Tooth Anatomy: The Structure, Function, and Types of Human Teeth

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The WHO states that the number of teeth in an individual’s mouth can be a key indicator of oral health status.

Tooth Anatomy

It is indisputable that teeth are essential for our sustenance and well-being. But how well do you know your teeth?

In this article, we discuss the anatomy of a tooth and the various types and their functions so that by the end, you know your teeth inside out.

Introduction to Teeth

What are teeth? Teeth are hard, calcified appendages that play a significant role in digestion. They are composed of unique tissues of varying densities and hardness that allow them to bite, cut, and crush foods, making them easier to swallow.

They are attached to the upper and lower jaws of the mouth with the help of ligaments and bones. Most humans have 32 permanent teeth, however, some have more (hyperdontia) or fewer (hypodontia) depending on their development.

Different types of teeth

Different teeth are labeled for identification. 

An adult dentition has two incisors, one canine, two premolars, and three molars in each half of the jaw. Children have two incisors, one canine, and two molars on each half of their jaw. Kids do not have premolars.

The type of tooth varies based on its function and form. 

Incisors: The incisor is wide and thin and is the front, most visible teeth found in your mouth. You have four incisor teeth on the upper jaw and four on the lower. They are used for cutting food when you bite.

Canines: These teeth are pointier than other types of teeth. You have four canine teeth, one on each half of the jaw. Due to their sharp form, they are used to shear foods into bite-sized pieces.

Premolars: These sit between your canines and molars. You have two premolar teeth on each half of your jaw (upper left, upper right, lower left, lower right). They help tear and crush food into smaller pieces.

The premolars and molars have a series of elevations (called cusps) for breaking up food into smaller pieces. Since the premolars have two cusps, they are also called bicuspids.

Molars: The molar teeth are the rear teeth of your mouth. They are used for crushing and grinding. You have 12 adult molars in your mouth – six molars in each jaw. The third molars are commonly called wisdom teeth and are often surgically removed. 

Teeth are also varied in the number of roots they have. While incisors, canines, and premolars are best known to have only one root, molars can have two or three.

Understanding tooth development

Primary (Baby) teeth vs Permanent (adult) teeth

Primary (Baby) teeth

A child’s first set of teeth are called primary or deciduous teeth. During development, a child goes through 20 primary teeth which are gradually replaced by adult teeth. A typical adult has a total of 32 teeth during life.

The process of tooth eruption

Tooth eruption begins at 6 months of age and may last till 3 years. During this stage of tooth eruption, your child’s gums may be sore and irritable. Using a cold or wet cloth to soothe the gums may be helpful.

The first teeth to erupt are the central incisors (6 to 12 months), followed by the lateral incisors, first molars, and canines. The second molars are the last ones to erupt between 23 and 33 months. 

The process of shedding

A baby’s teeth begin falling out by the time they turn 6. The centrals are the first to go, followed by the laterals at age 7. The first molars shed next, followed by the lower canines. The upper canines and the second molars are the last to shed at around 10 to 12 years.

By 12 years of age, all their milk teeth are replaced by permanent teeth. The primary molars are replaced by the permanent premolars and the permanent molars come in behind the primary teeth.

The tooth anatomy: Parts, structure, and function

Every tooth has four main layers: enamel, dentin, cementum, and pulp.

Enamel: You will find enamel on the crown portion of a tooth. The tooth enamel is the hardest substance in the human body and forms the outermost protective layer of the tooth. It helps shield the teeth from cavity-causing bacteria. It is only found in the tooth crown and not the root.

Dentin: Underneath the enamel is the softer layer of dentin. This is the protective casing that covers the innermost live tissue of the tooth. The crown of each tooth is made up of the enamel and the dentin. You will find this layer in both the crown and root of a tooth. 

Pulp: The pulp is a loose connective tissue found in the innermost portion of the tooth. This is the center of the tooth that contains blood vessels to supply blood and nutrients to keep the tooth alive and nerves for sensation and perception of temperatures.

Cementum: The root of the tooth does not have an enamel covering. Instead, the tissue covering the tooth root is called cementum. It is roughly as hard as the bone and helps anchor the tooth firmly to the jaw.

The tooth structure

Other soft and hard tissues

Gingiva: Gum or gingiva is a pink soft tissue that covers the neck part of the tooth. It protects the jaw bone and tooth roots from harmful bacteria and plaque.

Root canal: The space inside the root where the pulp extends from the pulp chamber is called the root canal. Nerves and blood vessels enter the tooth pulp from the surrounding tissue through the root canal. It spans the entire length of the tooth root.

Periodontal ligament: The periodontal ligament is made up of bundles of connective tissue fibers, each attached to the cementum. These fibers anchor the tooth root to the jaw and help hold the tooth in place. They also act as shock absorbers to allow the tooth to withstand the forces of chewing.

Alveolar bone: The alveolar bone is essentially the jaw bone that surrounds and supports the roots of each tooth. It contains the tooth sockets within which each tooth root is attached.

Parts of a tooth

Each of our teeth is composed of three different parts: the crown, neck, and root.

Crown: The crown is the top portion of the tooth that you can see in your mouth. It is exposed and visible above the gums.

Neck: The neck of the tooth, also called the dental cervix is the tooth’s dividing region. It is the neck that connects the crown and the root of a tooth. It forms the cementoenamel junction where the enamel of the crown of the tooth connects to the cementum of the root of the tooth.

Root: Just below the neck lies the root portion of the tooth. This makes up approximately two-thirds of the tooth and helps firmly attach the tooth to the jaw bone. center of the tooth

The function of teeth

All your teeth work harmoniously together to cut, mix, and crush your food into smaller pieces. Once the food pieces are finely ground up, the tongue and the upper part of your throat (oropharynx) turn the food into a small ball (bolus) that is easier to swallow.

The function of teeth

Additionally, they give structural support to the shape of the face. They also help aid in the pronunciation of certain sounds when speaking.

Importance of regular dental checkups: Visiting the dentist every six months for routine dental examinations and cleanings is crucial to maintaining proper oral health. 

Daily oral hygiene practices: Keep your teeth clean by brushing and flossing them at least twice daily. Use an alcohol-free, antibacterial mouthwash for added protection.

Healthy dietary habits for strong teeth and gums: Eat a well-balanced diet. Avoid overconsumption of hard, sticky, or sugary foods. You should also avoid adverse habits like smoking.

Addressing dental concerns promptly: At dental examinations, your dentist can check to see teeth that contain tooth decay, chips, or loose fillings. Harmful habits like teeth grinding and other pathologies like gum disease, loose teeth, or strained jaw muscles can be diagnosed and taken care of during these appointments.


Our teeth are an important part of our digestive system. Teeth differ in variety but are all required to conduct different functions. To keep your teeth healthy, visit your dental care provider regularly and practice good oral hygiene at home.


Can the tooth nerve be damaged?

Nerve damage can occur due to deep cavities, traumatic injury, or gradual wear-and-tear of the outer layer of the tooth. Even if you experience mild pain, contact your dentist and receive emergency care for your potentially damaged tooth.

What if I am missing teeth?

Some people may be born without certain teeth. Others may lose teeth due to cavities, trauma, or gum disease. If you’re missing many teeth and do not replace them, you may risk alignment and bite problems. For tooth loss, you can opt for dentures, crowns, or dental implants.

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