Early plaque colonization on human cementum.

We have described the morphology of developing plaque on cementum in an in vivo human model. Slabs of cementum obtained from sound teeth, rendered anorganic with 5% sodium hypochlorite, were glued to orthodontic brackets and positioned on the upper canines, premolars and molars in 8 volunteers. The brackets were removed after 2, 4, 8, 24 h and processed for scanning electron microscopy (SEM). Within 2 h, a thin pellicle covered the cementum surface, with few micro-organisms detectable. At 4 and 8 h, coccoid plaques were present. Filaments inserted perpendicularly to the plaque surface were seen at 24 h. The results indicate that early bacterial colonization of human cementum is a selective process, mediated by an organic pellicle and mainly involves cocci.