Cov tshuaj txhuam hniav yog muab tshuaj txhuam-zoo li cov khoom siv rau ntawm cov hniav los ntawm kev puas tsuaj, feem ntau yog siv los ntxuav. Nws feem ntau siv daim ntawv gel thiab feem ntau yog siv rau txhuam hniav. Cov neeg kho tshuab kev sib txhuam ntawm cov txhuam hniav ntxuav cov hniav, ntxuav cov hniav thiab cov cheeb tsam ib puag ncig, tawm hauv lub qhov ncauj kom huv thiab ua kom zoo dua qub.
Kev tu hniav yog qhov tseem ceeb rau kev tu cov hniav kom zoo nkauj, tiv thaiv cov pos hniav, thiab tiv thaiv ua pa phem. Cov tshuaj txhuam hniav tau dhau los ua qhov tsim nyog txhua hnub.
Cov tshuaj txhuam hniav hloov zuj zus los ntawm cov hmoov txhuam hniav. Cov hmoov txhuam hniav thaum ntxov feem ntau siv calcium carbonate ua cov tshuaj txhuam thiab xab npum ua surfactant. Txij li thaum xyoo 1940s, kev txhim kho thev naus laus zis sai tau ua rau muaj kev txhim kho tseem ceeb hauv kev lag luam tshuaj txhuam hniav. Txoj kev loj hlob thiab kev siv cov tshuaj abrasives tshiab, humectants, thickeners, thiab surfactants tau txuas ntxiv txhim kho cov khoom zoo ntawm cov tshuaj txhuam hniav. Tsis tas li ntawd, cov tshuaj txhuam hniav tau hloov zuj zus los ntawm kev tu hniav yooj yim kom muaj cov tshuaj ua kom huv ntawm qhov ncauj los tiv thaiv thiab kho cov kab mob hniav. Cov tshuaj txhuam hniav fluoridated yog cov piv txwv tseem ceeb tshaj plaws, txo qhov tshwm sim ntawm cov hniav caries.