The Anatomy of Teeth

Not all teeth are the same. Your mouth contains four types of teeth: incisors, canines, premolars, and molars. Incisors sit in the front of your mouth, four on your upper jaw and four on your lower jaw. Next come the canines, the pointed teeth on each side of our incisor sets, giving us a total of four. Next are the premolars, which sit in sets of two between the canines and the molars, giving you a total of eight premolars. Finally come the molars, which also sit in the same way that premolars sit. Most people also have four extra molars, known as wisdom teeth. Sometimes, dental professionals classify wisdom teeth as a fifth category.

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All four types of teeth have multiple layers. Immediately under the top-most coating of enamel is the dentin, followed by the pulp cavity, and cementum. Inside the tooth lie nerves, living cells, and blood vessels. Continual wear and tear will expose these vital parts of the tooth, and this can eventually cause irreparable damage.

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Enamel is the translucent layer that covers the visible part of the tooth. It is the hardest tissue in the entire body. While all teeth grow in with a layer of enamel, this layer can be slowly stripped away and leave the sensitive parts of the tooth exposed. Once enamel is gone, it does not grow back and dental problems often follow. Enamel also insulates the teeth and protects them from harmful substances into which they may come in contact. Avoiding certain foods and consistent cleaning can protect tooth enamel.

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Enamel is important, but the role dentin plays in healthy teeth is also crucial. This calcified tissue has tiny tubes throughout the area it covers. It can continue to form throughout our lifetime and can respond to a need, like the decay of a tooth. There are three types of dentin: primary, secondary, and tertiary. Primary dentin is the most prominent in the tooth, while secondary grows after the root forms. Tertiary dentin is the type that grows in response to a need or stimulation.

Underneath the dentin layer is the pulp cavity. Possibly the most important part of the tooth, this area contains blood vessels, nerves, and tissue. The tooth pulp also plays a vital role in healthy teeth. The nerves enable it to react to pain and stimulation, and it is also responsible for the formation of dentin. The pulp prompts the secondary dentin to form.

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Like the cement construction workers lay, cementum in the teeth provides solidity and helps the tooth keep its place in the jaw. Cementum is connective and there are four kinds: acellular afibrillar, acellular extrinsic fiber, cellular intrinsic fiber, and cellular mixed fiber. The loss of cementum can cause multiple problems, including sensitive teeth and dentin exposure.

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Teeth are not bones. While bones are made primarily of collagen, teeth are mainly made up of dentin, which provides their shape and the majority of their strength. Bones have incredible regenerative properties, but the same cannot be said for teeth. Teeth do not have the ability to grow back or heal themselves as bones can. On the other hand. teeth are the hardest part of the human body, even harder than bones.

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Only about a third of each tooth is visible. The rest lies below the surface, anchoring the tooth in your gums and providing vital but unnoticed services, like blood flow. The visible part of the tooth is the crown, while the part below the gum is known as the root.

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Cementum isn't the only thing that holds a tooth in place. The periodontal ligament, the PDL, also plays an important role in the structure and security of a tooth. Made of a special connective tissue, the PDL holds the tooth to the bone that it sits on within the jaw. It also contains vessels and neural connections.

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Not to be forgotten, the neck of the tooth is one more essential component. Connecting the crown to either two or four roots; incisor and canine teeth have only two roots, while molars and premolars have four. Gum tissue or gingiva surrounds the neck of the tooth.

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