Many cats and dogs present to the veterinary practice with established gingivitis, which may or may not have progressed to periodontal disease. Gingivitis is a condition that can be reversed, whereas periodontal disease cannot be reversed. It is the veterinary professional's responsibility to be examining all patient's oral cavities to identify signs of these inflammatory and disease processes, before advising the client about the best course of action to restore optimal oral health in their pet. This article aims to recap what periodontal disease is and how it develops from gingivitis due to the presence of plaque, before considering the treatment options for both gingivitis and periodontal disease.