Plaque is a general term describing a sticky, biological accumulation that forms in the body, referring to two entirely different substances found in the mouth and the arteries. Understanding what plaque looks like requires recognizing its unique composition and environment. Dental plaque on teeth differs significantly from the internal appearance of arterial plaque.
Dental Plaque: Visual Identification
Dental plaque is a soft, often nearly invisible film that continuously forms on the surface of teeth. In its early stages, it is a sticky, colorless or pale-yellow deposit, difficult to see without a disclosing agent. If left undisturbed, a person may notice a “fuzzy” texture on the tooth surface when felt with the tongue. Plaque is commonly found along the gum line, in the grooves of back molars, and between teeth. Dentists use disclosing agents (dye tablets or solutions) to stain the plaque bright red or orange-yellow, making it visible. This helps identify areas missed during regular brushing and flossing.
The Biofilm Structure of Dental Plaque
Dental plaque is a complex, structured community of microorganisms known as a biofilm. This sticky deposit begins to form within minutes of cleaning, starting with an initial layer called the salivary pellicle. Bacteria, such as Streptococcus mutans, colonize this surface, adhering to one another and the tooth. They embed themselves in an extracellular matrix—a sticky scaffolding made of polymers, carbohydrates, proteins, and nucleic acids derived from bacteria and saliva. This matrix accounts for 20% to 30% of the plaque’s mass, allowing the biofilm to resist removal. Within this structure, bacteria produce acids as they feed on sugars, leading to tooth decay and gum irritation.
Arterial Plaque: Appearance Inside the Body
Plaque that forms inside arteries is fundamentally different from dental plaque and is associated with atherosclerosis, or the hardening of the arteries. Since this plaque is internal, it cannot be seen directly. Its structure is a patchy, raised, and irregular deposit that forms underneath the innermost layer of the artery wall. Arterial plaque is a mixture of fatty substances, cholesterol, cellular waste products, calcium, and fibrin (a clotting material). It often starts as yellowish fatty streaks that accumulate, causing the artery wall to thicken and lose elasticity. As the plaque matures, calcification makes it hard and fibrous, narrowing the channel for blood flow. If this plaque ruptures, a blood clot can form, which is a major cause of heart attacks and strokes.
Understanding Plaque Versus Tartar
In the mouth, the distinction between plaque and tartar is based on hardness and color. Tartar, also known as calculus, is dental plaque that has calcified because it was not removed. This hardening occurs when minerals from saliva are absorbed by the plaque, a process that can begin within 24 to 72 hours. Tartar is much more noticeable than soft plaque because it is a rock-hard, rough deposit that typically appears as a darker yellow, brown, or sometimes black substance. Unlike plaque, which can be removed with regular brushing and flossing, tartar bonds firmly to the tooth enamel and requires removal by a dental professional. The rough surface of tartar makes it easier for new, soft plaque to adhere, leading to further accumulation.