What Do Teeth Look Like Under a Microscope? (Astonishing Facts)

In this brief article we are going to learn about how our teeth look under the microscope. We will also learn about the various structures of the teeth and their functions.

Teeth Under a Microscope

Everybody knows that humans have two sets of teeth, the milk teeth and the permanent teeth and on an average a person has 28 to 32 teeth. We also know the names of our teeth, which are the 8 incisors in the front, 4 canines, 8 premolars and 8 to 12 molars at the end of our mouth.

The functions of each type of tooth were taught to us in our early school years. The incisors help in biting food, canines help in tearing meat, and the premolars and molars grind the found so that we can easily swallow it. Though the function of our teeth seems simple and the size of the teeth makes them look like there is not much to them, it is quite the opposite. As small as they appear to the eyes, there is much more to our teeth.

Our teeth are made up of different layers and each layer has a different composition as well as function. It may not be as clear to the naked eye, but under the microscope, each layer of the tooth looks extremely fascinating.

What Is The Anatomy Of Our Teeth?

When we talk about the macroscopic anatomy of our teeth, they are made up of four different layers. These layers are the enamel, dentine, cementum and the pulp. The enamel is the hardest structure in the human body. It is the outermost layer to the teeth, which also acts as the protective shield of our teeth. Enamel protects our teeth from problems like sensitivity, cavities etc and also keeps the subsequent inner structures of the teeth covered. It is because of the loss of this enamel that people start experiencing sensitivity to cold and hot foods and beverages.

The next layer is the dentine. Dentine forms the second layer of the teeth and this layer is slightly yellow in colour as compared to the enamel, which is milky white in shade. The dentine is the thickest layer out of all the layers of a tooth and is located just below the enamel. Unlike enamel, the dentine of our teeth forms throughout life and has the capability to regenerate and repair itself. It has microscopic tubules in it which are calcified. The dentine is of three types, namely:

  • Primary dentine
  • Secondary dentine
  • Tertiary dentine

Primary dentine forms the first and it is located between the enamel and the pulp chamber of the teeth. This dentine is the first to form out of the other two types of dentine and is confirmed till the enamel and pulp only.

Secondary dentine forms after the root formation of teeth. Yes, you read it right. The root of the teeth form later and the crowns develop first. It takes about 1 to 2 years after the eruption of the crown, for the root of the tooth to form completely. Ready this article to know more about the development time, sequence of eruption and root formation of the teeth in detail.

The third type of dentine is the tertiary dentine. This dentine is the last type to form and does not always exist in a tooth. Tertiary dentine is also known as reparative dentine. As mentioned earlier, dentine has the ability to repair itself. It is this dentine which forms when a damaged dentine tries to repair itself. It is formed when a cavity occurs in the tooth due to bacterial attack, and the bacteria start dissolving the tooth structure.

 The dentine tries to arrest the spread of this cavity and in response to this repair, tertiary dentine is formed. Unlike the other two types of dentine, tertiary dentine is softer in nature and takes time to harden completely. It is also not the same color as normal dentine and is usually darker, mostly brown to even black in color.

The third layer is the cementum. Cementum is not present on the crown of teeth and it only covers the root of the teeth. It acts like a connection between the teeth and the gums and jaw bone. It envelops the entire surface of the root from all sides and keeps the tooth attached to the underlying gums and bone.

The last layer to the teeth is the soft pulp chamber. It is this layer which keeps a tooth alive. This layer houses all the nerves, blood supply arterioles and venules and connective tissue of the tooth. This is the most sterile part of the tooth and is also extremely sensitive.

 When the cavity in a tooth gets deep enough and reaches the pulp chamber, the tooth starts to hurt. And if the cavity is left untreated, the pulp can get necrosed, or in other words it dies and in order to save the tooth, this diseased pulp has to be removed, something which is done during a procedure called root canal treatment. This article will tell you more about this treatment.

What Are Teeth Made Of?

We have all grown up listening to our elders tell us to drink milk because it is good for the teeth and bones. Though it is not completely true, the main idea behind it is that calcium is needed for healthy teeth and milk has calcium in it. Our teeth are made of calcium and a lot many other particles. 

As mentioned earlier, each surface of the teeth is different and is made of slightly different contents. The enamel is made up of a mineral, which is extremely hard and gives enamel the property of being the hardest structure in our body. This mineral is known as calcium phosphate. Enamel contains the highest number of minerals, which is about 96%. Hydroxyapatite is the primary mineral out of this, which is a crystallised form of calcium phosphate. The cells which form the enamel are called ameloblasts

Dentine is composed of a bone matrix type substance and is made up of 76% of minerals. Like enamel the main mineral in dentine is also hydroxyapatite and some non crystalline calcium phosphate as well. Other than this, dentine is also made up of organic substances like type 1 collagen and dentine specific proteins. The cells which lay down dentine are called odontoblasts.

The third layer, which is cementum, is softer than the other two layers and is made up of up 56% of minerals like hydroxyapatite. Collagen and proteoglycans make up the rest of the cementum. The cells which form cementum are called the cementoblasts and cementocytes.

The pulp chamber has numerous cells and is also called the cell rich zone of the teeth. It has various kinds of cells such as odontoblasts, fibroblasts, histiocytes, mast cells, macrophages, plasma cells etc. This layer provides all the necessary nutrition to the tooth and without pulp, a tooth is declared dead.

How Do We Look At A Tooth Under The Microscope?

The structures of teeth have been studied under the microscope for a very long time. Countless research and literature has been published on the microscopic appearance of teeth. It might fascinate many that how a tooth is studied under a microscope. The process is quite simple. A tooth which is extracted is cut into various slices which are then studied under the microscope.

A tooth that is to be looked under the microscope, is first and foremost cleaned and sterilized to remove any microorganisms from it. It is then dried and stored in a preservative until it is ready to be cut into slices. The tooth is then cut into thin slices as per the requirement and the various slices are stained. Staining is done so that the different structures take up the stains and can be differentiated from each other.

These slices are mounted onto microscopic slides and are then studied under the microscope. Enamel is the only structure in the tooth that does not take up stain. The microscope which is used for this purpose is usually a scanning electron microscope (SEM) which is a highly sensitive microscope used to study the finest details of various tissues.

How Do Teeth Look Under A Microscope?

Enamel, which is made up of rod-like structures, looks like multiple lines running from the dentine to the surface of the teeth. These enamel rods are arranged in various patterns, which is mostly perpendicular to the dentine below.

The dentine has dentinal tubules which look like long empty tubules. These tubules called the dentinal tubules run all over the tooth from the root to the outer surface. Dentinal tubules are of different sizes at each part of the tooth.

When we look at the cementum under a microscope, it appears as alternative dark and light bands. This difference is because of the variations in the ability to reflect light. The part of cementum which appears light is the one that reflects light more than the part of cementum which appears dark because of its inability to reflect light.

The pulp is the most colorful part of the tooth under a microscope. All the cells are clearly distinguishable from each other due to their varying size and structure and the kind of stains they take up. The thin arterioles are also visible under the microscope and the various zones of the pulp, the cell free zone, cell rich zone and fleshy pulp core are all clearly seen. Have a look at this article to look at some images of the structures of teeth under a microscope.

Frequently Asked Questions

Are teeth alive?

Yes, teeth are alive structures of the body. They have a rich blood and nerve supply which reaches the tooth through the pulp chamber.

Do dead teeth smell bad?

Teeth do not smell when they decay. However, if you have an active infection in the tooth such as pus under the tooth, it can smell bad and may give a foul taste in the mouth as well.

Will a dead tooth fall out on its own?

Unless you have a disease in the gums which makes your gums weak, a tooth will not fall out on its own even if it is dead. If you suspect an infection in the tooth or gums, it is important that you visit your dentist at the earliest.

Will a dead tooth hurt?

A tooth becomes dead when the pulp of the tooth has died or has been taken out by the dentist. In such a case a tooth will not hurt. However, if a tooth is hurting that means the infection has reached the pulp of the tooth and this needs to be looked at by the dentist so that the tooth can be saved.

Can a dying tooth be saved?

Yes, a dying tooth can be saved if a dentist is involved immediately. Only a dentist will be able to provide the necessary medications and treatment that are required for saving a tooth with any kind of an infection. 

Conclusion

Teeth are a vital part of the human body and serve many important functions. Under a microscope, each and every part of the tooth looks dynamic. Teeth have been studied under the microscope for many years and researchers are still doing so in order to find out new things with every passing day.

References.

https://www.sciencedirect.com/science/article/pii/S0003996916300358
https://www.nih.gov/news-events/nih-research-matters/advanced-imaging-reveals-structure-tooth-enamel
https://www.mouthhealthy.org/en/az-topics/t/tooth
https://annex.exploratorium.edu/evidence/lowbandwidth/INT_tooth_zoom.html
https://en.wikipedia.org/wiki/Dentin
https://my.clevelandclinic.org/health/articles/11179-teeth-eruption-timetable
https://www.towncaredental.com/blog/what-substances-make-up-your-teeth/
https://en.wikipedia.org/wiki/Tooth_enamel
https://en.wikipedia.org/wiki/Cementum
https://en.wikipedia.org/wiki/Pulp_(tooth)

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