6x natural composite bonding — gaps and black triangles
Composite Bonding · Black triangles
What causes black triangles between your teeth — and how do you fix them?
Black triangles are the small dark gaps that appear at the gum line between teeth — dentists call them open gingival embrasures. They form when the little wedge of gum between two teeth no longer fills the space, usually because of gum recession, naturally triangular teeth, or a loss of gum and bone. The most common cosmetic fix is composite bonding, which adds tooth-coloured resin to gently close the gap — but if your gums aren’t healthy, treating them always comes first.
Black triangles: at a glance
- What they are
- Dark gaps at the gum line
- Also called
- Open gingival embrasures
- Most common causes
- Recession, tooth shape, bone loss
- Most common fix
- Composite bonding
- Bonding from
- £380–£480 per tooth
- If teeth can be moved
- Invisalign + IPR
- Gum disease present?
- Treat the gums first
- Consultation
- Free (£25 refundable deposit)
The causes
What are black triangles, and what causes them?
A black triangle is the small triangular gap you can sometimes see at the gum line, between two teeth, just below the point where they touch. The dark look is simply the shadow of that open space — normally the little triangle is filled by a peak of gum called the papilla. When the papilla shrinks or doesn’t reach, the space opens up. Black triangles are extremely common, particularly between the lower front teeth and the upper central incisors, and they usually have more than one cause working together. These are the main ones.
Gum recession
As the gums recede, the papilla between the teeth drops down with them and a space opens at the gum line. Recession can follow years of heavy-handed brushing, naturally thin gum tissue, or simply getting older.
Triangular tooth shape
Some teeth are naturally wider at the biting edge and narrow towards the gum. Their contact point sits high, leaving a larger space beneath it — one of the most common reasons black triangles show at all.
Gum & bone loss
Gum disease slowly destroys the bone and gum that support the papilla. Once that support is lost the tissue flattens, and black triangles are a frequent result. This cause needs treating, not simply covering over.
After orthodontics
Straightening crowded teeth can reveal triangles that were hidden while the teeth overlapped. The teeth are now beautifully aligned, but the true shape of the contact points — and any recession — becomes visible.
Age & thin tissue
Gum tissue naturally thins and recedes a little over the years, and the papillae become less plump, so black triangles tend to appear or widen gradually with age even if you never had braces.
Are black triangles a sign of gum disease?
Here is the honest and important part. A black triangle is not automatically a sign of gum disease — plenty of them are simply down to the shape of your teeth or a small amount of natural recession, with completely healthy gums underneath. But gum disease is one of the causes, and it is the one that matters most, because it is still actively destroying the support around your teeth. That is why the first job is never cosmetic.
Before any resin is placed, Dr. Albert checks the health of your gums — looking for inflammation, bleeding and the depth of the spaces around each tooth. If your gums are healthy, we can move straight to closing the triangle. If there are signs of active gum disease, treating and stabilising your gums always comes first, usually with a course of professional cleaning and a tailored hygiene routine. Bonding over gums that are still deteriorating only hides the problem and rarely lasts.
It is also worth knowing that once gum and bone have been lost, the tissue does not reliably grow back — so the aim is to stop any further loss and then close the space cosmetically, rather than to regrow the papilla. Good daily cleaning around a black triangle, with floss or small interdental brushes, protects the gums and helps stop the space widening. If you’re not sure what’s behind yours, our dental concerns page is a good place to start.
The fixes
How do you fix black triangles?
Once your gums are healthy, black triangles can be closed comfortably and, in most cases, without touching the healthy tooth underneath. There are a few routes, and the right one depends on why the triangle formed and how your teeth sit.
Composite bonding
The usual fix. Dr. Albert hand-layers tooth-coloured resin low onto the sides of the two teeth, extending their shape towards the gum to close the dark space — in a single visit, usually with no drilling and no anaesthetic. It’s reversible, because barely any natural tooth is altered. £380–£480 per tooth.
Aligning + IPR
Where the teeth can be moved, Invisalign can bring them closer and, with a little careful reshaping of the contact points — called IPR — lower the point where they meet so the gum fills more of the space. It won’t regrow gum, but it can shrink a triangle before any bonding. From £2,950.
Treating the gums first
If gum disease is the cause, professional cleaning and a solid hygiene routine come first to halt any further loss. This won’t fill the triangle itself, but it stabilises the area so that whatever cosmetic fix follows will actually last.
Pink composite or veneers
For more significant recession, gum-shaded “pink” composite can rebuild the look of lost tissue, and porcelain veneers (from £950) can close triangles as part of a fuller smile redesign rather than a single space.
Additive
Composite bonding
- Best for
- Most black triangles, closed the same day
- Tooth alteration
- None (or extremely minimal)
- Reversible
- Yes
- Typically lasts
- 5–8 years
Move the teeth
Invisalign + IPR
- Best for
- When the teeth can be moved closer together
- Tooth alteration
- Minimal (light contact reshaping)
- Reversible
- Held with a retainer
- Typically lasts
- Long-term with retention
Health first
Treating the gums first
- Best for
- When gum disease is the underlying cause
- Tooth alteration
- None
- Reversible
- —
- Typically lasts
- Ongoing care
Not sure which fits your smile? Start with what’s bothering you →
Keeping the result
Will black triangles come back after treatment?
Once a black triangle is filled with composite bonding, that particular space stays closed, because it is the material — not the gum — holding the shape. Bonding can chip, wear or pick up a little stain over the years, so an occasional polish or small repair at a review appointment keeps it looking fresh; treated well, it typically lasts around five to eight years before it needs any attention.
A closed triangle can reopen for a few reasons, and each is manageable. If gum disease is present and not kept stable, the gums and bone can keep receding and new triangles form — which is why healthy, monitored gums always come first. Teeth also drift with age, so if they shift out of line — especially without a retainer, or a fixed retainer after aligning — the spaces can open up again, and wearing your retainer is what holds everything in place. And the bonding itself can chip or wear over many years, so an occasional small refresh keeps it looking its best. Beyond that, gentle brushing with a soft brush, daily cleaning between the teeth, not smoking and regular hygiene visits all protect the gum tissue — and a thin night guard helps if you grind. With that care, most patients enjoy a smooth, closed gum line for many years.
If you’d like to see what’s achievable, our composite bonding before-and-after gallery includes real black-triangle cases, and the composite bonding cost guide explains the pricing in full. Closing a wider space between the teeth is a related question — our guide to closing a gap in your teeth covers that alongside this one.
Real results
Black triangles closed by Dr. Albert
Black triangle closure — 6x composite veneers/bonding
12x composite bonding — receding gums & black triangles
Black triangle questions
Black triangles: your questions answered
What causes black triangles between teeth?
Black triangles form when the small wedge of gum that normally fills the space between two teeth shrinks back. The usual causes are gum recession, naturally triangular-shaped teeth, and loss of gum or bone from gum disease. They can also appear after orthodontics, and tend to become more common with age as gum tissue thins.
Can composite bonding fix black triangles?
Yes — composite bonding is the most common cosmetic fix. Dr. Albert hand-sculpts tooth-coloured resin low onto the sides of the teeth to gently close the dark space at the gum line, usually in a single visit with no drilling. It works best once your gums are healthy and stable, and is £380–£480 per tooth.
Are black triangles permanent, or can they be reversed?
The gum tissue rarely grows back on its own, so black triangles do not usually disappear without treatment. They can, however, be closed or greatly reduced — most often with composite bonding, sometimes by aligning the teeth and reshaping their contact points. The right approach depends on why the triangle formed, which is assessed at your consultation.
Do black triangles mean I have gum disease?
Not necessarily. Many black triangles are simply down to tooth shape or a little natural recession, with perfectly healthy gums. But gum disease is one possible cause, so any black triangle is worth having checked. If active gum disease is found, treating and stabilising the gums always comes first, before any cosmetic work begins.
How much does it cost to fix black triangles?
At our Windsor practice, composite bonding is £380–£480 per tooth, and a black triangle is usually closed by bonding the two teeth either side of it. More complex or single-tooth cases are £580–£680. If aligning the teeth first is the better option, Invisalign starts from £2,950. Your exact quote is confirmed at your free consultation.
Can Invisalign fix black triangles?
Sometimes. Invisalign can help by moving teeth closer together and, combined with a little careful reshaping of the contact points (called IPR), lowering the point where the teeth meet so the gum fills more of the space. It does not regrow gum, so for many people a small amount of bonding still gives the neatest final result.
Are black triangles bad for your teeth?
Black triangles are mainly a cosmetic concern rather than a health problem, but the open spaces can trap food and plaque, which makes gentle, thorough cleaning important. Keeping the area clean with floss or interdental brushes protects the gums and helps stop the spaces widening. If they bother you, they can be closed comfortably once your gums are healthy.
Will black triangles come back after they are treated?
Once a triangle is filled with bonding, that space stays closed — but new ones can appear if the underlying causes are not managed. If gum disease is not kept stable the gums can keep receding; if the teeth shift out of line without a retainer the spaces can reopen; and the bonding itself can chip or wear after many years. With healthy, monitored gums, a retainer to hold the teeth in place, and the occasional small refresh, most people keep a smooth, closed gum line for the long term.
Reviewed by Dr. Albert Gajdos, GDC No. 265157 Last updated August 2026
Healthy gums first, then the finish
See the best way to close your black triangles.
Book a free 30-minute consultation with Dr. Albert — he’ll check your gums, measure the spaces, show you a preview of the result and recommend the most natural route, whether that’s bonding, aligning first, or treating the gums before anything cosmetic. £25 refundable deposit.