Dental crowns help restore the strength, bite functionality and appearance of a cracked or damaged tooth. Commonly made from porcelain, crowns get fitted and placed over your tooth and cemented into place.
Your dentist may recommend a traditional or same-day crown if you have a cavity that’s too large for a filling, to complete a root canal or preserve a cracked or damaged tooth. In select cases, a crown may help reduce certain cosmetic issues, such as visible discoloration or an abnormally shaped tooth.
Yet one myth about dental restorations persists: Crowns will not decay or develop cavities. While the restoration may not succumb to decay, bacteria can still get underneath to start this process. Neglecting dental hygiene or a damaged crown increase this risk.
How Bacteria Gets Underneath a Crown
After a crown has been placed over your tooth, you’re advised to brush at least twice a day and floss at least once. Not following these recommendations increases the risk bacteria will start to build up in your mouth, including underneath and inside a crown.
Bacteria go after what’s left of a tooth by converting sugars into acid, which eats through the enamel and results in rot and a cavity or infection underneath the crown. Saliva also cannot reach below the crown, so this pattern continues without resistance or interruption.
Other factors that can cause bacteria to get underneath a crown include:
- Regularly consuming sugary foods and drinks
- Trauma to the crown or the tooth underneath, which can occur from chewing on hard objects or not wearing a mouthguard
- A gum infection occurring below the tooth with a crown
Signs of Tooth Decay or Infection Below a Crown
Pain around the tooth with a crown may indicate the presence of more decay or an infection. The tooth structure underneath could be experiencing excessive decay in the form of a cavity or the rot and infection may have started to spread to the pulp and nerves.
The pain may also be related to a damaged or misaligned crown placing pressure on or exposing the pulp and nerves. Other signs include:
- Redness and tenderness around the crown
- Swollen or sore gums surrounding the crown
- A constant sensation of warmth on one side of your mouth
- Yellow, clear or greenish discharge near the crown
- Bad breath
- Running a fever
- Swollen neck glands
Ignoring these signs could result in serious complications:
- Decay can become an infection that spreads into the tooth and throughout your mouth, possibly even reaching the jawbone
- An abscess may develop near the crown
- The tooth underneath the crown may need to be extracted
Treatment for an Infection
If you notice any of the above signs, schedule an appointment with your dentist to examine the crown and source of pain.
Treatment for decay or infection below a crown may entail:
- Removing the existing crown
- Addressing the decay by filling or extracting the remainder of the tooth
- Creating a new crown to accommodate the filling and what remains of the tooth
- Recommending an implant or other artificial tooth be added in place
Caring for Your Dental Crown
After you’ve been given a permanent crown, you’ll be advised to:
- Avoid certain sugary, hard and acidic foods for a period of time
- Avoid habits like chewing on pens and ice cubes that could damage the new crown
- Brush your teeth at least twice a day with a soft-bristled brush
- Floss your teeth at least once a day, including around the crown
- Schedule regular dental cleanings, where your dentist will inspect your crown
- Notify your dentist if the crown cracks or you see a black line at its base