Craze Lines: Hairline Cracks In Your Front Teeth

Craze Lines: Hairline Cracks In Your Front Teeth

Dental Craze Lines - Hairline Cracks in Your Teeth

Catherine recently left a comment asking about the discolored lines that she has running vertically in her front teeth.  She was curious about what kinds of solutions there are to deal with this cosmetic problem.

Before I talk about the solutions to these lines that can occur in our teeth, I’ll give an overview of what they are, why they happen, and how to get rid of them.

Craze Lines: Vertical Lines in Our Teeth

These vertical lines in her front teeth are actually known as craze lines.  Over years of use, our teeth tend to develop tiny cracks in the hard outer layer known as enamel.  These cracks normally don’t cause any pain, but can easily stain, causing embarrassing discolored lines on your front teeth.

What Causes Craze Lines?

Craze lines can be caused by stress placed on a tooth.  This can happen over the course of a lifetime of chewing or by any other process that causes a lot of stress on our teeth.

Some common causes of craze lines are  biting your nails, grinding your teeth (many people do it in their sleep without realizing it), using your teeth as tools, trauma to your teeth, or simply routine use of your teeth.

In Dr. Cohen’s textbook about root canals, he states, “Craze lines are merely cracks in the enamel that do not extend into the dentin and either occur naturally or develop after trauma.”

This case report describes a situation where craze lines were caused by biting on hard objects such as the top ring of an aluminum soda pop can. Speaking of metal rings, wearing tongue rings can cause craze lines in your teeth.

Interestingly, some research points to temperature changes as a possible cause of craze lines.  That’s a great incentive  to not chew ice cubes (especially after drinking hot coffee!)

One other cause of craze lines that should be discussed is going to the dentist.  This research article states that he process of drilling away a cavity and filling a tooth can cause craze lines.  That’s certainly not a reason to avoid the dentist, though, since craze lines are harmless whereas untreated cavities can lead to significant complications.

Do Craze Lines Mean Your Teeth are Cracked?

Although craze lines are very tiny cracks in the outermost layer of your tooth, you don’t need to worry about your tooth cracking in half.

Porcelain Crazing on Doll

One good way to think about craze lines is to take a look at the above photo of this porcelain doll.  The cracks in the porcelain occurred after years of use.  Although they are cosmetically displeasing, the cracks don’t mean that the doll’s head is about to crack open!

If you suffer from craze lines, you’ll be pleased to know that the way that our teeth forms makes the enamel highly resistant to cracking.

A recent study looked at the crack resistance of the enamel in our teeth compared to a synthetic enamel.  The study concluded, “While enamel is the most highly mineralized tissue of the human body, the microstructural arrangement of the prisms promotes exceptional resistance to crack growth.”

If that isn’t enough, this study says that “The microstructure of enamel is functionally optimized to guide cracks from the more brittle outer enamel inwards where they experience higher growth resistance and are prevented from causing fracture and chipping.”

This study found that enamel is about three times as tough as the naturally-occurring crystals of hydroxyapatite (the crystal that our tooth is made from.)

Craze Lines Appearing on Stained Teeth
Enhanced image of stained teeth to emphasize prominent craze lines

How to Get Rid of Craze Lines

So, what should you do if you have craze lines and you hate how they look?  There are a few alternatives.

The least invasive option is to try teeth whitening.  Many craze lines show up because tiny amounts of debri get into the crack and stain the crack, making it visible.  Teeth whitening can bleach away the stain and make the craze lines very hard to detect.

There are other options that involve actual dental work.  Before trying these options, it’s good to keep in mind that craze lines can be caused by dental work, and that no dental work is better than your natural teeth.

These options include having an aesthetic tooth-colored filling material placed over the crack or having a veneer.  To do the filling, your dentist will simply smooth down the tooth in the affected area and add some filling material that is the same color as your natural tooth.  To do a veneer, your dentist will smooth down the whole face of the tooth and place a thin piece of porcelain over the tooth (kind of like a fake fingernail.)


With these alternatives in mind, it’s worth noting that most dentists agree that there’s no need to treat craze lines since they rarely lead to further breakdown of the tooth.  Some studies (like this one) do argue that the small lines may serve as a future site of a cavity, but if you’re going in for your regular check-ups, your dentist can usually detect potential problems.

Do you have any questions about craze lines or cracks in your teeth?  Leave a comment in the comments section below.  Thanks for reading!


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