Black triangles are small dark gaps that can appear near the gumline between teeth after braces or aligners, usually because the gum tissue does not fully fill the space where two teeth meet. They are common in adults, often cosmetic rather than harmful, and many can be reduced.
Seeing a new gap right after your teeth finally line up can be frustrating. The good news is that black triangles usually have an identifiable cause, and an orthodontist can often plan around them before treatment ends. Here is what they are, why they show up, and what can be done about them.
What Are Black Triangles Between Teeth?
When two teeth sit side by side, they touch at a contact point near the biting edge. Below that point, the gum tissue normally rises into a small peak, called the papilla, that fills the space down to the gumline. When the papilla does not reach the contact point, a small open triangle is left behind. Because the inside of the mouth is dark, that space looks black, which is where the name comes from.
Dentists call these spaces open gingival embrasures. They show up most often between the upper or lower front teeth, where they are easiest to see when you smile. They are not a sign that treatment failed, and they are not the same as the gaps between teeth that braces are designed to close.
Why Do Black Triangles Appear After Braces?
Black triangles rarely have a single cause. More often, a few factors combine, and some of them were already present before treatment started but were hidden by crowding.
Crowding Was Hiding the Space
When teeth overlap, the gum tissue between them has no room to form a full papilla. Once the teeth are straightened, the space under the contact point is suddenly visible, and the tissue may not have filled it yet. This is one of the most common reasons adults notice black triangles at the end of treatment.
Tooth Shape
Some teeth are wider at the biting edge and narrower near the gums, almost like a triangle. When two of these teeth sit next to each other, the contact point sits high and leaves a larger space near the gumline. Tooth shape is largely inherited, which our post on how genetics influences crowding and gaps touches on.
Gum and Bone Changes
The papilla needs healthy bone underneath it for support. Gum disease, past bone loss, aggressive brushing and normal changes with age can all lower that support. Our post on whether braces or Invisalign cause gum recession explains how hygiene and gum health interact with orthodontic treatment.
Are Black Triangles Harmful?
Why They Matter for Cleaning
In most cases they are a cosmetic concern rather than a health problem. They can, however, catch small bits of food and plaque, which makes careful cleaning more important. A larger triangle can also change how air moves when you speak, though that is uncommon. If you notice bleeding, swelling or sensitivity near a black triangle, mention it to your dentist, because those signs point to the gum health underneath.
Keeping the area clean with daily flossing or interdental brushes protects the tissue you have. Healthy gum tissue is what gives a papilla its best chance to fill in.
When to Mention Them to Your Dentist
Point out a new or growing black triangle at your next dental cleaning or orthodontic visit, especially if it appeared quickly. A sudden change can be a sign of gum inflammation or recession that is worth catching early. Your dentist can check the gum and bone around the space, and your orthodontist can look at whether tooth position or contact points are part of the picture.
How Can Black Triangles Be Reduced or Fixed?
The right approach depends on the cause, which is why an evaluation matters. These are the options an orthodontist and your dentist may discuss:
- Reshaping between teeth. Interproximal reduction, or IPR, smooths a small amount of enamel between teeth so they can sit closer together and move the contact point toward the gums. Our post on whether IPR is safe explains how it is planned.
- Adjusting root position. Changing the angle of the roots with braces or aligners can bring the contact point lower and help the gum tissue fill the space.
- Dental bonding. After orthodontic treatment, a general dentist can add tooth-colored material to reshape the sides of the teeth.
- Gum treatment. When tissue loss is the main cause, a periodontist can evaluate whether gum procedures are an option.
Often the answer is a combination, for example a small amount of reshaping during treatment followed by a check of how the gum tissue settles. Because each step affects the next, it helps to discuss black triangles early rather than after your braces come off. Some small triangles also become less noticeable on their own as the gum tissue settles after treatment, so your orthodontist may suggest waiting before adding any other step.
| Option | Who provides it | Best suited for | Good to know |
|---|---|---|---|
| IPR (enamel reshaping) | Orthodontist | Triangular tooth shape, high contact points | Small, measured amounts of enamel; planned in advance |
| Root angle adjustment | Orthodontist | Teeth that tip apart near the gums | Done during active braces or aligner treatment |
| Dental bonding | General dentist | Gaps left after teeth are straight | Usually done after orthodontic treatment ends |
| Gum procedures | Periodontist | Tissue or bone loss | Depends on the health of the bone underneath |
Can Black Triangles Be Prevented During Treatment?
Not every black triangle can be prevented, but planning helps. At Davis & Goldberg Orthodontics, our iTero 3D scanner gives our orthodontists a detailed model of your teeth, which they use to plan spacing and tooth movement with the final result in mind. The technology we use also helps us track changes during treatment instead of relying on memory from visit to visit.
What We Look at Before Treatment
Tooth shape, crowding, existing gum recession and gum thickness are all noted at your first evaluation. If you are an adult with existing gum or bone changes, we may coordinate with your dentist or periodontist before tooth movement begins.
What You Can Do
Brush gently with a soft brush angled toward the gumline, floss every day, keep up with dental cleanings, and wear your retainer as directed after treatment. Each of these protects the gum tissue that keeps the spaces between your teeth filled.
Frequently Asked Questions
Do black triangles go away on their own after braces?
Sometimes they shrink as the gum tissue settles in the months after treatment, especially when the tissue is healthy. Larger triangles or those caused by bone loss usually need another step, such as reshaping or bonding.
Can Invisalign cause black triangles?
Aligners do not create black triangles any more than braces do. The same factors apply: crowding that hid the space, tooth shape and gum health. Many adults who choose clear aligners have the same options for reducing them.
Are black triangles more common in adults?
Yes. Gum tissue and bone support naturally change with age, and adults are more likely to have existing recession or long-standing crowding, so black triangles appear more often in adult treatment than in teens.
Should I avoid orthodontic treatment because of black triangles?
No. Straight teeth are easier to clean and keep healthy, and most black triangles are small and manageable. Talk with your orthodontist about your gum health and tooth shape so you know what to expect before you start.
Talk With an Adult Orthodontist at Davis & Goldberg
If you are thinking about treatment and want to know how black triangles might affect your smile, our orthodontists will walk you through your options, including adult braces and Invisalign for adults. Call or text (336) 887-3168 or request a free consultation at our High Point or Greensboro office.