Evaluating Bacterial Acid Production and pH Dynamics in a Real Time In Vitro Polymicrobial Biofilm Model

Dental caries still remains a severe problem for both health and the economy. This oral disease is multifactorial and biofilm-dependent, caused by changes in the composition and metabolism of complex communities of oral biofilm. Streptococcus mutans is one of the most common species in oral biofilms associated with tooth decay (1, 2); however, several other microbial communities are spatially organised into complex structural arrangements and extracellular matrices, contributing to cariogenic biofilm formation. The established biofilms ferment available carbohydrates to produce lactic acid (2, 4). Lactic acid lowers the environmental pH and promotes demineralisation of the tooth's enamel leading to the formation of dental caries (5). The proportion of S. mutans cells within a biofilm-located population that actively undertake carbohydrate fermentation is unknown. It is also unclear what the relative location of the fermenting bacteria is within a biofilm and how this alters environmental microniches. The dynamics of the process is also uncharacterized. The biofilms in the human mouth are complex polymicrobial environments. It is not fully understood how the presence of other species in the oral biofilms influence fermentation by S. mutans (8).

Unilever requires complex and dynamic models that mimic oral biofilm communities to act as well-characterized testing platforms to evaluate the effectiveness of their oral products and formulations. Therefore, the development of a robust polymicrobial biofilm model and a comprehensive understanding of the dynamic environmental microniches within biofilms, including real time pH monitoring, would thus offer significant potential to address industry challenges and demands. Such a model can serve as a valuable testing platform for evaluating the effectiveness of oral products and formulations against complex and dynamic models that mimics the oral biofilm communities, ultimately ensuring the delivery of effective solutions to meet consumer needs.