The current status and future prospects of altering the pathogenic microflora of periodontal disease.

Modern periodontal therapy aims to suppress or eradicate periodontal pathogens and to maintain a posttreatment flora that is compatible with health. Systemic and local antimicrobial therapies have demonstrated effectiveness against several periodontal pathogens. Sustained-release devices, or irrigators, for local application of antimicrobial agents to periodontal pockets show great promise. Replacement therapy and periodontal vaccines, although still in the early research phase, represent very interesting approaches for preventing periodontitis. Using modern molecular genetic methods, it is theoretically possible to clone virulence determinants of periodontal pathogens into a nonpathogenic organism. The carrier organism with the expressed foreign antigens may be implanted in the oral cavity or the intestinal tract to induce long-lasting immunity against the targeted periodontal pathogens.