In the course of a dental treatment it is sometimes necessary to kill a tooth, if there is inflammation caused by a large caries reaching the nerve, by drilling, cleaning and filling the tooth’s canals. In other cases, already treated teeth showing signs of infection require retreatment. Whatever the case, the treatment of the canals must be performed with precision, all existing canals must be found, processed and filled tightly, to ensure long life of the treated tooth. In situations where the cleaning and processing of root canals is complicated, we use dental microscope.