completed within the next few years, adding to our understanding of these links. One aspect of this research is the potential for translocation of oral bacteria from the mouth to other parts of the body.
Oral bacteria have been associated with genitourinary tract infections, leading to increased levels of prostaglandin E2 and tumor necrosis factor, which are responsible for premature birth. Research is being conducted now to determine if translocation of bacteria into the amniotic fluid and, thus, into the system of the developing baby may lead to spontaneous abortion or altered brain development.
Oral bacteria also have been associated with both endocarditis and cardiovascular disease. Infection of heart valves by oral bacteria has been well established. Researchers now are showing that bacteria enter the blood stream from the mouth, attach to fatty plaques within blood vessels, and can contribute to clot formation.
The latest connection demonstrates a link between oral bacteria and respiratory diseases. Pneumonia, in particular, has been linked with oral bacteria.
Hospital-acquired or nosocomial pneumonia accounts for approximately 300,000 cases each year, resulting in nearly 20,000 deaths. These cases prolong hospital stays by seven to 10 days and increase medical costs by more than $2 billion. Hospital-acquired pneumonia represents a significant health care problem.
Pneumonia can be caused by a variety of agents: bacteria, mycoplasm, fungi, parasites, and viruses. The pathogenesis of hospital-acquired pneumonia usually involves aspiration of bacteria from the oropharyngeal area into the lower respiratory tract. The lower respiratory tract is normally sterile, despite bacterial contamination of the upper respiratory tract. If host defense mechanisms are unable to eliminate bacteria in the lower tract, these bacteria multiply and cause infection.
Aspiration of oropharyngeal bacteria is not limited to hospitalized patients. Studies have shown 50 percent of healthy adults aspirate oropharyngeal contents during sleep. However, individuals with impaired consciousness, swallowing disorders, or with nasogastric or endotracheal tubes have a higher incidence of bacterial pneumonia than the population in general.
Heavy plaque accumulation provides a surface to which potential respiratory pathogens can adhere, thus establishing a reservoir of pathogens. Poor oral hygiene leads to greater plaque levels, which increase the levels of hydrolytic enzymes in the saliva. These enzymes may alter the characteristics of mucosal surfaces, making them more favorable for bacterial colonization.
Viridans streptococci are found in dental plaque, but they are not considered pathogenic from a dental viewpoint. However, Viridans have been implicated as an etiologic agent in pneumonia. Therefore, poor oral hygiene may, in fact, provide the bacterial colonization necessary for aspiration pneumonia.
Researchers have evaluated patient records and found a trend between oral hygiene levels and the incidence of respiratory infections. This trend has also been shown among hospital intensive care patients. In the Preventive Dentistry Clinic at State University of New York in Buffalo, patients who had been treated for periodontal disease, including with antibiotics, had potential respiratory pathogens in their mouths.
In a recent study of nursing home patients, 72 percent had poor oral hygiene. A link between poor oral hygiene and the incidence of pneumonia in nursing homes has been suggested, but very little supporting evidence is available at this time. A preliminary report of a longitudinal study on nursing home patients does show an association between dental status and development of aspirating pneumonia.
Nursing educators have suggested giving at-risk patients antibiotic lozenges which would selectively decontaminate the digestive tract. A study comparing antibiotic and placebo lozenges demonstrated a significant reduction in the incidence of pneumonia: 16 percent versus 78 percent.
If antibiotics work, would chlorhexidine work? Probably not as effectively, say Drs. Frank Scannapieco and Joseph Mylotte, authors of a report in a 1996 issue of the Journal of Periodontology. Although chlorhexidine can inhibit bacterial growth, it may not be effective against the Gram-negative species associated with pneumonia. Effective oral hygiene may be the best way to reduce the risk of hospital-acquired aspiration pneumonia.
In light of the many reports linking periodontal status with systemic conditions, the American Academy of Periodontology has launched a national public awareness campaign, including a toll-free consumer information number: (800) 356-7736. They have also created an interactive Web site (www. perio.org). We will be seeing and hearing more about the possible links between oral and systemic health both from the profession and from our patients. Be prepared.
Trisha E. O`Hehir, RDH, BS, is a senior consulting editor of RDH. She also is editor of Perio Reports, a newsletter for dental professionals that addresses periodontics. The Web site for Perio Reports is www.perioreports.com. Her e-mail address is trisha @perioreports.com.