Relationship between sucrose concentration and bacteria proportion in a multispecies biofilm: : Sucrose challenges to a multispecies biofilm.

: The aim of this study was to evaluate the relationship between sucrose concentration and bacteria proportion in a multispecies biofilm model. : ( (), and (es) were chose to form a multispecies biofilm. Different concentration (0-40%) of sucrose was introduced to the multispecies biofilm 3 times per day (30 min per time). And then the bacteria proportion and acid production of the biofilms were analyzed. : Increasing sucrose level increased CFU count of up to a certain concentration (5% sucrose), after which the number of slightly decreased, but the CFU counts of and es continually decreased with sucrose concentration increase, especially, from 5% sucrose, the reduction was significant, and became the dominant species in the biofilms. Furthermore, the acid production ability of the multispecies biofilm gradually increased and slightly decreased with sucrose concentration increased, and the turning concentration was 5%. : Our findings suggest that increasing sucrose level could increase the competitiveness of in the multispecies biofilm, which may shift the biofilm to a more cariogenic one, and 5% sucrose formed a most cariogenic biofilm in this study.