Tetracycline: levels of achievable in gingival crevice fluid and in vitro effect on subgingival organisms. Part II. Susceptibilities of periodontal bacteria.

The sensitivity to tetracycline of 345 bacterial isolates from periodontal lesions was determined. Most species of bacteria, including those thought to be involved in the initiation and progress of destructive periodontal disease, were inhibited in vitro by tetracycline concentrations of 4 to 8 micrograms/ml. This concentration is equivalent to crevicular fluid levels of tetracycline at dosages of 1 gm/day. These data indicate that tetracycline is inhibitory at levels achieved in crevicular fluid for bacteria currently implicated in destructive periodontal disease.