Some dental problems are loud, announcing themselves with pain the moment something goes wrong. Root resorption is quieter. It can progress for a long time inside a tooth, sometimes with no discomfort at all, until it’s picked up on an x-ray or noticed as an unusual colour change.
Root Resorption Breaks Down Tooth Structure From Within
Root resorption is a process where the body’s own cells begin breaking down the dentine or root structure of a tooth, usually as a reaction to trauma, prolonged irritation, or inflammation inside the tooth. It can start internally, within the pulp chamber, or externally, along the root surface, and in many cases causes no pain at all until it’s more advanced.
- Resorption is often discovered incidentally, on a routine x-ray rather than through symptoms
- Trauma to a tooth, even years earlier, is a common trigger
- A pink discolouration in the crown of the tooth can sometimes signal internal resorption
- Once identified, resorption generally needs to be assessed by a dentist promptly, since it tends to be progressive
- It’s different from tooth decay, which is caused by bacteria attacking the tooth from the outside
Internal Versus External Resorption
Resorption is generally grouped into two broad categories, depending on where the process begins.
Internal Resorption
This type starts within the pulp chamber, the soft tissue at the centre of the tooth, and works its way outward. It’s often linked to inflammation inside the tooth following an injury or a deep cavity that’s affected the pulp.
External Resorption
This type begins on the outer surface of the root and can be triggered by trauma, prolonged pressure such as from orthodontic treatment, or an impacted neighbouring tooth. It tends to progress inward from the root surface rather than starting at the centre.
Both types are generally identified in the same way, through x-rays, and both are considered progressive if left untreated, though the treatment approach can differ depending on which type is present.
Why This Process Happens Internally
Under normal circumstances, the inner structure of a tooth is protected from the type of cell activity that resorbs bone elsewhere in the body. When that protective layer is disrupted, commonly by an injury to the tooth, an infection, or ongoing inflammation from a cracked or previously injured tooth, the body can mistakenly begin resorbing the tooth’s own dentine from the inside.
Common Triggers Worth Knowing
A few situations are more commonly associated with root resorption than others:
- A direct knock or impact to a tooth, even one that seemed to heal fine at the time
- A tooth that’s been repeatedly bumped or knocked over the years, such as through contact sport
- Prolonged orthodontic pressure during teeth-straightening treatment
- An unerupted or impacted tooth pressing against the root of a neighbouring tooth
- Ongoing inflammation from an untreated cavity or previous dental infection
Why Trauma Is Such a Common Trigger
A knock to a tooth doesn’t always cause an immediate, obvious problem. In some cases, the visible damage settles, but the trauma sets off a slower process inside the tooth that isn’t noticed until much later. This is one of the reasons a tooth that’s been knocked, chipped, or otherwise injured is worth monitoring over time, even once it feels fine, since resorption can develop well after the initial injury.
If you’re dealing with a recent injury, healthdirect’s guidance on dental injury covers what to do in the immediate aftermath, though ongoing monitoring afterward is a separate, longer-term consideration your dentist will factor into future check-ups.
What a Pink Discolouration Can Mean
One of the more distinctive signs of internal resorption is a pink or reddish tinge visible through the crown of an affected tooth. This happens when the resorption process progresses close enough to the outer surface that the reddish tissue inside becomes visible through the remaining tooth structure. Not every case of resorption produces this visible sign, and its absence doesn’t rule resorption out, but if you notice an unusual colour change in a tooth, particularly one with a history of injury, it’s worth having it checked.
How Root Resorption Is Identified
Resorption is most commonly picked up through routine dental x-rays, which is one of several reasons regular check-ups matter even for teeth that feel completely normal.
- X-rays can reveal internal or external resorption before any visible or noticeable symptoms develop
- A tooth with a history of trauma may be monitored more closely over subsequent visits
- Colour changes, if present, are usually noticed during a visual examination
- In some cases, resorption is found unexpectedly during treatment for an unrelated issue
What Happens Once Resorption Is Identified
Once resorption has been identified, your dentist will assess how far it has progressed and what’s driving it, since this affects what treatment, if any, is suitable.
Monitoring in Early Cases
Very early or minimal resorption may sometimes be monitored with periodic x-rays to track whether it’s progressing, particularly if the cause is uncertain or the affected area is very small.
Root Canal Treatment for More Established Cases
Where resorption is linked to inflammation inside the tooth, root canal treatment may be recommended to remove the affected tissue and stop the process from continuing further, similar to how root canal treatment addresses other forms of internal tooth damage.
When a Tooth May Not Be Restorable
In more advanced cases, particularly where a significant amount of tooth structure has already been lost, the tooth may not be restorable, and extraction may be discussed as part of a broader conversation about replacement options.
Living With a Tooth Under Monitoring
If your dentist recommends watching a tooth rather than treating it immediately, this generally means periodic x-rays at your regular check-ups to track whether the resorption is stable or progressing. It’s worth keeping to this schedule even if the tooth feels completely normal day to day, since resorption can progress without symptoms.
Frequently Asked Questions
Is Root Resorption Painful?
Often not, particularly in the earlier stages. This is part of why it’s frequently discovered on a routine x-ray rather than because of symptoms. Some cases do eventually cause discomfort as they progress, but this isn’t universal.
Can Root Resorption Be Reversed?
Generally, resorbed tooth structure doesn’t grow back once lost. Treatment instead focuses on stopping the process from progressing further and preserving as much of the remaining healthy tooth as possible. Outcomes vary depending on how early it’s identified.
Does Every Injured Tooth Develop Resorption?
No, most injured teeth heal without developing resorption. It’s a possible complication rather than an inevitable outcome, which is why monitoring after a dental injury is a precaution rather than an indication something is already wrong.
Can Resorption Affect More Than One Tooth?
It’s possible, particularly if there’s an underlying cause affecting multiple teeth, though it’s more commonly seen in a single tooth following a specific injury or localised source of inflammation. Your dentist can advise if wider monitoring is appropriate for your situation.
Will I Need a Specialist for Treatment?
Depending on the complexity of the case, your dentist may manage treatment directly or refer you for more specialised input. This is generally guided by how advanced the resorption is and where it’s located within the tooth.
Noticed a Colour Change or Have a History of Tooth Trauma?
If a tooth looks different than it used to, or you’ve had a past injury you’d like checked, having it assessed with an x-ray is the most reliable way to know what’s happening beneath the surface. You can book an appointment online to have it looked at.