If you mean the stuff that looks like a small phial of lipgloss I have and it's useless (on my teeth anyway). It's like a very faint coating of pearlised nail varnish that made my teeth look a bit pearlised but no whiter. It's also rough, flakes off in bits and disappears as soon as you eat anything. Complete wase of money.
Funnily enough only last weekend I found it in my 'make-up mistakes' box, had forgotten what it was and thinking it was lipgloss put it on my lips. Not nice!