What to Know About Craze Lines on Front Teeth

Craze lines are small, straight cracks in the teeth. Appearing as small, vertical lines, this hairline cracking, though potentially unsightly, isn’t a dental emergency. It arises most often in adults, especially those who bite their nails or have bruxism (teeth grinding) or malocclusion (uneven bite), among other poor dental habits.

Even though craze lines are primarily an aesthetic concern, the impact on your appearance can affect your self-esteem. This article highlights the causes of this issue, how it differs from other types of tooth cracking, as well as how it’s treated and prevented.

Young cheery woman brushing her teeth.

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All teeth go through some wear and tear as you age, and fundamentally, craze lines arise due to stress and strain on them. This is why the likelihood of developing them rises as you age. Several oral conditions and eating habits cause them, including:

  • Bruxism: Jaw clenching and teeth grinding, especially at night, places a great deal of strain on your teeth. As a result, hairline cracks are more likely to emerge in those with this condition.
  • Malocclusion: When your teeth aren’t lined up correctly, some experience increased wear and tear. This can cause craze lines, as well as more serious damage to the teeth.
  • Poor chewing habits: Habits that damage teeth, like nail-biting and chewing on pens or pencils, are frequent causes of craze lines.
  • Frozen foods: Hard, frozen foods and ice, when chewed, can damage the enamel (the outer layer of teeth), leading to tiny cracks.
  • Changing temperatures: Rapid shifts in temperature, such as drinking ice water immediately after very hot foods, can also affect the integrity of your enamel.

Craze lines aren’t related to tooth decay or serious dental issues, and they don’t cause pain or tooth sensitivity. When patients get treatment, it’s for cosmetic reasons.

Craze Line vs. Cracked Tooth

Though both are forms of damage to the tooth, clinically, craze lines aren’t the same as cracks. Here’s a quick breakdown of the differences:

  • Craze line: A craze line is a small split in the outer or inner surface of the tooth; only the outside layer, or enamel, is affected. This issue is asymptomatic and doesn’t require treatment, though some may opt to have cosmetic procedures to correct it. While craze lines can affect the way teeth look, they don’t progress to become tooth cracks. 
  • Cracked tooth: A true crack in the tooth is symptomatic and requires dental care. It affects not only the enamel, but also the dentin, or middle layer, and sometimes progresses to the inner layer of the tooth, or pulp. Cracks most often arise on occlusal surfaces—where the teeth join each other—but can progress toward the sides.

Craze lines are tiny, hairline cracks on the outside or inside of teeth. They have a vertical orientation, are straight, and are especially visible if you shine a light on your teeth. They may be translucent or can appear yellowish, brown, and gray as they have an increased risk of staining.


While craze lines don’t usually lead to significant dental issues, they can affect the appearance of your smile. In turn, this can have an impact on self-image and confidence. If they’re a concern, both at-home and in-office procedures can help. Here’s a quick breakdown.

Home Treatments

Though they may not outright remove or reverse craze lines, some at-home treatments can help whiten teeth and minimize their appearance. Treatments you can try include:

  • Using whitening toothpaste: In some cases, switching to toothpaste designed specifically for whitening can improve the appearance of craze lines.
  • At-home whitening: At-home teeth whitening procedures include using whitening strips, trays, or gels, all of which may help with the appearance of craze lines. Compared to in-office whitening treatments, these options may not be as effective and generally take longer.
  • Peroxide bleaching: Swishing your teeth with hydrogen peroxide can be another means of lightening and whitening teeth at home.  

In-Office Treatment Options

Several in-office cosmetic dental treatments can also be attempted to correct this issue. These include:

  • Teeth whitening procedures: With the aim of lightening and brightening your enamel, in-office teeth whitening can help with craze lines. Notably, studies have linked these procedures with tooth sensitivity.
  • Porcelain veneers: A customized thin, porcelain shell, or veneer, is placed over the tooth. This provides a durable, permanent means of correcting this issue.
  • Dental crowns: Some may opt for a dental crown—a permanent, natural-looking cap on the existing tooth—to cover over the damage.
  • Resin (tooth colored fillings): Cosmetic dentists can also fill the tiny cracks with specialized composite resin, restoring the natural appearance of teeth.


Primarily, preventing craze lines involves stopping or treating the issues causing them, because these issues don't improve the appearance or health of your teeth. Several methods help stop the issue from forming or can minimize its appearance, such as:

  • Avoiding nail-biting or other bad oral habits, like chewing on pens
  • Wearing a mouthguard at night to help with tooth grinding
  • Steering clear of foods or drinks that stain teeth, such as red wine and coffee
  • Quitting or avoiding the use of tobacco products


Craze lines, caused sometimes by grinding teeth or an uneven bite, are not a sign of tooth decay or serious dental issues. Instead, craze lines are small spilts on the tooth, and are hard to get rid of. Using at-home teeth whitening products, including special toothpaste, may help lessen the signs of craze lines. Dentists can also offer treatments like dental crowns.

A Word From Verywell

While craze lines are generally harmless, they can impact the appearance of your smile, affecting your confidence and self-esteem. It’s important to be able to recognize this issue and understand your options for managing it. When it comes to both the health and look of your teeth, it’s important to be proactive. If you’re concerned about craze lines or believe your teeth are damaged, don’t hesitate to seek out dental care.  

Frequently Asked Questions

  • Can craze lines appear horizontal?

    Craze lines don’t arise horizontally, and if you see cracks across the tops of sides of your teeth, you should get dental care soon. They appear strictly as small, vertical lines on the outside or inner sides of your teeth. These lines can be yellow, gray, brown, or even translucent.

  • Are craze lines harmful to teeth?

    Craze lines represent splits in only the outer layer, or enamel, of your teeth, and this damage isn’t progressive. As such, the inner layers and the overall health of the tooth are not affected, and this condition doesn’t cause pain or sensitivity. However, craze lines may arise due to underlying dental conditions or bad dental habits.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Emeh J. Craze lines in teeth (causes, pics, treatment & prevention). NewMouth.

  2. Dubuleanu M. How does one decide whether a crack/craze line on an asymptomatic tooth should be attempted to be removed, either with a restoration or a crown?. Oasis Discussions.

  3. Özcan M, Abdin S, Sipahi C. Bleaching induced tooth sensitivity: do the existing enamel craze lines increase sensitivity? A clinical study. Odontology. 2013;102(2):197-202. doi:10.1007/s10266-013-0104-7

Additional Reading

By Mark Gurarie
Mark Gurarie is a freelance writer, editor, and adjunct lecturer of writing composition at George Washington University.