Increasing evidence has linked the anaerobic bacteria forming periodontopathic biofilms with aspiration pneumonia in elderly persons.

Okuda K et al, J Periodontology 2005, Vol. 76, No. 11-s, pp2154-2160.
http://www.joponline.org/doi/abs/10.1902/ jop.2005.76.11-S.2154

Scientists believe that through the aspiration process, bacteria can cause frequent bouts of infection in patients with COPD.

http://www.perio.org/consumer/mbc.respiratory.htm

Rationale: Ventilator-associated pneumonia (VAP) is the most frequently occurring nosocomial infection associated with increased morbidity and mortality. Although oral decontamination with antibiotics reduces incidences of VAP, it is not recommended because of potential selection of antibiotic-resistant pathogens. We hypothesized that oral decontamination with either chlorhexidine (CHX, 2%) or CHX/colistin (CHX/COL, 2%/2%) would reduce and postpone development of VAP, and oral and endotracheal colonization.

Conclusions: Topical oral decontamination with CHX or CHX/COL reduces the incidence of VAP.] Koeman M, van der Ven, AJAM, et al. American Journal of Respiratory and Critical Care Medicine, Volume 173. pp. 1348-1355, (2006)

http://ajrccm.atsjournals.org/cgi/content/ abstract/173/12/1348

Considerable evidence exists to support a relationship between poor oral health, the oral microflora and bacterial pneumonia, especially ventilatorassociated pneumonia in institutionalized patients. Teeth or dentures have nonshedding surfaces on which oral biofilms (that is, dental plaque) form that are susceptible to colonization by respiratory pathogens. Subsequent aspiration of respiratory pathogens shed from oral biofilms into the lower airway increases the risk of developing a lung infection. In addition, patients may aspirate inflammatory products from inflamed periodontal tissues into the lower airway, contributing to lung insult. A number of studies have shown that the mouth can be colonized by respiratory pathogens and serve as a reservoir for these organisms. Other studies have demonstrated that oral interventions aimed at controlling or reducing oral biofilms can reduce the risk of pneumonia in high-risk populations. Taken together, the evidence is substantial that improved oral hygiene may prevent pneumonia in vulnerable patients.

Scannapieco FA. J Am Dent Assoc, Vol 137, No suppl_2, 21S-25S,
http://jada.ada.org/cgi/content/abstract/137/suppl_2/21S