Periodontal disease can painlessly destroy the bone between and around your teeth, whilst the gum on the outside remains at the existing height. This creates an invisible space where plaque and dangerous bacteria can be sheltered from the cleaning action of your normal toothbrush. These areas are called periodontal pockets. Many people have these invisible pockets or gaps between their gum and tooth. Normally the gap between the tooth and the gum is 2-3mm deep. If periodontal disease sets in that can increase to 5 or 6mm and at this point it usually becomes self degenerating. At 8-9mm, the outlook for the tooth is very poor. The deeper the pocket, the harder it is to stop it getting worse! That is why we practice preventive dentistry. Ask your dentist or hygienist to check your pocket depths and advise what should be done, if anything.