As a kind of dentistry, teeth whitening should only be performed by dentists or other qualified dental professionals. Teeth whitening involves bleaching the teeth to make them appear whiter. Even though it won't make your teeth completely white, it can lighten their hue by many shades. The whitening process involves a mouth-guard that is manufactured by your dentist. Routinely, you would apply a gel and wear your mouth-guard for a predetermined amount of time over a few weeks. The treatment time can be shortened by using whitening gels that can be applied for up to 8 hours at a time. Another type of teeth-whitening that a dentist might offer is laser whitening, sometimes referred to as power whitening. Your teeth are painted with a bleaching substance, which is then activated by a light or laser. It takes an hour or so to use laser whitening. Some tooth whitening techniques can also include at-home whitening treatments and remedies.