Studies have demonstrated that increased proportions of which bacteria in saliva are correlated with caries initiation and progression?

• A. Escherichia coli
• B. Mutans Streptococci and Lactobacilli
• C. Streptococcus Pneumoniae
• D. Actinomyces Viscosus

Answer: (B)

Bacteria in saliva that are most consistently linked to caries are Mutans Streptococci (Streptococcus mutans) and Lactobacilli. These organisms are highly acidogenic and aciduric, meaning they efficiently ferment sugars to acid and can survive in acidic environments, driving enamel demineralization. Streptococcus mutans is especially adept at colonizing tooth surfaces and forming sticky biofilms by producing glucans from sucrose, which helps the plaque adhere and persist. Lactobacilli thrive in established carious lesions and continue producing acid, contributing to progression from early lesions to deeper decay. The other bacteria listed are not as strongly associated with caries development in saliva; they play different roles in the oral or systemic microbiome and are not reliable indicators of caries risk like the combination of mutans streptococci and lactobacilli.