The mouth, or the oral cavity, plays a major role in healthy body functioning. In the oral cavity, there
are different types of teeth, which have different functions, shapes, and times of the eruption. Over
the course of your life, we develop two different sets of teeth; 20 primary teeth, which come in the
early months, and 32 permanent teeth, which later replace the primary teeth.
The tooth anatomy
The crown is the top part of the tooth that is exposed and visible above the gum. The main
morphological feature of the tooth crown is cusps, which ensure that the food is crushed and ground
The root of a tooth descends down the gum line and anchors the tooth in the mouth.
The neck is the region of the tooth that is at the gum line, between the root and the crown.
Types of teeth and their functions
Also known as the front teeth, incisors are most visible in front of the mouth. Incisors are used for
cutting and chewing food. There is a total of eight incisors in the mouth, four each on top and
bottom. Primary incisors usually erupt at around six months of age, and the permanent teeth come
around the ages of six and eight years.
Canines are the sharpest teeth in the oral cavity. There are four canines, two of which are present in
both the top and bottom. Apart from ripping and tearing food, canines serve to form the corners of
the mouth. The primary canines start to appear between the ages of 16 and 20 months, and the
permanent canines develop between the ages of 9-and, 12 years. Canines have a single cusp and a
single root. Canines have the longest root in the oral cavity.
Premolars are permanent teeth that are also known as bicuspids. The premolars erupt at the age of
10-12. There are eight premolars in the mouth, four of which are present on each side of the mouth.
Premolars can be considered transitional teeth, as they exhibit characteristics of both molars and
Premolars are classified as first and second premolars:
The first premolars are used for grinding and tearing the food, even though they are not sharp as
The second premolars are located behind the first premolars and molars. Their surface is
comparatively flat and is used to cut the food down to still smaller bits.
Molars or deciduous molars are the largest teeth in the mouth. The primary function of molars is to
vigorously chew the food previously broken down by premolars and make them ready for digestion.
There are 12 molars in an adult mouth. Molars are classified into first and second molars:
The first molars usually erupt around the age of six, before the falling of primary molars.
The second molars typically erupt sometime between the ages of 11 and 13.
Difference between molars and premolars
Premolars and molars both play a vital role in the process of grinding and chewing.
Molars have two or three roots, whereas premolars have one or two.
Molars have five cusps, while premolars have two.
Molars are wide, and premolars are narrow.
Molars are used for chewing purposes, while premolars are used for tearing and biting.
1. Third molars
The third molars are popularly known as wisdom teeth. These are the first set of permanent teeth
that come out and the last teeth that will develop. The third molars usually come around the age of
18-20; however, in some cases, they may never develop. These teeth have a flat surface and have
four cusps to enable the easy chewing of food. Generally, the third molars often cause overcrowding
of teeth, and therefore, many people have to get them removed.