Why Black Lines Form Around Dental Crowns

If you’ve had a dental crown for a while, you may have noticed a black line forming around the treated tooth’s base. Depending on your assumptions, the latter situation can feel surprising. Don’t crowns solve your smile’s cosmetic issues? Why would they go and create a new one?

Here’s a summary of the causes and solutions for a black line around a dental crown. Read on to learn the source of your current predicament and what you can do about it.

What Causes the Black Line Around a Crown?

Under normal circumstances, black lines form around dental crowns for one of two reasons:

• The Dental Crown’s Metal is Exposed: Many older crowns are porcelain-fused-to-metal (PFM) ones with gold or silver alloy underneath their porcelain surfaces. While that usually doesn’t cause problems, gumline recession from age or disease can expose these metal components. Consequently, said metal takes on the appearance of a black line.
• The Crown is Casting a Shadow: In some cases, the black line is simply an optical illusion. When caused by a poorly fitting crown, it’s usually just a shadow cast over the surrounding area. This type of black line is less prominent than one caused by exposed metal.

High-quality crowns can occasionally develop black lines for more unique reasons. PFM models have traits that sometimes prevent light from reaching the root, making the nearby gum look darker. It’s also possible for the cement that seals crown margins to leak, thus staining the tooth base.

How Your Dentist Can Help

Most of the time, your dentist can fix the black line problem by replacing your old crown.

To ensure a long-term solution, many professionals recommend ceramic options. Today’s most popular crowns are made entirely of porcelain, meaning they’ll match your pearly whites and never develop black lines from metal exposure. These newer kinds are also strong enough to resist food stains. They can last up to 15-20 years with proper oral self-care and regular dental checkups.

You shouldn’t have to endure black lines that take away from your crowns’ intended purpose. Instead, talk with your local dentist about ways to make your tooth as shiny and white as ever.

About the Author

Dr. Gary Rosenfeld is a top dentist based in East Islip, NY, having earned his dental doctorate from the Columbia University Dental School. He has not only practiced in the field for over thirty-five years but also completed over one-thousand hours of continuing education. His memberships include the American Dental Association, the American Academy of Cosmetic Dentistry, and more. Dr. Rosenfeld currently practices at East Islip Dental Care and can be reached at his website or by phone at (631)-581-8600.