Tooth decay is undoubtedly the most common dental disease. The course of its treatment depends on the stage of advancement. In the early stage, when only small white spots are visible on the tooth surface, remineralization may be a solution. In such cases, the dentist applies a special preparation containing a high amount of fluoride to the tooth surface to prevent further decay and contribute to the restoration of the damaged tooth. If the disease has progressed further and the decay has affected not only the enamel but also the inner structures of the tooth, it is necessary to remove the diseased tissue using a drill and fill the cavity with a composite filling. If the decay has reached the tooth pulp, root canal treatment is necessary, which is the last chance to save the tooth affected by decay. Failure to treat it can ultimately lead to the extraction of the affected tooth.