Vol,3 What is saliva power?


Mr. Tanaka :
Next, I would like to ask you about your study into the relationship between saliva and periodontal disease.
I have heard you are using term, saliva power. Could you explain briefly this term for people who have never heard of it before?


Pr. Tsukinoki :
Yes, just saying saliva power may not give you a good idea.
But saliva actually has numerous effects; these effects and functions I express as saliva power.

So, what is saliva power specifically?

Saliva consists of water mostly, like 99.5% or 99%.
On the other hand, 0.5%~1% contains a variety of substances such as protein, metal ions, or enzymes.
Saliva includes this water and organic compounds, but the water acts as a cleaning role inside the mouth.
As you said, the bacteria increases during the night. The reason for that is the secretion of saliva basically stops while sleeping. It almost stops completely.

Due to this lack of saliva water in the mouth, it lowers the cleaning effects.
Bacteria can increase easily under these conditions. This is happening during the night.

In this way, saliva water components help self-cleaning, and it is a very important role.
And the organic compounds contain various substances such as metal and other beneficial materials. Many things are involved indeed. 

For example, a well-known enzyme called amylase works to sweeten rice in the mouth while chewing and help it digest. This is very famous substance.

There are other things too. You may have heard that saliva can fix the early stages of tooth decay or repair wounds in the mouth pretty quickly.
factors that help to fix wounds and regenerate the nerves, which is a highly functional substance.

And we cannot forget about antibacterial agents in saliva.

There are many kinds and numbers of antibacterial agents in mouth.
Many different active substances in saliva can kill bacteria, promote digesting, or even repair wounds, and so saliva definitely helps in maintaining oral well-being, but we are getting to understand saliva plays a big role in general health too.

That is why I focus on saliva and suggest the strengthening of saliva power.

Mr. Tanaka :
Thank you very much.
Your story made clear that saliva is very effective to maintain good oral health.
From here, I would like to ask you some more details about oral hygiene and immunity, and also about the effect of saliva and mucosa on the throat.  
The mouth is the entry point for outside air to get into the body. Deep side of the mouth, mucosa on the throat and at the base of the trachea, helps to fight harmful germs and viruses and drive them out of the body.

What is saliva’s role against germs and virus?

Pr. Tsukinoki :
Saliva helps self-cleaning, as I mentioned earlier, by washing the inside of the mouth by itself. That leads to germs and viruses being washed away.

I said before that antibacterial agents are in saliva. These excellent agents can attach to the germs and virus in the mouth. Especially, a lot of antibody agents, called IgA, are contained in saliva.

These salivary IgA antibodies attach to germs and virus, and prevent them from reaching the mucosa.

We know these forementioned mechanisms enhance the immune system response by thus preventing harmful germs and viruses from reaching the mucosa and allowing saliva to wash them away.

We can say that saliva significantly acts as a protection against infection.

Mr. Tanaka :
Thank you very much.
I understood how saliva works.
I would like to ask about some diseases and how their conditions relate to saliva.
There is a high mortality rate with pneumonia in the elderly.

Do you think the correct oral care can lower the risk of progression or reduce the incident rate?

Pr. Tsukinoki :
Yes, pneumonia, and especially aspiration pneumonia, are serious problems.
Aspiration or dysphagia happens when you swallow something in the mouth and it enters your airway.
This goes down to the trachea and develops pneumonia.
If your mouth is clean, there is less bacteria.
This reduces the risk of aspiration pneumonia.

I don’t think it’s well-known, but cleaning one’s mouth before a surgery is covered in the national fee schedule for medical service in Japan.
There is a clear reason for that. For example, the surgery may require an endotracheal.
If you proceed without cleaning the mouth, debris from in mouth may be carried on and further the risk of pnuemonia after the surgery.

Patients with a clean oral condition are able to shorten their hospitalization after surgery.
It is critical to note that something may go down to trachea from mouth. 

We have to keep this fact in our mind. And in addition to the oral hygiene issue, we also need to be aware that the elderly who have often have trouble swallowing are more easily prone to develop dysphagia.

In this case, maintain good oral hygiene becomes even more important.
As one of the top causes of mortality is pneumonia, especially aspiration pneumonia, so oral hygiene, especially for elderly, is an essential concern.     

Mr. Tanaka :
Thank you very much.
I would like to ask if saliva power can be affective against this novel coronavirus, from a preventive perspective.

Are there any new studies examining the elements of saliva in relation to coronavirus infection rates, or any notable discovery on odontology?

Pr. Tsukinoki :
This novel coronavirus has become not only a national concern but a global public health crisis, with no certain prospect of when it can be contained.

We dentists take very seriously the need for a careful and hygienic approach to protect against coronavirus transmission.

Our laboratory has immediately started a study for the novel coronavirus and has already published an article.

The novel coronavirus, as with some other similar viruses, attaches to a certain receptor in the body. In other words, unless the virus attaches to the receptor the disease will not develop.

And there is also another substance for viral entry that propels the attached virus further into the body.
This is called a protease. 


So, both receptors for the virus and proteases play an integral role in processing the disease. 
Our study showed that high amounts of this receptor and protease are found in the periodontal pockets where the main inflammation occurs in periodontal disease.

This means there is a risk that the coronavirus can spread from gums.

As we see, severe cases often develop pneumonia and sometimes can be fatal. It is also clear now that persons with underlying medial conditions like diabetes, chronic respiratory disease, are at higher risk of severe infection.

As I mentioned earlier, both the receptors and proteases help the virus to enter the body.

We now know that these high-risk patients can easily be infected by the virus via those receptors and proteases, resulting in a more severe progression of the disease.

So, we should keep in our mind that our gums are a possible route for the novel coronavirus transmission.

Also we can see the same condition on the tongue. We can find substances that link to viral invasion on the surface of the tongue. 

So, oral hygiene could be a key factor for the prevention of the novel coronavirus disease, we are thinking it reduces the risk of the disease at least.

In cases of influenza, keeping good oral health is known to reduce the risk of infection at least as much as one tenth.  Influenzas are also initiated by receptors and proteases. So, we can say the mechanisms of the novel coronavirus are the same as influenza’s, both possessing these two triggers.

When we consider these prior studies of influenzas and the oral conditions of receptors and proteases, we think oral care can effectively help to prevent coronavirus transmission.

Mr. Tanaka :
Thank you very much.

Wakka ワッカ