Now, will this happen in just one application? Will it work as well as an in-office treatment from your dentist? Will it cause fewer side effects? All of these remain to be seen (we didn’t test the pen ourselves and there wasn’t any online feedback), although until we see some evidence, we remain skeptical. What about the competition? While pens like Steel bite pro might provide ease of use when on-the-go, keep in mind that you’ll have to keep your lips off your teeth for at least a minute, which could complicate matters if you’re whitening in public. Also, since tray-based systems sit firmly in place over your teeth and could provide better coverage for whitening gel, they might deliver faster, more pronounced results.