Plaque

Plaque is a general term for a soft, sticky coating that forms on surfaces as a result of microbial activity. In everyday use, it most commonly refers to dental plaque, a biofilm that develops on teeth. Plaque forms when oral bacteria adhere to the tooth surface, aided by a conditioning film from saliva, and produce extracellular matrix that helps them remain attached. If not routinely removed, plaque can mineralize into calculus and contribute to dental diseases.

Dental plaque contains bacteria, their metabolic byproducts, and salivary and dietary substances. It starts as a colorless film but becomes visible as it thickens. The bacteria within plaque metabolize fermentable carbohydrates to acids, which can demineralize enamel and lead to dental caries. Some bacteria irritate the gums, causing gingivitis; sustained inflammation can progress to periodontitis. Plaque removal relies mainly on mechanical cleaning—brushing, interdental cleaning, and professional scaling and polishing. Fluoride and good oral hygiene reduce plaque formation and its harmful effects. Dietary choices and frequency of cleaning influence plaque accumulation and disease risk.

Arterial plaque, or atherosclerotic plaque, forms within arteries as lipids, inflammatory cells, and connective tissue accumulate in the vessel wall. It narrows the lumen and can become unstable or rupture, leading to thrombosis and acute events such as heart attack or stroke. Risk factors include high LDL cholesterol, hypertension, smoking, diabetes, obesity, and age. Management focuses on risk reduction with statins or other lipid-lowering agents, antiplatelet therapy, blood pressure control, and lifestyle changes. In some cases, procedures or surgeries are needed to restore blood flow.

Other uses of the term plaque include decorative or commemorative plates and inscribed plaques used in buildings and monuments, but these are distinct from biological plaques.