When the gingiva are swollen, the epithelial lining of the gingival crevice becomes ulcerated and the gums will bleed more easily with even gentle brushing, and especially when flossing.

[8] "Studies have also found that the bacteria P. gingivalis – which are responsible for many forms of gum disease – can migrate from the mouth to the brain in mice.

Examples of plaque traps include bulky and overhanging restorative margins, clasps of removable partial dentures and calculus (tartar) that forms on teeth.

Although these accumulations may be tiny, the bacteria in them produce chemicals, such as degradative enzymes, and toxins, such as lipopolysaccharide (LPS, otherwise known as endotoxin) or lipoteichoic acid (LTA), that promote an inflammatory response in the gum tissue.

Early plaque in health consists of a relatively simple bacterial community dominated by Gram-positive cocci and rods.

As plaque matures and gingivitis develops, the communities become increasingly complex with higher proportions of Gram-negative rods, fusiforms, filaments, spirilla and spirochetes.

Later experimental gingivitis studies, using culture, provided more information regarding the specific bacterial species present in plaque.

[11] Further study of these taxa is warranted and may lead to new therapeutic approaches to prevent periodontal disease including systemic health.

Current research shows that activity levels of the following enzymes in saliva samples are associated with periodontal destruction: aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transferase (GGT), alkaline phosphatase (ALP), and acid phosphatase (ACP).

[26] The active ingredients that "reduce plaque and demonstrate effective reduction of gingival inflammation over a period of time" are triclosan, chlorhexidine digluconate, and a combination of thymol, menthol, eucalyptol, and methyl salicylate.

[19] Based on a limited evidence, mouthwashes with essential oils may also be useful, as they contain ingredients with anti-inflammatory properties, such as thymol, menthol and eucalyptol.

[28] Overall, intensive oral hygiene care has been shown to improve gingival health in individuals with well-controlled type 2 diabetes.