Osteopetrosis is a rare disorder characterized by systemic diffuse skeletal sclerosis. The disease is divided into the malignant type and the benign type. The former appears in infants or children and the latter appears in adults. We present here the case of a boy under oral treatment who was diagnosed as having osteopetrosis at 3 years of age. Results: 1. The erupted teeth were_??_and impacted teeth were_??_and_??_2.. The impacted tooth germs showed arrested root development, but the crowns of the_??_tooth germs were calcified.3. Since the patient was 5 years 10 months old, maxillary and mandibular dentures have been fitted.