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Can Flossing Loosen a Crown? When it Happens

Flossing should not loosen/dislodge a dental crown with permanent cement but if it does, it means there is something wrong with your tooth cap. Temporary crowns on the other hand can be easily/accidentally loosened while flossing and that is considered normal.


Conditions causing loose crown after flossing:


All of the oral conditions above could be a reason as to why your tooth cap is now loose after using floss. They are not normal but are indications of a complication.


Permanently cemented crowns shouldn't come off

A properly cemented crown with permanent adhesive should not loosen/budge/dislodge while you're flossing even if you floss aggressively. That is because permanent cement is much stronger than the force that you can exert with string dental floss.


Permanently cemented gold crown
Permanently cemented gold crown

Therefore, there is no need to floss differently for permanent crowns and your regular teeth. You floss and brush both of them the same exact way without the need for additional oral hygiene instruments.


However, if your tooth cap was cemented with temporary cement, then that'll be a different story because it can potentially come off.



 

Cement under crown has dissolved

If the cement under your crown has dissolved, it will be possible to loosen or dislodge the cap by flossing.


How it happens: Dental crown cement or any adhesive for that matter can potentially dissolve over time because the saliva contains a lot of enzymes. Therefore, as the saliva comes into contact with the adhesive, it may slowly wash it away over a long period of time.

  • An apt analogy would be the ocean washing away your sand castle with each wave that hits it. As you can imagine, you can picture the same thing occurring in your mouth.


But it's permanent: While the tooth cap cement may be labeled as permanent, it doesn't mean that it lasts forever. It merely means that it lasts a very long time, well over many years without any incidences happening.

  • We've had plenty of patients who've had crowns in their mouths for decades (30+ years) without the glue dissolving.


Signs of dissolved adhesive:

  • Crown is devoid of cement underneath and looks clean as a whistle.

  • Tooth itself also has no cement on it.

  • Both the cap and tooth look intact and undamaged.


Interior of crown with no residual cement
Interior of crown with no residual cement

residual cement inside crown
residual cement inside crown

What to do: If your crown gets loose from flossing, you should see your dentist to have it recemented. This means putting a fresh layer of adhesive of permanent cement. This procedure is called recementation.


 

Cavity under dental crown

If your tooth under the crown is decayed, it may be damaged enough to become loosened or dislodged by flossing.


How it happens: Decay will rot the tooth and change it from hard to soft which will increase the chances of the crown coming off while flossing over time.

  • Crowns are less stable when cemented on soft decayed tooth structure.

  • Crowns are most stable when cemented on rock solid intact tooth structure.

Signs of decay under crown:

  • Tooth looks black or brown.

  • Feels soft when you scratch it with an explorer.

  • Putrid smell or foul odor.

  • Pieces of tooth are missing.


What to do: You will need to see a dentist to have the decay addressed and depending on the severity, you may need different treatments.


Decay Severity

Treatment

Mild decay

  1. Excavate decay

  2. Core buildup

  3. New crown

Moderate decay

  1. Root canal

  2. Core buildup

  3. New crown

Severe decay

  1. Extraction

  2. Bridge/Implant/Denture

You won't know what treatment you'll need until you see your dentist for a full diagnosis.


 

Tooth fracture under crown

A fractured tooth with a crown can certainly be loosened and dislodged even with gentle flossing.


How it happens: If the tooth the crown is cemented on sustains a fracture/crack, the entire suprastructure will become compromised. Since the cap is now glued to an unstable surface it will become to wobble and eventually fall out.


How to tell if crown is loose due to fracture:


tooth attached to crown that fell off
tooth attached to crown that fell off

What to do: You must see a dentist because a cracked tooth is a serious condition and it cannot be treated at home.


 

Short clinical crown

A tooth with a short clinical crown underneath is more prone to getting dislodged by flossing and while eating.


Reasons short clinical crowns are prone to loosening by flossing:

  • Low resistance form. Due to the tooth being so short, it does not resist dislodging forces from sideways or oblique forces.

  • Low retention form. Due to the tooth being short, it does a poor job of resisting vertical forces in the path of insertion.


short clinical crown example

What to do: If it comes off you can simply have it recemented but if it occurs multiple times, you should consider other treatment options.


 

Temporary crowns are easily dislodged

A temporary crown is easily dislodged or loosened while flossing because it is cemented with temporary cement. This type of cement is meant to be temporary so its adhesive strength is significantly weaker/lower than their permanent counterparts.



As a matter of fact, your dentist will warn you to floss carefully or even to not floss the area while you wait for your permanent cap to arrive. Although if you were to floss it, there is a safer way to floss it which can minimize the risk of it loosening.


  1. Floss through the contact normally.

  2. Do not pull the floss back out the same way you went in.

  3. Instead, pull the floss out horizontally towards the cheek.


flossing through crown
flossing through crown

Reason temporary cement is used: You may be wondering why use temporary glue at all if it causes inconveniences such as being loosened or popped off while flossing... This is because your dentist still needs to be able to remove your temp crown so that they can give you your permanent one once it is fabricated.


 

Verdict

Flossing really shouldn't loosen a permanent crown but it can easily dislodge a temporary cap. However, if it does come off it most likely means your tooth is afflicted with a condition and you should see a dentist. Our dental office in Long island City can help you if you book a consultation with us.

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About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

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Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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