Summary: The ability of bacteria of dental plaque to activate metallo-proteinases may be one of the key mechanisms of damage of the periodontal tissue. In a group of patients with early onset periodontitis the authors investigated in the sulcular fluid, using the ELISA method, levels of the tissue plasminogen activator (tPA) and the effect of conservative and antibiotic treatment. Reduction of the tissue plasminogen activator (tPA) in sulcular fluid was influenced most by conservative treatment, three months after antibiotic treatment a lower level was recorded still in six of eight samples. The authors found that in treatment of periodontitis the most important part is played by conservative treatment. An important role in the treatment of periodontitis is, however, played by all drugs which inactivate metallopro- teinases.

        Key words: periodontitis – conservative therapy – metalloproteinases