A flowcell for the study of plaque removal and regrowth

A flowcell has been designed for microscopy of oral biofilm communities (plaque) during their colonization, removal, and subsequent regrowth. These processes were documented using low-magnification darkfield microscopy, high-magnification oil-immersion phase-contrast microscopy, and Confocal Laser Microscopy (CLM). The number of cells and microaggregates (both hereafter referred to as particles) that attached to the flowcell surface from whole saliva, as well as the area covered by these particles, increased linearly with time over a three-hour period. The smallest particle-size-class (1-6 mu m(2)) contained the greatest number of particles: at least 50% of the total number of particles. The biofilm can be removed using an internal scraping device. Two cycles of cleaning/regrowth were documented. Cleaning removed 50% of the initial biofilm; regrowth resulted in a four-fold increase in coverage over that initially present. The second cleaning removed 75% of this heavier colonization, and the second regrowth period resulted in a three-fold increase in coverage over that present in the first regrowth. High-resolution photomicrographs and CLM images were obtained that permit morphological analysis of the community structure within the mixed species biofilm in three dimensions. Exclusion-staining (cells are detected by the exclusion of fluorogenic dye) using fluorescein revealed differences in cellular chemistry between cells within a single morphological type.