If your dentist has used the word “resorption” about one of your teeth — possibly while looking at an X-ray with a small dark spot you hadn’t noticed before — and the conversation didn’t fully reassure you, this post is meant to help.
Resorption is real, it’s worth taking seriously, and it’s also more often treatable than alarming initial conversations suggest. The key in almost every case is the same: a 3D image and an unhurried evaluation before treatment decisions get made.
What resorption actually is
Tooth resorption is the loss of dental tissue — the dentin that makes up the bulk of a tooth, sometimes the cementum on the root surface — to cells in your own body. The cells responsible are normal cells that, for reasons we still don’t fully understand in every case, get triggered into eating away at tooth structure they normally leave alone.
It’s not decay. It’s not infection. It’s a misdirected version of the same process your body uses to remodel bone every day.
The two main types
Internal resorption
Internal resorption starts inside the tooth, in the pulp chamber or canal, and works outward. On a 2D X-ray it usually looks like a balloon — a smooth oval expansion of the dark canal space, sometimes with the original canal outline still faintly visible.
Internal resorption is most often:
- Detected incidentally. Most patients have no symptoms. The lesion is found on a routine X-ray, often years after whatever event triggered it.
- Linked to past trauma or chronic pulp inflammation. A tooth that took a hit decades ago, a deep cavity that was filled with a borderline pulp, an old root canal that didn’t fully resolve.
- Treatable when caught before it perforates the root. A small, contained internal resorption defect can usually be cleaned, disinfected, and filled with a bioceramic material that bonds to dentin and seals the defect.
External resorption
External resorption starts outside the tooth, in the periodontal ligament around the root, and works inward. There are several sub-types depending on where on the root surface it starts:
- Cervical resorption starts at or just below the gumline, often associated with past orthodontic treatment, trauma, or internal bleaching done years before.
- Apical resorption starts at the root tip, often from chronic infection or pressure (an unerupted tooth pushing into the root, for instance).
- Surface resorption is shallow, often self-limiting, and frequently doesn’t need treatment.
- Inflammatory root resorption is associated with active infection and tends to progress aggressively without treatment.
External resorption is more variable than internal — sometimes nearly invisible on 2D X-rays until late, sometimes obvious. The 3D image is what tells you which kind you’re dealing with.
Why a 3D image matters here, more than usual
In a routine root canal case, a 2D X-ray gives you most of what you need. In a resorption case, a 2D X-ray often misleads — and can mislead in either direction.
A small dark spot on a flat film might be a 2-millimeter surface defect (no big deal, often watch-and-wait). The same small spot might be a deep, broad lesion that’s already undermined the root wall (very serious, narrow window for save).
Across the resorption cases in our practice, CBCT (3D imaging) consistently changes either the diagnosis or the treatment plan in cases where 2D imaging suggested something else. That’s why every suspected resorption case in our office gets a CBCT before we make a recommendation.
If you’ve been told you have resorption and a treatment plan has been recommended without a CBCT, that’s a reasonable place to ask for a second opinion. Not because the original dentist is wrong — but because resorption is a diagnosis where the 2D picture genuinely isn’t enough to make confident decisions.
When resorption is treatable
Many resorption cases respond well to treatment. The good-prognosis categories include:
- Small to moderate internal resorption that hasn’t perforated the root wall
- Cervical external resorption caught before it reaches the pulp
- Apical external resorption associated with infection that resolves once the infection is treated
- Stable, arrested resorption that has stopped progressing — these sometimes need only monitoring
Treatment for internal resorption resembles a complex root canal: access the tooth, thoroughly clean the irregular defect, seal it with a bioceramic. Treatment for cervical external resorption is often surgical: lift a small flap of gum, access the defect from outside, clean it, restore it with a bioceramic.
Either approach usually takes two visits. The outcome depends on the specific anatomy of your case, which is why the CBCT-led evaluation matters.
When resorption is not treatable
Some resorption cases can’t be saved. The honest list includes:
- Internal resorption that has perforated the root wall and connected the canal to the bone or gum
- Aggressive cervical resorption that has wrapped around the root and undermined the crown
- Late-stage chronic inflammatory root resorption that has reduced the root to a shell
When a case is past the point of save, the right move is to know that early. Continuing to treat a tooth that’s structurally past saving costs you time, money, and ultimately the same outcome (extraction) you’d get by accepting it sooner. A consultation that says “this one we shouldn’t try to save” is doing you a service, not giving up.
What to do if you’ve been told you have resorption
Three steps:
- Get a CBCT if you haven’t already. The 3D image is where the real diagnosis lives.
- Get a thorough evaluation by an endodontist. Resorption is squarely in our specialty — most general dentists see only a handful of cases over a career, while a busy endodontic practice sees hundreds. Familiarity with the patterns matters.
- Don’t rush. Most resorption progresses slowly. A few weeks to get a proper imaging-led evaluation almost never costs you the tooth, and frequently changes the treatment plan.
If you’d like an evaluation, we have a resorption treatment service page with more on what we offer, and we’re happy to schedule a consultation. The first step is the CBCT and the conversation about what your specific case actually shows.