Pain and smell from a crowned tooth: how to spot decay under a crown and what's done
Pain, a smell or darkening at the edge of a crowned tooth that starts months or years later usually points to decay starting at the crown margin, nerve inflammation in the tooth beneath, or a gum problem. A crown doesn't protect a tooth completely; if its edge isn't kept clean, the tooth underneath can decay. Caught early, the tooth can usually be saved; left untreated, it may be lost.
Possible causes of pain and odour in a crowned tooth
| Sign | Possible cause |
|---|---|
| Odour or bad taste at the crown edge | Decay at the margin, washed-out cement, trapped food |
| Darkening at the crown edge, a dark line at the gum | An edge exposed by gum recession, or decay |
| Pain with hot or cold, or at night | Nerve inflammation in the tooth under the crown |
| Pain on biting, swollen gum | Inflammation at the root tip, a cracked root |
| Odour under a bridge | Build-up under the false tooth, inadequate cleaning |
| The crown feels loose | Washed-out cement, loss of tooth structure beneath |
How is decay under a crown detected?
You can't see under a crown. At the examination the margin is checked with a probe, the gums are measured and an X-ray is taken. Metal-based crowns can partly hide the tooth underneath on an X-ray, so symptoms and examination findings are assessed together. See dental X-rays.
How is it treated?
- Small decay at the edge: sometimes repaired with a margin filling while the crown stays in place.
- Extensive decay underneath: the crown is removed, the decay cleaned out, the tooth built up with a filling if needed, and a new crown made.
- Nerve inflammation: root canal treatment is needed; sometimes it can be done through the crown, but a new crown is often advised afterwards.
- Cracked root: saving the tooth is often not possible; implant or bridge options are discussed.
For crown options see types of dental crowns; for implants see a single missing tooth.
Protecting the tooth under a crown
- Brush the crown edge with the bristles angled towards the gum.
- Use floss or interdental brushes every day; for under a bridge, use superfloss or a water flosser.
- Have the margins checked with an examination and X-ray at least once a year.
- If you grind your teeth, a night guard protects crowns. See teeth grinding and night guards.
For how long crowns last, see how long zirconia crowns last.
Crown check-ups in Beylikdüzü
We can also examine and treat crowns made at other clinics.
Dent32 is at Barış Mah., Ginza Lavinya, E-5 Yanyolu No:30 D:179, 34520 Beylikdüzü, Istanbul and is open seven days a week. To book, call or WhatsApp +90 555 011 33 68, or use our contact page. At the examination we share the findings, the options and the approximate cost in writing; you are under no obligation to start treatment afterwards.
Frequently asked questions
Why does my crown smell?
The most common causes are decay at the crown margin, washed-out cement and food trapped under a bridge. An examination and X-ray find the cause.
Why does a crowned tooth hurt?
Nerve inflammation in the tooth under the crown, inflammation at the root tip, decay at the edge or a cracked root can all cause pain.
Can a root canal be done without removing the crown?
Sometimes it can be done through the crown. If there is decay underneath or the crown would be weakened, replacing the crown is usually advised.
Is a dark line at the crown edge decay?
Not always; a metal margin exposed by gum recession can also look dark. An examination tells the difference.
