Zoom! whitening procedure takes about 1.5 hours and does not require a second office visit. The procedure begins with a 20-minute preparation period where your gums and soft tissues get covered with gauze and protective materials to reduce the risk of damage to the tissues from the whitening gel and the ultra violet light. Next, the whitening gel is applied to your teeth with a brush. Then, there’s a series of four 15-minute sessions where light-accelerated whitening takes place.