What is the most common bacteria found in the mouth?

The most common bacteria found in the mouth is indeed Streptococcus, particularly Streptococcus mutans, which plays a significant role in dental caries (tooth decay). The oral cavity contains a complex microbiome, and while Lactobacillus is present, it is not the predominant species in healthy mouths.

Streptococcus species are well-adapted to the oral environment, and they are among the first organisms to colonize the tooth surface after dental plaque formation begins. They contribute to the biofilm that forms on teeth and can metabolize sugars to produce acids, leading to demineralization of tooth enamel.

Escherichia coli and Staphylococcus aureus are typically not major players in oral microbiology and are more commonly associated with gastrointestinal flora and skin infections, respectively. Thus, understanding the dominance of Streptococcus in the oral cavity is crucial for comprehending oral health and disease, especially in the context of caries development.