What is the role of glucosyltransferases and glucans in dental plaque formation?

• A. Glucosyltransferases convert sucrose into glucans that form the extracellular matrix, promoting adherence and three-dimensional biofilm structure.
• B. Glucosyltransferases break down glucans to release glucose for energy.
• C. Glucosyltransferases detoxify acids in dental plaque.
• D. Glucosyltransferases mediate host immune evasion.

Answer: (A)

The main idea is that glucosyltransferases use sucrose to build glucans that become the sticky extracellular matrix of dental plaque, enabling strong adherence to tooth surfaces and the assembly of a three-dimensional biofilm. Glucosyltransferases are enzymes produced by plaque-forming bacteria, most notably Streptococcus mutans, and they polymerize glucose from sucrose into glucans. These glucans form a cohesive, surface-attached scaffold that lets bacteria cling to the tooth enamel and to each other, creating a stable, layered community. This matrix not only anchors cells but also helps retain nutrients and acids, shaping microenvironments that promote plaque growth and cariogenicity near the tooth surface. The role of glucosyltransferases is not to break down glucans, detoxify acids, or mediate immune evasion—those functions involve different enzymes or processes. Here, the key point is the synthesis of glucans from sucrose and their function as the adhesive, three-dimensional scaffold for dental plaque.