Oral biofilm composition and phenotype in caries-active and caries-free children.

Introduction: During development of dental caries, oral biofilms undergo changes in microbial composition and phenotypical traits. The aim of this study was to compare the acid tolerance (AT) of plaque from two groups of children: one with severe caries (CA) and one with no caries experience (CF) and to correlate this to the microbial composition and metabolic profile of the biofilms.

Methods: Dental plaque samples from 20 children (2-5 years) in each group were studied.

inhibits the acid tolerance response in oral bacteria.

Probiotic bacteria show promising results in prevention of the biofilm-mediated disease caries, but the mechanisms are not fully understood. The acid tolerance response (ATR) allows biofilm bacteria to survive and metabolize at low pH resulting from microbial carbohydrate fermentation. We have studied the effect of probiotic strains: and on ATR induction in common oral bacteria.

Formation and Analysis of Mono-species and Polymicrobial Oral Biofilms in Flow-Cell Models.

The oral microbiota, which is known to include at least 600 different bacterial species, is found on the teeth and mucosal surfaces as multi-species communities or biofilms. The oral surfaces are covered with a pellicle of proteins absorbed from saliva, and biofilm formation is initiated when primary colonizers, which express surface adhesins that bind to specific salivary components, attach to the oral tissues. Further development then proceeds through co-aggregation of additional species.

Acid tolerance in early colonizers of oral biofilms.

Background: In caries, low pH drives selection and enrichment of acidogenic and aciduric bacteria in oral biofilms, and development of acid tolerance in early colonizers is thought to play a key role in this shift. Since previous studies have focussed on planktonic cells, the effect of biofilm growth as well as the role of a salivary pellicle on this process is largely unknown. We explored acid tolerance and acid tolerance response (ATR) induction in biofilm cells of both clinical and laboratory strains of three oral streptococcal species (Streptococcus gordonii, Streptococcus oralis and Streptococcus mutans) as well as two oral species of Actinomyces (A.