City & Guilds Level 3 Diploma in Dental Nursing Practice Test

Streptococcus mutans is the type of bacteria most commonly associated with dental caries, owing to its significant role in the formation of dental plaque and the initiation of tooth decay. This bacterium metabolizes sugars present in the oral cavity, producing acid as a by-product. The acid can demineralize the enamel of teeth, leading to caries. Streptococcus mutans is adept at adhering to dental surfaces, which enhances its ability to form biofilms that contribute to cavity development.

Other types of bacteria listed, while they have roles in oral health, do not primarily cause dental caries. For instance, Staphylococcus aureus is not typically associated with dental health and is more commonly linked to skin infections. Escherichia coli is a type of bacteria that primarily inhabits the intestinal tract and is not involved in oral health issues like dental caries. Lactobacillus, while it may contribute to the progression of caries, particularly in later stages, is not the primary bacteria responsible for starting the decay process. Therefore, understanding the pivotal role of Streptococcus mutans in caries development is key for effective dental care and prevention strategies.