After the gut, the human oral cavity has the second largest and diverse microbiota, (also called microbiome or microflora), harboring over 700 species of bacteria. The numerous microorganisms, which thrive in the mouth, include bacteria, fungi, viruses, and protozoa. The mouth is an exceptionally complex habitat, where microorganisms colonize the hard surfaces of the teeth and the soft tissues of the oral mucosa. The oral niches, which form their habitat, include the gingival sulcus, the tongue, the cheek, the hard and soft palates, the floor of the mouth, the throat, the saliva, and the teeth.
The function of oral microbiota –
In general, the promotion of health or progression toward disease is critically influenced by the microbiota. The majority of the oral microbes are commensal organisms. The oral microbes usually exist in the form of a biofilm in the mouth. Biofilms that contain pathogens are challenging to control. Biofilms are dense micro-communities that grow on inert surfaces. Some organisms that may exist in biofilms can adapt to environmental changes, which can make them resistant to disinfectant agents or antibiotics. Such biofilms can pose serious health issues.
The oral ecosystem comprises the oral microbiota, the different anatomic niches of the oral cavity, and its bathing fluid, i.e., saliva. It is crucial to maintain a state of equilibrium in the oral ecosystem. When the finely-tuned equilibrium in the oral ecosystem is disrupted, it allows disease-promoting bacteria to flourish and cause conditions such as caries, gingivitis, and periodontitis.
The condition of disruption of the equilibrium of the oral ecosystem is called dysbiosis. The modifiable factors that influence oral dysbiosis include changes in the flow and/or the composition of saliva, poor oral hygiene, gingival inflammation, and lifestyle choices, including dietary habits and smoking. Therefore, promoting a balanced microbiota is important to effectively maintain or restore oral health.
How to maintain healthy oral microbiota –
The following practices will maintain the healthy oral microbiota if observed regularly:
- It is important to regularly clean the dental plaque from your teeth by brushing twice a day. Flossing is important too because it removes dental plaque hiding between the teeth.
- Antimicrobial mouth rinses are not required unless recommended by your dentist. They will kill the bacteria that might be important for your oral health.
- Reduce the total amount of sugar a day that you eat. This reduces the availability of simple sugars that oral bacteria can turn into an acid, which in turn may help support a healthy oral microbiota and protect your teeth from decay.
- Diabetics should keep their blood sugar levels under control because diabetes causes periodontal inflammation, thereby increasing periodontal disease, a major cause of tooth loss. It has been reported that diabetes increases the pathogenicity of the oral microbiota.
- Eating a varied and healthy diet is also crucial for your oral microbial communities. It has been found that around 88 percent of adults do not eat the recommended five servings of vegetables a day, whereas 30 percent eat one or less serve a day. So the health of our oral microbiota depends largely on what we eat.
Role of saliva in promoting oral microbiota -
The role of saliva in promoting oral health is well established. In addition to facilitating mastication, swallowing, and speech, and aiding digestion, saliva contains vital enzymes and proteins that help maintain a balanced microbiota.
Saliva plays a major role in determining the composition and activity of the oral microbiota, via a variety of mechanisms as below:
- Saliva, form a conditioning film on oral surfaces, thus providing receptors for bacterial attachment. The attached cells use salivary glycoproteins, as their main source of nutrients for growth. Oral bacteria work sequentially and in a concerted manner to catabolize these structurally complex molecules.
- Saliva also maintains the pH in the biofilm to neutral, which is conducive to the growth of many oral bacteria that provide important benefits to the host.
- The adaptive and innate host defenses are delivered by saliva. They often function synergistically, and at sub-lethal concentrations, so a complex relationship develops between the host and the resident microbiota.
- Dysbiosis can occur rapidly if the flow or the composition of saliva is disturbed.
- Another salivary component with antimicrobial potential is nitrite, converted from dietary nitrates by oral bacteria. Nitrite is further reduced to nitric oxide that can inhibit the growth of cariogenic bacteria and, therefore, may help to protect against caries.
The bottom line –
The oral microbiota forms an important part of the human microbiota. It has a crucial function to protect against colonization of extrinsic bacteria, which could affect oral or systemic health. There exists a sensitive oral ecosystem, which can turn out of balance, thereby becoming a challenge to our health. Therefore, we should not allow the sensitive oral ecosystem to get disrupted. There are many factors that we can control to avoid disruptions.