Dissolving Mint Crystals

Many if not all oral health products advertise the "clean, fresh feeling" that the consumer's mouth will be left with after usage. The problem here is that a clean fresh feeling has nothing to do with whether or not there are still bacteria or sugar particles left on your teeth. In fact, this feeling sometimes invokes a false positive. You think you are clean, when in fact you have not done anything.

I want some crystals I can sprinkle on top of my toothpaste, or pop in my mouth while mouth-washing, that take some time to dissolve. At the centre of these crystals are flavour compounds that cause an intense minty sensation, signifying the end point. This way, my tastebuds will aid me, not trick me.