CUTTING AND BITTING TEETH: PROVEN ACTIVITIES OF IT
CUTTING AND BITTING TEETH
Teeth are the hardest non- bony structure in the vertebrate body, jaw bones attach with these
in cutting and biting teeth. In our body, we use these for biting, chewing and
grinding of the food or in catching of prey in cutting and biting teeth. We intake food with the help of teeth.
TYPES OF TEETH IN CUTTING AND BITING TEETH::–
Most animals have Teeth in their jaws. Teeth are used to cut and break
the food into smaller parts. The kind, number and arrangement of teeth
in a personal or animal we term it as ” dentition “. It is of two types:
a) HOMODONT: All the teeth in the jaws are similar in shape and structure e.g fish and frog.
b)HETERODONT: The teeth in the jaws are not similar in shape and
structure e.g. cows and humans.
Mammals have heterodont dentition since all the teeth are not alike in them .
There are four types of teeth in mammals; incisors, canines, premolars and molars.
The number, size and shape of the teeth depends on the food the animals consume.
STRUCTURE OF A HUMAN TOOTH IN CUTTING AND BITING TEETH::–
The Bony sockets or alveoli in the jaw bones encloses the human teeth.
These we term as ” thecodont”. Each tooth consists of three parts.
* ROOTS— The basal part, embedded in the alveoli.
* NECK— They middle part enclosed in the gum.
* CROWN— They visible part projected beyond the gum.
Fig#1 simplified diagram of a premolar
In longitudinal section of a tooth in cutting and biting teeth, the following parts are seen:-
The white shiny outer covering of the crown is called enamel or ivory.
Ø It is the hardest substance in the body. It can withstand tremendous pressure
while eating. Enamel wears away with age and dentine in cutting and biting teeth and there are exposed teeth. The
teeth start looking yellow.
b) Dentine: It is the yellowish bone- like tissue that lies inside the enamel.
Dentine is not hard like enamel but harder and stronger than a bone.
It is a bone like structure that covers and fixes the root of
tooth in cutting and biting teeth within the socket of bone.
d) Pulp cavity and pulp
: Pulp cavity is the central space in the tooth and is filled with soft
connective tissue. The pulp is richly supplied with blood capillaries, nerve fibers and
lymph vessels. These enter the pulp through root canal. The narrow part of the pulp
cavity in cutting and biting teeth is called root canal.
Fig#2 simplified diagram of an incisor
e) Odontoblasts: Dentine contains many canals in cutting and biting teeth having dentine producing cells we term as
f) Periodontal fibres: Many fibres connect cement at one end and the jawbone at the other
end and hold the tooth firmly in position which are known as periodontal fiber.
CHARACTERISTICS OF HUMAN TEETH IN CUTTING AND BITING TEETH::
The human teeth are;
a) THECODONT—The socket of jaw bones contains the teeth.
b) DIPHYODONT: In human, we get two sets of teeth during lifetime.
These we know as temporary or deciduous teeth and permanent teeth.
The temporary teeth appear first. Permanent set of teeth replaces the milk teeth.
The deciduous or milk teeth fall because their roots begin to dissolve making way for
permanent teeth. The total number of teeth in adult is 32 which are permanent, but children
up to age of 12 years have just 20 temporary or milk teeth in cutting and biting teeth.