What Are Teeth Craze Lines?

Medically Reviewed by Dan Brennan, MD on October 25, 2021
3 min read

Craze lines are small vertical cracks in the enamel of your teeth. They aren’t painful, but they can be unsightly.

Craze lines aren’t usually a health problem. But what causes them might be.

Each of your teeth has several parts.

Enamel. The enamel is the outermost layer of your tooth. It’s made of calcium and phosphorus. Tooth enamel is the hardest part of your body. This is where craze lines happen.

Dentin. Below the enamel is the dentin. This porous bonelike layer makes up most of the tooth. It is supported by the pulp beneath it.

‌Pulp. The pulp is the soft tissue made of your tooth’s nerves. The pulp creates dentin.

Root. Your tooth’s roots hold it in place in the jawbone, just like a plant in soil.

Teeth go through a lot of stress between everyday chewing and accidental impacts. Craze lines are usually surface cracks that are no cause for concern. But a painful crack in your tooth may be worse than you think.

The common types of tooth fractures include:

Fractured cusp. The cusp is the humps on your back teeth. A fractured cusp probably won’t reach the pulp of your tooth, so they typically aren’t too painful. Those teeth are used for chewing. Biting into something hard can cause a fractured cusp.

Extended cracks. Cracks that extend to your gumline are harder to fix. These fractures can be more painful. You may notice pain when breathing or drinking cold fluids. Early treatment is necessary to prevent complications.

Split tooth. This is a major fracture that extends below your gumline. It literally splits the tooth into two pieces. A split tooth is usually the result of a fracture that hasn’t been treated. There is a chance the tooth must be removed entirely.

Vertical root fractures. This type of major fracture seems to start from the gumline and moves up. You may not have any symptoms of this fracture. But it can lead to infection and force the tooth to be removed.

Tooth fractures are a dental emergency and need medical care right away. Without treatment, you might have complications like infections or tooth removal.

But craze lines are not an emergency. The small cracks are limited to your tooth’s enamel.

Craze lines on your front teeth may make you feel self-conscious about your smile. Your dentist can talk with you about how to handle these negative feelings.

It’s also important to have your dentist look at craze lines so they can find the cause. They often result from an underlying condition like teeth grinding or nail-biting. Finding the cause early can prevent additional damage to your oral health.

The causes of tooth fractures are not always obvious. Some of the main ones are:

  • Large fillings that put pressure on your teeth and weaken them
  • Chewing or biting something hard, such as ice, fruit stones, or bones
  • A heavy impact to the chin or jaw
  • Gum disease that causes bone loss, which can weaken your teeth
  • Rapid changes in your mouth’s temperature, typically caused by food and drinks

Bruxism or tooth grinding is another common cause of tooth fractures. You may not realize that you grind or clench your teeth. It can happen whether you’re awake or asleep.

Mild grinding typically doesn’t need treatment. Frequent and severe teeth grinding can lead to jaw disorders, damaged teeth, and headaches. A combination of weakened teeth and teeth grinding can lead to craze lines and other fractures.

Brushing your teeth properly will keep food and bacteria from getting caught in the slight crack of the craze line. This will keep your mouth clean and help prevent infections.

You have several treatment options if you’re worried that a fracture will get worse or you want to get rid of an unsightly crack: 

  • Bonding the fracture with a plastic resin
  • Cosmetic contouring to smooth the edges of the fracture
  • Veneers, a thin layer of porcelain or plastic that fits over the tooth’s surface