How do I check if I have decay around my crown?

Dental Designs Clinic Singapore
22 May, 2023

Are you experiencing pain and swelling around your dental crown? You might have some tooth decay on your crown — depending on the extent of the decay, it might cause dental infection and even result in permanent loss of the tooth. 

Although crowns are usually put in place to restore a tooth’s appearance and function, tooth decay can still occur. This is because patients go back to their old habits or neglect taking care of their restored teeth, resulting in bacteria that can cause cavities. Remember — dental restorations do not guarantee you a lifetime of perfect teeth especially if you do not maintain proper oral hygiene and regular visits to your dentist! 

Find out more about Dental Crowns with Dental Designs today!

How do I know if my crown is infected?

Some signs of a dental crown infection include: 

  • Redness at or around the site of the crown 
  • Tenderness, soreness or pain around the site of the crown
  • Swelling of the gums around the crown 
  • Unusual warmth around the site of the crown 
  • A yellowish or greenish fluid leaking out from the crown 
  • Swollen lymph nodes at the side of your neck 
  • Fever 
  • Bad breath or an odour from the crown 
  • Dark spots or discolouration at the gumline around the crown


If you experience any of these symptoms, please see your dentist immediately. In most cases, your dentist should be able to notice the infection immediately. However, if the affected area is too small to accurately detect anything, your dentist might call for an X-ray to confirm any damage to the teeth underneath.glove hand pointing to x ray

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Is it common to get decay under a crown?

Dental crowns can decay or be damaged due to the following reasons: 

a) Poor oral hygiene 

If you do not ensure proper oral hygiene (brushing, flossing, rinsing) with a crown on, then some tooth decay is hardly surprising at all. Decay stems from food left in your mouth after eating — bacteria in your mouth thrive on this! This bad bacteria over time develops an acid that attacks your enamel, causing holes within your teeth we identify as decay. 

b) Trauma/impact to the crown

Crowns can also be damaged over time due to trauma on the mouth or from chewing on hard food. It’s important to note that a portion of your enamel is removed for a crown to be placed. The newly fitted crown in some sense serves as enamel for the tooth. As such, when the crown is damaged, it is easier for bacteria to surpass the crown and get to the real tooth underneath. Additionally, because there is no way to clean the tooth directly, bacteria usually stays under the damaged crown for a prolonged period without the patient knowing. 

c) A poorly fitted crown 

A poorly fitted crown can cause bacteria buildup and aggravate tooth decay. Even without an infection, an ill-fitting crown can also lead to discomfort, causing pain when you bite down. A black line around your crown is one of the most obvious signs of crown fit problems. 

*Please note that gum pain and tenderness after a dental crown procedure are not uncommon, but please see your dentist if the pain persists for more than two weeks. 


When do I need a new dental crown?

A dental crown is a customised “cap” designed to cover a patient’s entire tooth. Its functions include: 

  • Restoring the tooth’s shape and size 
  • Increasing the tooth’s strength 
  • Enhancing the performance of the tooth, preventing it from further damage 

What do I do if I have decay around my crown?

You may need to get your crown removed to treat the decay. Depending on the extent of the decay, you may need to make a larger crown to cover the decay. At Dental Designs, this process will only take a day as we offer Same Day Crowns using CEREC technology. 

For severe cases, if the decay has spread throughout your tooth and cannot be saved, you might need to get your tooth extracted. Additionally, if the decay reaches your roots, you may require root canal treatment, a procedure that’s slightly more invasive. 

Early detection and treatment of decay are essential to prevent further damage and potential tooth loss. While you can't directly check for decay under the crown itself, being mindful of these signs can help you identify potential problems and get the treatment you need to keep your smile healthy.

As such, do not delay seeing a dentist if you experience pain around your crown to arrest and stop the cause early. Send us a message here to book an appointment. 

Find out more about Dental Crown with Dental Designs today!


  1. Innes, N. P., Ricketts, D., Chong, L. Y., Keightley, A. J., Lamont, T., & Santamaria, R. M. (2015). Preformed crowns for decayed primary molar teeth. The Cochrane database of systematic reviews, 2015(12), CD005512.
  2. Kosyfaki, P., del Pilar Pinilla Martín, M., & Strub, J. R. (2010). Relationship between crowns and the periodontium: a literature update. Quintessence international (Berlin, Germany : 1985), 41(2), 109–126.