Tooth root resorption is a dental condition whereby the body begins to turn on itself to breakdown, dissolve, and absorb tooth material. For children, this natural process helps to remove baby teeth to make way for adult teeth. In adults, resorption is a serious issue as there are no other teeth waiting to come out. It is difficult to calculate exactly how many people in the U.S. experience root resorption. The causes and symptoms are similar to other dental conditions.

How does your tooth’s structure contribute to root resorption?

Understanding a tooth’s structure can be helpful in understanding root resorption. The crown of your tooth (the part that is outside of the gum) consists of enamel that covers dentin. Dentin is the hardest part of the tooth. Inside the dentin is the dental pulp.

Both dentin and dental pulp are made of mineralized living cells. Connective tissue called cementum surrounds the tooth’s roots. The roots dive into the gums, and the periodontal ligaments attach to this cementum to hold the tooth to the jawbone.

In cases of root resorption, the body’s cells identify any part of the tooth’s structure as a foreign invader and begin to eat away at it. This is not unlike an immune-system response to a virus. In the case of tooth resorption, the adult tooth is often healthy and still necessary.

What are the major types of tooth resorption?

There are two major types of tooth resorption:

Internal resorption and external resorption differ in how it attacks the tooth. In the case of internal tooth resorption, the dental pulp and the dentin are resorbed from inside the tooth. External resorption is the most common of the two types. In this case, the resorption begins on the outside of the tooth and works its way inward.

Both internal root resorption and external root resorption act like an autoimmune disorder.

The body cannot distinguish between a healthy cell and a diseased one and so attacks both. In a healthy body, resorption is a natural process that, along with deposition (adding) helps maintain balance, especially in the case of bones. When the immune system gets confused, the rate or resorption can outpace deposition. This can lead to tooth loss.

What causes root resorption?

While the causes of root resorption are not definitive, there are some risk factors, including:

  • Trauma
  • Bruxism
  • Orthodontic work
  • Intra-coronal teeth bleaching
  • Periodontal disease


For both internal and external resorption, trauma to the teeth seems to be a major risk factor for root resorption. If trauma damages the periodontal ligament, the body may identify the tooth as foreign and begin the process of root resorption.


Grinding and clenching teeth seems to be another cause of this condition. It may be linked to trauma to the periodontal ligament. Bruxism also opens the teeth to host bacteria, and the body may attack both bacteria and healthy teeth indiscriminately.


When looking for causes, braces have to be considered.

Patients who wear braces for an extended period may experience a shortening of the tooth’s roots. The body may look at these tiny roots as something out of place. While some root shortening is common for nearly all orthodontic correction procedures, actual root resorption can occur to the point where a tooth becomes loose and falls out.

Intra-coronal tooth bleaching

This type of tooth whitening (meaning “inner crown”) is a risk factor for tooth root resorption. Root resorption is not usually an issue with other types of professional teeth whitening.

Periodontal disease

Periodontal disease can damage the periodontal ligament, prompting tooth