Functions of Saliva

Saliva is secretory fluid secreted in oral cavity from salivary gland.
It consists of water, an electrolyte, viscous liquid, and various kinds of enzymes.
Saliva is usually secreted 1000-1.500 ml (around 700-800 ml at rest) a day.
99.5% of ingredients are water, and mineral matter and organic quality account for by remaining about half.
Saliva is known as digestive juice including β-amylase breaking down the starch.
Furthermore, it performs action such as protection and washing of the oral mucosa, the antibacterial organization restoration or excretion.
And it performs the prevention of caries by making intraoral pH neutral.

When we watch food in fasting hungry state and when chewed, saliva of the serosity with a little stickiness is secreted in large quantities, and the food is in this way is moistened.
By this it becomes easy to crush, facilitate the formation of the meal lump and to swallow.
It becomes easy to crush it by this and facilitates the formation and the deglutition of the meal lump.
Saliva tasting bitter is secreted in large quantities prior to vomiting.
It is perhaps a lot of saliva will make easy to exhaust vomiting stuff.

Main components of saliva and works

99.5% of saliva are occupied with water, and remaining 0.5% consist of organic matter and inorganic matters, and then 0.5% of components do various surprising action as follows.
It is thought that this is an first entrance taking in food necessary for human growth, maintenance, an increase of the health.
In other words, it make a toxic substance included in the food exclusion, non-toxicity while performing restoration of the oral tissue consistently and work so that the digestion and absorption that are an original purpose are carried out smoothly.

DigestionamylaseHydrolyzes glucide such as starch, amylose, the amylopectin and produces maltose and glucose.
maltaseHydrolyzes maltose into grape sugar.
lipaseParticipates in lipid metabolism.
AntibacterialysozymeBreak down bacterial cell wall.
histamineBlocks up the wound with antibacteria activity.
lactoferinCombines with a ferric ion, and ferric ion is an ingredient necessary for bacteria to grow, and the bacteria cannot live when these ions decrease.
peroxidaseRemoves active oxygen and decreases cancer-causing agent.
agglutininControls bacterial increase and defeats bacteria.
defensinAntimicrobe peptide with activity for bacteria, funguses, virus viroid.
immunoglobulinIgA, IgG, IgM
Restorationproline rich proteinWhen combined with calcium and hydroxyapatite; has a function of upbringing, healthy maintenance of tooth.
EGFIt prevents an inflammation of the oral mucosa and the ulcer of the gastrointestinal mucous membrane.
NGFIt promotes the growth of a ganglion and the nerve fiber.
WashingIt washes away food residue and a bacterial metabolism product. Because the saliva protein scrambles saliva, the washing action is promoted more and more.
Cushioningbicarbonate, phosphateIt neutralizes acid and keep a fixed pH and prevents bacterial occurring acid and acid food from dissolving a tooth.
ProtectionmucinThere is a humidity retention effect to prevent the drying of the mucous membrane and is able to protect an intraoral mucous membrane for stimulation from the outside such as the food.

Salivary gland

Salivary gland
Salivary gland is a gland secreting saliva of the animal, and the pipe opens in oral cavity.
It is classified in major salivary glands and minor salivary gland.
In addition, it is classified in three of serous gland and mucous gland, mixed gland by the property of the secretion.
The major salivary glands of the vertebrate have submandibular gland, sublingual gland, and mammals have parotid gland more.
The salivary gland is conntrolled by autonomic nerve, and, in other words, the doubleness of sympathetic nerve and the parasympathetic nerve is controlled.
Serous gland saliva is secreted with the parasympathetic nerve mucous saliva with the sympathetic nerve.


Change of the quantity of salivation in the day

The secretion of saliva has a difference between individuals, but increases and decreases with constant rhythm among the individuals.
There is much quantity of secretion of the submandibular gland at the time of awakening, and there is few it during sleep.
It is thought that the cause of the change of such a salivation is secretion rhythm of the salivary glands.

At the time of the night sleep, not only the activity of the sympathetic nerve becomes weak, but also the activity of the parasympathetic nerve becomes weak at the same time, too.
Therefore it is thought that the quantity of overall secretion decreases.


Change of the quantity of salivation in the year

In quantity of parotid secretion, a change in extremely characteristic age is accepted.
Winter has much quantity of secretion and decreases in summer.
And, in spring and autumn it shows middle quantity of secretion in winter and summer.
Such a change is regarded as reflection of the adjustment action of the internal fluid volume.



About cushioning

The secretion speed of saliva after rinsing a mouth with 100% orange juice, and having swallowed it
Soon after having drunk juice, salivae more than 10 times at rest flow.
Because acid entered, if this is serious, salivary glands react, and saliva appears.
The value that exceeded pH 7.0 a little before drinking juice, falls to pH 6 right after drinking juice.
It is thought that it does not fall down below than enamel critical pH even if we put a sour thing in a mouth.
Even the drink which considerably had low pH was shown that the tooth decalcification was prevented under the influence of saliva in this way.


Shigeru WATABE, DDS, PhD. J Health Care Dent. 2010, 12: 25-31

Detergency (dilution by salivation and swallowing)

The left figure illustrated the principle of the siphon.

When water reached the line of the mark<**>, it is exhausted to the hight of exit<*> at a stretch.
If water is stored again when water disappears to hight<*> once, and when it comes to the mark<**>, water is exhausted at a stretch again.

In our mouth, there is system of the exchange of the water such as this siphon and maintains the whole mouth clearly.
When the inside of the mouth becomes dirty, saliva is secreted and is swallowed after it reaches the quantity.
It is diluted by repeating this way many times endlessly.
Therefore, it is thought that the attenuant efficient person has good oral environment.

Why do you chew?

Saliva prevents a cancer

Hajime Nishioka : Former Professor at Doshisha Univ.

Professor Nishioka discovered that there was mutagenesis (carcinogenicity) in Okoge(burnt up food) which was produced when we grilled a fish or meat.
Furthermore, it was understood that there was a cancer-causing thing in many other food, drinks.
If "cancer-causing supplies are in the body, how will they react and change?"
At first, it is the first reaction to join with saliva in a mouth.
Here, how do they change?
As a result, it is revealed that the strength to cause mutagenesis to bacteria by a cancer-causing agent became small by being mixed in bacteria with saliva.


On study what kind of components of saliva removed the toxicity of the cancer-causing agent, I understood the following thing .

  • Peroxidase and the catalase of the enzyme included in saliva deleting the toxicity of the cancer-causing material.
  • There is the strong work that these enzymes remove harmful active oxygen.
    Many cancer-causing agents are included in an additive and a pesticide included in the food, the ingredient of the cigarette and produce a large quantity of active oxygen when these are in the body.
    The active oxygen hurts the most important gene (DNA) in the living bodies and causes various geriatric diseases including a cancer and causes an allergy and the aging again.

This "saliva power" was enough just to dip into saliva for approximately 30 seconds.

Then, why are there few people suffering from a cancer for an old person, and is there many abnormally in the present age?
The Japanese until before war did not know that a carcinogen was in the plants such as green tea or vegetables, but did antidote habitually by "chewing" that was told by ancestors (parents).

Saliva is made from blood.
It may be said that this saliva is a source of the natural healing power.

Person's nameThe frequency to chew
/one meal
The time required
/one meal
Himiko3,990 times51 minutes
Ieyasu Tokugawa1,465 times22 minutes
Prewar Japanese1,420 times22 minutes
Modern Japanese 620 times11 minutes

It passed until a war from Ieyasu more than approximately 300 years, but the number of times to chew does not have the big change.
However, in the short period of approximately 70 years after the war, it had changed to the food culture not to bite only half or less in comparison with Ieyasu.


As for the modern people, fast food, grilled food, a soft meal, the food of thick seasoning flood the public, and the custom to chew decreases more even if people does not chew food very well to be delicious, and to be able to eat it.
The chewing frequency of modern people is said to be 1/6 of Himiko's age, half or less in the prewar.

We declared that it was necessary to let the people chewed well and to secrete many saliva in order to show the many effect of saliva more.
Surprisingly, there was a person who had already recognized importance of chewing about 100 years ago.
The person is American clock dealer, Fletcher.


Fletcher was born in the United States at the mid-19th century.
He succeeded as a clock dealer and was active very much and he ate very much and drank very much.
However, the weight remained 88 kg at about 40 years old, 168cm tall, and the physical strength has become decline, an old man of the white hair.

Fletcher surprised that life insurance is stopped abandons all work, and started the life that is specialized in good self-care according to the instructions of the doctor, and visited the medical treatment place of the various places in Europe and America and walk, and tried various therapies, hunted for medical books and read.
However, he did not improve at all.
Besides, the weight became by nearly 100 kg.

From just a thing, in summer of 1897, he decided to leave how to choose, how to get, how to eat food to the demand of one's stomach in the opposite of the doctor of saying.
At first do not eat until a stomach becomes hungry.
Eat a thing to want to eat.
The thing which he put in a mouth decided to chew many times until it became muddy.
While he continued this method, he learned that he became very well-conditioned.
And four months later, weight became to 74 kg, girth of the abdomen became 94cm from 150cm, and he gained physical strength strangely.
He came to be able to work for the feeling that 20 years old became younger.

His mealtime was 35 minutes from 30 minutes, and chewing number of times was around 2,500 times, but one meal became enough on a day for him.
He put just a small quantity into a mouth to drink water and drink it after warming it until body temperature.
His weight became 71 kg in the fifth month, and approximately 58 kg in finally.

To here, it is like an exaggerated biography, but his physical strength is restored surprisingly, and it may be said that rather physical strength was increased.

In 1903 years, he became the subject of the study of Yale University physiology professor Russel Henry Chittenden for the proof of being a fact.
As a result, Chittenden realized a previous nutritional fault for surprising data and started new nutritional construction manfully.

Furthermore, after performing a physical fitness test of group of the Fletcher ism practice and the group of of the Fletcher ism non-practice, Professor Irving Fisher of the Yale University was able to confirm that the numerical value of the practice group was predominantly superior.

Reference  What is "From just a thing"?
It is William Gladstone who acted as the prime minister in the U.K. for four terms (1809-1898).
One day one newspaper reporter asked him a question at the Prime Minister's office. "In spite of 85 years old, why are you well?"
The answer was like that. "Heaven gave 32 teeth to us, therefore I always chew 32 times. I tell this to children, and let them kept it."

With just a thing, it is like this news of "32 times of chewing" of William Gladstone.

Chewing and the effect of saliva

Tsuneo Katayama

How do you tell a patient "why do you chew?" "why do I let you chew?"

It gives you improvement, it is a social reform.
Social health being provided for the first time by making an effort forward.
If a dentist, person offering medical treatment is sick, he/she is unhealthy.
If a person of medical side is not healthy, he cannot cure a sick person.
First at all a person of medical side must be healthy, mentally and socially .
Then I think that it is the duty of the doctor that it is insufficient to let a patient be able to chew, but a person of medical side must lead a patient be able to chew consistently in their lives.
It is the duty of the doctor, and it is your obligation to do so strictly.

"Nobles" usually means "a noble person, a noble", but in this case does not mean so.
In other words, not the meaning person having socially high position, it means, "know it well" in Latin.
The origin of a word of "know" is "Nobles".
It is the word that you know well therefor you must take responsibility.
You will do it practically.
Therefore you must have the proper(complete) thing toward oneself by all means.
Then you must begin absorption because you do not do waste and remain in effect.
Talk so that it is said that the thing becoming the cause to begin the absorption is that saliva always appears.

Noblesse oblige is a French phrase literally meaning "nobility obliges".
It denotes the concept that nobility extends beyond mere entitlements and requires the person who holds such status to fulfill social responsibilities, particularly in leadership roles.

So you let a patient chew well.
Even if you said a patient "chew", "chew", "chew", a patient is necessary to know why he should chew.
But this is does not appeal one more only because it makes periodontal membrane health.

So I tell that saliva flows by chewing.
When saliva does not flow, the digestion does not begin.
In other words a thing called the digestion took in nourishment from the outside and you bought it and ate and put it to take in a nice thing in a body.

Then you must begin absorption because you do not do waste and remain in effect.
If though you took it in, it becomes the feces directly, and this is useless at all.
Talk so that it is said that the thing becoming the cause to begin the absorption is that saliva always appears.

You must think about the way of the explanation how explain the circulation that absorption happens only after saliva flows.
It is the words that a patient understands enough and is plain, and explain it while using various Medea and does not waste time.

The speech like me is poor.
You must act as this in talking better.

This thinks that after all it is important to study speech as the methodology of one of one of the education.
Therefore I associate to a teacher engaged in education and think that it is very important to have him tell me in various ways.
It thinks that after all a teacher of the junior high school degree is good.

Junior high school and Elementary School is the most important and changes a little afterward.
In other words the teachers of a junior high school and the elementary school are better and know the thing called the way of the understanding because the direction that I check it by oneself and understand by oneself opens, and because such a thing begins when students enter the junior high school they look up the word in the dictionary, and in the high school they check it with a reference book, sum up in the report
It is an important thing to be taught by such people.

That means, you must receive the nice serious presents from an expert(teacher), but you don't go out to check-up when you become a school doctor or a school dentist.
It is such a spirit "Turn anything to profit"
Therefore I go to school to study with nature which I pick up an important thing, and to return if I go to school.
I think that this is the most important.
Though I thought to say so for a long time, I do not become yet good very much.

Where does saliva come out of? This question is the most plain.
As for this, there is a hole in a mouth inside; it is salivary gland.
Then it comes out. But what is it made from?
OK, it does not come out of a glass and is squeezed from body fluid, blood.
Then I am troubled when I do not supplement it immediately.
So this is a mistake when I drank tea with a bowl.

Because I drink tea, the absorption worsens.
In other words I squeeze saliva and swallow it.
While I swallow it, it becomes with a nutritious food and puts back body fluid.
This is absorption.

Therefore at first primarily I squeeze saliva even more and reduce body fluid even more.
Then I am going to take it in even more.
And power to digest for the first time comes.
So I do not just take saliva in which flowed this time.
I take it in as a thing including the nutritious food in saliva this time.
We have the function of enzyme in this process and have power to let digestive juice act chemically.
Therefore I explain that the back does not act if there is not the beginning.

Oh, how much has saliva been squeezed per day there?
It is about 1 sho, one bottle of sake , 1,500㎖.
Because 1 sho is 1,800㎖, 1,500㎖ is eight-tenth of bottle.
It is time of the meal that saliva is secreted most, and approximately 3 go if saliva is secreted per one meal if we do not eat between meals. (1 sho = 10 go)
Then the quantity is two cups and a half in a beer glass, and this is quantity as a stomach is baggy if I drink at once.
Because I swallow it, I can not eat an extra food.
In other words quantity to eat is saved.
If there is not it, I overeat even more.
Therefore it is eight-tenth of stomach naturally if I secrete saliva enough and swallow saliva.
I must secrete a lot of saliva to swallow a lot of saliva.
I must chew to secrete saliva.
Therefore I perform 50 times of chewing.
If I chew one mouthfull food 50 times and eat, I become stuffed.
Therefore you become stuffed, and it is in the state that you do not already need by all means if you chew well and eat even if it becomes half as for the quantity to eat.

When it is said how many times it becomes a custom if do it; it is 1,000 times.
At first I understand anything if I have of 1,000 times.
I say, "I do not say that I did it at all" and "do not talk" when not after you have done 1,000 times

Therefore it takes three years if it is once a day.
Because there are 365 days, it takes three years.
But we eat three times a day.
So how many times do you carry the food to your mouth during a meal?
If it is 50 times, It becomes 1,000 times in one week. 50 times(chewing) × 3 times(meal) × 7 days = 1050
Therefore, anyway, you do the 50 times of chewing surely for one week.
If you promise in whole family and did to chew well from Sunday to the night of Saturday only for one week, you will chew 50 times unconsciously.

Got it?
Therefore I attach a habit in that way.
In other words I begin with the digestion and absorption clearly, and there is amylase engaged in digestion in saliva this time.
About this acting on starch, you do not need to say even if you say.
It may say only that there is a digestive enzyme called amylase.

Because an enzyme is in saliva, I chew 50 times.
Because an enzyme is in saliva, I chew 50 times.
How many minutes does it take time to bite 50 times?
It takes 50 seconds if I chew slowly when I regard 1 time as one second.

There is a lot of a cancer-causing agent like a pesticide and an additive to show it neatly for a long time and the thing to coat not to wither up again.
A carcinogenic material enters in the body consistently.
It becomes non-toxicity.
Many carcinogens become the non-toxicity if they are mixed with saliva in a mouth for 30 seconds.

It is an opinion of Hajime Nishioka of Doshisha that lactoperoxydase working such is in saliva.
Oh, does he discover it?
Therefore Nishioka writes to the various places that "chew 30 seconds namely 30 times by all means".
It is only a dentist not to know and is troubled because a patient knows it.
Therefore I have a reliable talk.

Then if a patient wants to hear pyorrhea and gingivitis, I will explain that pyorrhea and gingivitis become sick by bacterial infection, but a thing called lysozyme is included in saliva, and when a strange thing entered into the mouth, the lysozyme that acts not to let you infect, has important power to prevent the disease is included in saliva.

Without that alone it will be said "The longer you chew, the more flavorsome it becomes" in various ways
In saliva, the component called a gastin that develops taste to be delicious and have power to remind you of taste when you chew anythug well and eats, is included.

Then I say that the other profits by the prevention of dental caries。
Dental caries is that a tooth dissolves and there be a hole.
The retroaction happens this time.
In other words at first the protein in saliva sticks to a tooth plane by saliva touching a tooth, and has been concentrated as a pellicle in it.
The condition called acquired pellicle is made.
Calcium in saliva sticks to the place where dissolved, and it becomes apatite and cures the dental caries from the surface.
It means that an enzyme called statherin which makes enamel apatite is included in saliva.

With this, I think that I talked about six components.
I talked about amylase, lysozyme, mucin, lactoperoxydase, gastin and statherin.
I think that you should talk this much.

Then it is the other.
This time I talk that it helps treatment and the recovery is early.
In other words I speak that the recovery of the organization damaged by periodontal disease in the mouth becomes very early by chewing well and saliva coming out.

I talk about the recovery being bad when you do not chew.

I talk that [though you come for treatment, it worsen for stimulation even more if I apply medicine].

You lack the power what repaired by oneself, and what all the healthy people have.

When it is said where the repaired power comes out, it come out from saliva.
Therefore the wound in the mouth will be cured than others early.
Or the dog licks the wound and will cure.
There is such power of saliva.
What kind of power this was?
It is epidermal gross factor that is founded by Stanley Cohen.
This is included in saliva and does not come out in the mouth even if created.
It is reabsorbed in the middle to come out in oral cavity; therefore this is a hormone.
Such a hormone is found.

The other.
It means that you become smart which I talked about yesterday.
This is a nerve.

Nerve growth factor.

It is N. G. F for short.
The component called nerve growth factor was found by the Italian woman.
Because she is one younger than me, I think that she will be 82 or 83 years old now.
It is the woman called Rita Levi-Montalcini.
She found it, and it was accepted clearly in a academic society

When did these two people get the Nobel Prize by this discovery?

Without a positive mistake……. 

Though I thought that it is wrote there, was it eight years ago?

When is it?

(a voice of Hirai: It is 1986)
This is correct..

There are two, and it enters the body as a hormone, and it is carried to the physical every corner by blood and gathers to the place with the wound and cures a wound.

Therefore the getting well of the wound is slow when there are few factor.

It is not cured.

Therefore it is to chew if you cure a gingival wound.
Going to extremes, it is not cured if you do not chew.
Therefore you let a patient chew well.
You should make him to chew 50 times.

To that end, it is the duty of the dentist to prevent you from having a pain.
It will be the power of saliva.
This is already certain from having been demonstrated clearly so as to get the Nobel Prize in 1986.
Therefore it means that it is not cured when a patient does not chew well.

Even if you say “rub” ”rub” by brush without letting him chew well, he turns up skin and do only worsen it without being the explanation about the function of saliva.

Therefore the dentist cures the place having a pain of the tooth to let him understand two work.
And it is the role of the dentist to say it, and is duty.
You master it to yourself tight.
You will have victory in your hand last.
It is such a thing.

From The 23th Katayama seminar/fourth day
1993. 6.13 (in Hakone)

The meal is life itself. Nanboku Mizuno

Der Menssch ist, was er isst.  Ludwig Feuerbach

The basics are to chew well and to be able to chew. Tsuneo Katayama

Oral flora

Because amplifications are different, the bacteria cannot compare the size

Streptococcus mutans

Actinomyces viscosus


Porphyromonas gingivalis

Tannerella forsythia

Treponema denticola

In oral flora, which bacteria will be said to be the pathogenic bacteria?

It is said that approximately 700 kinds of bacteria exist in the oral cavity, and that there are bacteria more than 100 million in 1 mg of plaque.

Mutans Streptococci or Lactobacillus such as S.mutans and S.sobrinus which I produce strong acid, and participate in the formation of the pathogenic biofilm deeply attract attention as caries cause of the disease bacteria.
In addition, A. viscosus is detected for the caries of the root surface, too, and the association attracts attention.

It had been said that as for the periodontal disease bacteria, many bacteria participated than caries, and the identification was difficult, but various bacterial etiologic factors became clear by recent remarkable results of research.

About 3 species of bacteria in periodontal disease bacteria, A.actinomycetemcomitans, P.gingivalis, T.forsythia, strong association became clear, and they were admitted as periodontal disease bacteria in world periodontal disease workshop in 1996 by various studies.
Afterwards, Socransky and others added T.denticola to P.gingivalis, T.forsythia and named 3 species of bacteria Red Complex (red inferiority complex), and classified them as the bacteria which are strongly related to periodontal disease.

Various oral bacterias

By the way, the fetus is revealed by the bacteria inhabiting the birth canal in the case of delivery, but bacteria of air and the outside world invade in oral cavity with delivery.
The intraoral microbe after the delivery is an aerobic bacterium and a facultative anaerobic bacterium.
However, obligate anaerobe comes to be detected when deciduous tooth grows.

There are many aerobic bacteria in the healthy oral cavity, but proteolysis due to the obligate anaerobe becomes strong when cleaning is insufficient and suffers from disease of oral cavity (bad breath).
When a tooth completely disappears, it becomes only the facultative anaerobic bacterium again, but obligate anaerobe comes to be recognized when person puts on a denture.
In this way, our oral cavity is the acquaintance with bacteria throughout until we die since we were born.

In addition, disease of oral cavity becomes rarely serious because a kind and the quantity of oral bacteria change by intraoral environment, and these a great variety of bacteria usually balance each other.

Prevotella intermedia

Streptococcus salivarius

Streptococcus mitis

Campylobacter rectus

Streptococcus sanguinis

Streptococcus mitior

Bacterionema matruchotii

Propionbacterium acnes

Treponema pallidum500
Treponema pallidum


Lactobacillus sp
Lactobacillus sp

Fusobacterium nucleatum




Oral bacteria of the periodontal disease patient

Bacteria in the plaque

Etiology of the disease of oral cavity

In a foregoing paragraph, I explained the main bacterial outline thought to be the pathogen of caries and periodontal disease.

And, vast time and labor have been spent more than the past 100 years to investigate the pathogen of these caries and periodontal diseases.
In other words, the study on cause of the caries began with chemical germ theory and changed in the lactic acid bacterium theory which had high acid-producing ability afterwards.
However, the then scholar was not able to prove the cariogenicity of the lactic acid bacterium by animal experiment.
Finally it leads to discovery of Streptococcus mutans which meets 4 principles of Koch.
Besides, several kinds of bacteria class including Streptococcus mutans which was well-known as a pathogen of cavity bacteria, attracts attention as a strong candidate of the pathogens of caries and periodontal disease, but none reaches the etiologic total picture elucidation.

Paradigm shift
Though the oral cavity is an entrance of many disease-causing germs, many disease-causing germs cannot colonize.
This is because disease-causing germs are removed because the indigenous bacterium is formed in oral cavity.
Therefore, most of infectious diseases of the oral cavity are caused by oral bacteria.
In addition, because the individual bacteria have weak pathogenicity, independent bacteria do not cause a disease, and mixed infection causes a disease and needs time before a symptom appears.
The existence of the intraoral indigenous bacterium more than 700 kinds becomes obstruction, and it is not easy to identify cause of the disease bacteria from these.
Possibility to show pathogenicity by collapsing with the constitution balance is usually suggested even if it is bacteria considered to be harmless.
It begins to be said that it is insufficient to handle with good or bad bacteria.

Because it is thought that bacteria of the having many kinds get twisted up complicatedly and develop an illness, it is thought that exhaustive analysis to grasp whole constitution and a change of the oral flora becomes required.

The oral mucosa reflects a state of immunity of whole body

Approximately 700 kinds of indigenous bacterium inhabit including unidentified bacteria In the oral cavity.
The main habitation part is biofilm formed in the gingival margin neighborhood that is dental plaque (following plaque).
The bacteria density is much higher than that of feces.
The plaque which is under management acts on oral environmental maintenance, and good symbiosis is kept with the host.
However, the abnormal increase of plaque by insufficient care develops into disease of oral cavity such as "chronic inflammation-related disease, periodontal disease" when the factors such as caries, aging or the drop of the living body defense ability increase.

Because oral infection is a typical endogenous mixed infectious disease and it shows chronic symptom, it may be extremely said that oral infection is the model which is interested in studying the interaction with the living body and symbiosis bacteria.
Whereas in the large intestine which is a main symbiosis part of enteral Flora, there are few intestinal bacteria at a mucous membrane epithelium and an opportunity to touch it directly because it is covered with the mucin layer thick, bacteria attach to a direct mucous membrane and tooth through a pellicle (acquisition film) of thickness 0.1-0.2μm consisting of the saliva ingredient mucin in the oral cavity.

The sensitized lymphocyte by bacteria antigen in oral cavity is detected from the peripheral blood of the whole body .
In addition, when intestinal mucosa is stimulated by oral bacteria, the sensitized lymphocyte moves under oral mucosa by a homing circulation course and produces an antibody.
As a result, the secretion type IgA antibody that is an antigen-specific is detected in salivary gland, and IgG is detected from gingival sulcular fluid.
This phenomenon shows, "the information of the oral cavity reaches the whole body, and the information of the whole body reaches the oral cavity".

The oral mucosa epithelium cell exposed to bacteria contact produces various antibacterial factors lively and always removes bacteria.
And it controls production of inflammatory cytokine and prevent inflammation of the mucous membrane.
Because bacteria always invaded, and slight inflammation might be caused in the oral mucosa, such device might develop.
In other words, the onset of oral infection means drop itself of the immunocompetence from head to foot.
In other words, the onset of oral infection means that the immunocompetence of the whole body declines itself.

Meaning of the whole body disease onset

Bacteria itself may cause the whole body disease caused by the oral infection lesion, but it is thought with the cause that a factor of the host side including the deterioration of the living body defense ability of the patient, and, the structural and functional disorder of the tissue of the host by the aging.

Phenomenons to show this definitely are that various disease of oral cavity and infectious diseases develop in chemotherapy and the radiotherapy of cancer.
A ulcer and dry mouth of the oral mucosa develop, and the immunity is accepted to deteriorate more by chemotherapy and radiotherapy.
As a result, infectious diseases such as candidiasis, a severe periodontal disease and the oral herpes are frequent by intraoral indigenous bacteria and virus.

However, inflammation of the organization is improved surely, and the symptom is relaxed by decreasing an intraoral number of bacteria by mouth care in these patients.

In other words the organ which can recognize definitely the power relations of the state of immunity of the whole body and indigenous bacteria is oral cavity.


EGF: Epidermal growth factor
NGF: Nerve growth factor

Saliva has a material promoting the growth of the epithelium called the EGF.
This EGF was discovered by Stanley Cohen in 1962 along with Rita Levi-Montalcini.

When they gave the extract which they got from the thing which ground submandibular gland to a newborn mouse day after day, the mouse became early that eyes opened and the tooth erupted.
This was the beginning of the discovery.

It was understood that this material brought the remarkable increase and cornification of the epithelium cell afterwards.
The action of the EGF is known to have various work as well as the growth of the epithelium cell now.
Because it is included a lot in mother's milk other than saliva, it is thought that it participates in the growth of the individual.

By discovery of this EGF and NGF, the Cohen and others won Nobel Prize for Physiology medicine in 1968.

Stanley Cohen 
Rita Levi-Montalcini

Intestinal Flora



There will be the person with the question why it is Intestinal Flora though it is the page of "Saliva".

In Homo sapiens, a newborn baby which was in a germfree state at the age of a fetus is revealed to be exposed from the bacteria of a birth canal and the outside world at the time of delivery.
Those bacteria attache to oral cavity and a nasal cavity, eyes, anus, every part including the urinary organ official not to mention skin and invades it.
And most suitable bacteria class in residence environment settle down and inclease, and becomes extinct at the place where it is hard to live in.
It is bacteria inhabiting the alimentary system organ that I metabolize the thing which Homo sapiens cannot digest, and produce various materials, and make a toxic substance no damage, and remove.
In addition, the Homo sapiens give bacteria feeds and residence environment.
Symbiosis meant relations of such an interdependence, but continued coevoluting to adapt itself to the environment that changed for hundreds-thousands of years since Homo sapiens appeared on the earth.
From the above, it is thought that enteral Flora and saliva namely Oral Flora commit for the same purpose although their habitation part are different.

The evolution of two or more species that interact closely with one another, with each species adapting to changes in the other.
We can consider the intestinal bacteria as one superorganic (superorganism) which accomplished coevolution with us.

In the intestines of a healthy person, the intestinal bacteria of 2 kilograms from 1.5 kilograms settle down in a good balance, is more than 400 kinds, and the total number of 100 trillion approximately.

Because it is said to be 60 trillion of the cell count constituting a human body, we know whether how many bacteria spread.
The state of the large intestine in particular is compared to a flower garden and is called "Intestinal Flora".
This Flora is right the state that bacteria are spread all in the intestines closely like a flower garden.

The main bacteria which constitute Intestinal Flora


Intestinal Flora metabolizes a undigested meal component of the Homo sapiens and supplies a human being with an amino acid, vitamins or a fatty acid.
Furthermore, it has various functions which are the detoxification of the harmful metabolism product and the biological defense barrier for a pathogen invading from the outside, including the differentiation induction of the intestinal epithelia.
The intestinal bacteria are existence that it is indispensable for us, and the intestinal bacteria are considered as one superorganism which accomplished coevolution with a human being in this way.

The intestinal bacteria are greatly classified in three

A change of the bacteria flora until the seventh day after birth


While a baby is in the interior of the womb of mother, the baby is in the germfree state that there are not other microbes basically.

The baby is infected by coming in contact with environment outside neighboring air, a human body, the mother's milk 3-4 hours after birth later.

A part of the microbe colonizes the body surface, the intraoral digestion jurisdiction, the intranasal urogenital apparatus and becomes the indigenous bacteria in the area.

A change of intestinal bacteria by the aging


The intestinal bacteria group changes with age.
The ratios of number of the bacteria of each generation are different, but the ratios of bad bacteria (harmful bacteria) increase when with aging.

The fetus is kept germfree in a mother's body.
When they are born and drink mother's milk, bifidus bacilli begin to multiply by milk sugar and galactooligosaccharide in mother's milk as a nourishment source.

It changes into the bacteria flora of adult when a baby begin to eat a baby food a weaning period later.
In the adults, a bifidus bacillus exists in the intestine at the share of the 10-20%.
Furthermore, when aging becomes progress, the elderly, the number of Bifidobacterium decreases more and more, and instead comfortable Lactobacillus or welchii (Clostridium perfringens) increase.

From Tomotari Mitsuoka "Intestinal Flora and Diet"


The diet that a human and an animal took in arrives at the upper small intestine such as the duodenums through a mouth, the esophagus, stomach, and it is sent out afterwards to large intestine, rectum while nutrition is absorbed by a host.
Therefore, a difference occurs to the nutrition included in the contents depends on a gastrointestinal place.
Furthermore, because in addition to that originally oxygen density sent into gastrointestinal tract is not high and intestinal bacteria inhabiting the upper intestinal tract use oxygen, the oxygen density in the intestinal tract decreases so as to advance to the lower part, and it is in almost completely anaerobic environment when it reaches the large intestine.
In this way, because nourishment and oxygen environment vary according to the part in the intestinal tract of the same host, the ratio and spieces if bacteria are different depending on the part.
Generally, there are few bacteria numbers at the small intestinal upper part, and the ratio that a facultative anaerobic bacteria performing both breathing and fermentation occupies is high, but numbers of bacteria increase as it fall down below, and obligate anaerobe suitable for the environment that there is not of oxygen becomes mainstream.


Rough explanation of the immune system

The work of immunity is comprised of very complicated structure.
The immune system distinguishes non-self from self, and the self does not attack itself and is a system removing non-self to give a self damage.
Furthermore, it memorizes the partner who attacked and changes attacking method depending on a partner.
These work is carried out automatically.
Furthermore, I memorize the partner whom I attacked and change striking force depending on a partner. These work is carried out automatically.
The immune system is classified roughly into natural immunity and acquired immunity (adaptive immunity) by difference in work.

Natural immunity
It is natural immunity to deal with the antigens such as a virus or disease-causing germs first, and the natural immunity is an internal standing self-defense system.
The right figure; IgM, IgG, lysozyme or macrophage, the NT cell included in saliva are main factor of the self-defense of the natural immunity system.


Acquired immunity
The acquired (adaptive) immunity is a system dealing with an antigen breaking through natural immunity, and we generally call it "immunity".
As for this, the characteristics of immunity that are the recognition of self and the non-self and the variety, the specificity, work to appear conspicuously.
The memory made from the first reply to specific pathogen of immunity brings a reply enhanced for the second encounter of the same pathogen.


Immune tolerance

Big characteristic of the intestinal tract immune system

  1. Remove the dangerous disease bacteria and virus
  2. Tolerant for the things such as safe food or intestinal bacteria (do not remove)

I spoke about 1. roughly, but the characteristic of 2. is important.
In other words, the antigen derived from food is digested almost and is disintegrated and loses allergenic (antigen) activity.
This system which it suppresses the reaction, and we can eat food in peace is oral immune tolerance.

Of course allergenic activity is left, and sensitive immunoreaction may happen, and this is so-called food allergy.
It means that oral immune tolerance mechanism does not act for every food in all people.

Why will the intestinal bacteria not be removed?
It shows that tolerance is established for the intestinal bacteria.
It recognizes self and non-self and attack the non-selves such as disease-causing germs, but it provided with a property not to attack things which are recognized as self.
This is the self-immune tolerance.

Today, it is well-known that people of the allergic predisposition increase, but it is said that the prevention and improvement suffer from the study and solution of intestinal flora .


It is reported that the oral immune tolerance was not derived when intestinal bacteria was removed in the experiment of the mouse.
About food allergy, it was thought that establishment of the sensitization for the cause food was an obstacle of the resistant acquisition by the oral ingestion mainly.
However, importance of the percutaneous sensitization in conjunction with the skin barrier functional disorder is pointed out recently.

Diet and evolution of immunity

The biological classification began to Aristotle, and Linnaeus made a modern classification system.
There is the taxonomic group which gathered up a vertebrate having a jaw called Gnathostomata in that.

As for the jaw, it is thought that an organ (gill arch) which ever supports gills develops, and it came to have work to gradually open and to close the mouth effectively, and to carry water to the gills.
In this way, the mouth became gradually big and wide, and became easy to catch game.
And it is thought that power is more necessary to open and close a mouth, and it became to a jaw at last.

Having this jaw or not has a very big influence on immune system.
In the eating habits, there are different between the living thing with the jaw and the living thing without the jaw.
It can eat various kinds of things by there being a jaw.
If kinds of the food increase, many microbes come to invade the body and will take a variety of antigens in the body.
It is thought that a living body protective system namely immune system was developed to be opposed to it, and a system producing an antibody was done.
It may be said that the precise and high system of the intestinal tract immunity is was completed necessarily from evolution and the variety of the eating habits.

In this way, the relations of the diet and the immunity are close and important problems.

Improving the dietary habits

Dietary guideline for health
It was a guidance "to eat with the goal of 30 foodstuffs of days" by the Ministry of Health and Welfare in 1985.
However, in the new dietary guideline that Ministry of Health, Labour and Welfare, Ministry of Agriculture, Forestry and Fisheries showed in 2000, it changed to the
 expression of "to combine various foodstuffs together" and “with the balance of the meal on the basis of staple food and the main dish".

It might be said that most nutrients exceeded 
daily required intake including energy in the family who took approximately 30 foodstuffs (calcium is apt to be short), and that it is thought about there being a lot of people who greatly lack an intake of the food though only this is the times when food is rich now.

Let's review traditional foods culture.

What we should pay attention to in a new dietary guideline is that words "to make use of food culture and a local product" were added.
In other words it is traditional foods and the culture which our ancestor ate and to review.
Distribution system did not develop in old days like now.

Because the people was able to eat only food produced in the area and the season, there could not be many at all edible foods per day.


Let's pay attention to saliva now

Jun Oki

The traditional dental treatments such as caries or periodontal disease and the treatment of restoration or prosthesis are important, but, the contribution to society of dentistry is limited.
It is necessary for dentistry in the future to watch relations of whole body and to shift to medical care to do mainly on the prevention more and supports the maintenance and the increase of the health of all nations, and it is necessary to contribute so that the nation can live a healthy life throughout the life.

We should pay attention to the saliva from now on.
From saliva, we have been able to already to measure the stress by the amylase measurement and digitize masticatory efficiency by a glucose conjugation in saliva by the chewing.

In future by performing meta genome analysis of the oral flora of saliva, it may come to be possible for the investigation of the cause of illness and intervention for the prevention and ME-BYO(non-illness) and meal instruction based on evidence.
It is necessary to gather feces for analysis of the intestinal flora, but there is an advantage to be able to easily perform in our clinics because we can gather oral flora from saliva.

In addition, by the progress of a technique and a measuring instrument of the meta genome analysis, it becomes much cheaper than the early days.
And the program of prevention appropriate for each individual may be made if we could analyze infant oral flora and could judge a risk degree of the disease.
The eating habits is culture from a process of the evolution and it had a big influence on Homo sapiens.
The eating habits are important elements about bacteria flora and genetic change.
The times when the instruction of the eating habits based on evidence have already come to there.
Which stage is the instruction of the eating habits carried out at?
Who performs it?
Of course it is a parent and is school education, but it should be necessary for a healthcare worker to be concerned.
Above all, I think so that the dentistry (stomatology) is most suitable among other things, because dentistry (stomatology) treats the oral organ which is an entrance of the food, and concernes with from the infants period to an elderly person for a long term.

At first it is necessary to bring up a researcher concerned with these in the dentistry world, and to establish evidence.
The cooperation with a clinician and a researcher and the people of the different field becomes more and more important, too.

Now the times is changing greatly.

Play a role as Oral Physician

Professor emeritus at Tokyo Dental College  Katsuji Okuda


In 2005, the writer introduced "The things which do not change and change" written in "The flower clock" of Shusaku Endo published by Bungei-shunju Corporation in 1990 to Japan Dental Association magazine in a commentary article titled "the intraoral biofilm about healthy failure".

The author who was well known for the name of Korian teacher wrote as follows.

"When suffer from diabetes, a problem happens to eyes and suffer from the disease of the tooth.
However, an oculist is a doctor, and the dentist is not a doctor.
The disease of the mouth affects various diseases.
A dentist should be a doctor in a fair meaning as well as oculist in the future.
And the dentist should study relations with an organ and the illness of the human body, too."

When Japanese-American Eugine Sekiguchi who was American Dental Association's chairperson visited our country, he spoke "the dentistry world should devote itself to the prevention and treatment of the disease of oral cavity, while repeating evidence contributing significantly to health promotion.

While the oral cavity was an entrance of illness, the importance has been missed, but, by epidemiology, clinical and fundamental researches, the relation of periodontal disease and the whole body disease is elucidated, and periodontal medicine is established, and it may be said that the dentist is demanded to acquire further medical knowledge.

Therefore, I emphasize that the dentist must value "a stance as Oral Physician” more than before.

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