Tooth Stains · Indigo CP

1What & why

Two axes: where it sits, where it came from.

Stain questions are a Domain I staple, and they all rest on two axes. Where the stain sits: extrinsic (on the outside surface) vs. intrinsic (inside the tooth structure). Where it came from: exogenous (a source outside the body — coffee, tobacco) vs. endogenous (from within — developmental, systemic, drug-related during tooth formation).

The payoff rule: polishing removes extrinsic stains only. If the color lives inside the tooth, no rubber cup will touch it.

2The two big words

Extrinsic vs. intrinsic.

The stainWhat it means

ExtrinsicStain ON the outer surface of the tooth.

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On the surface — polishablecoffee, tea, tobacco, chromogenic bacteria, chlorhexidine

IntrinsicStain WITHIN the enamel or dentin — part of the tooth itself.

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Inside the tooth — NOT polishabletetracycline, fluorosis, pulpal trauma; needs whitening/restoration

3The gallery of named stains

The stainClassify it

☕Coffee, tea, red wine, dark foods

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Extrinsic · exogenousbrown — the everyday surface stains

🚬Tobacco (smoked or chewed)

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Extrinsic · exogenoustar-brown to black; heavy but polishable

🧄ChlorhexidineA prescription antimicrobial mouthrinse.

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Extrinsic · exogenousyellow-brown; a classic "medication that stains" answer

Green / orange stainColored deposits from chromogenic (color-producing) bacteria, most common in children with poor hygiene.

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Extrinsic · exogenouschromogenic bacteria; green often on cervical thirds of children’s anteriors

💊TetracyclineAn antibiotic that binds into forming dentin if taken during tooth development (pregnancy/childhood).

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Intrinsic · endogenousgray-brown banding built into the tooth — polishing can’t touch it

💧FluorosisMottled white-to-brown enamel from too much fluoride during enamel formation.

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Intrinsic · endogenouswhite flecks to brown mottling; developmental

🩸Pulpal trauma / necrosis

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Intrinsic · endogenousa single darkened tooth after injury — blood products stain the dentin

4Make it stick

Ex = exit-side. In = built in.

Extrinsic and exogenous both start with "out": on the outside, from the outside — and out they come with a polish. Intrinsic and endogenous mean built in, from within — and in they stay, no matter how long you polish.

Watch the crossover trap: chlorhexidine and tobacco stains look dramatic but are extrinsic — while a subtle gray tetracycline band is intrinsic and permanent. Darkness ≠ depth.

Two rows of teeth. The extrinsic row shows heavy brown-black tobacco stain, a yellowish-brown chlorhexidine film, a thin dark black line along the gumline, and a light brown stannous fluoride stain. The intrinsic row shows grey-brown tetracycline banding, chalky white fluorosis mottling, and a single uniformly darkened non-vital tooth. — **Darkness is not depth.** The dramatic tobacco stain lifts with a cup; the subtle grey tetracycline band never will. Classify first — **extrinsic** sits on the surface and comes off, **intrinsic** is built into the tooth and does not.

5Beat the exam

"Which stains can coronal polishing remove?"→extrinsic only — surface stains

"Stain from chromogenic bacteria in children"→green (or orange) stain — extrinsic

"Antibiotic taken during tooth development"→tetracycline — intrinsic, endogenous

"Mottled enamel from excess fluoride"→fluorosis — intrinsic, endogenous

"Yellow-brown stain from an antimicrobial rinse"→chlorhexidine — extrinsic, exogenous

"One dark tooth after an injury"→pulpal trauma — intrinsic

"Stannous fluoride leaves what kind of stain?"→a light brown to yellowish-brown extrinsic stain — from the agent, not the diet

6Check yourself

Which stain CANNOT be removed by coronal polishing?

Tetracycline. It bound into the dentin while the tooth was forming — it’s intrinsic and endogenous. The other three all sit on the surface.

6Check yourself

A stain that originates from a source outside the body is classified as:

Exogenous — from outside the body (coffee, tobacco, rinses). Endogenous stains originate within (drugs during development, trauma, fluorosis).

Recap

The whole thing in 5 lines.

✓Extrinsic = on the surface = polishable. Intrinsic = inside the tooth = not.
✓Exogenous = source outside the body. Endogenous = source within.
✓Extrinsic gallery: coffee/tea, tobacco, chlorhexidine, green/orange chromogenic stains.
✓Intrinsic gallery: tetracycline, fluorosis, pulpal trauma.
✓Darkness ≠ depth — classify by where the stain lives, not how bad it looks.