Which probiotic strains are cited as examples used to improve oral health by modulating biofilm composition and host responses?

Which probiotic strains are cited as examples used to improve oral health by modulating biofilm composition and host responses?

• A. Streptococcus mutans and Actinomyces israelii
• B. Streptococcus salivarius K12 and Lactobacillus reuteri
• C. Porphyromonas gingivalis and Tannerella forsythia
• D. Streptococcus sanguinis and Veillonella atypica

Answer: (B)

Probiotics in the mouth work by reshaping the biofilm and guiding the host’s immune responses toward a healthier state. Streptococcus salivarius K12 and Lactobacillus reuteri are classic examples studied for this role because they can actively inhabit oral surfaces and exert beneficial effects. Streptococcus salivarius K12 produces bacteriocin-like substances that inhibit certain pathogens in the mouth, helping to reduce harmful microbial colonization and shift the biofilm away from disease-associated communities. It also tends to interact with the mucosal surfaces in a way that can modulate local immune responses, potentially lowering inflammatory triggers.

Lactobacillus reuteri similarly competes with pathogenic microbes and can produce antimicrobial compounds that limit harmful bacteria in dental plaque. Beyond direct antagonism, it can influence host inflammation, contributing to reduced gingival inflammation and a more balanced biofilm composition. Together, these strains illustrate how oral probiotics can both suppress problem-causing microbes and favor host-appropriate responses to support overall oral health.

Other options list organisms that are either well-known cariogenic or periodontopathogenic pathogens or common oral commensals not typically highlighted as probiotic agents, so they don’t exemplify the probiotic approach described.