Periodontal Disease has four stages, but it is only reversible when it's detected during the first stage, gingivitis. Gingivitis is the first stage of periodontal disease. In this stage, the periodontal disease has a chance of being reversed because the infection has not yet attacked the bone. Gingivitis is reversible, because it is only inflammation, and no damage to the supporting bone structures or tooth sockets has occurred. If your dog has Stage 2 or Stage 3 periodontal disease, it won't be reversible, but there are steps you can take to prevent its progression. The prognosis for any dog with Stage 1 periodontal disease is usually very good. Treating gingivitis can reverse periodontal disease, and this can be done by taking your dog to a veterinary dentist for a professional dental cleaning. After a professional dental cleaning for Stage 1 periodontal disease, no further clinical treatment will be necessary. However, you will need to brush your dog's teeth daily. Without daily oral hygiene care, your dog's Stage 1 periodontal disease could easily progress into a later stage, causing tooth decay and tooth loss.