The Role of Oral Microbes in Systemic Diseases

Oral health is not only related to chewing function, speech, and aesthetics, but is also closely linked to systemic health. Microorganisms living in the oral cavity, particularly within dental plaque and biofilm, can become sources of chronic infection that trigger or exacerbate systemic diseases.
The oral cavity is a complex ecosystem containing more than 700 species of microorganisms, including bacteria, fungi, viruses, and protozoa. When the balance of oral microbiota is disrupted (dysbiosis), pathogenic microorganisms can penetrate tissues and enter the bloodstream, leading to significant systemic effects.

Oral Microbiota and Mechanisms of Systemic Spread

Under normal conditions, oral microbiota help maintain balance by competing with pathogenic microbes. However, in the presence of plaque accumulation and periodontal inflammation, pathogens such as Porphyromonas gingivalis, Fusobacterium nucleatum, and Treponema denticola can:

1. Enter the bloodstream (bacteremia) through microscopic wounds in inflamed gingiva.
2. Induce systemic immune responses by triggering the release of proinflammatory cytokines such as IL-6, TNF-α, and CRP.
3. Disseminate to other organs and cause or worsen systemic diseases such as atherosclerosis, diabetes, pneumonia, and even pregnancy complications.

Thus, oral and periodontal health has a bidirectional relationship with various chronic diseases.

The Role of Oral Microbes in Specific Systemic Diseases

1. Cardiovascular Disease
   Chronic periodontal infection can increase C-reactive protein (CRP) levels and promote atherogenesis. P. gingivalis is known to invade vascular endothelial cells and contribute to atherosclerotic plaque formation.
2. Diabetes Mellitus
   Inflammation from periodontal infection increases insulin resistance. Conversely, high glucose levels in diabetic patients worsen periodontal infections, creating a vicious bidirectional cycle.
3. Respiratory Diseases
   Oral microbes can be aspirated into the lower respiratory tract, causing lung infections such as aspiration pneumonia, particularly in elderly individuals or those with compromised immunity.
4. Pregnancy Complications and Preterm Birth
   Periodontal bacterial endotoxins such as lipopolysaccharides can stimulate prostaglandin and cytokine release, contributing to preterm labor and low birth weight..

Related Research

A study conducted by FKG UGM student Ichfan Aji Nugroho under the supervision of dr. Dyah Listyarifah, M.Sc., D.Med.Sci., drg. Asikin Nur, M.Kes., Ph.D., and drg. Heribertus Dedy Kusuma Y., M.Biotech., Ph.D., titled “The Relationship Between Periodontal Disease and the Risk of Severe Pneumonia in COVID-19 Patients”, showed that patients with periodontal disease had a higher risk of developing severe pneumonia due to SARS-CoV-2 infection. This was associated with increased systemic inflammatory burden and possible oral microbial colonization of the respiratory tract.
These findings reinforce the theory that oral microbes play an important role in modulating systemic immune responses and worsening the course of infectious respiratory diseases, including COVID-19.

Public Health and Clinical Implications

1. Prevention and oral health education should be integrated into public health strategies to reduce the risk of systemic diseases.
2. Interdisciplinary collaboration between dentists, general practitioners, and internal medicine specialists is essential in managing patients with chronic diseases.
3. Periodontal screening can serve as an additional indicator in assessing systemic disease risk, particularly in patients with a history of diabetes, cardiovascular disease, or immune disorders.

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Oral microbes play a significant role in influencing various systemic diseases through inflammatory, immunological, and infectious mechanisms. Research highlighting the link between periodontal disease and pneumonia in COVID-19 patients emphasizes the importance of maintaining oral and gingival health as an integral part of overall health.
Through interdisciplinary approaches, promotion of good oral hygiene, and increased public awareness, the risk of systemic complications related to oral microbes can be significantly reduced.

References
ICHFAN AJI NUGROHO, dr. Dyah Listyarifah, M.Sc., D.Med.Sci; drg. Asikin Nur, M.Kes., Ph.D.; drg. Heribertus Dedy Kusuma Y., M.Biotech., Ph.D., HUBUNGAN PENYAKIT PERIODONTAL TERHADAP RESIKO KEPARAHAN PNEUMONIA PADA PASIEN COVID-19, https://etd.repository.ugm.ac.id/penelitian/detail/212232

Author: Rizky B. Hendrawan | Photo: Freepik