天然菌斑生物膜中细菌的空间分布

Objective: To examine the spatial distribution of dead/vital bacteria in the early formation of native dental biofilm. Methods: To establish an experimental dental biofilm model in the oral cavity by enamel slabs, observe the spatial distribution of dead/vital bacteria in the early colonization of native dental biofilm on the enamel surface by in situ、real-time and dynamic observations and optical sections utilizing confocal laser scanning microscope (CLSM) and live/dead bacterial fluorescence staining technique. Results: At the initial stage of dental biofilm formation, the structure was sparse and the percentage of dead cells reached 70%～80% at the inner layers. In the middle layers the structure became denser than in the inner layers, also it was found more vital cells(40%～70%) and void-like structures were surrounded by vital bacteria. In the outer layers, the structure was sparse and vital cells occupied 20%～40%. It was similar in the percentage of vital cells to the outer layers. Conclusions: Native dental biofilms showed an uneven spatial distribution of vital and dead microorganisms. The percentage of vital microorganismswas lower adjacent to the enamel surface, increased in the z-axis towards the central parts, and decreased again towards the outer layers. It is assumed that dead bacteria is an integral component in the early formation of native dental biofilm. Bacteria at every time slot increased and biofilms contained abundant channels with time.