CONICET | Buscador de Institutos y Recursos Humanos

The need to treat bone loss from various etiologies, extension and localization, have stimulated material development to replace bone. In SAIO 2010, we had demonstrated biocompatibility, bone promotion, bone conductivity, bioactivity and local toxicity absence from a new biogenic Hydroxyapatite (bHA), using rat bone marrow after 7 and 21 days implantation. Objetive: to study long term (12 weeks) bHA biological behaviour by ISO 10993-6 norms into rat bone marrow tibiae, and compare two biocompatibility systems. Method: cortical defect on tibia was performed using 12 Wistar rats (200g +/- 20g) to access bone marrow. Animals with bHA implanted were divided in two groups; Group 1(G1) cortical cavity in left tibia sealed with gutta-percha (g), and Group 2 (G2) cortical cavity in right tibia unsealed. The samples obtained after 12 weeks implantation were submitted to histological a semi-quantitative studies. Results: G1: the defect area was sealed with gutta-percha, covered by fibrous tissue and bone neoformation. bHA particles persisted, and new bone formation around some particles was observed. G2: cortical defect was repaired by bHA with new bone. At bone marrow, scarce bHA particles surrounded by bone formation was observed. In both groups, there was inflammation absence. Bone formation absence was observed when particles were closed. Conclusions: G1 demonstrated be a better system because more material remains inside bone marrow. In both groups, bHA showed biocompatibility, bioactivity, bone conductivity and not local toxicity after 12 weeks implantation. When particles were close, there was no bone formed. It is necessary to develop a new material presentation. The results encourage to continue the research to develop it as a bone grafts material.