What Are Black Triangles Between Teeth? Causes and Treatment Options

You’re smiling in a photo and you notice it: small dark gaps at the base of your teeth, right where your gums should be. These are called black triangles, and they are one of the most common cosmetic concerns we hear about at Domino Dental in Williamsburg, Brooklyn. The good news is that in most cases, they are very treatable.

Black triangles often look like a piece of food is stuck between your teeth, even right after you have brushed and flossed. If you have a high smile line, meaning your gums show more when you smile, the gaps tend to stand out even more. Spaces at the gumline are also commonly associated with poor gum health and advanced age, which is part of why so many patients are eager to have them addressed rather than just living with them.

What Is a Black Triangle, Exactly?

A black triangle is the small triangular gap that appears between two teeth near the gumline. It happens when the gum tissue between your teeth, called the papilla, does not fully fill the space below where the teeth touch. It is not decay and it is not damage to the tooth itself. It is a gum and spacing issue, and it is far more common than most patients realize.

What Causes Black Triangles?

There is rarely just one cause. Some of the most common include:

Black Triangles and Invisalign or Braces

If you noticed black triangles for the first time after finishing Invisalign or braces, you are not alone, and nothing went wrong with your treatment. Crowded teeth often overlap enough to hide the natural shape of the roots and the gum tissue between them. Once the teeth are straightened, that shape becomes visible for the first time. In other words, orthodontic treatment usually reveals black triangles rather than causing them.

The same orthodontic process that reveals black triangles can sometimes also be used to reduce them. A technique called interproximal reduction, or IPR, removes a small amount of enamel from the side of the tooth, which raises the contact point between two teeth and can make the black triangle less visible. This tends to work best when it is planned as part of your Invisalign or orthodontic treatment from the start, rather than added on afterward.

IPR has real limits, though. If your teeth are naturally quite triangular in shape, closing a black triangle fully with IPR would require removing a significant amount of enamel from the sides of the teeth. The result can be teeth that look like long, narrow rectangles rather than natural teeth, which is rarely the outcome patients are looking for. This is another example of why the right treatment depends on your specific tooth shape, not just the size of the gap.

You can read more about our approach to Invisalign in Why Choosing a Cosmetic Dentist for Invisalign in Williamsburg Matters. If your teeth have shifted since finishing treatment, our article on Invisalign Relapse in NYC may also be relevant.

What If You Notice Black Triangles After Getting Veneers?

If you recently had veneers placed and you notice small black triangles near the gumline, try not to panic right away. During the temporary phase, the gum tissue can get pushed up or become irritated by the temporary veneers, and this usually settles down and heals on its own once your final veneers are placed.

That said, if the gaps are still there several months after your final veneers have been placed, there is typically not much that can be done to close them at that point. This comes down to a simple rule: the level of your gum tissue is directly tied to the level of bone underneath it. If the bone is not there to support it, the gum tissue will not fill in, no matter how much time passes.

At Domino Dental, we evaluate bone levels before veneer planning ever begins. Knowing where the bone sits lets us determine precisely where to place the veneer margin, the edge where the veneer meets your natural tooth, so the final result works with your gum tissue rather than against it. It is a detail that takes real experience to account for, and it is a large part of why planning matters so much when it comes to veneers.

How Are Black Triangles Treated?

The right treatment depends on what is causing the gap and how much of a change you are hoping for.

Composite Bonding and the Bioclear Method

For mild to moderate black triangles, composite bonding is usually the most conservative option. This can only be done on natural tooth structure. A tooth-colored material is added to gently reshape the base of the tooth and close the gap, without touching the gum tissue itself.

Getting a natural result depends as much on technique as it does on material. At Domino Dental, we start by using air abrasion to clean and prep the enamel, which allows composite to bond more predictably than surface preparation alone. From there, many cosmetic dentists use a specific matrix system called Bioclear to shape and mold the composite precisely along the natural curve of the tooth and gumline as it is placed. It has become popular enough that many patients search for Bioclear bonding by name, but the technique behind it matters far more than the brand.

Where Composite Bonding for Black Triangles Can Go Wrong

Done well, this kind of bonding is virtually undetectable. Done poorly, it tends to go wrong in one of two ways.

The first is at the gumline. Without a dry, well-isolated field, small amounts of excess composite can be left just under the gum, which can irritate the tissue and cause bleeding or inflammation. Rubber dam isolation prevents this, which is why we use one at Domino Dental for every case. Learn more in Why Rubber Dams Are Just as Important for Cosmetic Dentistry and Fillings

The second has nothing to do with the gumline and everything to do with shape. Closing a black triangle adds width to the base of the tooth, and if that width is not shaped carefully, the tooth can end up looking too square. This is especially noticeable when only the two front teeth are treated and the teeth next to them are naturally more triangular in shape, or when a squared-off shape simply does not suit your facial features. Closing the space is only half the job; getting the shape right so it still looks like it belongs in your smile takes a cosmetic eye, not just technical skill. You can read more about avoiding an unnatural result in Why Does Composite Bonding Look Fake?

Because composite placed for black triangle closure is difficult to remove or adjust once it has set, this is not a treatment where you want any surprises. Every consultation for black triangle closure at Domino Dental includes a mock-up, so you can see and approve the shape of your results before anything is permanently placed.

For the same reason, choosing the right provider matters more than price. We have seen patients come in wanting bonding done at other practices removed or adjusted because the result was too bulky. Before choosing a provider for black triangle closure, ask to see high-definition, close-up before-and-after photos of black triangle cases they have completed themselves.

Porcelain Veneers

If a black triangle is caused by something other than an existing veneer, such as tooth shape or old bonding, veneers can be used deliberately to close it, often as part of a broader smile plan that also changes shade, shape, or size. See Crowns vs Veneers and No-Prep Veneers vs Minimal-Prep vs Traditional Veneers for more on how these compare.

Orthodontic Treatment with IPR

If you are currently in Invisalign or braces, a technique called IPR can sometimes reduce black triangles as part of that treatment, though it works better for some tooth shapes than others. See Black Triangles and Invisalign or Braces above for how this works and where its limits are.

A Removable Option, Sometimes Called Party Gums

If you have several black triangles and are hesitant to commit to composite bonding because you are worried it could look bulky, a removable appliance is worth knowing about. Informally nicknamed party gums, this is a custom, removable appliance with pink material built in that fits over your gums and fills the gaps between your teeth for a natural-looking smile. You put it in and take it out yourself, similar to a retainer, and no changes are made to your natural teeth or gum tissue.

This is not a permanent fix, but it can be a good option if you have a significant number of black triangles and want a cosmetic solution with no risk to your natural tooth structure.

Gum Filler

You may come across gum filler, sometimes marketed as hyaluronic acid filler, as another option for black triangles. The idea is to inject filler into the gum tissue between the teeth to help rebuild the papilla and close the gap without touching the tooth itself.

In practice, this treatment is highly technique sensitive and results tend to be inconsistent. Most dental practices do not offer it for this reason, and we do not recommend it at Domino Dental. If gum tissue loss is the primary cause of your black triangle, a periodontal evaluation is a more reliable place to start.

Can Black Triangles Be Prevented?

Not every black triangle can be prevented, especially when the cause is related to tooth shape, root position, or bone structure. But a few habits can lower your risk:

Frequently Asked Questions

Are black triangles permanent?

Not necessarily. Many black triangles can be closed with conservative treatment like composite bonding. Whether they are permanent without treatment depends on the underlying cause.

Will black triangles get worse over time?

They can, particularly if the underlying cause is ongoing gum recession or bone loss. This is one reason it is worth having them evaluated rather than waiting.

Are black triangles a sign of gum disease?

Sometimes, but not always. They can also be caused by tooth shape, root position, orthodontic movement, or thin gum tissue in patients with otherwise healthy gums. A proper evaluation, including looking at the bone levels beneath the gum, is the only way to know for sure.

Why do I have black triangles after getting veneers?

This is common during the temporary phase, since temporary veneers can push up or irritate the gum tissue, and it usually resolves once your final veneers are placed. If the gaps are still there several months later, it typically means the bone level beneath the gum could not support full gum coverage in that spot. Evaluating bone levels before veneer planning begins is meant to prevent exactly this.

Can toothpaste or home remedies close black triangles?

No. Black triangles are a structural gap between the tooth and gum tissue, not a surface stain or buildup, so there is no over-the-counter product that can close them.

What is Bioclear bonding?

Bioclear is a brand name for a specific matrix system used during composite bonding to close black triangles and other gaps between teeth. It is not a different material, it is a technique for shaping composite more precisely along the natural curve of the tooth and gumline.

Will black triangle closure make my teeth look square?

It can, if the shape is not planned carefully. Closing the gap adds width to the base of the tooth, and an inexperienced provider may prioritize closing the space over keeping the shape natural. That is why a mock-up before treatment, done by an experienced cosmetic dentist, matters so much.

Can black triangle bonding be adjusted or redone if I do not like it?

It can be adjusted in some cases, but composite placed specifically for black triangle closure is difficult to modify once it has fully set. Previewing the shape with a mock-up beforehand matters far more here than it does for most other cosmetic treatments.

Do black triangles come back after bonding?

When the cause has been properly diagnosed and the bonding is well maintained, results are typically long-lasting. If the underlying cause, such as active gum disease, is not addressed, the gap can reopen over time.

Can Invisalign fix black triangles?

In some cases, yes, when combined with a technique called IPR to reshape the contact point between teeth. It tends to work best for mild black triangles on teeth that are not naturally very triangular in shape. For more noticeable gaps, or teeth with a lot of natural taper, composite bonding or veneers are usually a better fit.

What are “party gums” for black triangles?

Party gums is an informal name for a custom, removable appliance that fits over your gums and fills in the appearance of black triangles for photos or social occasions. It does not involve any permanent changes to your teeth or gum tissue and can be taken in and out as needed, which makes it a good option if you have a lot of black triangles and are not ready to commit to composite bonding or veneers.

Does gum filler work for black triangles?

Not reliably. It is a highly technique-sensitive treatment with inconsistent, often short-lived results, which is why most practices, including ours, do not recommend it. Composite bonding, veneers, or IPR during orthodontic treatment tend to produce more predictable, longer-lasting results.

Ready to Find Out What’s Causing Yours?

Black triangles can come from several different places, and the right fix depends on identifying the actual cause and using the right technique, not just covering up the gap. This kind of precise, technique-sensitive work is one of the reasons patients travel to see us from across New York City and the tri-state area, not just Williamsburg and the surrounding neighborhoods. Dr. Lilya Horowitz evaluates your gum tissue, tooth shape, and the root and bone position underneath, and reviews a mock-up with you, before recommending a treatment plan, so the approach fits the reason the gap is there and still looks right on you.

Schedule a consultation at Domino Dental. We are in Williamsburg, Brooklyn, about a fifteen minute train ride from Union Square, and see patients from throughout NYC and the tri-state area.