Endodontics, commonly referred to as – both by doctors and patients – root canal treatment - is a branch of conservative dentistry concerned with the study and treatment of the dental pulp and study and treatment of periapical tissue diseases. Endodontic treatment is recommended in case of very deep cavity holes, pulp necrosis or after displacement or breaking of a tooth due to prosthetic indications – before making a crown or bridge. Root canal treatment is performed with the use of a very thin (0.06-0.40 mm) instrument called files. The size, length and deepness of the canals is measured by means of a specialized device called endometer. After measuring and shaping, the canals are filled with gutta-percha and sealers. In endodontics we use the highest class operation microscope SmartOPTIC, which provides the doctor with full view of the interior of the tooth chamber and canals, and the newest devices for shaping and thermal filling of root canals. In line with microscopic treatment, X-ray diagnostics is also applied.