black lines on teeth

Black lines on teeth can cause embarrassment and self-consciousness, especially when they occur on visible anterior teeth. Although common, they should be taken seriously as they can have serious implications for oral health. This blog will discuss the causes, signs and symptoms, diagnosis, treatment, and management of black lines on teeth.



Causes of Black Lines on Teeth:

There are many causes of black lines on teeth, but the most common one is due to tooth decay. Tooth decay is caused by bacteria that feed on sugars and release acid that erodes the tooth enamel. When the enamel wears away, the dentin underneath becomes exposed, and it can appear black.

Teeth that turn black are usually due to one of two common types of causes: extrinsic or intrinsic.

  • Extrinsic:¬†Extrinsic damage comes from the outside of the teeth. This includes staining, tartar, or other damage that affects the outer dental enamel.
  • Intrinsic:¬†Intrinsic damage starts on the inside and progresses outward. This occurs when a condition within the tooth causes decay and damage.

Other causes of black lines on teeth include:

black lines on teeth mild to severeTartar buildup

Poor oral hygiene can lead to the buildup of plaque and tartar on the teeth, which can cause discoloration and black lines. Plaque forms naturally on teeth, particularly near the gum line. If not removed through brushing and flossing, this plaque will calcify and harden into tartar, also known as calculus. A dentist can only remove tartar. This can appear black in some cases, for example, if levels of copper or iron in your body are high.

A dentist can remove the black tartar buildup through a dental exam clean and recommend correct brushing and flossing techniques to prevent further buildup.


When the tooth experiences trauma, such as a blow to the mouth, it can cause bleeding inside the tooth. This blood can seep into the dentin’s tubules, which is the layer underneath the enamel, giving the tooth a black or dark appearance.

Another way trauma can cause black stains on teeth is through necrosis, which is the death of the dental pulp, a tissue in the center of the tooth that contains nerves and blood vessels. Trauma can cause irreparable damage to the pulp, leading to its death. The dead pulp can break down and cause discoloration of the tooth, including black lines or stains.

In addition to discoloration, trauma can cause other dental problems, including chipping or cracking of the tooth or even tooth loss. It is important to seek dental treatment if you experience trauma to the teeth to prevent further damage and potential complications.


There are several medications that can cause black stains on teeth, and discoloration is often a side effect of the medication. Here are some of the ways medications can cause black stains on teeth:

  1. Iron: Iron supplements can cause dark stains on teeth, especially in children who take them. This is because excess iron can build up in the body and lead to a condition called iron overload, which can cause a bluish-black discoloration of the teeth.
  2. Antihistamines: Some antihistamines, such as Benadryl, can cause tooth discoloration, including black stains. This is because antihistamines can cause dry mouth, leading to plaque buildup and bacteria on the teeth. This can, in turn, cause staining and discoloration.
  3. Tetracycline: Tetracycline antibiotics can cause black stains on teeth if taken during the development of the teeth, usually during childhood. This is because tetracycline can bind to the calcium in the developing teeth, causing them to become discolored.
  4. Minocycline: Minocycline is another antibiotic that can cause tooth discoloration, including black stains. Like tetracycline, this antibiotic can bind to the calcium in the teeth and cause them to become discolored.
  5. Chlorhexidine: Chlorhexidine is an antiseptic mouthwash that can cause brown or black stains on teeth if used regularly. This is because chlorhexidine can bind to the surface of the teeth and cause staining.

If you take any medications and notice black stains on your teeth, you must talk to your dentist or doctor. In some cases, discontinuing the medication or switching to a different one may help. Your dentist may also be able to recommend treatments to help improve the appearance of the stains, such as teeth whitening or veneers.


black lines on teeth quit smokingCigarettes or other tobacco products are known to cause black stains on teeth. Smoking can cause black stains on teeth because tobacco smoke contains tar and other chemicals that can build up on the surface of the teeth over time.

When a person smokes, the smoke enters the mouth and comes into contact with the teeth. The tar in the smoke can stick to the tooth surface and form a sticky residue. Over time, this residue can accumulate and harden, leading to black or brown stains on the teeth. Because smoking can also lead to dry mouth, it can cause a buildup of plaque and bacteria, which can exacerbate the staining.

Furthermore, smoking can also cause tooth decay and gum disease, which can also contribute to black stains on teeth. Gum disease can cause the gums to recede, exposing the roots of the teeth, which are softer and more susceptible to staining.

Signs and Symptoms

The most common sign of black lines on teeth is discoloration. The teeth may appear yellow, brown, or black. In some cases, the black lines may appear on just one tooth, while multiple teeth may be affected in others.

In addition to discoloration, black lines on teeth may also cause:

  1. Bad Breath: Bad breath can be a sign of tooth decay, which can cause black lines on teeth.
  2. Tooth Sensitivity: Tooth decay can cause sensitivity to hot or cold temperatures on the affected tooth.


Diagnosing black lines on teeth typically involves a dental exam and X-rays. The dentist will examine the teeth for signs of decay and may take X-rays to check for decay between the teeth or underneath fillings.


The type of treatment for black lines on teeth will depend on the cause and severity of the discoloration.

  1. black lines on teeth whiteningDental Fillings: If the black lines are caused by decay, the dentist may recommend a dental filling to remove the decayed portion of the tooth and restore it.
  2. Teeth Whitening: For surface stains and discoloration caused by poor oral hygiene or smoking, teeth whitening may help lighten the teeth and reduce the appearance of black lines.
  3. Veneers: If the black lines on teeth are extensive and cannot be treated with fillings or whitening, veneers may be an option. Veneers are thin shells of porcelain that are bonded to the front of the teeth, hiding the black lines and providing a whiter appearance.


Preventing black lines on teeth involves maintaining good oral hygiene practices, including:

  1. Brushing twice a day using fluoride toothpaste.
  2. Flossing once a day removes plaque and food particles from between the teeth.
  3. Limiting sugary and acidic foods and drinks to reduce the risk of tooth decay.
  4. Quitting smoking or using tobacco products.

In conclusion, black lines on teeth can be a sign of tooth decay or other underlying issues, and it is important to seek treatment from a dentist if you experience them. Maintaining good oral hygiene practices and avoiding sugary and acidic foods and drinks can help prevent black lines on teeth.