Teeth whitening can be a tricky affair. The strips are a great, economy choice that perform the function as well as well as the other devices. However, a strip is much safer, and it is far less likely for you to accidentally poison your gum and your mouth with the bleach. A syringed gel is a great choice as well, especially if used with a fitting tray. It is important, though, to buy a product that is reputed for quality and is certified by appropriate dental affiliations. The full kit is the best option, even if it is not the most economic.