What Are the Main Parts of a 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 on Tooth Anatomy: Parts and Functions
1. What are the main parts that make up the structure of a human tooth?
Every human tooth consists of two main parts: the crown and the root. The entire structure is composed of several distinct layers, each with a specific function:
- Crown: This is the visible part of the tooth that sits above the gum line.
- Root: This is the part of the tooth embedded within the jawbone, holding it in place.
- Enamel: The outermost, protective layer of the crown. It is the hardest substance in the human body and protects the tooth from decay and wear.
- Dentin: A hard, bone-like tissue found directly beneath the enamel. It forms the bulk of the tooth and contains microscopic tubules that can transmit sensations like hot or cold to the nerve.
- Pulp: The innermost, soft tissue of the tooth containing nerves, blood vessels, and connective tissue. It provides nourishment and sensation to the tooth.
- Cementum: A hard layer of connective tissue that covers the tooth's root and helps anchor it to the jawbone via the periodontal ligament.
2. What are the four types of teeth in an adult human, and what are their specific functions?
An adult human has four different types of teeth, each adapted for a particular role in breaking down food:
- Incisors: These are the eight sharp, chisel-shaped teeth at the front of the mouth (four on top, four on the bottom). Their primary function is to cut and slice food.
- Canines: Located at the corners of the dental arches, these four pointed teeth (two on top, two on the bottom) are used for tearing and ripping tough foods like meat.
- Premolars (Bicuspids): These eight teeth are situated between the canines and molars. They have a flatter surface with ridges, making them ideal for crushing and grinding food.
- Molars: These are the largest and strongest teeth, located at the back of the mouth. With their broad, flat surfaces, their main function is the intensive grinding and chewing of food before swallowing.
3. Why do humans have two different sets of teeth during their lifetime?
Humans have two sets of teeth, a condition known as diphyodont, to accommodate the growth of the jaw from infancy to adulthood. The first set, called milk teeth or deciduous teeth, consists of 20 smaller teeth that fit in a child's small jaw. As the child grows, their jaw expands, requiring larger, stronger teeth for effective chewing. Consequently, the milk teeth fall out and are replaced by a set of 32 larger permanent teeth that are designed to last for the rest of a person's life.
4. What is the human dental formula, and how is it written for an adult?
The human dental formula is a simple way to represent the number and types of teeth in one half of the jaw, both upper and lower. For an adult human, the permanent dental formula is 2123/2123. This is interpreted as follows:
- The numbers in the numerator represent the teeth in one half of the upper jaw: 2 incisors, 1 canine, 2 premolars, and 3 molars.
- The numbers in the denominator represent the teeth in one half of the lower jaw, which mirrors the upper jaw: 2 incisors, 1 canine, 2 premolars, and 3 molars.
- Adding these numbers (2+1+2+3 = 8) and multiplying by four (for all four quadrants of the mouth) gives the total of 32 permanent teeth.
5. How do the different shapes of our teeth relate to their function in eating?
The varied shapes of our teeth are a direct reflection of their specialized functions, a key principle of anatomy. This design allows for the efficient mechanical digestion of a wide variety of foods:
- The sharp, flat edges of the incisors act like scissors, making them perfect for biting off pieces of food.
- The pointed, conical shape of the canines is ideal for piercing and tearing tougher foods.
- The broad surfaces of the premolars and molars act like millstones, providing a large area for crushing and grinding food into a paste, which is easier to swallow and digest.
6. What makes tooth enamel the hardest substance in the human body?
Tooth enamel is the hardest substance in the human body primarily because of its extremely high mineral content. It is composed of about 96% minerals, mainly a crystalline form of calcium phosphate called hydroxyapatite. This dense, tightly packed crystal structure gives enamel its incredible strength and durability, enabling it to withstand the immense pressures of chewing and protecting the sensitive inner layers of the tooth from damage and decay.
7. What is the fundamental difference between the dentin and the pulp of a tooth?
The fundamental difference lies in their composition and function. Dentin is a hard, calcified, bone-like tissue that forms the main mass of the tooth, providing structural support to the enamel. In contrast, the pulp is the living, innermost part of the tooth, composed of soft tissue. The pulp contains the tooth's nerve and blood supply, making it responsible for providing nourishment, growth, and sensation. Essentially, dentin is the protective, hard structure, while pulp is the living core.
8. What holds a tooth so securely in the jawbone?
A tooth is held securely in its socket in the jawbone by a specialised structure called the periodontal ligament. This ligament is a group of strong connective tissue fibres that anchor the cementum, a hard layer covering the root of the tooth, to the alveolar bone of the jaw. This connection is firm enough to withstand biting forces yet flexible enough to act as a shock absorber, preventing the tooth from fracturing under pressure.
