Most dogs and cats have periodontal disease by 3 years of age. This is a slowly developing disease although some individuals can develop it very fast.
It causes gum recession, loose teeth, gum inflammation, pain, halitosis and in small breed dogs can lead to a broken jaw.
Periodontal disease is caused by bacteria. Plaque which is very hard to see on teeth harbours the bacteria. Bacteria are tiny - you cannot see them with the naked eye. Plaque is also not seen with the naked eye. If you eat a whole bunch of candy, after an hour or so your teeth will feel rough. If you scrape that off your teeth the goo that you scrape off is the plaque and that is loaded with bacteria. After 24 to 48 hours the plaque layer becomes a network (matrix) which is very stable. The only way you can remove plaque for teeth is with the mechanical action of brushing it away. Chemicals such as mouthwashs will not remove it...and treats will miss the areas between the teeth and close to the gum line. It is these missed areas that over time lead to the advancement of periodontal disease.
Over time the number of bacteria builds up and they produce toxins (poisons) that make the body to react with inflammation. It is the inflammation that causes the bone loss seen in periodontal disease. With bone loss there is a loss of the supporting structures around the root of the tooth. This is a slow process in some pets and fast in others. It is also something hidden from your sight. This is why X-rays are so important so that the bone can be examined by your veterinarian.
Many people believe that if the crowns of the teeth look white the teeth are healthy. This is not so. For more information please see Non anesthetic Dental Cleaning.