Intro to Dental Anatomy

8/3/2019 Intro to Dental Anatomy

1/15

Introduction to Dental Anatomy

To start with , The doctor began the lecture in explaining the main topics of

"dental anatomy and occlusion" in general. The lectures topics cover detailed

dental macroscopic anatomy and the basic principles of dental occlusion. Each

lecture covers one class of permanent teeth and there is a separate lecture for

deciduous teeth.

Normally human dentition is diphyodont, diphyodont

means that we have two sets of dentition; we haveprimary dentition and secondary dentition.

Primary dentition is a temporary dentition thats

why it is called deciduous dentition. And the

secondary dentition is the more permanent

dentition.

Remember this term diphyodont means we

have two sets of dentition:

1-primary: is deciduous, temporary this means that these teeth serves for alimited time.

2-secondary: is permanent dentition. Humans have 20 deciduous teeth in

total and 32 permanent teeth

Classes of teeth


2/15

We have three classes for deciduous teeth; we have Incisors, canines, and

molars only three classes. In contrast, we have four classes for permanent

teeth.

Why do we have four classesfor permanent teeth?This means we have an extra class which is " premolars ".So in permanent

teeth we have Incisors, canines, premolars and molars.

Could number of Teeth differ with Age ?!

Now deciduous teeth are smaller in size ,this means we have a

difference on the number of teeth. we have 32 permanent and 20

deciduous .This means that we have 12 teeth that erupt without replacing

previous teeth.

Types of Teeth !

So teeth are divided into two kinds: one kind is successorsthe

other kind is no n successor teeth. Successor teeth ( ): theseare teeth that are going to succeed or replace another set of teeth

.Nonsuccessor teeth: that teeth that erupt without replacing another set of

teeth,

# Permenant incisors are going to replace deciduous incisors

# Permanent canines are going to replace deciduous canines

# Permanent premolars are going to replace deciduous molars

VIPthe permanent molars erupt by themselves without having toreplace another teeth.

So again, Successor teeth are permanents incisors, canines and

premolars. And the non successors teeth are the permanent molars. All thedeciduous teeth are going to be replaced (succeeded) thats why they are

called predecessor (opposite of successors).


3/15

Now let's answer few Questions :

Why do we have two sets of dentition?

Why we are created with two sets of dentition?

Why dont we have only one set?

This is an important info, by age the upper and lower jaws are growing

larger in size. The other important thing that Teeth dont grow in size . Once

the tooth is formed and calcified it doesnt grow in size . Bones are different,

it undergoes growth while teeth dont undergo growth.

Why do we need to change our teeth with age ?

If we were created with one set of dentition .we would have only

deciduous teeth which are small and they are only 20. by growing in age the

jaws will be bigger and the 20 small teeth will have big spaces between

them. Thats why we need to have another set of dentition.

New set means a New Properties :

1-it should be composed of bigger teeth

2- it should be composed of more teeth.

Because the jaws grow in all directions. (anterio posteriorly,mediolaterally

,and also superior inferiorly), so that Permanent teeth should be bigger in

size .


4/15

The dental formula:*

In the dental formula we use the initials of the classes (the first letter)

I for incisor

C for Canines

PM for premolars

M for molars

* VIP

Deciduous teeth are indicated by the letter D before the initial. For example Dm

(for molar(

*Human dental formula:

- Deciduous teeth: for one side

- DI 2/2, DC 1/1, DM 2/2 = 10 "for the two side 10x2 = 20"

Permanent teeth: for one side


5/15

I 2/2, C 1/1, PM 2/2, M 3/3 = 16 " 16x2 = 32 "

Concentrate here*The numbers following the letter refer to the number of teeth of each type in the

upper then the lower dentition for one side only. For example { I 2/2 } means that if

we take teeth from one side we will have two incisor on the lower jaw and another

two on the upper one thats why {2/2{

*Mammal Exceptions

This dental formula for humans but it differ by different mammals for ex: carnivores

have 3 incisor, but all mammals have one canines on each side and its themaximum number for all mammals canines tooth , premolars can be up to four in

one side , molar the maximum number is three so, as humans we have the

maximum number of canines and molars but we haven't got the maximum number

of premolar and incisor so we have 32 .

*The Highest number of teeth!!The maximum number for Mammals to have is 44 teeth. " 3 incisor 1 canines , 4

premolar , 3 molar (11 on each quadrant thus 11x4 = 44.(


6/15

P.S:You have to know what we call "dental formula".because there will be some

question in the exam about it .

*Mirror image theory!!

-Dental formula: it's a way to describe all the teeth in an animal. In general human

& animal have specific dental formula composed of 32 teeth for permanent and 20

teeth deciduous. Teeth in the right side are identical for the teeth in the left side

"mirror image".Thus we don't have to provide the dental formula for both sides

because the teeth in right just like the teeth in the left.

Quadrants

Dental formula only describes the teeth of one side and because of that any number

you see in the dental formula you have to multiply it by "2" in order to get the full

number.

-For example : we have {2/2} which means two incisors in the upper over two

incisor in the lower but remember we have 4 incisor because you have to add the

incisor of the other side.

-we have a maximum number for the dental formula in mammals.

The maximum number of incisor is Three , but in human we have Two incisor ..we

are talking about one quadrant.

- What is "Quadrants" ?

If you divide the teeth or the dentition by the vertical line "mid-line" you will get

right & left side. Also you can put line between the upper and the lower teeth and in

this case now you will have Four Quadrants.

-The maximum number of canine is One .. No one can have more than one canine

but some animal have Three incisor which is the maximum Number of incisor ..We

are talking here about the placental mammals. "Placental mammals are mammals

with ovary". While other mammals like "kangaroo" they may have Four incisor.

- For premolars the maximum number is Four and the maximum number for molars

is three, so as human we have got the maximum number in canine and the


7/15

maximum number in molars but we have not got the maximum number in incisor &

premolar.

-If we want to calculate the maximum number in mammals it willbe "44" .How??

We will have : Three incisors 3/3 .. One canine 1/1 .. Four premolars 4/4.. and Three

molars 3/3 that will be 22 . Once again the other side have also 22 that will be

"44. "

-For example: Cats have 3 incisors ,1 canine ,4 premolars ,1 molar.

Do all mammals have 2 sets of dentition?

Yes, but we have one exception."R odents " have one set of dentition thats mean

they don't have deciduous teeth then permanent teeth. All the reminder mammals

have 2 set of dentition..Primary dentition followed by permanent dentition.

}Rodents =}

-Lets divide the teeth into 4 quadrants:

* Right maxillary

*

Left maxillary.

*Left mandibular.

*Right mandibular.What are these numbers from ( 1 to 4) ?

when we divide the teeth into 4 quadrants ,the right maxillary we give it number

1 ,the left maxillary we give it number 2 ,the left mandibular number 3 and the right

mandibular we give it number 4.


8/15

*VIPWhen you examine a patient and you want to go from Q1 to Q4 you will go

clockwise. You have to remember that the right and left is not your R.t & L.f , it'syour patient R.t & L.f

In Genral Dentistry the R.t & L.f is the R.t & L.f of the patient not the DR.

What is occlusion plane !!

-For dental notation system if you want to give the quadrants number you give from

1to 4 for the permanent teeth and from 5 to 8 for the deciduous teeth. As you see

here this is the mid-line and this is the area between the upper and lower teeth and

we call it the occlusion plane

" occlusion plane = "

Occlusion plane is a plane that separate between the upper and lower teeth, also in

addition of giving number to quadrants we give number to teeth and there are

different ways. We use the number starting from the mid-line and going distally we

begin in tooth #1 until tooth # 8. For the deciduous teeth we don't give number we

give letters from A to E.

*VIPRemember that we start giving the number from the mid-line going distally.

THE DENTAL NOMENCLTURE

Naming teeth by their names:

First you have to identify whether the tooth is deciduous or permanent and you

have to mention whether the tooth is in the maxillary or mandible jaw. Then you

have to know the class of the tooth is it an incisor \ canine \ premolar \ molar. For

the deciduous teeth incisor\canine\molar. Then the order within the class ; is the

tooth central o lateral incisor? Is it first or second premolar? And so on .And finally

you give

the side if it right or left, that is how to name the tooth.

For example let's name the central incisor :


9/15

"The permanent maxillary right central incisor"

So you have to give 5 words.

* Once again

1- Identify whether the tooth is deciduous or permanent.2- Mention whether the tooth is in the maxillary or mandible jaw.

3- Knowing the class of the tooth.

4- Ordering within the class.

5- Giving the side if it right or left.

That is how to name the tooth.

Doctor said that "Describing teeth by words is really very boring and sometimes

takes time." What do you think guys?!

If I want for example to name each tooth by words it takes time, specially

sometimes as a dentist , I can refer my patient to another dentist so I have to

indicate the problem in one of the teeth instead of saying : the patient suffers from

pain in the permanent maxillary right central incisor, it's could to agree on a

notation system instead to give the full name of the tooth.

This is called the dental notation system ; which is the way of abbreviating the long

5 words that is used to describe teeth.

* Notation Systems

-Palmer notation system

-Universal numbering system


10/15

-FDI numbering system

*Palmer notation system

The first one is the palmer notation system and is also called the Zsigmondy

notation system. Developed by the American dental association in 1974.

In this system the tooth is represented by a number from 1-8 for permanent, and

by a litter from A-E for deciduous teeth.

*VIP1-We use numbers for permanent teeth or letters for deciduous teeth.

2-All the time we number the teeth from the midline distally.

"tooth number one will be close to the midline and tooth number A also will

be close to mid-line in case of Deciduous teeth".

Example : Number 8(the third molar) will be far away from the midline"

Then we have to provide 2 lines , on line is a horizontal line presenting a

horizontal plan, and the second is a vertical line presenting the midline " these

lines are in the palmer notation system ".For example if we want to describe the

maxillary right central incisor we say first:


11/15

It is tooth number one , then we put the two lines the first one is the midline and

the second is the occlusal plane. We must put them in a way to describe the

region of the tooth.

this is the maxillary right central incisor located in the maxillary right

quadrate .The number is at the left of the line and above the the occlusal plane

thats why it should be presented this way.

Let's suppose that we have 2 teeth in the palmer system; and I want to describe

the maxillary right central incisor and the maxillary right first premolar , I will put

1and 4

1:the maxillary right central incisor

4:the maxillary right first premolar

*Remember that :Sometimes in the palmer notation system we can use the lines for more than

one tooth.

P.S : Nothing more you should know about palmer notation system.

*The FDI Notation system:

*Rules

-we don't use lines or letters.

-we use numbers only

Each tooth is presented by two digits, the first digit which is on the left the

quadrant where the tooth belongs, and the second describes the order of thetooth in that department.

For example:

If I want to describe the mandibular right permanent canine, first I have to put a

number which is 4 that indicate this tooth belongs to mandibular right quadrant


12/15

( which is number 4) , the second number (3) presents the order of the tooth in

the midline.

This is the FDI Big Four !

1-In the deciduous tooth we must make sure that the numbers are

from 5-8(not 1-4).

2-The tooth is permanent If it begins with 1,2,3,4.

3-The tooth is deciduous if it begins with 5,6,7,8.

4-The second number describes the order of that tooth starting from the midline.

It is wrong to say that the tooth number is 11(eleven) it is 11(one one) because

in the Universal system it is possible to have a tooth called ( eleven ) .

Q: Is it possible to have a tooth number (56)?

No 5 mean deciduous and there is no 6 teeth per quadrant.

Q: Do we have zero in the FDI notation system?

No..Impossible.

*The Universal Numbering System:-This system was developed because palmer system

was hard to type on keyboard.It is developed by the

dental American association In 1968.

*In this system

-In this system we use numbers for permanent teeth

and letters for deciduous teeth.


13/15

-In this system the order of this number is this way , we star in the maxillary

third molar and then we go to maxillary right central incisor then maxillary left

central incisor and we continue to tooth number 16 which is the maxillary left

third molar then to 17 which is the mandibular left third molar and then we go

until we 24 which is the mandibular left central incisor then mandibular right

central incisor then to 32 which is the mandibular right third molar.

-In this system we go this way (clockwise(.

- In this system we don't read it as two digits we read it as one number. For

example: We don't say 25(two five) we say twenty five.

For example when a patient come to me suffering from tooth number twenty five .it

is obvious to know it is the universal system and in America they use the American

system.In Jordan we use palmer notation system but I am sure your Malaysian

colleagues when they back to their country they will use FDI .Because I cannot be

sure that all of you are Jordanian or all of you will work in Jordan so you need to

understand other systems. For example when I go to Australia I use FDI system .

* Again for deciduous teeth we use letters start with A , end with T .

*Zero Theory !!In Universal system the zero is possible like 10, 20, 30 ,BUT it is impossible to see

zero in FDI system and Palmer notation system.

That's all about today lecture,Next week lecture will be a Full Practice about Dental

Notation System.

Dont close your Sheets there is one important page left !!


14/15

To sum up, this is the Skeleton of this Lecture

1-Human dentition : 2 sets of dentitions,

-Primary/deciduous

-Secondary/permanent

2-Why do we have to have two sets of teeth.

3-Dental formula such as:

I for incisors, C for canines... Etc

4-Quadrants:Tooth-bearing region of the jaw can be divided into 4 quadrants.

Quadrants in permanent dentition have the numbers 1 - 4 and in deciduous have

the numbers 5 8.

5-What do we mean by "notation system". It's tooth numbering orshorthand system of tooth notation.

6-How to call teethThree main systems:


15/15

-Palmar notation system.-Universal notation system.-FDI notation system.

Quote of the Day : the only person who dont have any mistakes , is the person who

do nothing in Life.

This Work Done by

Dental Anatomy Script team

Sawsan Z. Jwaied

Hadeel Sumrien Hebah Ramadnah

AseelGhawanmeh Russia ElShboul Salam Ahmed Abeer M. Dirawi

Sondos Abu-zaid Eman Idkaidek

Eman Nazal Hibah Jarrah

Rmz Rabadi Noha Mohamad

Rawda Najjar GaYda'a Kana'an

Ahmed AlShamary
http://www.facebook.com/profile.php?id=100003022704049http://www.facebook.com/profile.php?id=100003022704049http://www.facebook.com/profile.php?id=100003022704049http://www.facebook.com/profile.php?id=100003022704049http://www.facebook.com/profile.php?id=100003022704049http://www.facebook.com/profile.php?id=100003022704049http://www.facebook.com/profile.php?id=100003022704049

Intro to Dental Anatomy

Documents

Transcript of Intro to Dental Anatomy