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 Unpublished manufacturer studies were included.