Tooth resorption is the body breaking down and absorbing its own tooth structure. It’s uncommon, usually painless in the early stages, and almost always found on a routine X-ray rather than because something hurt. Caught early it’s often treatable, and left alone it can cost the tooth.
Nothing about it is contagious or related to decay. It’s a biological process that goes wrong, and restorative dentistry handles the repair once the active cells are stopped.
Resorption is completely normal in one situation.
Baby teeth loosen because their roots are deliberately resorbed to let adult teeth through. In an adult tooth, the same machinery switching on is the problem, which is why the dental clinic in North York you attend should be taking regular X-rays even when nothing hurts.
The two main types
Internal resorption
Starts inside the pulp chamber and eats outward. Usually follows trauma or long-standing pulp inflammation, sometimes years after the original injury.
Its classic sign is a pink patch showing through the crown, because the expanding tissue becomes visible through thinning dentin. Root canal treatment removes the responsible cells and usually stops it outright.
External resorption
Starts on the outside of the root and works inward. More common, and more variable.
Surface resorption after a knock often heals on its own. Inflammatory resorption follows infection or trauma and progresses quickly. Replacement resorption fuses the root to bone and is the hardest to manage. External cervical resorption starts at the gumline and is the type most often caught late.
What triggers it
- Trauma, including knocks from years earlier that seemed to heal fine
- Orthodontic treatment, particularly heavy or prolonged forces
- Internal whitening of a root-treated tooth, which is why technique matters
- Impacted teeth pressing against the root of a neighbour
- Chronic pulp inflammation from deep decay or a large restoration
- Periodontal treatment in some cases
- No identifiable cause in a meaningful share of patients
That last point is worth stating plainly. Plenty of resorption cases have no clear trigger, so nobody did anything wrong. It’s one of the reasons it gets missed without X-rays.
How it’s found and diagnosed
| Sign | What it suggests |
|---|---|
| Pink discolouration in the crown | Internal or cervical resorption |
| Dark shadow on a routine X-ray | Any type, often first sign |
| A tooth that sounds dull when tapped | Replacement resorption |
| Gum swelling at one spot | Cervical resorption reaching the surface |
| Tooth feels fused and immobile | Replacement resorption |
| Sudden pain or sensitivity | Late stage, pulp involved |
A flat X-ray shows that something is there. A 3D CBCT scan shows how far it extends and whether the defect has broken into the pulp or the root surface, which is what decides whether the tooth is restorable.
Ask for 3D imaging if resorption is suspected. Treatment planning from a flat image alone underestimates these lesions regularly.
Treatment options
- Monitoring, for small surface lesions after trauma that often arrest without intervention. X-rays at 6 and 12 months.
- Root canal treatment, which removes the cells driving internal resorption and halts it in most cases.
- Surgical access and repair, where the defect is reached from outside, the active tissue removed, and the cavity filled with a biocompatible material.
- Orthodontic extrusion, gently pulling the tooth up so a defect below the gum becomes accessible and restorable.
- Extraction and replacement where too much structure is gone.
Success depends almost entirely on how early it’s found. A small cervical lesion repaired at the right moment keeps the tooth for decades. The same lesion 3 years later often can’t be saved.
Where a tooth is lost, dental implants replace it predictably, since resorption affecting one tooth doesn’t affect an implant.
Reducing the risk
You can’t prevent it reliably, and a few things help.
Keep regular check-ups with X-rays at sensible intervals, since early detection is the entire game here. Mention any history of dental trauma even from childhood, because those teeth deserve closer monitoring.
Wear a mouthguard for contact sport. And have any discolouring tooth looked at rather than assuming it’s a staining issue, since internal whitening on a tooth with undiagnosed resorption makes things worse. Discuss whitening options properly rather than treating a grey tooth at home.
Sudden pain, swelling or a tooth that becomes mobile warrants prompt attention from an emergency dentist.
Getting it assessed in North York
Celina Dentistry is a premium clinic at 500 Wilson Ave Unit 108, North York, ON M3H 0E5, combining artistry with dental excellence, advanced imaging and a comfort-focused environment.
We’re accepting new patients and same-day appointments are available for urgent concerns. The practice covers emergency, cosmetic and restorative dentistry, implants, veneers, laser treatment and whitening.
Call +1 647-905-7372 or email info@celinadentistry.ca. If a previous dentist mentioned a shadow on an X-ray and suggested watching it, that’s worth a second look rather than leaving indefinitely.
Resorption is diagnosed with imaging by a licensed dental professional, not from symptoms, because the early stages produce none. Nothing in this article replaces an examination of your own teeth.
Frequently asked questions
Is tooth resorption painful?
Usually not in the early stages, which is why it’s found on X-rays rather than through symptoms. Pain appears late, once the pulp becomes involved or the defect reaches the root surface and gets infected.
Can resorption be reversed?
The lost tooth structure doesn’t grow back, so treatment aims to stop the process and repair the defect. Small surface lesions after trauma sometimes arrest on their own and heal with normal tissue.
Does orthodontic treatment cause it?
Minor root shortening occurs in many orthodontic patients and rarely matters clinically. Significant resorption is uncommon and linked to heavy forces, long treatment times and individual susceptibility. Orthodontists monitor with X-rays during treatment.
Will I lose the tooth?
Not necessarily. Early internal resorption responds well to root canal treatment. Cervical lesions caught while still small are repairable. Extensive defects below the gum or fused roots are the cases where extraction becomes likely.
How often should it be monitored?
Typically with X-rays at 6 and 12 months for a lesion being watched, then annually if stable. Any change in size, symptoms or tooth mobility brings the review forward.
The key point
Resorption is silent until it’s advanced, which makes routine X-rays the only reliable way to catch it. Found early it’s often treatable and the tooth is kept. A pink patch or an unexplained shadow on a film both deserve proper 3D imaging rather than watchful waiting.