Australian Dental Council (ADC) Test 2025 – 400 Free Practice Questions to Pass the Exam

Extracellular polysaccharides in dental plaque are predominantly formed from bacteria utilizing sucrose as a substrate. When bacteria in the oral cavity metabolize sucrose, they synthesize polysaccharides such as glucans and fructans through the action of specific enzymes. These polysaccharides serve as a matrix that helps to anchor the bacteria together and to the tooth surface, contributing to biofilm formation.

Sucrose plays a critical role in this process because it is a readily fermentable carbohydrates that many oral bacteria can use efficiently. The resulting extracellular polysaccharides not only help form the biofilm around the bacteria but also provide a protective environment for the microbial community, allowing it to thrive amid fluctuations in nutrients and oral hygiene. This underlines the importance of dietary sugars, especially sucrose, in plaque development and the overall cariogenic potential of certain foods.

Other options provided do not adequately represent the primary source for these polysaccharides. For instance, while glycoproteins and carbohydrates can contribute to some extent, they are not the main contributors to the polysaccharides in plaque as directly as the bacterial metabolism of sucrose. Additionally, the destruction of tooth enamel is a result of caries process and not a source of polysaccharide formation in plaque