Update on Oral Bacterial—What You Need to Know

Jamie J. Alexander on May 12, 2022

Bacteria that cause periodontal disease reduce the body’s defense against viruses.

Researchers from the University of Louisville School of Dentistry and their colleagues have discovered details of how proteins produced by oral epithelial cells protect humans against viruses entering the body through the mouth. They also found that oral bacteria can suppress the activity of these cells, increasing our vulnerability to infection.

Their report was released in December of 2021. In this report, they conclude that “a family of proteins known as interferon lambdas produced by epithelial cells in the mouth serve to protect humans from viral infection, but the oral bacteria Porphyromonas gingivalis (P. gingivalis) reduces the production and effectiveness of those important frontline defenders.”

Epithelial cells that compose our skin and the lining of our mouth and other hollow spaces of the body are a barrier between our internal cells and the dirt and microbes in our environment. But it has now been demonstrated that the bacterial species, P. gingivalis, which causes periodontal disease, can completely suppress interferon production and destroy the protective quality of the epithelial cells. 

The mouth is one of the primary gateways for viruses to enter the body and infect the gastrointestinal tract and lungs. Maintaining a healthy mouth is important in protecting us from such viruses as SARS-CoV-2, human immunodeficiency virus (HIV), herpes simplex, and cancer-causing viruses such as human papillomavirus (HPV).

Previous research has linked the common oral bacterium P. gingivalis to numerous other diseases, including Alzheimer’s disease and rheumatoid arthritis. Recent clinical studies have shown that immune suppression in patients with periodontitis can enhance susceptibility to HIV, herpes simplex and HPV.

“Understanding how oral bacteria interferes with interferon production, thereby suppressing our immune system, may help people understand the importance of regular dental cleanings and checkups. A healthy mouth, with minimal P. gingivalis, protects us from viruses as well as reduces systemic inflammation that is known to fuel a multitude of diseases conditions, including two very prevalent ones—diabetes and heart disease,” says Boynton Beach, Florida dentist Dr. Jamie Alexander.

Are there other types of oral bacteria that harm us?

There are three types of common oral bacteria that impact our health.

  1. The first is Porphyromonas gingivalis (P. gingivalis) discussed above. This bacterium grows in crevices of our gums and is a primary contributor to dental plaque and gum disease. It has been linked to Alzheimer’s disease and to rheumatoid arthritis.
  2. The second is Treponema denticola (T. denticola) is a bacterium that grows in the crevices of our gums and contributes to gum diseases, along with the bacterium P. gingivalis. <T. denticola bacteria can penetrate gingival tissues and circulate through blood vessels, with opportunity to invade the heart and cardiovascular epithelium in medium to large arteries – including aorta, coronary and carotid arteries. T. denticola is a factor in oral cancer because it encourages oncogenesis, the process by which healthy cells become cancer cells.
  3. The third is Streptococcus mutans (S. mutans). This bacterium is everywhere in our mouths and when it contacts sugar or sucrose-containing foods and beverages, it secretes an acid that is harmful to our teeth and causes dental decay.

Both P. gingivalis and T. denticola can survive in the mouth without oxygen and easily multiply in gum pockets around the base of each tooth. As they multiply, they cause gum inflammation, and if left untreated, they can attack the bone and connective tissue around the teeth, leading to loose teeth. Together, they produce toxins that disrupt the good bacteria in the mouth.

What is “good” bacteria in the mouth?

Gut bacteria like probiotics are good because they protect your mouth and overall health. Healthy mouth bacteria fight against germs that cause bad breath. They aid in digestion by starting the actual breakdown of the proteins and sugar in your food while it is in your mouth. And they have anti-inflammatory properties that help keep you safe from the bad bacteria that cause oral diseases.