Disclosed is a system and method for the delivery, into interdental spaces, of oral care active agents contained in particles. The particles are made of one or more superabsorbent polymers (SAP), andare of size generally small enough to be easily applied into an interdental space. To this end, the particles typically have a length of below 1.5 mm. By virtue of the SAP's ability of absorbing several times its own weight in water, the particles will swell once in contact with saliva. As a result, the volume of the particles as applied in between teeth increases by at least eight times, therebyeffectively making the particles larger than the average interdental gap size. The particles, once swollen, are thus held more firmly between the walls of the interdental space, thus preventing them from being easily washed away.