Induction of root growth in nonvital immature permanent teeth with revascularization procedures evaluated using triantibiotic paste or Calcium hydroxide paste as a disinfectant intracanal medicament. The coronal seal using Mineral trioxide aggregate or Glass ionomer cement was evaluated. Sixty five permanent non vital immature teeth of 7-13 years old children with signs and symptoms of periapical pathosis were included in the study. Teeth were classified into two main groups according to the disinfectant material Group 1, (triantibiotic paste) and Group 2 (calcium hydroxide paste); each group was subdivided into two subgroups A and B (MTA or Glass ionomer) according to the sealing material. The disinfectant pastes were placed in the first visit and were removed in the second visit using 2.5% NaOCl irrigation. After root canal drying, apical bleeding was induced by over instrumentation in the apical region with 15 K-files. The sealing materials were placed in the coronal third of the root then composite restorations were placed in both subgroups. Children were followed up each three month up to 18 months clinically and radiographically. Standardized digital radiographs were evaluated for thickening of canal walls, continued root development and changes of periapical lesions. At 18 month, the success rate was 70.5%, 33.2%, 26.3% and 22.2% in 1A, 2A, 1B and 2B groups respectively regarding marked thickening of canal wall, while it was 64.7%, 33.3%, 42.1% and 22.2% in 1A, 2A, 1B and 2B groups respectively regarding marked root development. Regarding decrease of periapical lesions it was 88.2%, 66.7%, 57.9% and 55.6% in 1A, 2A, 1B and 2B groups respectively. Thickening of canal wall was significantly increased in 1A, 2A and 2B groups. Root development was significantly increased in 1A, 2Aand 2B groups. Periapical lesion was significantly decreased in group 1A, 1Band 2B groups. IntroductionPulp necrosis of an immature permanent tooth due to trauma or caries arrests the tooth development and it becomes prone to fracture. The vitality of dental pulp preserves the capacity of dentin regeneration particularly in case of immature permanent teeth because of their incomplete apical and dentinal wall development (1) .Revascularization treatment of immature necrotic permanent teeth allows continuation of root development has been introduced newly instead of conventional methods that induce formation of barrier against which the obturation materials can pack as apexification with calcium hydroxide (2) .Pulp revascularization success depends on a reliable cell source capable of differentiating into odontoblast, an appropriate scaffold to promote cell growth and differentiation, and signaling molecules as growth factors capable of stimulating cellular proliferation and directing cellular differentiation (3) .The apical end of the pulp, periodontal ligament, apical papilla and bone marrow are rich in dental stem cells so they are considered as a reliable cell source in immature teeth. Blood clot formed after induce bleeding in the ...