There are several types of periodontal diseases, each with its own characteristics and effects on the gums and supporting structures of the teeth. The most common types include Gingivitis (the mildest form relating to an inflammation of the gums), Chronic Periodontitis (characterised by progressive inflammation and destruction of the gum tissue and bone supporting the teeth), Aggressive Periodontitis (characterised by the rapid destruction of the gum tissue and bone, leading to tooth loss if left untreated) and Necrotising Periodontal Disease (characterised by the death of gum tissue due to factors such as smoking or poor nutrition).