When waking up in the morning, many of us yearn for that first cup of coffee, not only for the caffeine kickstart, but also to tame the worst of the morning breath. Contributing to the foul taste in your mouth, no doubt, were the activities of more than 700 species of microorganisms in your oral cavity.
Microorganisms in the mouth?
Sharing our body space are microbes more or less equal to the number of cells in the body. This vast community of microorganisms that are resident in the body is called the microbiome. The human microbiome consists of a core microbiome that is common to all individuals, and a variable microbiome that is unique to individuals, depending on physiological differences and lifestyle. The second largest microbial community in the body, after the gut, resides in the oral cavity and is called the oral microbiome.
The oral microbiome is established soon after birth. While the womb of the fetus is usually sterile, the baby comes in contact with microorganisms at birth and colonization begins shortly after birth. The mouth, in particular, comes in contact with microorganisms from the first feeding onwards, starting the process of a resident oral microbiome. Eruption of the baby’s teeth establish more surfaces for colonization. The accumulation of plaque at different sites on the tooth results in even more different microbial colonies to be established. Bacteria not only adhere to oral surfaces, but also to each other. Interestingly, when all the teeth are lost due to aging, the oral microbiome becomes similar to that in a child before tooth eruption.
Although the gut contains the largest community of microorganisms, the oral microbiome ranks first in terms of bacterial diversity and to date 775 microbial species have been identified, as listed on the Human Oral Microbiome Database. Oral microorganisms include bacteria, archaea, fungi, protozoa, and viruses.
The oral microbiome has two types of surfaces on which microbes can colonize, namely the hard surfaces of the teeth, and the soft surface of the mucous membrane (called the oral mucosa) that lines the soft structures within the oral cavity, such as the tongue, cheeks, tonsils, lips, throat, hard palate, soft palate, and the little ridge where the teeth meet the gums (called the gingival sulcus), all of which are microbial habitats.
These surfaces provide a rich environment in which microorganisms can flourish, as the conditions are favourable, such as a fairly constant temperature of 37°C without significant changes, and saliva with a stable pH of 6,5-7, which is a favourable pH for most species of microorganisms.
Health effects of the oral microbiome:
The microorganisms in the oral cavity exist in a symbiotic relationship, which is based on mutual benefits. This community of microorganisms do not cause harm to the host and in fact plays a protective role by not allowing pathogenic species to adhere to the mucosa. These species only become pathogenic and cause infection and disease after they manage to breach the barrier formed by the normal harmless microorganisms in the mouth.
What happens in the oral microbiome, however, does not stay in the oral microbiome. Normally the oral microbes and the cells in the body are in perfect dynamic balance and create an environment that supports overall health, especially inflammation. Inflammatory conditions in the oral cavity, for example gum disease, cause changes to the oral microbiome and have been linked to inflammatory conditions elsewhere in the body, for example inflammatory bowel disease and even bowel cancer.
The majority of these oral bacteria live on the tongue, of which the back part may also carry the specific bacteria (periodontal pathogen bacteria) that cause gum disease. (One of the reasons why daily tongue scraping is such an important part of oral hygiene.) Studies have indicated that oral dysbiosis, which refers to an imbalance of microbial species due to a reduction in microbial diversity, can result in compounds that can alter the immune system and trigger inflammatory response.
Oral pathogens, which refer to organisms that cause disease to their host, can migrate from the tongue to the saliva and then to the gut. Pathogens can also migrate to the bloodstream through inflamed oral tissue, allowing bacteria or their toxins to enter the bloodstream, which can contribute to the onset of various inflammatory linked degenerative conditions, such as rheumatoid arthritis, atherosclerosis, heart disease, chronic periodontitis, colorectal cancer, and even Alzheimer’s disease.
Studies have indicated that a balanced oral microbiome helps to prevent inflammation not only in the mouth, but also in other parts of the body.
Dysbiosis of the oral microbiome can induce various oral infectious diseases, such as caries (tooth decay), periodontal (gum) disease, and oral candidiasis (infection caused by a group of yeasts called Candida). Oral diseases are not caused by a single pathogen, but by microbial dysbiosis. Despite studies in this regard, with different findings, the exact nature of oral dysbiosis remains unclear.
Keeping the oral microbiome in balance:
The connection between dysbiosis in oral microorganisms and various health conditions highlights the importance of comprehensive oral care. By maintaining good oral hygiene practices, one can potentially reduce the risk of developing various degenerative conditions.
There are a number of scientifically proven ways to prevent and manage dysbiosis of the oral microbiome.
- Good oral hygiene practices, such as regular brushing, regular flossing, and dental check-ups, as well as dental cleanings. Equally important is monitoring of the tongue’s coating. A study has shown that wiping accurately from the rear of the tongue to the front is more effective at reducing bad breath and tongue coating than the tool itself, whether it is a toothbrush or a tongue scraper, or even a combination of the two.
- Healthy lifestyle factors help to maintain a balanced oral microbiome, such as following a healthy diet, quitting smoking, and managing stress.
- In the event of dysbiosis, such as halitosis (bad smelling breath), specific oral probiotics, alongside tongue brushing, may help to maintain a healthy balance of the oral microbiome.
Conclusions:
The oral microbiome is a complex organism, which is acquired from birth and is influenced by genetic, environmental, and lifestyle factors. It forms an ecosystem that helps to maintain health in a state of equilibrium and is crucial to health. Imbalances can allow pathogens to cause disruption in the form of dysbiosis, causing both oral and other health problems. Good oral hygiene practices contribute to maintaining a state of equilibrium, also contributing to fresh breath. Except for first thing in the morning.
References:
The oral microbiome; A double face in health and disease. Published 12 June 2024. Gut Microbiota for Health. European Society of Neurogastroenterology & Motility. (www.gutmicrobiotaforhealth.com)
The oral microbiota: Community composition, influencing factors, pathogenesis, and interventions. Published 29 April 2022 in the journal Frontiers in Microbiology. Vol 13, 2022. (www.frontiersin.org)
Oral microbiota: A major player in the diagnosis of systemic diseases. Published 30 July 2021. MDPI. (Scholarly, open access publishing.) (www.mdpi.com)
Oral microbiome: Unveiling the fundamentals. Published in Journal of Oral and Maxillofacial Pathology. 2019 Jan-Apr 23 (1). National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
The effect of mechanical tongue cleaning on oral malodor and tongue coating. Published January 2022 in International Journal of Environmental Research and Public Health. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
HEALTH INSIGHT
September 2024