Dog peridontitis. Illustration of the mouth and teeth of a dog with peridontitis (inflammation of the periodontium). The periodontium is the tissues that surround and support the teeth, including the gums and jaw bones. This condition progresses from gingivitis (inflammation of the gums) and is caused by the accumulation of dental plaque (bacterial biofilms). If not treated, the condition can lead to tooth loss. For a sequence of images on dog dental diseases, see images C029/9572 to C029/9575.