YOUR 
TEETH 
JI Study in 
Oruj Hygiene 
W. M. WELCH MANUFACTURING COMPANY, 1516 ORLEANS STREET, CHICAGO, ILL., U.S.A YOUR 
TEETH 
A Study in 
Oral Hygiene 
By : 
R. S. TOWNE, D. D. S 
m 
Published by 
W. M. Welch Manufacturing, Company 
1516 Orleans Street, Chicago, Ill., U. S. A. Copyrighted 1922 
R. S. Towne 
All Rights Reserved This book is dedicated to the Boys and Girls of 
America. If, by a careful study of its pages, they 
are helped just a Jittle, I shall be very proud. CONTENTS 
Page 
Chapter 1. Nutrition 1 
Chapter 2. Description of the Dental Tissues 9 
Chapter 3. Diseases of the Dental Tissues . 18 
Chapter 4. The Home Care of the Mouth . 29 PREFACE 
The question of Oral Hygiene is attracting more 
and more public attention. 
Facts which have become known during the last 
few years go to show that the health of a person is 
greatly influenced by the hygienic condition of the 
mouth. 
Physicians and dentists realize as never before that 
many diseases of the body have their beginning in 
infections coming from diseased teeth. 
Reports of the examination of school children 
throughout the United States show that nine out of 
every ten people have defective teeth or unclean 
mouths. 
The problem of overcoming this condition is receiv- 
ing much serious thought and attention. 
Doctors who have studied the question a great 
deal say that a large part of the trouble is unneces- 
sary and preventable. They agree that the solution 
lies along the road of education. 
In order for people to be able to safeguard them- 
selves'they should have some knowledge of the mouth 
and teeth. One should know how the teeth are 
formed and how they are lost. They should under- 
stand something of the gum tissue and the tissues 
which hold the teeth in position in the jaw. Aside from these important matters, a study of 
Oral Hygiene should include a careful consideration 
of nutrition and recreation. 
People without experience would not think of 
making even the simplest adjustment on their motor 
car without carefully studying the book of instruc- 
tions. 
Why not a book of instruction for the home care 
of the mouth? It is the intention of this book to 
place within the reach of every one a few simple 
truths which, if intelligently applied, should help in 
solving this problem of mouth hygiene. 
This book was intended primarily as a text book 
for use in the public schools of the state, but it might 
well have a place in every household. The need of 
such a book has been apparent to the author in teach- 
ing Oral Hygiene in hospital training schools for 
nurses. 
Some of the technical terms used throughout this 
book may seem new and strange; the object of using 
them was to make the book more explicit. 
The chapter on Nutrition was written by Dr. Fanny 
Dunn Quain, who has been a careful student of 
public health. We are indeed grateful to Dr. Quain 
for her enthusiastic cooperation and many helpful 
suggestions. 
I wish to thank the members of the Oral Hygiene 
Committee for their encouragement and support. 
I wish to especially thank Miss Josephine Welch, the talented young artist, who helped with the illus- 
trations. 
To Roy Horner, a Bismarck school boy, age 16, 
is due the credit for the many excellent sketches and 
drawings. This young man, with no art training or 
instruction, executed practically every illustration in 
the book. His work deserves much credit and he has 
our best wishes. 
It is greatly to the credit of Miss Minnie J. Nielsen, 
State Superintendent of Public Instruction, that North 
Dakota is the first state in the Union to introduce 
Oral Hygiene in the public school as a regular course 
of study. 
I claim no originality for many of the facts pre- 
sented. So many men in medicine and dentistry 
have contributed to the fund of knowledge from 
which such books as this originate that it would be 
impossible to mention all of their names. However, 
I feel that the book would not be complete without 
a tribute to Drs. A. C. Fones of Bridgeport, Conn., 
F. A. Bricker of Rochester, Minn., and C. N. Johnson 
of Chicago. 
Dr. Johnson has been especially helpful in reading 
the proof and in making certain valuable suggestions. 
R. S. T. CHAPTER I 
NUTRITION 
"A Strong Mind In A Strong Body" should be the 
slogan of every boy and girl in America. Try to think 
of your body as your bank. Your greatest bank cap- 
ital is your health. If you are a good manager your 
bank will be of service to you for many years. Long 
life and simple life go hand in hand. A simple life 
means a life of regular hours for work or exercise; 
regular hours for sleep or rest, and regular hours for 
Figure 1 
meals. The work and rest should be in the fresh air 
Page One as much as possible, and the meals should consist of 
plain wholesome food. If it is not possible to get out 
into the big outdoors to rest, allow the windows to 
be opened and let the big outdoors in. Sleep in a 
room where there is plenty of fresh air (See Fig. 1 ). 
Wholesome food means simple food, food that 
has not been changed by the refining processes 
of machinery. Wheat is a wholesome food when it 
is ground and used before it is refined into white 
flour. Rice is a wholesome food before it is polished. 
Potatoes are wholesome food when they are cooked 
Figure 2 
with the skin on them, and clean milk cannot be 
improved as a wholesome food. 
Page Two You are your own banker. Your nerves are your 
messenger boys and the blood stream is your cashier. 
The messenger boys 
report what parts of 
the body have been 
drawn on during the 
day. At night, while 
you rest, the cashier 
replaces whatever 
has been taken away 
and balances the ac- 
count, ready to start 
again the next morn- 
ing. Your deposits 
and credits are carefully recorded as in Fig. 4. Il 
Figure 3 
the cashier does not need to use all material for re 
Figure 4 
Page Three placing he puts the surplus into your savings account 
or reserve. This savings account can be drawn on 
Figure 5 
when you are sick or during old age. It is very 
important to give the cashier plenty of time to put 
back all that has been drawn out during the day. 
The best way to balance the account and put a little 
reserve into the savings account is to sleep ten hours 
each night. The cashier is a faithful worker and will 
keep the bank in good order if the blood stream is 
properly supplied with material which is good for 
Page Four replacing the losses and storing in the reserve. Food 
supplies the blood stream with these materials. Foods 
are divided into four classes: Tissue builders, heat 
producers, energy and reserve producers, and salts. 
A mixed diet of 
milk, eggs, vege- 
tables and fruits will 
furnish these foods 
to the blood stream. 
A mixed diet is best 
because it furnishes 
the right amount of 
each material. Too 
much of any one 
material makes it 
hard for the cashier 
to take care of it- 
for example: An 
over supply of heat- 
producing food 
causes the cashier to 
store away too much 
fat. 
The farm is the mint which supplies funds for the 
bank. The different departments of the farm furnish 
the wholesome foods. These foods are the currency 
for the bank. The department of the mint which 
sometimes fails, because of drouth or lack of care, is 
the garden where the vegetables are grown. The 
Figure 6 
Page Five energy and reserve producing foods, such as beans, 
Figure 7 
peas, carrots, cabbage and tomatoes, are very neces- 
sary to the growth and development of the bank. To 
insure a mixed diet to the youth of America it is 
necessary to encourage all branches of farm work. 
The mint will then have plenty of food stuffs to feed 
the bank. 
The mouth is the receiving window for the bank. 
There are twenty to thirty-two guards to this window. 
These guards are the teeth. It is their business to 
properly prepare material which is furnished by the 
mint for the bank. There are many enemies of the 
bank. Among these enemies are the germs of disease. 
Sometimes they stay in the mouth a long time waiting 
for a chance to get into the bank. Cavities in the 
Page Six Figure 8 
teeth or inflammation of the soft parts of the mouth 
and throat will give them a chance. Unwholesome 
foods act as aids or accomplices to these enemies and 
together they rob the bank. One of these unwhole- 
s o m e foods is 
free sugar. It is 
received in the 
form of candy, 
syrups and cake 
(Fig. 9). Sugar 
has a great at- 
traction for the 
Figure 9 
Page Seven salts of the teeth and. causes cavities to form in the 
teeth. These cavities are places where germs like 
to live. Some of these germs cause toothache. 
Toothache prevents the food from being chewed 
up properly and prepared for the body. This robs 
the bank of valuable material. Some of the germs 
attack other parts of the body and cause disease. 
Then the cashier must draw on your reserve, which 
has been laid aside for old age, to fight the disease. 
If the disease is severe it may be necessary to draw 
on your original capital. If the capital is drawn on, 
life is shortened, unless the cashier is helped by long 
rest and good food to replace the loss. There are two 
ways for the banker to combat these robbers who 
get into the mouth-by refusing unwholesome food 
and by using the toothbrush to keep the teeth clean. 
A clean mouth is one of the best insurance policies 
for a sound body and a long life. 
You should see that your health bank account is 
balanced every day and that your reserve is added 
to every night. You can do this by obeying four 
rules of health: 
Sleep ten hours. 
Eat plain wholesome food. 
Breathe fresh air. 
Keep the teeth clean. 
Page Eight This book is dedicated to the Boys and Girls of 
America. If, by a careful study of its pages, they 
are helped just a little, I shall be very proud. CONTENTS 
Page 
Chapter 1. Nutrition 1 
Chapter 2. Description of the Dental Tissues 9 
Chapter 3. Diseases of the Dental Tissues . 18 
Chapter 4. The Home Care of the Mouth . 29 PREFACE 
The question of Oral Hygiene is attracting more 
and more public attention. 
Facts which have become known during the last 
few years go to show that the health of a person is 
greatly influenced by the hygienic condition of the 
mouth. 
Physicians and dentists realize as never before that 
many diseases of the body have their beginning in 
infections coming from diseased teeth. 
Reports of the examination of school children 
throughout the United States show that nine out of 
every ten people have defective teeth or unclean 
mouths. 
The problem of overcoming this condition is receiv- 
ing much serious thought and attention. 
Doctors who have studied the question a great 
deal say that a large part of the trouble is unneces- 
sary and preventable. They agree that the solution 
lies along the road of education. 
In order for people to be able to safeguard them- 
selves they should have some knowledge of the mouth 
and teeth. One should know how the teeth are 
formed and how they are lost. They should under- 
stand something of the gum tissue and the tissues 
which hold the teeth in position in the jaw. Aside from these important matters, a study of 
Oral Hygiene should include a careful consideration 
of nutrition and recreation. 
People without experience would not think of 
making even the simplest adjustment on their motor 
car without carefully studying the book of instruc- 
tions. 
Why not a book of instruction for the home care 
of the mouth? It is the intention of this book to 
place within the reach of every one a few simple 
truths which, if intelligently applied, should help in 
solving this problem of mouth hygiene. 
This book was intended primarily as a text book 
for use in the public schools of the state, but it might 
well have a place in every household. The need of 
such a book has been apparent to the author in teach- 
ing Oral Hygiene in hospital training schools for 
nurses. 
Some of the technical terms used throughout this 
book may seem new and strange; the object of using 
them was to make the book more explicit. 
The chapter on Nutrition was written by Dr. Fanny 
Dunn Quain, who has been a careful student of 
public health. We are indeed grateful to Dr. Quain 
for her enthusiastic cooperation and many helpful 
suggestions. 
I wish to thank the members of the Oral Hygiene 
Committee for their encouragement and support. 
I wish to especially thank Miss Josephine Welch, the talented young artist, who helped with the illus- 
trations. 
To Roy Horner, a Bismarck school boy, age 16, 
is due the credit for the many excellent sketches and 
drawings. This young man, with no art training or 
instruction, executed practically every illustration in 
the book. His work deserves much credit and he has 
our best wishes. 
It is greatly to the credit of Miss Minnie J. Nielsen, 
State Superintendent of Public Instruction, that North 
Dakota is the first state in the Union to introduce 
Oral Hygiene in the public school as a regular course 
of study. 
I claim no originality for many of the facts pre- 
sented. So many men in medicine and dentistry 
have contributed to the fund of knowledge from 
which such books as this originate that it would be 
impossible to mention all of their names. However, 
I feel that the book would not be complete without 
a tribute to Drs. A. C. Fones of Bridgeport, Conn., 
F. A. Bricker of Rochester, Minn., and C. N. Johnson 
of Chicago. 
Dr. Johnson has been especially helpful in reading 
the proof and in making certain valuable suggestions. 
R. S. T. CHAPTER I 
NUTRITION 
"A Strong Mind In A Strong Body" should be the 
slogan of every boy and girl in America. Try to think 
of your body as your bank. Your greatest bank cap- 
ital is your health. If you are a good manager your 
bank will be of service to you for many years. Long 
life and simple life go hand in hand. A simple life 
means a life of regular hours for work or exercise; 
regular hours for sleep or rest, and regular hours for 
Figure 1 
meals. The work and rest should be in the fresh air 
Page One as much as possible, and the meals should consist of 
plain wholesome food. If it is not possible to get out 
into the big outdoors to rest, allow the windows to 
be opened and let the big outdoors in. Sleep in a 
room where there is plenty of fresh air (See Fig. 1 ). 
Wholesome food means simple food, food that 
has not been changed by the refining processes 
of machinery. Wheat is a wholesome food when it 
is ground and used before it is refined into white 
flour. Rice is a wholesome food before it is polished. 
Potatoes are wholesome food when they are cooked 
Figure 2 
with the skin on them, and clean milk cannot be 
improved as a wholesome food. 
Page Two You are your own banker. Your nerves are your 
messenger boys and the blood stream is your cashier. 
The messenger boys 
report what parts of 
the body have been 
drawn on during the 
day. At night, while 
you rest, the cashier 
replaces whatever 
has been taken away 
and balances the ac- 
count, ready to start 
again the next morn- 
ing. Your deposits 
and credits are carefully recorded as in Fig. 4. If 
Figure 3 
the cashier does not need to use all material for re- 
Figure 4 
Page Three placing he puts the surplus into your savings account 
or reserve. This savings account can be drawn on 
Figure 5 
when you are sick or during old age. It is very 
important to give the cashier plenty of time to put 
back all that has been drawn out during the day. 
The best way to balance the account and put a little 
reserve into the savings account is to sleep ten hours 
each night. The cashier is a faithful worker and will 
keep the bank in good order if the blood stream is 
properly supplied with material which is good for 
Page Four replacing the losses and storing in the reserve. Food 
supplies the blood stream with these materials. Foods 
are divided into four classes: Tissue builders, heat 
producers, energy and reserve producers, and salts. 
A mixed diet of 
milk, eggs, vege- 
tables and fruits will 
furnish these foods 
to the blood stream. 
A mixed diet is best 
because it furnishes 
the right amount of 
each material. Too 
much of any one 
material makes it 
hard for the cashier 
to take care of it- 
for example: An 
over supply of heat- 
producing food 
causes the cashier to 
store away too much 
fat. 
The farm is the mint which supplies funds for the 
bank. The different departments of the farm furnish 
the wholesome foods. These foods are the currency 
for the bank. The department of the mint which 
sometimes fails, because of drouth or lack of care, is 
the garden where the vegetables are grown. The 
Figure 6 
Page Five energy and reserve producing foods, such as beans, 
Figure 7 
peas, carrots, cabbage and tomatoes, are very neces- 
sary to the growth and development of the bank. To 
insure a mixed diet to the youth of America it is 
necessary to encourage all branches of farm work. 
The mint will then have plenty of food stuffs to feed 
the bank. 
The mouth is the receiving window for the bank. 
There are twenty to thirty-two guards to this window. 
These guards are the teeth. It is their business to 
properly prepare material which is furnished by the 
mint for the bank. There are many enemies of the 
bank. Among these enemies are the germs of disease. 
Sometimes they stay in the mouth a long time waiting 
for a chance to get into the bank. Cavities in the 
Page Six Figure 8 
teeth or inflammation of the soft parts of the mouth 
and throat will give them a chance. Unwholesome 
foods act as aids or accomplices to these enemies and 
together they rob the bank. One of these unwhole- 
s o m e foods is 
free sugar. It is 
received in the 
form of candy, 
syrups and cake 
(Fig. 9). Sugar 
has a great at- 
traction for the 
Figure 9 
Page Seven salts of the teeth and. causes cavities to form in the 
teeth. These cavities are places where germs like 
to live. Some of these germs cause toothache. 
Toothache prevents the food from being chewed 
up properly and prepared for the body. This robs 
the bank of valuable material. Some of the germs 
attack other parts of the body and cause disease. 
Then the cashier must draw on your reserve, which 
has been laid aside for old age, to fight the disease. 
If the disease is severe it may be necessary to draw 
on your original capital. If the capital is drawn on, 
life is shortened, unless the cashier is helped by long 
rest and good food to replace the loss. There are two 
ways for the banker to combat these robbers who 
get into the mouth-by refusing unwholesome food 
and by using the toothbrush to keep the teeth clean. 
A clean mouth is one of the best insurance policies 
for a sound body and a long life. 
You should see that your health bank account is 
balanced every day and that your reserve is added 
to every night. You can do this by obeying four 
rules of health: 
Sleep ten hours. 
Eat plain wholesome food. 
Breathe fresh air. 
Keep the teeth clean. 
Page Eight CHAPTER II 
DESCRIPTION OF THE DENTAL TISSUES 
Everyone is born without teeth. But five or six 
months later they begin to arrive and at the age of 
2^ years there should be twenty teeth in your mouth. 
These are called the baby or temporary set. They 
are arranged in curved rows called the dental arches, 
RIGHT 
LEFT 
UPPER TEETH 
RIGHT LOWER TEETH LEFT 
Figure 10 
ten teeth in the upper arch and ten teeth in the lower 
arch (See Fig. 1 0). 
Page Nine By the time you are 1 2 years old the temporary 
teeth should be gone and replaced by your second or 
last set, called the permanent teeth. Twenty-eight 
permanent teeth are all you have until you are 1 7 or 
1 8 years old. Soon after this your four wisdom teeth, 
or third Molars, erupt (come through the gums). 
Your teeth are hard and bone-like, their color 
should match the whites of your eyes. They usually 
have a bluish, yellowish tint and harmonize with 
your complexion. Few people would look well with 
perfectly white teeth. 
Enamel ■ 
Pulp center - 
Dentine 
Root canal L 
Cementum 
Crown 
Neck 
Root 
Fig. 1 1 shows a bicuspid tooth. It is divided into 
three parts: the crown, the neck and the root. The 
crown is what shows in the mouth, the root extends 
Figure 1 1 
Figure 12 
Page Ten into the jaw to hold the tooth firmly in place, and 
the neck is the line where the crown and the root 
join at the edge of the gums. 
Fig. 1 2 shows the same tooth split in two to show 
how it is formed. The bulk of the tooth is made of 
material called dentine. In the crown portion of 
the dentine is a cavity called the pulp chamber, which 
contains the pulp. Leading from the pulp chamber 
to the end of the root is a canal called the root canal. 
Blood vessels and nerve fibers enter the pulp through 
this canal and supply the tooth with nourishment. 
The dentine is different from any other material 
found in the body. It resembles ivory. The root 
portion is covered by a bone-like 
material called cementum. The 
cementum is one of the tissues 
which help to attach the root to 
the surrounding bone. Did you 
ever wonder what made your 
teeth feel so firm and solid in 
your jaws? 
Fig. 13 shows one-half an 
upper cuspid tooth growing in 
the jaw. See the network of 
fibers which run from the sur- 
rounding bone to the cementum 
covering the root. These are 
fibers of the peridental mem- 
brane; this membrane and the 
Figure 13 
Page Eleven cementum are the two principal tissues that anchor 
the teeth. Pyorrhea is a disease of these tissues. As 
the disease progresses, the cementum and peridental 
membrane are destroyed, the teeth loosen from the 
jaw and are lost. 
The enamel is the hardest material found in the 
body. It covers the crown of the tooth and protects 
it from injury (See Fig. 1 2). Enamel is made up of 
many tiny rods bound together by a cementing sub- 
stance. These rods are laid down at right angles to 
the surface of the dentine, the same as paving brick 
are laid on the street. You know what takes place 
when a paving brick is broken or misplaced-the rest 
of the paving begins to break down and has to be 
Figure 1 4 
repaired (See Fig. 14). If the enamel rods are injured 
a cavity soon forms in the tooth. 
In Fig. 1 5 you are looking straight at a set of tem- 
porary teeth. They number I to 5 each way from 
the center, making twenty in all. Each kind of tooth 
Page Twelve Right Left 
Upper 
Lower 
Figure 15 
has a -name-you should call your teeth by their 
right names: 
Number 1 Central Incisors. 
Number 2 Lateral Incisors. 
Number 3 Cuspids. 
Number 4 First Molars. 
Number 5 Second Molars. 
The lower Central Incisors are the first to erupt or 
come through the gums. They are soon followed by 
the upper Central Incisors between the fifth and 
eighth months. The other temporary teeth erupt at 
the following ages: 
Number 2, Lateral Incisors, between 6 and 10 
months. 
Number 3, Cuspids, between 14 and 20 months. 
Number 4, First Molars, between 1 1 and 16 
months. 
Number 5, Second Molars, between 20 and 36 
months. 
Many people think that the temporary teeth are of 
Page Thirteen little importance because they are all soon replaced 
by the permanent teeth. The fact is that good care 
given to your temporary teeth will prevent much 
trouble with your permanent ones. 
Your body makes its greatest growth during the 
temporary tooth period. Such important organs as 
your heart, lungs and kidneys are all being built up 
for the long, hard work of the future. Would you 
like to have a cavity in one of your temporary teeth? 
The pulp would likely become infected, an abscess 
develop at the end of the root, and bacteria or germs 
from the abscess be absorbed by the blood stream and 
carried to your heart and kidneys. Do you know that 
many children have heart and kidney disease? 
Doctors say that germs in the blood are the greatest 
cause for such trouble. If parents understood this 
better they would pay more attention to their chil- 
dren's teeth. 
PERMANENT TEETH 
The following table gives the names and time of 
eruption for your permanent teeth: 
Name Time of Eruption 
1. Central Incisors 6 to 8 years 
2. Lateral Incisors 7 to 9 years 
3. Cuspids 11 to 13 years 
4. First Bicuspids 9 to 10 years 
5. Second Bicuspids 10 to 12 years 
6. First Molars „ 5 to 6 years 
7. Second Molars 12 to 16 years 
8. Third Molars 17 to 21 years 
Page Fourteen You see that they are numbered in the same way 
as your temporary teeth, excepting that the Bicuspids 
take the place of the temporary Molars and the three 
permanent Molars are added, making eight teeth on 
Right Upper Left 
Lower 
Figure 16 
each side of each arch instead of five (See Fig. 16). 
Your first permanent Molars are the most important 
teeth of your permanent set. When you are about 
six years of age they take their places in your dental 
arches right back of the second temporary Molars 
(See Fig. 17). They are frequently called "Six-year 
Molars." Parents often think that they are temporary 
teeth because they erupt at such an early age. Since 
they are back in the mouth and not easily seen it is 
hard to keep them clean. They erupt early to be 
ready for work when your temporary teeth are being 
shed. They help to keep your lower jaw in correct 
position so that your bicuspids can come in straight. 
Your most abused teeth are the wisdom teeth, or 
Page Fifteen Fig. 1 7 Nos. 4 and 5 are the first and second temporary Molars. 
No. 6 is the first permanent or six-year Molar. 
third Molars. Most people think that they are of no 
importance and should be removed. After they are 
gone your second Molars move backward and this 
makes a space between the first and second Molars. 
Food packing into this space injures the gums, fre- 
quently causing pyorrhea. Exercise your wisdom 
and take care of your wis- 
dom teeth. Sometimes your 
jaw is too short, then your 
third Molars cannot erupt 
properly and have to be 
extracted. (See Fig. 19.) 
Page Sixteen 
Figure 19 Fig. 1 8 The first temporary Molar, No. 4, is gone and the first 
Bicuspid, also No. 4, is taking its place. Note the roots of the second 
temporary Molar, No. 5, are melting away, making space for the 
second Bicuspid, also No. 5. The first permanent Molar, No. 6, has 
kept the jaws in correct position all through this changing process. 
The second permanent Molar, No. 7, may be seen preparing to erupt. 
Page Seventeen CHAPTER III 
DISEASES OF THE DENTAL TISSUES 
DENTAL CARIES 
Your teeth are wonderful so long as they are in 
a healthy condition. But there are three ways that 
teeth sometimes cause trouble. 
The most common trouble is Dental Caries, or 
tooth decay. Of all the cavities that dentists find, 
four out of five are found in the parts of the teeth 
that are hardest to clean. 
Fig. 20 shows the chewing surface of a Molar 
tooth. The high points, called cusps, 
help to grind the food, but the deep 
grooves between the cusps are hard 
to keep clean. Sometimes a little 
food remains in the deeper grooves 
and unless this is removed with a 
brush a cavity is apt to start decay. 
Decay begins as often on the surface between your 
teeth as in the grooves (See Fig. 21). If you haven't a 
good brush, or if you aren't an expert in the use 
of your brush, you will likely have trouble in keeping 
these places clean. Your food polishes and cleans 
Figure 20 
Page Eighteen the other surfaces of your teeth-the coarser your 
food the better will be the polishing. Do you know 
that you would have little use for a brush if you ate 
the right kind of food? 
Figure 2 1 
Figure 22 
So long as you eat so much sugar and soft food 
you must become skillful with the use of your brush 
or continue to have tooth trouble. 
Millions of brushes are sold each year, but few 
people know how to use them properly. Study your 
mouth and teeth; be an expert at keeping them clean. 
Americans consume 100 pounds of sugar per 
person a year. Their dental troubles are increasing. 
Page Nineteen Figure 23 
Figure 24 
Italians consume thirteen pounds and have wonder- 
ful teeth. 
Should one of your teeth decay, as in Fig. 22, have 
it repaired at once. A good filling will save the tooth. 
People often have decayed teeth and do not know it. 
See how large the cavity in Fig. 22 has become. The 
opening through the enamel is still small but the 
softer dentine is being rapidly destroyed, leaving the 
enamel unsupported, the same as a tunnel under the 
street weakens the paving. Fig. 23 shows that the 
enamel rods are falling apart; the owner of the tooth 
at last realizes the trouble (Fig. 24). A filling might 
still save the tooth, but how much better had the 
owner known of the trouble in the beginning. 
Page Twenty Figure 25 
Figure 26 
Frequent examinations by the dentist prevent large 
cavities. Such cavities are sometimes neglected and 
in time the decay reaches the pulp (Fig. 25). There 
is then no longer a doubt in the owner's mind. 
If the tooth is not ex- 
tracted now, infection from 
the pulp may pass through 
the root and cause an abscess 
(Fig. 26). Bacteria ab- 
sorbed from the abscess 
by the blood are carried 
through the system. 
Don't you think it is time 
to bid farewell to such a 
tooth? (See Fig. 27.) 
Figure 27 
Page Twenty-one PYORRHEA 
Pyorrhea does not bother much while you are 
young, but conditions which cause pyorrhea often 
develop in early youth. Anything that inflicts an 
injury to the gums, the cementum or peridental mem- 
brane, is apt to cause pyorrhea. It is a disease which 
destroys the tissues that bind the root of your teeth 
fast in the jaw. Your gums are a covering of the 
jaw and should come up close around the necks of 
your teeth. They protect the cementum and peri- 
dental membrane from injury and infection. If you 
are careless about the care of your mouth your gums 
are apt to become soft and bleed easily. Healthy 
gums are hard and tough and should not bleed even 
though you brush them thoroughly. If your gums 
are not hard and firm and haven't a nice pink color 
have them examined. Don't give pyorrhea a chance. 
Figure 28 
Brush your gums as well as your teeth if you want 
a healthy mouth. 
Page Twenty-two OCCLUSION 
The bringing together of your teeth in biting or 
closing your jaws is called occlusion. Teeth that come 
Figure 29 
Figure 30 
together nice and straight, like in Fig. 29, are in 
normal occlusion (normal meaning as intended by 
nature). Crooked or irregular teeth, like Fig. 30, 
are not normal, so we say they are in malocclusion. 
Normal occlusion means straight teeth. Malocclusion 
means crooked teeth. In Fig. 29 you see the upper 
Incisors are wider and overlap the lowers; they close 
together like a pair of shears. The Bicuspids and 
Molars have cusps that grind the food-they come 
Page Twenty-three Figure 3 1 
Figure 32 
together, or occlude, like the cogs in a wheel. Com- 
pare Figs. 31 and 32. 
When you eat an apple the thin cutting edges of 
your Incisors, coming together like two blades, cut 
off each bite, which is then passed back by your 
tongue to be ground up fine by your molars. 
Did you ever see a face like Fig. 33? Notice how 
the upper teeth protrude. When this girl was a 
baby she sucked her thumb 
or fingers. She continued 
the habit for several years. 
The pressure of her fingers 
in her mouth and the force 
caused by sucking ruined the 
shape of her face. Teething 
rings and pacifiers often do 
the same thing. Parents 
should never allow such 
things. Mouth breathing is 
a common cause of malocclu- 
Page Twenty-four 
Figure 33 sion and usually results from adenoids. They tend to 
close up the nasal open- 
ings and in order to get 
enough air you are com- 
pelled to breathe 
through your mouth. 
The constant pressure 
of the muscles holding 
the mouth open changes 
the sh^pe of your jaws 
and forces the teeth out 
of line (Fig. 34). See 
how the shape of the entire face and head has been 
changed. Compare Figs. 35 and 36. 
Figure 34 
The loss of teeth during early youth while the 
jaws are growing almost always causes some form of 
malocclusion, especially the loss of your first perma- 
nent or six-year Molars. 
Figure 35 
Figure 36 
Page Twenty-five Figure 3 7 
Fig. 37 shows the lower jaw of a man. The left first 
and second Molars are missing. See how much 
shorter the jaw is on that side. These teeth were 
lost while he was still a boy. Until the third Molars 
came this side had no teeth. Nearly all the work was 
done on the right side. 
You know that work is one of the things that 
makes us grow. 
A jaw shorter on one side might not be so bad, but 
notice Figs. 38 and 39. The right side of the face 
and whole head is much wider and larger than the 
Page Twenty-six left. A lop-sided head is caused by the loss of two 
Molar teeth. 
Figure 38 
Figure 39 
People might think it was natural for this man 
to look queer. 
A crooked tree might be natural, 
but it is not normal like a straight 
tree. 
People are apt to confuse the 
words natural and normal. 
A tree planted close to a wall or 
to a larger tree is usually crooked 
in a few years. The sun and wind 
Figure 40 
Figures 37, 38 and 39 are pictures of skulls belonging to Dr. Tom 
Smith of Langdon. Dr. Smith kindly loaned them for the purpose. 
Page Twenty-seven can only reach one side of it. The tree becomes 
naturally crooked, but being unlike the straight tree 
we call it abnormal-something prevented it from 
being normal or straight as intended by nature. 
Crooked teeth, jaws and heads are all abnormal. 
Something, sometime, goes wrong or we should all 
have straight teeth and heads. 
Trees growing under extremely bad conditions, like 
certain kinds of cedars on the edge of a rocky butte, 
become badly twisted and gnarled, almost losing any 
resemblance to a tree. Conditions in the mouth 
sometimes are so unfavorable that the face and head 
become just as unattractive as the crooked cedar tree. 
Would you expect to have your brain fully develop 
in a cramped, misshapen skull? 
During the recent war more than one out of five young men 
called for service were rejected due to some physical or mental defect. 
According to intelligence tests, a large percentage of the men who 
actually entered the army were below par in mental development. 
It is a well known fact that approximately 80 per cent of our popula- 
tion have some form of malocclusion. 
Page Twenty-eight CHAPTER IV 
THE HOME CARE OF THE MOUTH 
No part of Oral Hygiene is more important or as 
little understood as the home care of the mouth. 
Toothbrushes have been known for years, yet few 
people have mastered their use. 
The foundation of Oral Hygiene is knowledge. 
First: A knowledge of nutrition. 
Second: A knowledge of the teeth and of the dis- 
eases that affect them. 
Third: A knowledge of how to keep them clean. 
Remember that most of the food that lodges around 
the teeth is found in the grooves on their surfaces 
or in the spaces between them. 
Figure 41 
A small medium stiff brush is ideal for cleaning 
these surfaces (Fig. 41). You must have a regular 
system or plan to follow in brushing your mouth. 
Begin in the same place and have a fixed place for 
leaving off. This will help to establish a habit so 
Page Twenty-nine that in a short time the work will become a regular 
part of your daily life. 
You should brush your mouth after each meal, if 
possible, but never fail to do so before retiring for 
the night and when you first arise in the morning. 
Spend at least two or three minutes by the clock. 
The evening brushing is most important. 
Bacteria or germs which are always found in the 
mouth do their greatest harm while you are asleep. 
Your tongue, lips and cheeks are at rest and there 
is little to disturb them. 
Bacteria, you know, are very tiny (Fig. 42). Until 
the high-powered microscope was perfected no one 
knew much about them. Now we know that they 
are everywhere. There are many different kinds. 
Do you know that bacteria are what cause milk to 
become sour and food to spoil? They work best in 
Figure 42 
Page Thirty- a warm place. Milk and such things are kept in 
refrigerators because bacteria cannot stand the cold. 
The mouth is always warm. The number of bacteria 
in the mouth varies. The cleaner the mouth the 
fewer the bacteria. They thrive on filth. 
A mouth can look and feel perfectly clean, yet the 
smallest mite of food lodged around a tooth might 
be the home of millions of 
bacteria They cause these bits 
of food to change. They be- 
come rotten, as we say. During 
the changing process an acid is 
produced. This acid dissolves 
the cementing material from be- 
tween the enamel rods and the 
rods fall apart, as described in 
Chapter III. Practically all cavi- 
ties start in this way. 
Next in importance to the care 
of the mouth is the care of the 
brush. Wash it thoroughly after 
using, then sprinkle salt between 
and around the bristles (Fig. 43). 
Soak the bristles of your brush 
in luke-warm salt water (one- 
half thimbleful of salt to a half 
glass of water). Beginning on 
Figure 43 
Paga Thirty-one Figure 44 
the upper right side, as in Fig. 44, place your brush 
on the chewing surface of your last Molar tooth. 
With a short, circular vibrating movement, like the 
quivering of jelly (Fig. 45), pass 
the brush over the surface of the 
Molar, seeing that the bristles 
reach well onto the gums behind 
the tooth. Work forward, brush- 
ing the chewing surfaces of the 
Molars and Bicuspids. Continue 
this on the lower right side, then on the same sur- 
faces of the left upper and lower teeth. This move- 
ment forces the bristles into all the grooves, thor- 
Figure 45 
Page Thirty-two Figure 46 
oughly cleaning and polishing them (Fig. 46). 
Fig. 47 shows the common way followed by most 
people in brushing these surfaces. Notice that the 
deep grooves, where the danger lurks, are not reached, 
yet this person guessed that she had done her duty. 
Guess work leads to disaster; success comes to those 
who know. People who study and understand how 
their teeth are lost do the best job. They see the need 
of thoroughness and know how to apply it. 
Figure 47 
Page Thirty-three Figure 48 
Fig. 48 shows the next step. The brush is placed 
so that the bristles can reach all of the outer surfaces 
of these teeth. Begin with the last Molar on the upper 
right side, giving the same vibrating motion to the 
brush, moving slowly forward to the Central Incisors, 
then slowly backward to the starting place, making 
a round trip. Continue this on the lower right side 
and on the upper and lower left side. This covers 
the outer surfaces of all of your teeth. 
Be sure that you feel the bristles passing into the 
spaces between your teeth where so much decay 
begins. Remember that the gums around the necks 
of your teeth require brushing as much as the teeth 
themselves. If your gums are to be healthy they 
must have exercise. The soft cooked food that you 
eat requires so little chewing that your teeth and 
gums do not have enough work, and the result is 
that your teeth are not kept polished as they would 
be if you ate coarser food. The farmer's plow doesn't 
work well in too soft ground-it clogs up. Working 
in harder ground, it is kept polished like a mirror. 
Page Thirty-four Figure 49 
Examine your dog's mouth and see how clean and 
polished his teeth are and how hard and pink and 
healthy his gums look, then watch him eat some time. 
Figure 50 
Was your arm ever injured so that it had to be 
carried in a sling? Remember how weak it felt when 
Page Thirty-five you began using it again? But a few days of exercise 
and work made it strong once more. Exercise makes 
the blood circulate better. Perfect circulation of the 
blood is required for the perfect health of your gums 
as well as your arm. 
Caution: If your gums are not used to the brush, 
don't brush too hard at first. Remember your injured 
arm. It will take a few days of light brushing to 
toughen them up. 
Fig. 51 shows the commonly used back-and-forth 
movement of the brush. The bristles ride over the 
Figure 5 I 
Figure 52 
high spots but fail to reach the gums and spaces 
between the teeth. The dark, shaded surfaces next to 
the gums, shown in Fig. 52, are missed entirely. 
Page Thirty-six Much honest effort is frequently lost because of the 
lack of knowledge in applying it. The surface of the 
teeth on the inside of the dental arches in contact 
with the tongue are called the lingual surfaces. 
The lingual surfaces are usually neglected; they 
are not easily seen. 
Did you ever hear of anyone keeping their bodies 
clean simply by washing their hands and face? 
Figure 53 
Fig. 53 shows the brush on the lingual surface of 
the right upper Molars. Work forward past the mid 
line of the mouth (a line between the Central Incisors) 
to the back of the last Molar on the left side. These 
surfaces of the teeth are so formed that the gums 
require extreme care. Brush them carefully. 
Fig. 54 shows the palatal surface or roof of the 
mouth. See the three openings on the palate, one 
back of the Incisors and one on either side near the 
last Molars. Blood vessels and nerves that supply 
the gums on the lingual surfaces of your upper teeth 
come through these openings. Brush the palate in 
Page Thirty-seven these regions and see how good it feels. The brush 
ing causes the blood to circulate better. 
Figure 54 
The hardest parts of the mouth to reach with a 
brush are the lingual surfaces of the lower teeth. 
Figure 55 
Fig. 55 shows the brush in position. Notice how 
Page Thirty-eight the bristles are directed towards the gums, also see 
how they are reaching in between the teeth. Can't 
you almost feel how clean and refreshed your 
mouth will be? 
People are always saying: "My brush can't reach 
the back of my lower front teeth.'' Using the vibrat- 
ing movement, as described, and with the brush placed 
Figure 56 
as shown in Fig. 56, you can't fail. But don't forget 
that the brushing of your mouth and teeth is a difficult 
and particular piece of business. Intelligent effort 
produces results. You can't use your brush while 
your mind is busy elsewhere and do much good. 
Page Thirty-nine After finishing your teeth and gums, brush your 
tongue. It's the final touch to a job well done. Pass 
the brush from the back forward in a sweeping motion. 
By teaching people how to prevent and avoid disease the average 
length of life has been increased approximately ten years during the 
last half century. Dr. Charles Mayo is credited with the statement 
that the next great step in the prevention of disease should be made 
by the dentists. In 1922 the American Dental Association, with 
Dr. Thomas Hartzell as its president, adopted this slogan, "Dentistry 
can add ten years to human life." 
Page Forty