“Black triangles” refer to the small, dark-looking triangular spaces that can appear between your teeth, especially near the gum line. Clinically they’re known as open gingival embrasures — essentially places where the gum tissue (papilla) that normally fills the gap between adjacent teeth has receded or is missing.
These gaps are not only an aesthetic concern but may signal underlying gum or bone health issues.
Why These Gaps Form
Gum Recession & Bone Loss
One of the primary culprits behind black triangles is gum tissue that has pulled back from the tooth surface, often due to gum disease, aging, or aggressive brushing. As the bone supporting the teeth also diminishes, the gum can’t maintain its full shape and the triangular gap becomes visible.
Tooth Shape, Position & Orthodontics
Even if your gums are healthy, the shape of your teeth plays a role. Teeth that are narrow at the gum line but wider toward the biting surface (triangular in profile) leave more space for a visible gap. Additionally, after orthodontic treatments which move teeth into new positions, the small papilla between teeth may not fill in the changes, making black triangles more likely.
Hygiene Habits & Other Factors
Using a firm-bristled toothbrush, brushing too aggressively, or flossing harshly can injure gum tissue and increase the risk of gaps. Other contributing factors include smoking, age, thin gum biotype, and existing periodontal issues.
Why They Matter Beyond Appearance
While black triangles often draw attention because they affect how a smile looks, the implications go deeper. These gaps can trap food particles, plaque and bacteria — increasing the risk for cavities, gum inflammation, and more severe periodontal problems. Moreover, the presence of a black triangle can signal that gum or bone support has already been lost, suggesting that intervention may be needed to prevent further dental damage.
Options for Treatment and Repair
Non-invasive & Cosmetic Fixes
For minor gaps, treatments like composite bonding (applying tooth-colored resin to fill the space) or veneers (thin porcelain shells placed on the tooth fronts) can improve appearance. These are less invasive and focus on closing the visible space.
Orthodontic & Structural Solutions
If the gap is due to tooth alignment or shape, orthodontic realignment may help by bringing teeth closer together so the gum tissue can fill the space. In some cases, reshaping the tooth (inter-proximal reduction) can change its profile enough to reduce the gap.
Periodontal & Surgical Approaches
When the root issue is significant gum or bone loss, procedures like gum grafting (adding tissue), tissue volumizing (such as with hyaluronic acid), or bone grafts may be necessary to rebuild support and allow the papilla to fill in the gap.
How to Prevent Them from Getting Worse
Use a soft-bristled toothbrush, and brush with gentle, circular motions rather than aggressive scrubbing. Floss carefully and consistently; avoid forcing floss harshly to avoid injuring the gum tissue. Maintain regular dental check-ups so your dentist can identify early signs of gum recession or bone loss. Avoid habits that damage gum health, such as smoking or neglecting oral hygiene.
Recognise that if you’ve had orthodontic work, you might be more prone to gaps — and discuss preventive options with your dentist.
Final Thoughts
Black triangles between your teeth are more than just an aesthetic nuisance. They often reflect changes in your gum and bone health, or structural shifts in your teeth. The good news: many treatment options exist, from simple cosmetic fixes to more involved restorative ones. If you notice a new gap forming or widening between your teeth near the gum line, it’s wise to seek dental advice early. Addressing the issue promptly not only improves how your smile looks — it helps preserve the health and longevity of your teeth and gums.
