Succesful root canal therapy reguires a complete obturation of the root canal system. The majority of endodontic failures have been caused by the incomplete sealing of the root canal. Therefore, we have to find an ideal technique and material. For the evaluation of microleakage we can use several methods. The most popular are fluid transport studies and penetration studies. The aim of this summary was to compare both kinds of this methods.

        Key words: microleakage – dye penetration – fluid transport