Cleaning abrasives
Calcium carbonate
Also listed as chalk, CaCO3
Chalk used as a toothpaste abrasive, usually paired with sodium monofluorophosphate. Cleans well; claims that it 'remineralises' teeth are mostly theory.
What it is
Calcium carbonate is a mild-to-moderate abrasive that has been used in toothpaste for over a century. Because its calcium would bind free fluoride, chalk pastes use sodium monofluorophosphate rather than sodium fluoride.
Manufacturers suggest the chalk particles also raise calcium in plaque and neutralise acid, which in theory could help fluoride work. That is plausible, but it has not been shown to prevent more decay than silica pastes with the same fluoride.
How strong is the evidence?
Moderate evidenceCalcium carbonate-SMFP toothpastes prevent decay in clinical trials, with the effect attributed to the fluoride. The added calcium/acid-neutralising benefit is mechanistic and comes largely from industry-authored reviews.
What it's used for, checked
Cleans plaque and stain
Holds upA proven abrasive.
Rebuilds or remineralises enamel
UnprovenPlausible mechanism; no trials showing benefit beyond the fluoride it is paired with.
Works well with
- sodium-monofluorophosphate
Don't combine with
- sodium fluoride in the same paste (the calcium inactivates it)
Who should be careful
- Generally safe; if you have sensitive or exposed roots, prefer a low-abrasion paste.
The studies
Every citation is checked against its PubMed record.
- The anti-caries efficacy of calcium carbonate-based fluoride toothpastes. Lynch RJ, ten Cate JM · Int Dent J · 2005 · Narrative review (industry author)
Sodium monofluorophosphate in calcium carbonate toothpastes is an effective anti-caries combination in numerous clinical trials; the authors propose that calcium carbonate may add benefit by raising plaque calcium and neutralising acid, which is mechanistic and not separately proven.