Ever wonder what the most common health problem is for dogs? It's periodontal disease. A staggering 75-80 percent of dogs two and a half years and older may start to develop trouble with their teeth. Tooth and gum problems can become painful and serious if left untreated and may possibly cause your dog to become aggressive or stop eating. Symptoms of Periodontal Disease in dogs: Bad breath Yellow or spotty teeth Swollen gums Difficulty in chewing Weight loss Broken o