Close-up of the teeth & gums of a person with a history of poor oral hygiene. The upper teeth are particularly affected, appearing irregular & stained; the blue staining may be due to the death of the internal pulp or because of caries - external tooth decay. The gums appear swollen & inflamed from gingivitis, an inflammation of the gums caused by accumulation of bacteria around the edges of gums which form a hard plaque (tartar or calculus). This can accumulate & enlarge spaces between teeth & gums (gingival crevices) - the first stages of periodontal disease, which may lead to the destruction of underlying structures & loss of teeth.