Gum disease develops in the absence of good oral hygiene. A thin biofilm of plaque develops around the tooth and gingival margin, which may accumulate over time if not removed through manual cleaning with a toothbrush. There is a direct correlation between plaque biofilm and the severity of gingivitis. This accumulated plaque eventually mineralises, forming calculus, both supra (above) gingival and sub (below) gingival. Calculus is associated with periodontal disease, and it also acts as a retention site for the accumulation of more plaque and bacterial colonies harmful for oral health. There is a shift of the microbial flora of the mouth from Gram positive organisms to Gram negative and this is also strongly associated with periodontal disease.
Periodontal disease begins as mild inflammation of the gums. This stage of periodontal disease is called gingivitis and includes the classic triad of redness, swelling of the gum tissue around the tooth and bleeding on gentle probing. Healthy gingiva is coral pink in colour with stippled appearing margins, in gingivitis however, as it becomes inflamed, it turns red with a more shiny appearance. The next stage is mild periodontitis in which the appearance remains ultimately the same, however there is slight bone loss and probing attachment loss with pocket size going up to 4-5 mm.
As the disease keeps progressing from mild to moderate, the inflammation increases and extends deeper down, there is a significant increase in bone loss with pocket depths going up to 4-8 mms. Chronic periodontitis is the final stage of gum disease, and clinical signs show gingival inflammation causing bleeding, pocketing, gum recession and tooth mobility. By this stage, the infection and inflammation has spread in the deeper tissues of the periodontal membrane, eroding the surrounding tissues around the teeth which hold it into place.