You’ve invested in your smile with high-quality dental crowns, and you’re doing the right thing by flossing daily. But then it happens—you pull the floss from between those two crowns and notice a foul-smelling odor, perhaps like sulfur or rotten eggs.
As an oral care brand, we hear this concern often. While it’s alarming, that "crown smell" is a signal from your mouth that something needs attention. Let’s break down why this happens and how you can fix it.
Why Does it Smell? The Common Culprits
When you have a sour or metallic taste after flossing, it’s usually not the porcelain of the crown itself—it’s what is trapped under or around it.
1. The "Open Margin" (The #1 Reason)
A dental crown is supposed to fit perfectly over your natural tooth. However, if there is a tiny gap where the crown meets the gum line—known as an open margin on crown—it creates a microscopic ledge. This is the perfect hiding spot for anaerobic bacteria buildup. These bacteria thrive without oxygen and produce Volatile Sulfur Compounds (VSCs), which are responsible for that unmistakable "rotten egg" scent.
2. Food Impaction (The "Food Trap")
If the contact point between your two crowns isn't tight enough, you have a food trap between teeth. Tiny particles of fiber or protein get wedged there. If they aren't removed immediately, they begin to decay, leading to food impaction and a very noticeable odor.
3. Recurrent Decay Under the Crown
Contrary to popular belief, a crowned tooth can still get a cavity. If a leaking dental restoration allows sugar and bacteria to seep underneath, recurrent decay under the crown can occur. This rotting tooth structure emits a distinct, unpleasant smell that you'll notice specifically when flossing.
4. Gum Disease & Periodontal Pockets
If the area is difficult to clean, the gums can become inflamed. This leads to Gingivitis or, more seriously, deep periodontal pocket depths. These pockets collect biofilm on dental margins and can even produce a foul-smelling discharge or pus, indicating a possible infection or dental abscess.
How to Fix the "Crown Smell"
Don't ignore the odor! Here is how to handle a foul-smelling floss situation:
Step 1: Level Up Your Cleaning Tools
Standard string floss sometimes isn't enough for the complex margins of dental crowns.
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The Water Flosser Advantage: A water flosser is incredibly effective at flushing out anaerobic bacteria from under the crown margins and deep within periodontal pockets where string floss can't reach.
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Interdental Brushes: These small, pine-tree-shaped brushes are perfect for mechanical scrubbing between two crowns to break up stubborn biofilm.
Step 2: Use an Antimicrobial Rinse
If the smell is caused by bacteria, an alcohol-free antimicrobial mouthwash can help neutralize the Volatile Sulfur Compounds and soothe inflamed gums.
Step 3: See Your Dentist (The "Red Flag" Check)
If you have bleeding gums when flossing between crowns or a persistent bad taste, it’s time for a professional check-up. Your dentist can check for:
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A fractured root under the crown.
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The integrity of the dental cement.
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Signs of an ill-fitting dental crown gap via X-ray.
Prevention is Better Than a Replacement
A dental crown should last 10–15 years, but only with the right care. To prevent future odors:
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Water Floss Daily: Especially around the gumline of your crowns.
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Monitor Your Gums: Healthy gums are pink and firm; red, swollen gums are a sign that bacteria are winning.
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Regular Cleanings: Professional hygienists have specialized tools to scale away the biofilm on dental margins that home tools might miss.
Does your current flossing routine feel like it's missing something? If you're struggling to keep the area between your crowns fresh, our Professional Series Water Flosser is designed specifically to reach those tricky margins and blast away odor-causing bacteria.