Brush it real good!

December 20th, 2022

Written by: Vanessa Sanchez

Do you brush your teeth? Floss? You were probably taught to do so twice a day and were told it is because brushing and flossing prevents cavities. Plus, who doesn’t love fresh breath! But brushing your teeth doesn’t just prevent cavities. It also helps keep your brain healthy.

What is an oral microbiome?

Your oral/dental hygiene regime is important for maintaining your oral microbiome. Just like your gut microbiome, your oral microbiome is home to a community of 700 different types of bacteria in your mouth1. Normally, these types of bacteria are found everywhere in your mouth from the surfaces of your teeth to your tongue, cheeks, and lips1. Because your mouth is the first point of digestion, it plays the important role of maintaining your oral microbiome (to prevent cavities) and overall, systemic health (the entire body)1.

What happens if your oral microbiome is not maintained?

If your oral microbiome is not maintained, then bacteria can grow out of control, which could lead to cavities, bad breath, and even gum disease (periodontitis)2. In serious cases, the bacteria can spread throughout your body and infect your cardiovascular, digestive, immune, and nervous system3.

Oral microbiome and the brain

In 2020, a group of scientists reviewed a plethora of papers and tried to examine if there is a link between the oral microbiome and neurological disorders. Surprisingly, they found a link between poor oral microbiome health and at least four neurological disorders: Alzheimer’s disease, autism spectrum disorder, Down’s syndrome, and bipolar disorder4. The relationship between the oral microbiome and brain health is an entirely new but exciting field of research that scientists are just beginning to understand and explore, especially how your oral microbiome can directly lead to a neurological disorder and how to develop novel treatments for these disorders.

If your oral microbiome is not maintained, can it be fatal?

Unfortunately, yes. A study published this year reported that the bacteria known to cause oral infections may be a major contributing factor to life threatening brain abscesses, pus-filled swellings in the brain5-6. The link between bacteria and brain abscesses is like having a cut on your finger. If your cut is not protected, then bacteria will get in, and you will get a white abscess that will swell. In the case of your brain, the abscesses can lead to neuron (brain cells) damage and death (Figure 1).

Figure 1. Schematic diagram depicting link between oral microbiome (blue bacteria) and section of a human brain with an abscess (red inflammation). Created with

Oral bacteria and brain abscesses

While brain abscesses are extremely rare, about 1 in 100,000 people can get one1. Patients with brain abscess experiences symptoms like seizures, headaches, muscle weakness, and even paralysis2. Fortunately, a brain abscess can be treated with antibiotics or surgery1,6. When doctors surgically remove a brain abscess, they find that they are typically accompanied by bacteria that is believed to get into the brain through the bloodstream6,8. However, when scientists examine brain abscesses and their bacterial counterparts, sometimes they cannot pinpoint where in the body the bacteria could be coming from. The study published this year found that out of 87 patients, 52 patients for which there was no direct cause of their abscess were 3 times as likely to have the bacteria (Streptococcus anginosu)known to cause oral infectionsin their brain abscess1,6,9. In another study, scientists found two additional types of oral/dental bacteria (Fusobacterium and Streptococcus anginosu) in brain abscesses removed from patients10.

These two studies further support a direct link between our oral microbiome to potentially fatal brain abscesses. Perhaps, you will consider trying to boost the good and helpful bacteria for your oral microbiome by doing things like cutting back on sugar, eating more plant-based foods, and incorporating a strict oral regime and a regular visit to the dentist2. A lot of scientists have focused their work into the gut-brain axis, hopefully this study will inspire more studies into the field of the oral-brain axis. Stay tuned!


  1. Deo, P. N., & Deshmukh, R. (2019). Oral microbiome: Unveiling the fundamentals. Journal of oral and maxillofacial pathology: JOMFP, 23(1), 122.
  2. Oral microbiome: What it is & how it impacts your health. Rejuvenation Dentistry. (2022, March 13). Retrieved December 12, 2022, from,can%20get%20out%20of%20control.
  3. Maitre, Y., Micheneau, P., Delpierre, A., Mahalli, R., Guerin, M., Amador, G., & Denis, F. (2020). Did the brain and oral microbiota talk to each other? A review of the literature. Journal of Clinical Medicine, 9(12), 3876.
  4. Willis, J. R., & Gabaldón, T. (2020). The human oral microbiome in health and disease: from sequences to ecosystems. Microorganisms, 8(2), 308.
  5. NHS. (2022, October 18). Brain abscess. NHS choices. Retrieved December 11, 2022, from
  6. Roy, H., Bescos, R., McColl, E., Rehman, U., Cray, E., Belfield, L. A., … & Brookes, Z. (2022). Oral microbes and the formation of cerebral abscesses: a single-centre retrospective study. Journal of Dentistry, 104366.
  7. Brouwer, M. C., Coutinho, J. M., & van de Beek, D. (2014). Clinical characteristics and outcome of brain abscess: systematic review and meta-analysis. Neurology, 82(9), 806-813.
  8. Kong, W., Lan, F., Awan, U. F., Qing, H., & Ni, J. (2021). The oral-gut-brain AXIS: the influence of microbes in Alzheimer’s disease. Frontiers in Cellular Neuroscience15, 633735.
  9. University of Plymouth. (2022, December 7). Study identifies potential link between oral bacteria and brain abscesses. ScienceDaily. Retrieved December 11, 2022 from
  10. Andersen, C., Bergholt, B., Ridderberg, W., & Nørskov-Lauritsen, N. (2022). Culture on Selective Media and Amplicon-Based Sequencing of 16S rRNA from Spontaneous Brain Abscess—the View from the Diagnostic Laboratory. Microbiology Spectrum, 10(2), e02407-21.

Original photo by Sane Sodbayar on Unsplash.

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