Probiotics may compete for an ecological niche, or otherwise create
conditions that are unfavorable to the pathogen taking hold of the
intestinal tract rather than directly inhibiting the pathogen's growth
or viability via immunomodulation. probiotics have the potential to
alter the oral microbiota, and are further being researched to prevent
or treat oral diseases such as dental caries and periodontal diseases
that are associated with a shift in the biofilm's microbial composition
and activity, and the resulting host reaction.