Craze Lines – What Are They?

Excerpt: Craze lines are tiny vertical hairline cracks that appear in the tooth enamel.
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Craze Lines

Craze lines are tiny vertical hairline cracks that appear in the tooth enamel.

Your teeth go through significant wear and tear on a daily basis due to the nature of their existence. Sometimes teeth experience enough stress to fracture the enamel, craze lines, however concerning, are usually only cosmetic imperfections and do not pose a serious risk to oral health.

What Do Craze Lines Look Like?

Craze lines appear on the surface of your enamel as tiny hairline vertical cracks, they are shallow and are fairly easy to notice. If you do happen to notice a crack or fracture in your enamel you should never assume it is harmless unless a dentist tells you. If you misdiagnose a craze line, it may turn into a more serious fracture which could cause damage to your tooth. The best way to get craze lines diagnosed is to go to a dentist during your regular dental checkups or you can book a dentist appointment if you are concerned about them.

Craze Line Causes

Repetitive stress is the main cause for craze lines, this mainly involves chewing and teeth grinding (bruxism) among other activities. 

Clenching Your Jaw

During times of emotional or physical stress, some people tend to clench their jaw, this can create immense pressure on your teeth.

Uneven bite alignment

If your teeth are uneven, some of them may receive more pressure than others which can cause craze lines.

Eating hard or frozen foods

Accidentally chewing on a bone, or on ice cubes, etc. may cause enough pressure to crack the enamel if you are not careful.


As we age, the constant usage of our teeth can cause damage. If you have poor oral care, your teeth may become even weaker over time. Keeping up good oral habits can maintain your oral health even into old age.

Temperature Changes 

Have you ever broken a glass plate by running cold water over it while it was still warm out of the dishwater? Tooth enamel can react the same way to significant changes in temperature.

Nail biting, toothpick chewing, etc.

These activities are usually unnecessary and can cause undue stress on your teeth. If you partake in these activities often, you may cause them unnecessary damage. 

Are Craze Lines Common?

Tooth fractures in general are fairly common to find among individuals of any age. Between 34-74% of adults between the ages of 30 and 50 experience cracked tooth syndrome. Cracked tooth syndrome occurs when a tooth is cracked, but it’s not completely fractured. Craze lines are a phenomenon that can be classified under this umbrella term.

Are Cracks Worse Then Craze Lines?

Craze lines may not need to be treated as they usually don’t get worse, and will not cause any significant damage to the overall health of the tooth. Cracks, however, are a serious concern and can cause many serious health issues, including infection, dental abscesses, sensitivity, and more. 


The difference between a crack and a craze is how deep the fracture is, a crack will break through the enamel and go all the way to the dentin, and it may even affect the pulp of the tooth if it is severe. If you do crack a tooth you may also experience a feeling like you are chewing on sand or gravel, this is because of the enamel that has broken off of the tooth.


A craze line does not go past the enamel of the tooth, and won’t affect the dentin layer, if the dentist does not believe the craze line will get any worse, they may not see a reason to fix it. 

Craze lines are not a serious medical concern, however, if the individual wants to get it repaired for aesthetic reasons there are a number of different dental bonding solutions available.

Can A Craze Line Fracture A Tooth?

Craze lines are not a sign that the tooth has had its oral health compromised in any way. They do not indicate weak tooth or dental decay. It is unlikely that a craze line will cause a full fracture to occur. Craze lines also will not damage the structural integrity of the tooth once they occur, even if they are not treated.

Can Craze Lines Be Prevented

You may not be able to entirely prevent a craze line from happening, but you can minimize their chances of occurring:


  • Stop bad habits like nail-biting and opening bottles with your teeth
  • Avoid chewing very cold or frozen foods like ice cubes
  • Use a night guard or mouthguard to protect against teeth grinding
  • Avoid eating staining foods or beverages like red wine and coffee as they can make craze lines more visible.
  • Avoid using tobacco products to reduce the visibility of craze lines

Can You Fix Craze Lines?

You can’t fix craze lines at home, but you can decrease their visibility through the use of tooth whitening products which will make the craze lines less noticeable. A dentist may either recommend fixing it using composite resin, or dental veneers.  
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