Pharmacology of antibiotics used in dentistry.

The term antibiotic is now generally used to include antimicrobial substances produced by chemical means as well as those produced by micro-organisms. They may be either bacteriostatic or bacteriocidal. A bacteriostatic antibiotic inhibits the growth and replication of bacteria thereby giving the body's natural defence mechanisms time to become effective in overcoming an infection. In the majority of cases, and particularly in patients whose natural resistance is lowered by disorders of the immune system, it is preferable to choose a bacteriocidal agent. The first bacteriocidal antibiotic was penicillin G. The structure of the penicillin molecule is discussed as a basis for the understanding of its mode of action and of the mechanisms which lead to bacterial resistance. The modified and semisynthetic derivatives of penicillin are discussed and specific indications for their use are described in detail. Alternatives to the use of penicillin are also discussed and particular attention is paid to the cephalosporins and the tetracyclines.