Basics of dental anatomy.
- Human Dentition: The teeth that are located in
the upper and lower jaws are collectively referred
to as the human dentition.
- Maxillae: The upper jaw is known as the
- Maxillary Teeth: The teeth located in the
maxillae form an arch and are referred to as
- Mandible: The lower jaw is called the mandible.
- Mandibular Teeth: The teeth located in the
mandible are referred to as mandibular teeth.
- As humans, we have two sets of teeth during our
- Primary Dentition: The first set of teeth we get.
These are often referred to as baby teeth. There
are 20 teeth in the primary dentition.
- Permanent Dentition:The second set of teeth
we get. These are often referred to as adult teeth.
There are 32 teeth in the permanent dentition.
- There are several terms that help to define
locations on and around the teeth. These terms
are used often to refer to specific areas of the
mouth when describing conditions there.
- Posterior: Towards the back of the mouth.
- Anterior: Towards the front of the mouth
- Mesial: Towards the midline of the mouth.
- Distal: Away from the midline of the mouth
- Buccal: Any area on the cheek side of the teeth
- Lingual: Any area on the tongue side of the
- Facial:Any area on the cheek or lip side of the
teeth. Is often used interchangeably with buccal
but mostly in the anterior portion of the mouth.
- Palatal: Any area on the tongue side of the
- Occlusal: Any area on the chewing surfaces of
- Incisal: Any area on the biting surfaces of the
The Four Parts of A Tooth
- Each tooth in the mouth contains four different
tissues that serve different functions. The teeth
are made up of two major parts: the crown and
- The crown of the tooth is what is visible
in the mouth
- The root of the tooth
is the portion which normally not visible in the
mouth and is anchored within the bone (Figure 2).
Within each tooth, the four different tissues that
are present are the enamel, the dentin, the pulp
and the cementum.
- Enamel: Makes up the protective outer
surface of the crown of the tooth.
- Dentin: Makes up the majority of the inner
surface of the tooth. It cannot normally be
seen except on x-rays.
- Pulp: This is the area inside the tooth that
holds the nerves and blood vessels of the
tooth. It is in the centre of the tooth and is in
both the crown and the root of the tooth.
- Cementum: Makes up the outer surface of
the root of the tooth. It is much softer than
- In both the maxillary and mandibular arch there
are similar teeth. There are four types of teeth
in both arches. These include the incisors, the
canines, the premolars and the molars. Each of
these teeth is located in a different area of the
mouth and serve different functions.
- Incisors: The four front teeth in the mouth are
known as incisors. They are located in both
the maxillary and mandibular arches. The two
centre teeth are known as central incisors and the
teeth on either side of them are known as lateral
incisors. All of these teeth are responsible for
cutting or biting food. They act like scissors.
- Canines: The teeth located distal to the lateral
incisors are known as canines. These teeth
form the corners of the mouth. There are 2
canines in the maxillary arch and 2 canines in the
mandibular arch. These teeth are responsible for
tearing food particles when chewing.
- Premolars: The teeth located distal to the
canines are known as premolars. There are
4 premolars in each arch and two are located
behind each canine in the arch. These teeth are
smaller than the molars and are responsible for
crushing food in the chewing process. These
teeth are also only present in the permanent
dentition. The primary dentition only consists of
incisors, canines and molars.
- Molars: There are normally 6 molars in each
arch; three on the left and three on the right side.
They are referred to as first, second and third
molars. Some people never develop third molars
and often these are the molars that are so far
back in the mouth that they have difficulty coming
in and may have to be taken out. The role of the
molars in chewing is to grind the food.
Tooth Numbering Systems
- In order to effectively and efficiently refer to
teeth we often use numbering or lettering
systems. There are several systems that are
used throughout the world. These include
the Universal Numbering System, the Palmer
Notation System and the International Numbering
- The most widely used system in the U.S.
dental schools is the Universal Numbering
System. This consists of assigning numbers to
the teeth in the permanent dentition from 1 to
32 starting with the upper right third molar and
continuing over to the upper left third molar and
then down to the lower left third molar and onto
to the lower right third molar. For example The
the mandibular right canine tooth would be tooth #27
- Using the Universal Numbering System the
the primary dentition is identified using letters.
Beginning at the second molar on the upper right,
the teeth in the maxillary arch are assigned letters
: Then continuing with the mandibular left
second molar and around to the mandibular right
the second molar, the teeth are assigned letters K:T
- The teeth have two major parts, the crown and
the root. When looking at a cross-section of the
tooth the four main tissues that make up the tooth
are the enamel, the dentin, the cementum and the
pulp. All of these parts play important roles in the
proper functioning of the dentition.
- The primary dentition is made up of 20 teeth, while
the permanent or adult dentition contains 32 teeth.
Most dental professionals refer to numbering or
lettering system when identifying the teeth. There
are four main types of teeth, the incisors, the
canines, the premolars and the molars. Each type
of tooth serves a different function in eating.
Understanding dental anatomy is essential in
order to begin to develop an appreciation for the
role of teeth indigestion, appearance, speech
and sensory input. Without the proper function of
the teeth, usually due to disease such as decay
or cavities, a person's health, appearance and
nutrition can be affected.