The Composition of a Tooth

How much do you know about your teeth?

Your teeth begin to grow while you’re still a baby inside your mother’s womb. While they aren’t visible until a few years after birth when they “erupt” or come up from within the gums, they are there. Baby teeth, or primary teeth grow in and fall out in the same order and are replaced with permanent, or adult teeth. Your permanent teeth will be the teeth you have for the rest of your life. If you lose an adult tooth, it may be able to be re-attached at the root if you see a dentist immediately. In many cases, a lost permanent tooth means a fake tooth, such as a dental implant will be needed to replace the lost, natural tooth.

Your teeth are able to withstand much wear and tear as well as grinding and pressure. What makes teeth so hard and long-lasting? It likely has something to do with their composition.

Each tooth is made up of enamel, dentin and cementum and each tooth has a dental pulp.

Tooth Enamel

The part of the teeth you’re most familiar with is the tooth enamel. This is the hard, translucent, outer covering of the tooth. It is this part of the tooth that cavities can destroy and leave the tooth vulnerable to further decay and disease. The enamel is said to be the hardest and most mineral-packed substance of the body. Tooth enamel is made up of mostly minerals, with some organic compounds and water. The enamel is the thickest (and strongest) at the cusp of the tooth and is weakest along the tooth edges.

As we age, the years of use, abuse and wear and tear, the enamel slowly wears off in what is called attrition.

What is enamel made of? Crystalline calcium phosphate called hydroxyapatite accounts for most of the minerals found in tooth enamel. These minerals give teeth their strength, as well as their brittleness. Enamel also doesn’t contain collagen like other parts of the tooth. Tuftelins, ameloblastsins, ameloblenins and enamelins are proteins that help develop enamel.

Dentin

Underneath the enamel is a porous, yellowish material called dentin. It is this material that gives teeth their classic yellow, or preferably white color. Dentin is made up of inorganic and organic materials as well as water. It is made of mineralized connective tissue and collagen proteins. Dentinogenesis, or the process of forming dentin involves the secretion by odontoblasts of the tooth pulp. Dentin contains a matrix of microscopic tubules that don’t criss-cross each other. The length of the tubules are determined by the radius of one’s tooth. Dentin is the substance between enamel or cementum and the pulp chamber.

While dentin isn’t as strong as enamel, it still gives your teeth extra strength, support and protection. Because it is softer than enamel, it decays more rapidly and is subject to severe cavities if not properly treated, but dentin still acts as a protective layer and supports the crown of the tooth.

Cementum

The innermost layer of the tooth is called the cementum. This part of the tooth resembles bone and it covers the tooth pulp. Like the tooth enamel and dentin, the cementum is made of inorganic (mostly hydroxyapatite), organic (mostly collagen) and water. Cementum is softer than the enamel and dentin and is secreted by cementoblasts that are in the root of the tooth. It too has a yellowish color and is the thickest around the apex of the tooth root. This part of the tooth has the purpose of being a medium through which the periodontal ligaments (the ligaments of the gums) attach to the tooth, giving the tooth stability.

Tooth Pulp

In the center of each tooth is the pulp. The pulp consists of connective tissue that contains nerves and blood vessels. The tooth pulp supplies the tooth with blood and nutrients as well as infection-fighting macrophages and T lymphocytes. It is in the pulp where the odontoblasts which make dentin are located as well as nerve endings, which give the tooth the ability to react to hot or cold food and drink.

Teeth are simple, yet complex, which make them strong and durable. They are, however vulnerable to trauma from wear and tear and disease and decay from poor oral hygiene. Certain tooth conditions like tooth sensitivity can be indications that something is wrong and you should see your dentist.