Your dentist may have spotted something on an x-ray near the gum line and called it cervical resorption. It usually causes no symptoms, which is why it so often turns up this way.
What cervical resorption is
Resorption means the hard structure of a tooth is being broken down and lost. In external cervical resorption, also called invasive cervical resorption, this usually starts on the outside of the root at the neck of the tooth, near the gum line. It can extend up or down the root, wrap around it, and move toward the pulp, the nerve and blood supply in the center of the tooth.
In a 2023 study of 215 affected teeth, most lesions were small to moderate in height and in spread around the root, but most lay close to the pulp. The teeth affected most often were upper central incisors (21.4 percent) and lower first molars (10.2 percent).
How it is usually found
Most teeth with cervical resorption cause no symptoms. In that study, 58.1 percent of cases were first spotted by chance on an x-ray or 3D scan. About 23.3 percent had symptoms of a nerve or root-tip problem, and symptoms were linked to the lesion probably reaching the pulp rather than to its size.
You may have read that it shows up as a pink spot on the tooth. It can, but a pink spot was seen in only 5.1 percent of cases, and a visible cavity in 14 percent. A tooth can look and feel normal and still have it.
What may make a tooth more likely to develop it
No one knows for certain what starts it. A 1999 study by Heithersay reviewed 222 patients with 257 affected teeth. Out of all those patients:
- Orthodontic treatment was the only possible factor in 21.2 percent.
- Dental trauma was the only possible factor in 14.0 percent.
- Surgery, especially around the neck of the tooth, was the only possible factor in 6.3 percent.
- Internal bleaching of a root canal-treated tooth was the only possible factor in 4.5 percent, and appeared with trauma, orthodontics or both in another 10.4 percent.
Grinding was uncommon, and about one patient in seven (15.0 percent) had no identifiable factor.
A 2025 study of 215 lesions in 194 patients in London found a similar pattern. Orthodontic treatment (25.6 percent) and dental trauma (20.9 percent) were again the most common potential factors, and habits such as grinding or clenching were a potential factor in 10.2 percent. No factor was found in 22.3 percent.
These studies show an association, not proof of cause, and the 2025 authors say larger studies that follow patients forward are still needed.
Dr. El-Refai sees cervical resorption more often than she used to, and in her experience many cases are linked to orthodontic treatment or to heavy biting forces on the tooth, which dentists call occlusal overload. The research has not established overload as a cause, so this is her clinical observation. The 2025 authors do suggest a related idea: in people who grind their teeth, sideways jaw movements may overload the ligament that holds the back teeth in place.
Why a 3D scan is needed
A flat x-ray can hide how far the damage goes. In a study of 115 teeth, regular x-rays underestimated the size of the lesions and were limited at showing where they were and how far they spread around the root. Treatment plans made from regular x-rays differed significantly from plans made with cone beam CT, and the authors concluded that a 3D scan should be considered before treating a lesion that may be restorable.
The American Association of Endodontists and the American Academy of Oral and Maxillofacial Radiology agree. Their joint position statement, updated in 2025, says a small-field 3D scan should be the preferred imaging to locate resorption, tell external from internal resorption, and decide on treatment and the outlook for the tooth.
The scan also lets the lesion be graded in three dimensions, using the Patel classification. It describes how far up or down the root the lesion reaches, how far it wraps around the root, and how close it comes to the pulp. In a 2026 study, it was more closely linked to which teeth survived than the older Heithersay classification, which is based on a flat x-ray.
Treatment options
That 2026 study followed 296 teeth at five specialist practices. Each tooth was managed in one of three ways, chosen by how easy the lesion was to reach, whether there were symptoms, and what the lesion looked like:
- Monitoring. The tooth is checked at regular reviews.
- Repair from the outside. The lesion is reached from the outside of the root and repaired, with or without root canal treatment or other treatment of the pulp.
- Repair from the inside. The lesion is reached and repaired through the tooth itself.
Not every tooth can be restored. In the study, a tooth was counted as lost when it had to be removed because the lesion kept growing or the tooth could no longer be restored.
What the outcomes look like
The study estimated that 95.5 percent of teeth were still in place after one year, 93.3 percent after two, 85.7 percent after five, and 80.5 percent after both seven and ten years. These are statistical estimates, and teeth were followed for 2.9 years on average.
Estimated survival was 93.6 percent for monitored teeth, 90.2 percent for repair from the outside and 59.1 percent for repair from the inside. Because each approach was chosen to suit the tooth, the authors caution that these are associations, not evidence that one approach is better. Lesions that wrapped more than halfway around the root were linked to a higher chance of losing the tooth.
How we approach cervical resorption
Treating cervical resorption is complex work that not every office is comfortable taking on, and some of our patients with it are referred to us for that reason. Dr. El-Refai takes and reads your small-field 3D scan herself and goes through it with you slice by slice, so you can see how large the lesion is, where it sits and how close it comes to the nerve. We explain the options that fit your tooth and are honest about the odds. If a tooth is not a good bet, we will tell you.
Learn more about our 3D imaging, or contact us about a tooth your dentist has flagged. You do not need a referral to see us.
