What is Enamel and How is it Harder than Steel! (With diseases)

What is enamel cover image

Every time you smile, you show people your enamel. It is a layer of crystalline minerals on your teeth. Look into a mirror and smile. All the teeth that you can see are covered with enamel. The color may vary from very yellow (no brushing, eh?) to glistening white (kudos to you) or anywhere between these two. So what’s the use of the crown (enamel)? And how is it that our body can make something that is as hard or even harder than steel? 

So what is enamel? Chemically, it is majorly hydroxyapatite, which is calcium phosphate in crystalline form. Crystalline forms mean that calcium phosphate molecules are arranged in a repeating pattern, giving it enormous strength. Enamel crystals are rod-like structures called enamel rods called carbonated apatite crystals, that are arranged adjacent to each other, forming the layer of this white, tough compound.

Why is enamel so tough? 

Enamel evolved in animals some 500 million years ago. This strong coating allows animals to eat tough food, break it down and help indigestion. And as the rule of evolution is, if an organ is very useful for survival and has been around for millions of years, it will get better.

It is the hardest substance in the body. The reason for this is it is 96% minerals. This essentially makes it a very hard rock. It is not a separate part of the tooth, but rather a layer of coating over it. This layer is thickest over the crown and thinnest near the gums. So how hard is the crown of your teeth that you eat burgers with? 

Enamel can handle forces of up to 770 N. To get a perspective of it, it is like a person weighing almost 176 pounds (80 kg) standing on the teeth and it won’t crack or break. In Mohs hardness scale, enamel scores 5, which is harder than steel and just behind platinum. The crown of your teeth is tough.

What is dentin?

A confusing part about teeth is enamel and dentin. These are two different components of the tooth and are very well separated. Enamel is the topmost layer over the tooth. Dentin is another layer that sits right below the enamel. It is similar to enamel but not as mineralized as it. Dentin is also tough and is believed to provide structural support to the enamel. 

In some teeth like incisors, one can see a tint of blue/gray/yellow near the gums. This is the color of dentin. Since enamel is translucent, the color of dentin affects the overall appearance of teeth. The dentin also protects the sensitive pulp and the nerves inside the teeth. So what happens if the enamel starts degrading?

The structure of a teeth showing the enamel and dentin
The structure of a teeth showing the enamel and dentin

Enamel diseases 

No matter how strong something is, there are always some diseases that will affect it. That’s true for the hardest substance of your body too. Poor hygiene, abrasion, and other mechanical forces, corrosive substances, or bacteria can lead to various conditions of the crown. Here are some common conditions of the enamel. 

Enamel hypoplasia: This is a rare and congenital condition where the production of enamel is affected, resulting in a thin and staggered layer of it. This also leads to very small teeth, since the crown is deprived of enamel. There are pits, grooves, and yellow spots (exposed dentin) on the surface of the teeth. Hypoplasia is the reason for enamel dysplasia, which is a symptom. 

Corrosion: There are four types of corrosion of the enamel. These are:

Abrasion: This is the corrosion caused by external sources of friction such as using a hard-bristled toothbrush, biting and chewing hard substances, etc.

Attrition: This is the fractional corrosion that occurs due to the rubbing of teeth.

Abfraction: This is when mechanical forces cause a crack in the crown of your teeth, leading to painful conditions.

Acidic corrosion: Perhaps the most common form of corrosion, acidic corrosion is caused by eating too much acidic food such as citrus fruits, vitamin C-rich food, etc. This also occurs due to frequent vomiting (bulimia) and GERD (acidity).

Decay: This one is the condition that made all of us scared when we were kids. Don’t eat too much candy or sugar or else your tooth will decay. It is true. Food with high sugar content such as candies, carbonated sugary drinks, poor oral hygiene, etc can lead to the decay.

This decay is caused by bacteria. Sugar and other leftover food particles that sit on the teeth allow the growth of bacteria. These bacteria break down the food and release harmful chemicals that cause the decay of tooth enamel. 

Enamel fluorosis: Another acquired condition of the where it gets white or brown lacy spots over it due to the excessive intake of fluoride during the developmental ages (till 8 years old) of the teeth. Fluoride content in water is one of the main reasons for fluorosis.

Why do bones heal but not teeth?

We all know that a fracture needs some time to heal and fix itself. A broken bone heals itself, but not a broken or chipped tooth. So why does a chipped or cracked tooth heal? This is because of the composition.

Enamel is 96% minerals and there are hardly any living cells present in it. It is like a rock and we know that if a rock breaks or chips, it cannot heal itself. Crown restoration helps up to a certain level, but the complete restoration of a chipped tooth without artificial inserts is not possible. Teeth are very precious, make sure you take good care of them.

Enamel cannot grow back on its own. So if you notice any signs of degradation, go to your dentist before it is too late. It is very crucial for the health of teeth. Thinning enamel can result in painful cavities, infections, and tooth sensitivity.

Enamel gives teeth their strength for mastication. Ensure that you have good oral hygiene, brush your teeth two times a day using a soft-bristled brush, floss every day, and rinse your mouth after every meal, even after your regular snacks. Once lost, it won’t come back again. And you have to use the crown you have now for decades. 

Reference: Nature’s article.

This concludes the article, but here are some more articles about the human body that you will find interesting. Take a look:

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