The Flu and Dental Care: A Closer Look

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The 2018 flu season has been one of the worst in 15 years. According to the Centers for Disease Control, in the final week of January 2018, 7.1% of all outpatient visits were for flu-like symptoms, an increase of .5% from the week before. This season has already led to the tragic deaths of 53 children from influenza, and it may only be half over.

While it has already been established that oral health care is systemic health care and that a healthy mouth is positively linked with reduced rates of heart disease and other chronic illnesses, the specific links between harmful bacteria in the oral cavity and susceptibility to harmful systemic viruses are only recently being explored.

According to a recent review from researchers at North Carolina State University in collaboration with the CDC, illness-causing viruses and bacteria interact in two ways:

  • Direct interactions, in which a virus exploits a bacterial component to penetrate a host cell
  • Indirect interactions, in which a viral infection causes increased bacterial pathogenesis

According to this review, many common oral bacteria associated with gum disease also have an immune-suppression effect that increases susceptibility to cold and flu viruses like influenza and rhinovirus. Two of the most virulent bacteria are:

Porphyromonas gingivalis. P. gingivalis is found in the oral cavity. While it is generally present in low numbers, it has many ways of suppressing the immune system to evade immune responses. Specifically, it delays neutrophil recruitment, impairs immune signaling, modulates the effectiveness of leukocytes, and compromises the integrity of epithelial cell layers. All of these functions cause a microbial shift in the oral cavity, not only increasing the virulence of other harmful oral bacteria but leads to an environment necessary for the survival of other harmful species like Streptococcus gordonii. P. gingivalis. Therefore, is not only a cause of periodontal disease, but a cause of other immune system failures, and has been linked to chronic immune conditions rheumatoid arthritis, and viruses like HIV and herpes.

Streptococcus pneumoniaeS. pneumoniae is a bacteria generally found in the respiratory tract, sinuses, and nasal cavity. It becomes pathogenic when the host immune system is suppressed and colonizes the air sacs of the lungs. S. pneumoniae has a powerful ability to repair its own DNA when damaged by the host immune response, continuing to transfer itself to non-infected cells. While most frequently associated with pneumonia and meningitis, it is also positively associated with periodontitis and oral plaque and increases the risk of death when comorbid with the influenza virus.

Repeated studies have demonstrated the benefits of oral interventions to improve the respiratory health of hospitalized patients, including reducing the need for systemic IV antibiotics, and even shortening the duration of mechanical ventilation in hospitalized ICU patients.

In short, a review of the literature suggests that heightened oral care may be an under-utilized avenue for prevention of disease and mitigation of lethality during cold and flu season. In addition to conventional flu prevention methods such as handwashing, avoiding exposure, and getting a flu shot, additional preventive methods specifically targeting oral health may be beneficial. Here are some additional ways patients can take care of themselves during the flu season:

  • Get regular dental checkups and dental cleanings
  • Brush and clean in between teeth regularly
  • Wash your hands before flossing to prevent bacteria from entering the mouth
  • Replace toothbrushes every 3-4 months, and discard a toothbrush if it was used while suffering from the cold or flu
  • Thoroughly rinse toothbrushes after use and allow them to air-dry in an upright position between uses
  • Never share toothbrushes

Oral hygiene is important year-round but is especially important during flu season. It should be a part of a comprehensive approach to the preservation of health and avoidance of illness.

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