An ultrastructural investigation of the filamentous surface appendages of suspensions of plaque bacteria as revealed by negative staining.

The filamentous surface appendages of freshly-collected aqueous suspensions of plaque bacteria, obtained from 1 day old supragingival plaque have been examined in the electron microscope by the technique of negative staining with methylamine tungstate. Approximately half of the bacteria revealed surface appendages as either fimbriae (45%), flagella (13%) or both (3%). The appendages were distributed either polarly, intermittently or peri-trichously around the bacteria and varied in length from 0.2 micron to more than 20 micron. It was not possible from these observations alone to determine either the topology of the appendages or their role as they existed originally in dental plaque.