Relationship between the oral cavity and respiratory diseases: Aspiration of oral bacteria possibly contributes to the progression of lower airway inflammation

The global population is aging, and elderly people have a higher incidence of lower airway diseases owing to decline in swallowing function, airway ciliary motility, and overall immunity associated with aging. Furthermore, lower airway diseases in the elderly tend to have a high mortality rate. Their prevention is important for extending healthy life expectancy and improving the quality of life of each individual. In recent years, the relationship between chronic periodontitis and oral bacteria, especially the periodontopathic ones and respiratory diseases (e.g., pneumonia, chronic obstructive pulmonary disease, and influenza) has become clear. In addition, the association of several periodontal pathogens with the onset and aggravation of coronavirus disease 2019 (COVID-19) is also being reported. In support of these findings, oral health management has shown to reduce deaths from pneumonia and prevent influenza in nursing homes and inpatient wards. This has led to clinical and multidisciplinary cooperation between physicians and dentists, among others. However, to date, the mechanisms by which chronic periodontitis and oral bacteria contribute to lower airway diseases have not been well understood. Clarifying these mechanisms will lead to a theoretical basis for answering the question, Why is oral health management effective in preventing lower airway diseases? (c) 2021 Published by Elsevier Ltd on behalf of The Japanese Association for Dental Science This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/ ).

Automated summary

The global aging population has a higher incidence of lower airway diseases, which are related to oral bacteria and periodontal diseases. Oral health management can reduce mortality and prevent pneumonia, highlighting the importance of collaboration between physicians and dentists.