Periodontal disease (periodontitis)

Plaque can exist above the gum (supragingival), or below it (subgingival). The type of bacteria seen in each type of plaque is different, with those living below the gum being particularly virulent to the gums and the adjacent bone. Their continuing existence tends to lead to damage these, known as periodontal disease or periodontitis. In this, the bone which supports and holds the teeth becomes lost. Since there is a finite amount of bone holding each tooth, loss of these foundations if left untreated leads to mobility, infection and loss of teeth. Unfortunately the bone does not grow back when the bacteria are removed, and as such the damage is irreparable. Almost all individuals with periodontitis exhibit considerable subgingival calculus deposits. There is also evidence linking these types of bacteria to heart disease and pre-term low birth weight babies.

The x-ray above shows some teeth exhibiting generalized severe bone loss of 30-80%. The red line outlines the existing bone level, whereas the yellow line shows where the bone was originally, prior to the patient developing periodontal disease. The pink arrow, on the right, points to an area where the bone loss is severe enough to expose the point at which the roots of a molar teeth divide (a furcation involvement); this is a sign of advanced periodontal disease. The blue arrow, in the middle, shows up to 80% bone loss on that tooth, and clinically, this tooth exhibited gross mobility. Finally, the peach oval, to the left, highlights the aggressive nature with which periodontal disease generally affects lower incisors. Because their roots are generally situated very close to each other, there is little bone between them. In addition, plaque and calculus tend to accumulate on these teeth because of the pooling of saliva. The split in the red line depicts varying densities of bone that contribute to a vague region of definitive bone height.