In short: Toothpaste uses two different silicas for two different jobs. Thickening silica builds the structure that holds the paste together, keeps it on the brush and stops liquid separating in the tube. Abrasive silica does the cleaning. Most formulations need both, and the ratio between them — not either one alone — sets how the paste behaves.
The two functions pull in opposite directions. Cleaning needs particles hard and coarse enough to lift film from enamel without damaging it. Structure needs a particle population that builds a network through the whole paste and holds liquid inside it.
A silica optimised for one of these is mediocre at the other. Push the abrasive up to get structure and the paste gets harsh. Push the thickener up to get cleaning and you get a stiff paste that still does not clean. The formulation uses both and tunes the ratio.
This is why "which silica for toothpaste" is not answerable as a single question, and why a sample request that does not say which job the material is doing gets a question back rather than a jar.
Structure and stand-up. Whether the ribbon holds its shape on the brush rather than slumping into the bristles. This is the most visible property to the consumer and one of the first things a panel comments on.
Syneresis — liquid separating in the tube. A paste that weeps a clear layer at the nozzle after weeks on a shelf reads as a spoiled product, whatever the assay says. The structure built by the thickening silica is what holds the humectant phase.
Extrusion force. How hard the tube is to squeeze, which is a real usability property and a real complaint driver at both extremes. Too easy and the paste runs; too hard and older consumers cannot use it.
Optics. In a clear or gel paste the thickener has to build structure without clouding it, which narrows the choice considerably compared with an opaque paste.
Cleaning performance, and the wear it causes, are the two sides of the same property. The formulation has to clean adequately while staying within the abrasivity limits your market and your claims require — and those limits are measured, not assumed.
It also contributes to the mouthfeel: the sensation during brushing, and whether the paste reads as gritty or smooth. This is judged by panel, not by instrument, and it is why two pastes that test the same can be received very differently.
Because abrasivity is a regulated and claim-relevant property, we take the position that it is confirmed by the customer's own testing against the standard their market applies. We do not publish a figure on a web page that could be read as a claim.
Change one component at a time. If you are evaluating a thickener, hold the abrasive and everything else constant; if you are evaluating an abrasive, hold the thickener. Changing both at once produces a result you cannot attribute.
Make the paste on your own equipment, at your own shear and vacuum conditions. Silica structure in a paste is shear-history dependent — a paste made in a laboratory mixer does not predict one made in your production vessel.
Then hold samples. Structure, syneresis and extrusion force all drift over the first weeks. Check at intervals out to at least a month, at ambient and at an elevated temperature, and look at the nozzle as well as the bulk.
Our starting points on this track are CENSIL 310 and CENSIL 320 from the porous silica family, with CENSIL 500 alongside where the structure requirement is heavier. Customers commonly benchmark toothpaste silica against products such as Evonik ZEODENT® and W. R. Grace SYLODENT® grades — reference points, not equivalences.
Tell us which job you are filling and what the paste has to do, and we will name the starting grade and send comparison grades with it. The porous silica family covers this track; the specific choice depends on whether the paste is opaque or clear and how much structure it needs.
Not as a published number. Abrasivity is claim-relevant and market-specific, and it is confirmed by your own testing against the standard your market applies. The current-revision technical data sheet, with the test method behind each figure, is issued per enquiry.
Usually the structure side rather than the abrasive. Run the same formulation with the thickener held constant and then varied, hold samples for a month at ambient and elevated temperature, and check the nozzle. Humectant level and the gum system are the other two places to look.
We confirm the destination-country position per enquiry rather than making a blanket claim on the website, because requirements differ by market and by use. Tell us the country and the application and we will state exactly what documentation we can provide.
Third-party product and brand names are the trademarks of their respective owners and are used here only to identify the reference points customers benchmark against. No equivalence, affiliation or endorsement is claimed or implied.
The material you use now, the formulation or resin, the equipment and the target you need to hit. That is enough for us to say whether we have something worth testing.
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