Private practitioner, Dr Paul Gallop, replies: You can have your teeth bleached by a dentist or do it yourself using a dental surgery home bleaching kit. If you go to a surgery the dentist will put a protective latex covering on your gums. Then they paint a thick jelly, made of a natural bleach called carbamin peroxide, onto your teeth. A high-intensity light is then shone onto your teeth to speed up the action of the peroxide. The light is only shone on each part of the tooth for a few seconds, but the whole process takes two hours. Your teeth are then rinsed with water. This gives immediate results, but as it's quite intense you may feel some sensitivity during and after the procedure. Make sure you follow any instructions your dentist may give you. This procedure costs around