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Antimicrobials

Zinc citrate

Also listed as zinc, zinc salts

Zinc in toothpaste slows tartar build-up and plaque bacteria and binds bad-breath compounds. Modest benefits; doesn't interfere with fluoride.

Moderate evidenceTypical strength: About 0.5-2% in toothpaste

What it is

Zinc ions stick to teeth and plaque for hours. They slow bacterial growth, bind the sulfur compounds behind bad breath, and interfere with the mineral crystals that turn plaque into hard tartar (calculus). Zinc citrate is the usual form in toothpaste, often with fluoride and sometimes stannous fluoride.

How strong is the evidence?

Moderate evidence

Industry-run clinical trials show zinc pastes reduce new tartar formation and plaque, and zinc does not blunt fluoride's anti-decay effect. Evidence on bad breath is low certainty. A meta-analysis of six-month trials found no anti-gingivitis benefit for older pastes combining zinc citrate with triclosan. Existing tartar needs professional cleaning.

What it's used for, checked

Slows tartar build-up

Holds up

Reduces new tartar; does not remove existing tartar.

Reduces bad breath

Mixed

Mechanism is sound; clinical evidence is limited and short-term.

Treats gum disease

Unproven

Small plaque effects; not a treatment for gum disease.

Works well with

  • sodium-fluoride
  • stannous-fluoride

Who should be careful

  • Can leave a slight metallic or astringent taste.
  • Children under 3: a smear the size of a grain of rice; ages 3-6: a pea-sized amount, with an adult supervising so they spit rather than swallow.

The studies

Every citation is checked against its PubMed record.

  1. Zinc in the mouth, its interactions with dental enamel and possible effects on caries; a review of the literature.
    Lynch RJ · Int Dent J · 2011 · Narrative review (industry author)

    Zinc is added to toothpastes and rinses to control plaque, bad breath and tartar and persists in the mouth for hours. In caries trials, adding zinc to fluoride toothpaste did not reduce fluoride's anti-caries effect.

  2. A meta-analysis of six-month studies of antiplaque and antigingivitis agents.
    Gunsolley JC · J Am Dent Assoc · 2006 · Systematic review / meta-analysis

    Six-month trials showed a clinically meaningful anti-gingivitis effect for stannous fluoride pastes, the largest body of support (21 studies) for essential-oil rinses, and variable results for cetylpyridinium chloride rinses depending on the formula. Unpublished manufacturer studies were included.