The study aims to determine the efficiency and effectiveness ofapexification treatment using mineral trioxide aggregate (MTA). For thispurpose, two cases were taken into consideration in the examinationon the basis of clinical records in the Faculty of Dentistry at RecepTayyip Erdoğan University. These cases were a female patient at theage of 16 and a male patient at the age of 8. A treatment protocol wasdesigned for and applied on both cases. This way, the whole treatmentcould be divided into three stages: preoperative, procedural andfollow-up steps. The follow-up process consisted of two parts: clinicaland radiographic examinations. In the procedural stage, the clinicianfirst rinsed the root canals with 5 ml of 2.5% NaOCl and administeredcalcium hydroxide (CH) in the canals and allowed it to remain within a1 -week period in order to fill the apical area (4 mm) of the immature,necrotic permanent incisors with an MTA plug. After MTA application,the clinic doctor filled the rest with gutta-percha cones. On the clinicaland radiographic follow-ups performed semi-annually within one year,the lesions were dissected, and the tissues were regenerated in theperiradicular area. In conclusion, use of MTA material was determinedas an efficient and effective method in apexification with respect to timeand quality of treatment and it is still a well-accepted technique.