Tooth Stains and Discoloration Explained

Discoloration falls into three broad groups: extrinsic staining on the outer surface, intrinsic discoloration within the tooth structure, and age-related change that combines thinning enamel with darker underlying dentine. They have different causes and different solutions.

Extrinsic — on the surface

• Coffee, tea, red wine, cola, and dark sauces
• Tobacco use, which stains heavily and persistently
• Plaque and hardened calculus holding pigment
• Some mouthrinses and iron supplements
• Rough surfaces or worn restorations that pick up stain quickly

This group usually improves substantially with a professional cleaning and better daily plaque control, before any whitening is considered.

Intrinsic — within the tooth

• Trauma to a tooth, which may darken it over months or years
• A tooth that has had root canal treatment
• Dental fluorosis, seen as white or brown mottling
• Certain medications taken during tooth development
• Developmental enamel defects
• Old amalgam restorations showing through, or greying at a crown margin

External whitening has little effect on most of this group. Options discussed instead may include internal bleaching of a single treated tooth, bonded restorations, or coverage — decided after examination.

When darkening is a warning, not a cosmetic issue

1. A single tooth becoming distinctly darker than its neighbors
2. A dark or grey spot with a rough edge or a catching surface
3. Darkness with sensitivity, pain on biting, or a gum bump
4. Discoloration at the margin of an existing filling or crown
5. A brown or black line in a groove that catches a fingernail

These can indicate decay, a fracture, or a nerve problem. See signs a tooth needs restorative care and, if painful, urgent dental concerns.

Reducing stain sensibly

Cutting how often staining drinks are sipped, rinsing with water afterwards, keeping plaque control consistent, and stopping tobacco all help. Waiting about half an hour after acidic drinks before brushing avoids scrubbing softened enamel. Whitening toothpastes work mainly by abrasion — heavy use can wear enamel rather than whiten it, and hard-bristled brushing does the same.

Next step

Have discoloration looked at before treating it cosmetically. Request an appointment or call the Florence dental service. See also teeth whitening. This page is general information only.