What are open gingival embrasures or black triangles? 

As white movie star smiles become increasingly popular, more and more people seek to correct their dental imperfections.

Black triangles between your teeth, called open gingival embrasures, are one of the conditions people often want to fix.  Repairing these openings isn’t just cosmetic, though. There are important health reasons to mind the gaps.

What are open gingival embrasures or black triangles? 

They’re triangle-shaped gaps between your teeth. About 67% of people over 20 years old have them.

It’s important to understand how they develop and what to do about them, because they can lead to further problems with your oral health.

What causes them?

Gum recession

Plump, pink, healthy gum tissue hugs your teeth, filling the spaces between them.

Age, smoking, and periodental (gum) disease can cause gums to recede or pull away from the teeth. This can expose the roots, leaving them vulnerable to bacteria, plaque and cavities.

Bone loss 

Gum disease, osteoporosis and other conditions can cause a loss of bone near the base of a tooth. When bone is lost, the gum tissue in that area may also recede. This leads to the formation of black triangles.

Dental hygiene habits 

Gum tissue is sensitive. If you brush your teeth too aggressively, you can damage your gums over time.

Orthodontic treatment 

If you’ve had orthodontic care, small gaps may form between your teeth as they move into new positions.

Sometimes, orthodontic bands or other parts of the appliance can damage the gums, too.

Triangular tooth shape 

Some people have rectangular teeth, where the width of the tooth at the gum line isn’t much different than the width at the biting point.

Some people have teeth narrower at the gum line so that the tooth has a more triangular shape. Triangular teeth are more likely to develop these gaps.

How can you get rid of the gaps?

Depending on the cause and severity of the gap, a number of treatment options exist.

Here are several to consider and discuss with your dentist.

  1. Gentle dental hygiene
    Flossing your teeth and brushing twice daily is recommended though floss with care to avoid hurting your gums.
  2. Hyaluronic acid treatment
    In some cases, your dentist can regenerate gum tissue with injections of hyaluronic acid.  Because this treatment is relatively new, there’s little research on how long the effects last.
  3. Composite resin
    Some people elect to have their dentist fill the gaps with composite resin bonding. This process doesn’t require surgery but may take some time to complete — a period of months, in some cases – because the resin is applied in thin layers so it looks natural, and your gums can adapt to the smaller space. Your dentist can also add tooth-coloured composite veneers to round out the appearance of the teeth.
  4. Braces
    If black triangles formed between your teeth because of a procedure or process that moved your teeth, you may be able to close the gaps by moving teeth together with braces. Orthodontic treatment takes time, but the aesthetic results may be worth the time and cost.
  5. Veneers
    Your dentist can cement ceramic or porcelain veneers to the surface of the tooth to fill in gaps and create a more even smile. Most of the time, applying veneers involves altering the surface of your natural tooth so the veneer and tooth form a strong bond.


Black triangles called open gingival embrasures can form between your teeth when your gums pull away from your teeth.

Age, harsh dental hygiene methods, gum disease, bone loss, and the size and shape of your teeth and gums can all contribute to the formation of these triangles.

Appearance isn’t the only reason people want to correct triangles. They can trap food and bacteria, which causes further dental problems.

There are a range of treatments available, starting with changing your toothbrushing and flossing habits.

Depending on the severity of the condition, your dentist, oral surgeon, or periodontist might recommend hyaluronic acid injections, composite resin bonding, veneers, braces, or surgical corrections.

If you notice black triangles forming between your teeth, talk to your dentist to decide which intervention makes the most sense in your case.