Introduction. Gangrenous pulpitis is characterized by septic modifications of the dental pulp and its decomposition under the action of aerobic and anaerobic germs that strictly involve the teeth and apical periodontium. The fermentative decomposition of proteins in dentinal canals and the organic substance in the tooth structure causes a decreased tooth resistance. Pulp gangrene can be an infection focus for the whole organism. It is therefore necessary to remove the infection focus in time, endodontically and effectively. The effectiveness of endodontic treatment depends on several factors: biomechanical preparation, irrigation, medicated dressings, endodontic space sealing and restoration of the anatomical shape of the dental crown.  Aim of the study. To study the etiology, pathogenesis and clinical evolution of chronic gangrenous pulpitis and the optimal treatment methods.  Materials and methods. A group of eight patients (3 women and 5 males) aged 25-50 years, were subjected to complex examination and endodontic treatment, being diagnosed with chronic gangrenous pulpitis. To increase the treatment efficacy, APEXDENT preparation was used, being applied on temporary dressings. It has an effect of inducing the formation of calcified tissue, antimicrobial action, decomposition and elimination of necrotic material and its discharge from the root canal. In the treatment we have applied modern technologies of permiabilization, sterilization and filling of the root canals.  Results. Of the 8 patients treated endodontically, only 2 relapsed. The study confirms that APEXDENT preparation corresponds to 75% of its properties and is effective in the treatment of chronic gangrenous pulpitis.  Conclusion. Temporary application of APEXDENT paste in the root canal resulted in a good sterilization of the root canals. Most importantly, the obtained results allowed us to use APEXDENT paste in the treatment of chronic gangrenous pulpitis.