Which type of bacteria primarily contributes to tooth decay?

Streptococcus mutans is the primary bacterium responsible for tooth decay, also known as dental caries. This microorganism is highly adept at fermenting carbohydrates, particularly sugars, and converting them into acids. These acids then start to demineralize tooth enamel, leading to cavities. As a predominant species in dental plaque, Streptococcus mutans plays a significant role in the cavity formation process, making it a key focus in discussions about oral health and caries prevention.

While other bacteria like Lactobacillus casei also contribute to the carious process, especially in the later stages when lesions have already formed, they are not as pivotal in the initial stages of tooth decay as Streptococcus mutans. Escherichia coli is primarily found in the intestines and does not play a significant role in oral health issues. Actinomyces naeslundii is present in the mouth and can be involved in periodontal disease, but it does not have the same impact on cavity formation as Streptococcus mutans. Thus, understanding the role of Streptococcus mutans is crucial for effective dental care and prevention strategies.