In daily practice, dentists meet with trauma and advanced carious lesions of immature permanent teeth. Determined by the type of trauma and the progression of the caries, infection of the pulp can lead to the loss of its vitality and the consequent halting of root growth and development. Depending on root development stage, the formed root can become short with thin dentine walls that are susceptible to fracture. Apex is wide open without constriction, which makes it impossible to perform a routine endodontic treatment. Knowing the development of the teeth, performing diagnostic procedures correctly, setting the right diagnosis, accordingly choosing the correct treatment method and material are the keys to the success of the therapy. The goal of treatment of pulp disease in immature permanent teeth is to preserve the vitality of the pulp by eliminating bacteria from the pulp-dentin complex and establishment an environment that allows apexogenesis to continue. Depending on the extent of inflammation, direct pulp capping, partial or complete pulpotomy may be indicated. If apexogenesis is stopped due to pulp necrosis, the therapy is focused on apexification and pulp revascularization. The use of a bioactive material such as MTA for the aforementioned therapeutic purposes has proven to be extremely successful. MTA is distinct from other materials because of its biocompatibility, antibacterial properties, sealing abilities and stimulation of cementogenesis and osteogenesis, and finally because of its hydrophilic nature.