Tooth - Anatomy

About Tooth

‘Tooth’ is the singular form of teeth, it is a hard and resistant structure. It is found on the jaw or in or around the mouth and pharynx region of the vertebrates. Their main function is to do catching and masticating food, for defence, and for other specialized purposes. 

It represents the descendants of bony dermal plates that are known to be armoured ancestral fishes. Tooths are made up of a crown and one or more than one roots and this root part is not visible. It is present under the gum and does the function of supporting the tooth. 

The tooth is known to be the strongest and the most rigid substance of the human body and normal adults have 32 teeth. The human tooth is divided into four types: incisor, canine, molars and premolars. Wisdom teeth are the third molar teeth that appear in a person’s late teens or early twenties.


Functions of Tooth

Some of the major function of the tooth are listed below:

A. The incisors are mainly used for the cutting and biting process. Along with that, they are also used for gripping. 

B. Tooths are used for the chewing process as while chewing, food is being converted into a bolus which can be easily swallowed for further digestion process. 

C. Tooth also gives support and shape to the face. 

D. Tooth also helps in the pronunciation of sounds during speech. 


Parts of Tooth

Parts of the tooth include:

  • Enamel: It is known to be the hardest part of the tooth which is white in colour. It is made up of calcium phosphate, a rock-hard mineral.

  • Dentin: Dentine is the underlying layer of the enamel. It is made up of hard tissue having microscopic tubes. In the case of damaged enamel, heat or cold can enter the tooth through these paths and cause sensitivity or pain.

  • Pulp: It is the softer, living inner structure of the tooth and through these blood vessels and nerves run through the pulp of the teeth.

  • Cementum: It is a layer of connective tissue that does the function of binding the roots of the teeth firmly to the gums and jawbone.

  • Periodontal Ligament: It is a kind of tissue that helps to hold the teeth tightly against the jaw.

Anatomy of Tooth

The tooth is made of three parts: root, neck and crown. 

A. The Root: It is a part of the tooth that extends into the bone and holds the tooth in place. It consists of almost two-thirds of the tooth.

  • The root is further made up of several parts, they are:

  • Root Canal: It is a kind of passageway that has pulp in it. 

  • Cementum: It is also called cement and it is a bone-like material that covers the tooth root, further, it is also connected to the periodontal ligament.

  • Periodontal Ligament: It is made up of connective tissue and collagen fibre. It has both nerves and blood vessels. It also acts as a connection to the teeth to the sockets along with cementum. 

  • Nerves and Blood Vessels: These blood vessels do the functioning of supplying the periodontal ligament with nutrients, while nerves help control the amount of force used when you chew.

  • Jaw Bone: It is also called an alveolar bone, and also contains the tooth sockets and surrounds the teeth’s roots; it does the function of holding the teeth in place.

B. Neck: This part is called the dental cervix, which is present between the crown and root. It acts as a line where the cementum meets the enamel.

Three main parts of the neck are:

  • Gums. It is also called gingiva. They are fleshy in nature with a pink colour connective tissue that’s attached to the neck of the tooth and the cementum.

  • Pulp: It is the innermost portion of the tooth that is made up of tiny blood vessels and nerve tissue.

  • Pulp Cavity: it is also called a pulp chamber as it is the space inside the crown that contains the pulp.

C. Crown: it is the visible part of the tooth. It further comprises three parts, they are: 

  • Anatomical Crown:  It is the topmost part of the tooth, which is easily visible.  

  • Enamel: It is the outermost part of the tooth and also the hardest part of the body. It protects teeth from different harmful bacterias and also provides strength to the tooth. 

  • Dentin: It is a layer of mineralized tissue which is present just below the enamel, which is extended through the crown down through the neck and root. Its main function is protecting teeth from heat and cold.

FAQs (Frequently Asked Questions)

1. Explain Different Types of Teeth in Humans?

Ans. There are four types of teeth in the human body, they are:

A. Incisors: They are present in front of the mouth and have sharp edges. They mainly do the functioning of cutting food into small, chewable pieces. There are a total of eight incisors in the human, four in the upper jaw and four in the lower jaw. 

B. Canines: They are also called cuspids which are situated at the corner of the dental arches. They are sharp, with elongated and pointy surfaces that do the function of tearing food especially meat and flesh. The human body has four canines, two in the upper jaw and two in the lower jaw. 

C. Premolars: They are also known as bicuspid and are located behind the canine. These teeth have a flat surface with ridges and do the function of crushing and grinding. Humans have a total of eight premolars, two on each side of the canines. 

D. Molars: They are known to have the largest and strongest teeth, they are flat in look and used for biting purposes. The human body has a total of twelve molar teeth, six in the upper jaw and six in the lower jaw. 

2.  Explain How Many Teeth Do Humans Have?

Ans. Human teeth are diphyodont i.e. grow two times in a lifetime. Humans possess two sets of teeth in a lifetime - milk teeth and permanent teeth. Children usually have 20 milk teeth which get gradually replaced by 32 permanent teeth as they mature.