Title: Modeling Oral Multispecies Biofilm Recovery After Antibacterial Treatment,
Abstract: Recovery of multispecies oral biofilms is investigated following treatment by
chlorhexidine gluconate (CHX), iodine-potassium iodide (IPI) and Sodium
hypochlorite (NaOCl) both experimentally and theoretically. Experimentally,
biofilms taken from two donors were exposed to the three antibacterial
solutions (irrigants) for 10 minutes, respectively. We observe that (a) live
bacterial cell ratios decline for a week after the exposure and the trend
reverses beyond a week; after fifteen weeks, live bacterial cell ratios in
biofilms fully return to their pretreatment levels; (b) NaOCl is shown as the
strongest antibacterial agent for the oral biofilms; (c) multispecies oral
biofilms from different donors showed no difference in their susceptibility to
all the bacterial solutions. Guided by the experiment, a mathematical model for
biofilm dynamics is developed, accounting for multiple bacterial phenotypes,
quorum sensing, and growth factor proteins, to describe the nonlinear time
evolutionary behavior of the biofilms. The model captures time evolutionary
dynamics of biofilms before and after antibacterial treatment very well. It
reveals the crucial role played by quorum sensing molecules and growth factors
in biofilm recovery and verifies that the source of biofilms has a minimal to
their recovery. The model is also applied to describe the state of biofilms of
various ages treated by CHX, IPI and NaOCl, taken from different donors. Good
agreement with experimental data predicted by the model is obtained as well,
confirming its applicability to modeling biofilm dynamics in general.