A portable tooth-sensitivity demonstration apparatus and a process. The apparatus includes a main unit with a top cover having at least one tooth station thereon; an electrical circuit, a sensitivity indicator, and an on/off switch. A sensor in the tooth station is part of the electrical circuit to activate a response by the sensitivity indicator. A water-permeable tooth piece, treated with an oral-care product, is placed into the tooth station, and a few drops of water are deposited on top of the tooth piece. Lack of response from the sensitivity indicator shows an absence of sensitivity and hence effectiveness of the oral-care product, while a response from the sensitivity indicator shows existing sensitivity and thus failure of the oral-care product to seal the tooth piece. In an apparatus having multiple tooth stations, different oral-care products can be assessed simultaneously and side-by-side.