I keep brushing, but this black line around my cap won’t go away. What can I do?

There are several reasons why this appearance might occur. Firstly, it could be due to the material of the crown. Many crowns are made from porcelain fused to a metal base. While the porcelain is crafted to resemble natural teeth, it is layered over metal to provide enhanced strength and support. When gum recession happens, the metal layer may become visible, appearing as a dark line along the gum line.

Another possible reason for the dark line is if the tooth had experienced trauma or a root canal before the crown was placed, and gum recession has exposed part of the natural tooth. The natural tooth beneath the crown might be discolored, but this does not necessarily mean there is decay or a cavity. A clinical examination is needed to assess the health of the tooth structure beneath the crown.

Lastly, the black line could indicate decay or a cavity. Although the cap is a false tooth covering the natural tooth, it does not make the natural tooth immune to cavities. With proper home care (brushing twice a day, flossing once a day) and regular check-ups (at least every 6 months), patients with crowns can ensure their longevity. Some patients complain of bad breath or halitosis around their old crowns. Indeed, bacteria and decay trapped under crowns needing replacement can cause unpleasant breath.

In our office, although porcelain/metal crowns are sometimes used, nearly 99% of our crowns are made from zirconia, porcelain, or ceramic. With modern technology, these materials can be very strong, eliminating the need for a metal base. This ensures you won’t see the dark metal color around the gum line.

With our office’s 3D scan technology (we love staying updated with the latest technology), when necessary, we can match a new crown to the appearance of a previous tooth so your retainer will still fit, and your bite will feel just like your old tooth!

Examine the images below to discover what might be hidden beneath old crowns that need replacement. 

This specific crown, made of porcelain fused to a metal base, lasted for nearly 20 years, equating to around 20,000 meals for our patient! It was finally time to replace it with a new zirconia crown. We hope the new one will also endure another 20,000 meals.

Once the old cap is taken off, all decay is eliminated, and the tooth is reconstructed with a build-up filling to fill the gaps left by the decay. This build-up filling also safeguards the nerve inside the tooth if it is still alive, or it protects the previous root canal treatment. Afterward, we perform a 3D scan of the natural tooth to create a brand new custom-made crown.