Teeth Anatomy: How many teeth do humans have?


We see our teeth every day – flossing, brushing, or even smiling at the mirror before leaving the house. But have you ever checked how many teeth you have?

Perhaps you learned the correct number of teeth back when you were in school or before getting braces fitted in. However, as we approach adulthood, our teeth structure changes and grows, as wisdom teeth begin to come through – meaning it can be difficult to know how many teeth you have as an adult.

During childhood, we grow 20 primary teeth (milk teeth), which are replaced by 32 secondary, or permanent teeth. Our secondary teeth have different roles to maintain healthy mouth function and contain a range of tissue types.

The more we know about what our teeth are made of and what they do can help us to keep them clean and healthy throughout the rest of our lives.

What are teeth made of?

All human teeth are made up of dental tissue: cells that grow together to perform specific functions. Each tooth contains four types of tissue, ranging from soft and sensitive, to as hard as a bone. While they all perform different roles within the anatomy of the tooth, each form an integral part of our overall teeth and mouth health.

1. Enamel

Your enamel is a bit like a ‘bodyguard’ – it protects your teeth from harmful bacteria and infection, and it’s the hardest tissue in your entire body. Forming the outside layer of the crown, this hard substance covers sensitive nerve tissue, and helps your teeth to withstand the pressure of chewing food.

Your tooth enamel can change in temperature from hot or cold foods, expanding or contracting to protect you from painful sensations caused by extreme temperature changes. If you’ve ever felt pain when drinking an ice-cold soda, it’s possible that your enamel may have started to wear down, which would allow these cold sensations to seep through to nerves underneath.

2. Pulp

The pulp is the soft, innermost part of the tooth. Deeply sensitive with nerves and connective tissue, the pulp also helps to keep the tooth nourished through blood vessels. The pulp is made up of two parts: the root canal and the pulp chamber. Blood and nerve signals travel through the root canal and into the pulp chamber.

3. Dentin

Dentin is a hard, yellowish substance that lives underneath the enamel. Surrounding the pulp, dentin helps to protect the soft centre of the tooth from harmful bacteria, whilst giving teeth a natural, yellowish tinge. The wearing down of the enamel, through sugary or acidic foods, can leave the dentin more exposed, causing teeth to look more yellow. However, nowadays there are various methods for you to choose from to whiten your teeth.

4. Cementum

Cementum, as the name suggests, is incredibly hard – as strong as the bones in your body. A calcified tissue, cementum sits inside the gums, covering the outside layer of the root and helping with the repair and regeneration of teeth. It’s also what keeps your teeth in place within the jawbone.

Teeth names/Types of teeth

Once your permanent teeth are fully developed, you’ll have 32 teeth, which are classified into different groups: incisors, cuspids (canines), bicuspids (premolars), molars, and wisdom teeth.

However, knowing the human teeth numbers only tells one part of the story of how your teeth process food, fight infection, and maintain a healthy mouth. So which types of teeth fall into each group and what are they used for?

1. Incisor teeth

Give yourself a big smile into a mirror and it’s your incisors that you’ll likely see first. Sitting within the centre of your mouth, you have 4 incisors in the bottom set of your teeth and 4 in the top front. Each with a flat, wide appearance and a chiselled edge, they’re perfect for biting into your favourite foods.

2. Cuspids/Canine teeth

Cuspids are commonly known as canines because of their sharp, pointed appearance. With 2 cuspids on your top set of teeth and two on the bottom, they help us to tear into tougher foods, like steak or crusty bread.

3. Bicuspids/Premolar teeth

Bicuspids’, or premolars, have a flatter top surface with ridges. With a similar appearance to molars, you can distinguish the two by knowing that your bicuspids/premolars are smaller and closer to the front of your teeth, with molars sitting at the back. You have 8 bicuspids, with four on your top set of teeth and four on the bottom – this symmetry helps them to grind against food and break it into smaller pieces.

4. Molar teeth

Molars are the large teeth at the back of your mouth. Of all tooth types, they are the strongest and with 6 on the front set and 6 on the bottom, they form the ‘brute strength’ that helps to grind down even the toughest foods, making them small enough to swallow.

5. Wisdom teeth

Unfortunately, they don’t make us any wiser – but the growth of our four wisdom teeth is a sign that we are getting older! Developing the latest out of all teeth, wisdom teeth are also known as third molars because they sit right at the back of your mouth.

Sometimes, wisdom teeth need to be extracted by a dentist, to give the rest of your teeth enough room to work without pain or swelling. But don’t worry if this does happen – your wisdom teeth are largely functionless and are merely an example of how our bodies have evolved over time.

While some of us may have teeth removed for dental or medical reasons, the majority of adults have 32 secondary teeth. This includes wisdom teeth, which set in later in life and may cause some pain as they grow. Speak to your dentist if this has been causing you discomfort and they can recommend the best course of action for wisdom teeth removal.