Admission Test for Dental Hygiene (ATDH) Practice

Which type of bacteria is primarily responsible for dental caries?

1. Lactobacillus acidophilus

2. Streptococcus mutans

3. Actinomyces viscosus

4. Bacteroides fragilis

The correct answer is: Streptococcus mutans

The bacterium primarily responsible for dental caries is Streptococcus mutans. This organism plays a crucial role in the formation of dental plaque and is highly adept at metabolizing sugars, leading to the production of lactic acid. The accumulation of lactic acid lowers the pH of the dental environment, causing demineralization of the enamel, which is the initial step in the development of caries. S. mutans is particularly effective at adhering to tooth surfaces, contributing to the formation of biofilms and the progression of carious lesions. Its ability to thrive in acidic conditions, which are often created by the fermentation of dietary sugars, makes it a key player in the pathology of dental decay. While other bacteria mentioned in the context of dental caries do exist, they do not have the same primary role as Streptococcus mutans in the disease process of dental caries. Understanding the mechanisms of this specific bacterium is essential for preventing and managing carious lesions effectively.