When it comes to our bodies, teeth often don’t get the attention they deserve. Yet, they play a vital role far beyond just giving us a great smile. Teeth are essential for digestion, helping break down food through chewing and making eating easier. Structurally, they also support the shape of your face and contribute significantly to your overall appearance.

But there's much more to a tooth than the white enamel you see in the mirror. Beneath the surface lies a complex structure made up of different layers and tissues, each with its own purpose. By understanding normal tooth anatomy, patients can better recognise early signs of dental issues, make more informed decisions, and take a more active role in their oral health.

In this post, we’ll explore both the visible and hidden parts of a tooth and explain how different types of teeth are uniquely designed to perform specific functions in the mouth.

Understanding Tooth Structure: The Crown & The Root

Every tooth is made up of two essential parts that work together to perform its function: the crown and the root. The Crown is a visible functional part of the tooth involved in daily activities, and the root operates beneath the surface, providing essential support and stability. Together, the crown and root form a complete and functional unit. A healthy balance between the two is primary for lasting dental health.

The Crown – The Visible Surface

The crown is the top part of the tooth that sits above the gumline, which you see when you smile or bite into food. This part of the tooth is responsible for cutting, grinding, and chewing. It is coated in enamel, the hardest substance in the human body, which acts as a strong protective shield against daily wear, decay, and temperature changes.

Just beneath the enamel lies dentin, a supportive, yellowish layer that reinforces the structure of the crown and helps transmit sensation.

The Root – Structural Foundation of the Tooth

Below the gumline lies the root, which makes up about two-thirds of the tooth’s total length. It extends deep into the jawbone, anchoring the tooth firmly in place. The root is connected to the surrounding bone through the periodontal ligament, a network of tiny fibers that absorb pressure from chewing and provide stability. Inside the root is the root canal, which continues from the pulp chamber in the crown and carries the nerves and blood vessels that keep the tooth alive.

Inside the Tooth: A Closer Look at Its Internal Structure

Enamel Enamel is the thin, outermost layer of your tooth and the hardest substance in the human body, even tougher than bone. Its main job is to protect the inner layers of the tooth from daily wear, pressure from chewing, and harmful bacteria. Despite its incredible strength, enamel can wear down over time. Acidic foods and drinks, poor oral hygiene, and teeth grinding can all contribute to enamel erosion. Unlike other tissues in your body, enamel has no living cells; it can't regenerate once it’s damaged or lost. Once enamel is gone, only a dentist can restore it using treatments like fillings, crowns, or dental bonding.

Dentin Dentin is the layer found just beneath the enamel and makes up the bulk of the tooth’s structure and gives teeth their slightly yellowish colour. Although not as hard as enamel, dentin is still strong and durable. It is also porous, containing thousands of tiny tubules that lead directly to the tooth’s pulp, where the nerves are located. When enamel wears away or gums recede and expose the root, these tubules can allow hot, cold, sweet, or acidic sensations to reach the nerves, causing tooth sensitivity.

Pulp The pulp is the soft, innermost part of the tooth, found at the center of both the crown and the root. Often called the tooth’s “nerve center,” it contains nerves, blood vessels, and connective tissue that help nourish the tooth and support its growth during development. If bacteria reach the pulp, it can cause severe pain due to infection. However, once a tooth is fully developed, it no longer relies on the pulp to survive. This is why root canal treatment can be done removing the infected pulp allowing the tooth to be saved and function normally.

Cementum
Cementum is a thin, hard layer of tissue that covers the root of the tooth, located below the gumline. It plays a crucial role in anchoring the tooth securely within the jawbone by serving as the attachment point for the periodontal ligament. Acting like a protective coating, cementum helps cushion the tooth during chewing by absorbing some of the pressure between the root and the surrounding bone. Although it is not as hard as enamel, it is tougher than dentin. Cementum is also essential for the ongoing repair and maintenance of the tooth root throughout life.

Periodontal ligament
Attached to the outer layer of the tooth root (cementum), the periodontal ligament is a network of soft connective tissue fibers. It plays a vital role in stabilising the tooth by anchoring it to the alveolar bone, the part of the jaw that forms the socket around the root. Acting as a natural shock absorber, the periodontal ligament helps cushion the forces of chewing and biting. In addition to providing support and sensory feedback, it also contributes to the repair and regeneration of nearby tissues and allows for slight, controlled movement of the tooth within its socket.

Gums
The gum tissue, also called the gingiva in medical terms, surrounds the base of each tooth and forms a soft, pink covering that protects both the teeth and underlying bone. It acts as a barrier, sealing out bacteria and debris to help prevent infection from reaching deeper parts of the tooth. Healthy gums also help hold the teeth firmly in place and play a key role in preventing inflammation and disease from spreading below the surface. When gums become inflamed and begin to recede, the sensitive root surfaces may become exposed, leading to the risk of tooth sensitivity and decay.

Alveolar bone
The alveolar bone forms the foundation that supports your teeth, keeping them securely anchored in the jaw. The health of your jawbone directly impacts both the firmness of your teeth and the overall appearance of your face. When this bone is damaged or lost often due to advanced gum disease, also known as periodontitis, it can lead to tooth loosening, shifting, or even loss.

Tooth Types and Their Function

The human mouth has four main types of teeth: incisors, canines, premolars, and molars and each tooth type has a unique shape that helps it do a specific job during chewing. The way each tooth is built, including its shape and root, matches its function in breaking down food efficiently.

1. Incisors: Incisors are the frontmost teeth, four on the top and four on the bottom. These teeth have thin, sharp edges designed like scissors to slice through food. Their primary role is to cut pieces of food into manageable bites, especially fruits, vegetables, and other soft items.

2. Canines: Located next to the incisors, canines are the pointed, fang-like teeth one on each side in the upper and lower jaws. These strong teeth are built to grip and tear food, particularly helpful when biting into tougher items like meat. Their shape and strength make them essential for breaking down fibrous foods.

3. Premolars: Behind the canines are the premolars, or bicuspids. These teeth have two pointed cusps on their biting surface and serve a dual purpose: tearing like canines and crushing like molars. Their transitional function makes them essential in preparing food to be properly chewed as it moves toward the back of the mouth.

4. Molars: At the very back of the mouth are the molars, the largest and strongest teeth. Adults typically have 12 molars, including four wisdom teeth. Molars have broad, flat surfaces with multiple cusps, designed to crush and grind food thoroughly. In fact, they handle about 90% of the chewing work. Their wide crowns and multiple roots (usually two or three) give them the strength needed to process even the toughest foods.

Prioritise Your Oral Health

Are you due for a dental check-up or have questions about your teeth and gums? Don’t hesitate, your oral health matters. Whether your smile goals are, our friendly team at Warwick Lodge Dental in Herne Bay, Kent is here to help. Book your appointment today!