In recent times, new methods of modern endodontic treatment are increasing. Among endodontic treatments, uncomplicated treatment of permanent teeth with no root formation remains a problem. This article is devoted to a cross-comparative analysis of the effectiveness of treatment of periodontitis of permanent teeth without root formation using calcium hydroxide and MTA. In the results of the analysis, when filling with calcium hydroxide, root formation lasted from 3 to 18 months, after post-filling with a Rutdent stopper-from 2 to 12 months. An increase in Root Length was observed in 60% of all cases. Indications for apexification with calcium hydroxide are those that can be indicated in the teeth of stages III and IV of root formation, in the presence of signs of tooth root resorption, regardless of the stage of post - placental root formation of a Rutdent plug to 1/3 of the root canal.