Final answer:
The principal cause of dental caries is Streptococcus mutans (S. mutans), a facultative anaerobic bacterium that forms plaque on the teeth and converts sugars to acids, resulting in tooth decay.
Step-by-step explanation:
The principal cause of dental caries is Streptococcus mutans (S. mutans). Dental caries, also known as cavities, are caused by the conversion of sugars in the mouth to acids by bacteria, leading to tooth decay. S. mutans is a bacterium that contributes significantly to this process by forming a biofilm known as plaque on the surface of teeth. When sucrose is consumed, S. mutans breaks it down into glucose, which is then used to make dextran for the biofilm, and fructose, which is fermented to produce lactic acid. This lactic acid is responsible for dissolving the tooth minerals such as enamel, leading to dental caries.
S. mutans, being a facultative anaerobe, can live with or without oxygen, which is relevant to its survival in various conditions of the oral environment. Moreover, S. mutans produces adhesins like P1 that allow it to adhere to tooth surfaces, thereby facilitating the development of plaque and tartar. Consistent oral hygiene, including tooth brushing and flossing, and professional dental cleanings are essential to manage the growth of S. mutans and prevent dental diseases such as cavities and gingivitis.