Intermediate Knowledge of Teeth

Biology

definition

Teeth

Teeth are the hardest substances in the human body. Besides being essential for chewing, the teeth play an important role in speech. There are different kinds of teeth. They are as follows:
1. Incisors
2. Canines
3. Premolars
4. Molars

definition

Dental formula

Dental formulae indicate the number of each type of tooth in a given species.
The jaw is bilaterally symmetrical. Hence, the dental formulae represent the number considering the half jaw only. 
The numerator of the fraction represents the number of teeth in the upper jaw and denominator represents the number of teeth in the lower jaw.
The formula represents number of teeth in the following order (left to right): Incisors, Canine, Premolars, Molars
Example:

definition

Human teeth

Dental formula is used to calculate the number of teeth in mammals. The human dental formula is as follows:
  1. Human child (upto 2 years):
    Thus, the total number of teeth are = 2x10= 20 (milk teeth)
  2. Human adolescent (17-20 years): 
    Thus, the total number of teeth are = 2x14= 28 (permanent teeth)
  3. Human adult: 
    Thus, the total number of teeth are = 2x16= 32 (permanent teeth + wisdom teeth)

definition

Milk teeth and Permanent teeth

Teeth are present in the buccal cavity and help to churn food.
The first set of teeth grows during infancy and they fall off at the age of 6-8 years are known as milk teeth.
The second set of teeth which remains for rest of the life are known as permanent teeth.
The different types of permanent teeth are molar, premolar, canine and incisor.

definition

Types of teeth

The teeth are classified into different types on the basis of its use. They are mainly used for cutting, biting, tearing, chewing and grinding.
They are differently shaped permanent teeth to break the food into small chunks which make the digestion easy.
Permanent teeth are divided into four types. Each has special structure and functions. They are:
  • Incisors
  • Canine
  • Premolars
  • Molars

definition

Incisors

Incisors are situated in the center of both- top and bottom jaw. They have the following features:
  • There are 4 incisors in each jaw.
  • They are thin, flat-bottom, narrow- edged and sharp in shape.
  • Incisors are mainly adapted for cutting.
  • Incisors help us to make the initial bite.

definition

Canine

Canines are 'V shaped peak' located beside the incisors. The have the following features:
  • 2 canines are present in each jaw. 
  • They help the premolars and incisors during chewing.
  • Canine are strong and pointed for tearing food.

definition

Premolars

Premolars share features of both, canines and molars. They have the following characters:
  • Each jaw consists of 4 premolars.
  • They are slightly flat with ridges on top. 
  • Premolars are used to chew and tear food.
  • Initial grinding is done by them.

definition

Molars

Molars are stronger than the premolars. They are located at the back of the mouth. Molars are known to have the following characteristics:
  • There are 6 molars in each jaw.
  • They are broad and flat on top.
  • Molars help in crushing and grinding food.

definition

Difference between different types of teeth

Type of toothLocationFeatureFunction
1.IncisorIncisors are situated in the centre of both, top and bottom jaw.
  • 4 incisors are present in each jaw.
  • They are thin, flat-bottom, narrow-edged and sharp in shape.
They are adapted for cutting.
2.CanineLocated beside the incisors.
  • Canines are 'v-shaped'.
  • There are 2 canines present in each jaw.
  • They are strong and pointed.
They are used for tearing food.
3.PremolarThey are located beside canines.
  • There are 4 premolars in each jaw.
  • They are slightly flat with ridges on top.
Premolars are used to chew and tear food. Initial grinding is done by them.
4.MolarThey are located at the back of the mouth.
  • They are stronger than the premolars.
  • There are 6 molars in each jaw.
  • Molars are broad and flat on top.
Molars are responsible for crushing and grinding the food.

definition

Dental formula

Dental formulae indicate the number of each type of tooth in a given species.
The jaw is bilaterally symmetrical. Hence, the dental formulae represent the number considering the half jaw only. 
The numerator of the fraction represents the number of teeth in the upper jaw and denominator represents the number of teeth in the lower jaw.
The formula represents number of teeth in the following order (left to right): Incisors, Canine, Premolars, Molars
Example:

formula

Dental formula in humans

Dental formula is used to calculate the number of teeth in mammals. The human dental formula is as follows:
  • Human child (upto 2 years):
    Thus, the total number of teeth are = 2x10= 20 (milk teeth)
  • Human adolescent (17-20 years): 
    Thus, the total number of teeth are = 2x14= 28 (permanent teeth)
  • Human adult: 
    Thus, the total number of teeth are = 2x16= 32 (permanent teeth + wisdom teeth)