Symptoms & conditions
Black spot or dark line on a tooth
The short answer
A black spot or dark line on a tooth is almost always decay — usually deeper than it looks on the surface. A small visible black pit can correspond to a cavity that's already reached the dentine. Get it checked; waiting 6-12 months typically turns a OMR 40 filling into a OMR 400 root-canal-plus-crown.
What's happening
The clinical picture
Three main causes. Decay (most common): bacteria produce pigment as they digest food remnants, and the surface darkens as demineralisation deepens. Stain from coffee/tea/smoking typically affects all teeth uniformly — a single dark spot on one tooth is almost never plain staining. A dark line along the gum margin on an older crown is usually the metal substructure showing through as the gum recedes — cosmetic, but the crown should be replaced at its next scheduled renewal. A vertical dark line in the middle of a front tooth can be a crack — painful on biting, invisible on X-ray, diagnosed with a bite stick.
Warning signs
Contact us the same day if:
- Black spot with any pain
- Spot you can feel with your tongue (surface is broken)
- Spot growing visibly larger month to month
- Accompanying bad taste
- Spot paired with sensitivity to cold or sweet
What we do
Our approach
Exam with magnification, bitewing X-ray of that tooth. Dental decay: filling, onlay, or crown depending on depth. Metal-line-on-crown: discuss timing of replacement at next routine visit — not urgent. Crack: bite test with tetric bite stick, then crown or extraction depending on how deep the crack goes. We photograph what we find so you have documentation.
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