Black triangles between teeth: causes and what can be done

Black triangles are small dark gaps just below where two teeth touch, where the gum no longer fills the space. They come from gum recession, tooth shape or straightening crowded teeth. At Toothi in Edgware the options are gum health first, Invisalign with IPR, and edge bonding at £195 per tooth.

They’re common, especially as we get older, and they don’t usually mean anything has gone wrong. But they can make a smile look older or less tidy, and they trap food. Here’s why they happen and how each option works.

A black triangle appears when the triangle of gum between two teeth (the papilla) doesn’t reach up to the point where the teeth touch. Usually the gum has shrunk, the bone underneath has reduced, or the teeth are shaped so the contact point sits too high.

• ✓  Gum disease and bone loss. Inflammation over years can reduce the bone that supports the gum, and the gum follows it down. This is the cause to rule out first.
• ✓  Ageing. Gums naturally recede slowly with age.
• ✓  Tooth shape. Triangular teeth, wider at the edges than at the gum, leave a bigger space near the gum line.
• ✓  Hard brushing. Over-vigorous brushing can wear the gum back.
• ✓  Straightening crowded teeth. When overlapped teeth are lined up, a space can be revealed that the overlap was hiding.

Invisalign doesn’t cause gum recession. But straightening crowded or rotated teeth can uncover a black triangle that was, in effect, already there and hidden by the overlap. It can happen with any kind of brace, and it’s more likely in adults whose gums have receded a little.

If we think it might happen, we’ll mention it at your consultation, and we can often plan for it. A little IPR, or interproximal reduction, gently reshapes the sides of the teeth so they meet lower down, closer to the gum, which can reduce the space. Our guide to IPR in Invisalign explains how this works, and edge bonding can be added at the end if needed.

The right fix depends on why the triangle is there. Gums come first. After that it’s a choice between moving teeth, adding to them, or both. No option can promise to make the gap disappear completely, and we’ll tell you what we expect for your teeth.

Yes, in many cases. Composite is built up on the sides of the teeth, close to the gum, so the teeth meet lower down and the dark space is reduced. Nothing is taken away, so healthy tooth is generally left alone, and it can be polished, repaired or adjusted later.

Getting the shape right is the hard part. Too much composite near the gum can make teeth look square or make cleaning harder, so we take photos and plan the shape with you at a free bonding consultation first. Read more in our guide to edge bonding or see our composite bonding in Edgware page.

Prices are fixed and taken from our fees page. Every bonding price includes consultation, shade match, treatment and a review appointment. Every Invisalign package includes an Airflow hygiene clean and Boutique whitening.

You can’t regrow lost gum at home, but you can protect what’s there. Brush gently with a soft or electric brush, clean between teeth daily with interdental brushes sized for your gaps, and keep up regular hygiene visits. If you smoke, stopping helps your gums. Keep it up after bonding too. Healthy gums frame any cosmetic work.

• → Invisalign in Edgware
• → Composite bonding cost
• → How long does composite bonding last?
• → Composite bonding with receding gums
• → Gap between front teeth: your options