One tooth is darker than the others: why a whitening kit may miss the cause
A single tooth that is darker than its neighbors usually has an internal cause rather than surface stain: an old injury, a nerve that has died or been treated, a large or old filling, or decay. A whitening kit applied to the whole smile may lighten the other teeth and leave the dark tooth more noticeable.
An examination with an x-ray and a vitality test usually identifies the cause first.
Common causes
| Cause | How it tends to look |
|---|---|
| An injury, even years ago | Gray or yellow-brown tooth; the American Dental Association notes an injured tooth can lay down extra, darker dentin (ADA) |
| A nerve that has died, or a root canal | Gray, sometimes darkening slowly over years |
| Decay or a leaking filling showing through | Brown or gray shadow near a filling or at the gum |
| An old metal filling or post | Gray shadow through the enamel |
| A developmental spot | Present since the tooth came in |
| A crown or veneer that no longer matches | The restoration is the "tooth" that looks different |
What the dentist checks
Any history of a blow to the tooth, an x-ray of the root and surrounding bone, a test of whether the nerve responds, the tooth's color and translucency, the gum around it, and any pain or swelling.
Treatment paths, depending on cause
- Decay or infection: treated first
- A root-canal-treated tooth: internal whitening of that tooth alone; the studio lists single-tooth internal whitening (studio)
- A healthy but darker tooth: external whitening of that tooth alone
- Deep color: bonding, a veneer or a crown, which the examination selects
Whitening does not change existing fillings or crowns (ADA).
When it is more urgent
Pain, swelling, a pimple on the gum, looseness, or a recent injury need an appointment soon, not a cosmetic consultation.
If any of these apply, this is not a dental-office problem first: trouble breathing or swallowing, rapidly spreading swelling of the face or neck, fever with facial swelling, bleeding that will not stop, or a serious injury to the head or jaw. Call 911 or go to the nearest emergency department. Do not use the appointment request form for these.
Next step: Request a consultation or call (805) 565-5111. A request is not a confirmed appointment; the office confirms times during its listed hours (Monday to Thursday, 8 am to 5 pm, plus select Fridays).
Single dark tooth assessment flow
| What you notice | What the exam usually checks | Which path may be discussed |
|---|---|---|
| Gray tooth, old injury | X-ray, nerve test | Internal or external whitening, bonding, veneer or crown after any needed treatment |
| Tooth had a root canal | X-ray, seal of the root filling | Internal whitening, then bonding or veneer if needed |
| Brown shadow near a filling | X-ray for decay | Treat decay; replace filling |
| Gray shadow over a metal filling | Filling type and depth | Replace filling; sometimes a crown |
| Darker since childhood | Enamel development | Whitening of that tooth, bonding or veneer |
| Pain, swelling, gum pimple, looseness | Urgent examination | Treatment of infection first |
History to bring: when you first noticed it; any injury; past treatment on that tooth; any symptoms.
Guides are general education; an examination is needed for individual advice.
Sources
- MouthHealthy: Teeth Whitening — American Dental Association
- Oral Health Topics: Whitening — American Dental Association
- Loul Dental Studio: Teeth Whitening — Loul Dental Studio
- Clinician statement — Loul Dental Studio
- Clinician statement — Loul Dental Studio
Sources were current when this guide was last updated.
Educational content, not a diagnosis. Please contact the studio to discuss your own situation.