It's no wonder why teeth whitening methods have come a long way because it's obviously gaining popularity among people. From teeth cleanings in dentists' offices, to laser treatments, to at home methods - you can certainly choose what you want and what you can. Just beware of teeth whitening systems that use animal by products or higher concentration of fluoride or propylene glycol. A good choice would come from an all-natural quality ingredients that ensures oral health safety. An indication of a good teeth whitening gel is thicker and one that stick to your teeth and doesn't leak out of the mouth tray. Knowing a higher percentage of active whitening agents in a teeth whitening method or brand is a must to consider.