Determinants of Microscale pH in In Situ–Grown Dental Biofilms

Dental biofilm pH plays a crucial role in the development of caries lesions. In experiments on simplified biofilm models, the study discovered steep pH gradients and localized acidogenic areas that contribute to enamel demineralization. This comprehensive study, involving 9 healthy participants and 54 in situ-grown biofilms, examined the impact of whole saliva flow on microscale pH. Results varied between individuals and even within a single biofilm, with pH differences of up to 2 units. Notably, 96-hour biofilms exhibited more significant pH drops than 48-hour ones. While stimulated saliva flow helped raise biofilm pH, it didn't fully equalize pH gradients. Factors like biofilm age, thickness, saliva film coverage, and bacterial composition were found to influence pH.