Part Of Decayed Tooth Fell Out: What To Do?

Written & Reviewed by Dr David Chen

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

Whether that rotten broken tooth hurts or is painless does not make a difference. It is in a dire situation and needs help as soon as possible.

What it means

If pieces of your decayed tooth actually fell out, that is a tell-tale sign of a severe cavity. That won’t happen in the beginning stages of a cavity but it’s possible for the later stages of tooth decay.

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, you may already have a dead tooth in your mouth because the cavity already penetrated through to the pulp and killed it.

How it happened

Teeth with small cavities will not fall off on its own since the decay hasn’t caused enough damage. However, large cavities do possess the potential to destroy enough of your enamel and dentin to make it fall out.

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 and destroy tooth structure. Over time the tooth becomes hollowed out and 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.

That rotten tooth now needs treatment pronto.

What to do

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.

Dentin decayModerateCrown or Filling
Pulp decaySevereRoot canal
Furcation decayCatastrophicTooth extraction
Treatment options for extent and severity of tooth decay

The image below shows the layer of a tooth.

  • 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 - Mouthhealthy
Credit: Mouthhealthy – ADA

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 of molars showing furcation
Furcation area of molars on x-ray

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.


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