Example Dental Practice can provide you with teeth-whitening trays and gels that can be worn at home. These can be very effective, but results take longer to achieve than getting treatment done at our practice. We will take an impression of your teeth and give this to a dental technician, who will build a tray to the exact measurements of your mouth. We will check that the tray fits and demonstrate how to carry out the procedure at home. The tray fits closely around the teeth, and is filled with a whitening gel. Depending on the strength of peroxide in the gel, these trays are usually worn for a couple of hours a day or overnight. Treatment can take anywhere from three days to a couple of weeks. In market over-the-counter whitening kits are available, although we do not recommend using them as they use a generic sized tray, which could allow the bleaching agent to come into contact with your gums, causing irritation or any other side effects. Not only they are not made to fit your mouth exactly, it may also be the case that bleaching isn’t suitable for you, especially if you have gum disease or crowns. Proceeding with the treatment in these circumstances could be harmful.