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Part Of Decayed Tooth Fell Out: Causes & Next Step

Updated: Nov 13, 2023

If a part of your decayed tooth fell out, it means that you've late stage tooth decay and it is no longer manageable at home. In other words, the condition of your cavity is too severe and will need professional dental treatment.

large piece of tooth missing due to decay
large piece of tooth missing due to decay

Whether that rotten broken tooth hurts or is painless does not make a difference, you need to see a dentist as soon as possible. It won't fix itself if you leave it alone and it'll only get worse.

What this condition is

If a piece of your decayed tooth actually fell out, that is a tell-tale sign of a severe cavity. As a matter of fact, it signifies late stage tooth decay because this doesn't happen in the earlier stages.

decayed piece of wisdom tooth fell out
decayed piece of wisdom tooth fell out

Appearance: What it looks like

  • A part of your tooth is now missing.

  • There is a large hole (cavity) in the affected tooth.

  • Color looks black or brown.

  • Food is probably getting stuck in the hole whenever you eat.

Ultimately, your tooth condition is considered severe and certainly not mild. You should expect to have more complex and more costly treatment in order to remedy it.

What if it's painless?

If your rotten tooth has pieces of it falling off and it does not hurt you, that is a very bad sign. You may think it's good news since it's painless but it's actually the opposite.

If your broken tooth is not hurting, there is a good possibility that the nerve may already be dead. Yes, that means the tooth is already dead because the cavity already penetrated through to the pulp and infected it.

How it happened

Teeth with small cavities will not fall off since the decay hasn't caused enough damage to affect the structural integrity. However, large cavities do possess the potential to destroy enough of your enamel and dentin to make it collapse.

It'll make a lot more sense if you understand how cavities progress through each stage of tooth decay. Below are a series of dental x-rays which will exemplify what we mean.

The x-rays above show the progression of a cavity which is denoted by a dark area (radiolucent) on the tooth.

  • Small cavity in the enamel has a small black area in the enamel only.

  • As the cavity progresses into the dentin and become medium sized, you can see the black area balloon out or mushroom out.

  • Once the cavity has become big enough, the black area will be very large and you can even see pieces of the enamel missing.

In summary, what happens is that when a cavity is left untreated, it will grow in size. Over time the tooth becomes hollowed out once enough of the tooth is decayed. If you happen to bite into a hard food, the exterior will give way and collapse.

Therefore, a part of your decayed tooth fell out because the cavity got so big that it hollowed out the inside of it to the point where it collapsed under its own weight.


It is time to seek professional dental treatment if you're holding a piece of your fallen out rotten tooth in your hand. It should be in your mouth attached to your tooth and not in your hand. That's not what normal healthy teeth should look like.

The treatment for a tooth where part of it fell off due to decay would depend on the severity and extent of the cavity.




Enamel decay


Dental filling

Dentin decay


Crown or Filling

Pulp decay


Root canal

Furcation decay


Tooth extraction

Tooth anatomy:

  • Enamel is the outermost layer.

  • Dentin is the next layer.

  • Pulp is the innermost layer.

  • The furcation is the area where if you penetrate through, you've perforated the tooth.

tooth anatomy diagram
Credit: Mouthhealthy

Enamel involvement

Decay that is located solely within the enamel will not be severe enough to cause a piece of your tooth to fall out. This condition only requires a small conservative filling.

Dentin involvement

If the extent of the decayed tooth is limited to the dentin only, it is considered moderate severity. Depending on your dentist's judgement, the very least you'll need would be a dental filling.

However, to temper your expectations, you should expect to get a crown instead because it provides better protection. By covering the entire tooth in porcelain, it will make it much stronger and resistant to breaking.

Pulp involvement

If the extent of the decayed tooth has reached the pulp (nerve) of the tooth, you would definitely need a root canal. That is the only treatment available that can treat the nerve and preserve the tooth in your mouth.

No, fillings, bondings, and crowns do not treat nerve pain nor nerve infections. Once the nerve has been involved, it will need to be removed from the pulp chamber and canals.

Furcal involvement

When tooth decay is left untreated for an extended period of time, it can progress from the pulp to the furcation of the tooth. This is a catastrophic event because once that happens, the tooth is deemed non-restorable meaning it can't be saved.

x-ray showing furcation of molars

The x-ray above shows the furcation area of lower molars. Essentially the furcation is what connects the two roots of the molar together. If there is a cavity in that area, you've basically split the molar in half into two separate roots.

The only treatment option left for a furcally involved tooth would be an extraction. Yes, that means you will need to remove the entire tooth from your jaw.


It is not a good sign if pieces of your rotten tooth are falling out left and right. It is an indication that your tooth is at one of the later stages of a cavity.

We highly encourage you to see a dentist as soon as possible because if you leave it untreated, the decay will only grow in size and complexity. What that means is that you'll most likely end up with more complicated and more expensive treatment the longer that you wait to fix that broken tooth.



David Chen 200 x 200.jpg

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!

Association Memberships:

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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