Objective of the presentation is to show bone response in an orthodontic challenging case. Material for the analysis was gathered during treatment of 32 years old Polish woman suffering from Aggressive Periodontitis (AP). She presented a very good oral hygiene, big loss of periodontal tissue support and a deep overbite. Her Osteoprotegerin (OPG) serum concentration level was low. OPG is a protein, osteoclastogenesis inhibitory factor. The treatment goal was to intrude the lower front teeth (canines and incisors). Appliance was build with the use of long Fiber Reinforced Composite (FRC), miniscrew and 50 gram niti coil spring. The intrusion was isolated and pure without support of Periodontally Accelerated Osteogenic Orthodontics (PAOO). Results after 19 months of intrusion and after 29 months of total active orthodontic treatment from the clinical point of view were satisfying. At head films the distance from the Incision Inferius (ii) to the Gnathion (gn) decrease about 10 mm. Dental roots of intruded teeth had similar bone support before and after the treatment. In intrusion region, at orthopantomogram x-rays, the distance from the lower margin of mandible to the upper margin of alveolar part of mandible decrease about 10% during treatment. The intruded segment moved down together with alveolar bone. In conclusion we can suspect that dental roots could not immerse in bone because of three-dimensional bone architecture and bone’s level of metabolism in this aggressive periodontitis case.