Dental implants placed in bone defects filled with three biomaterials

The aim of this study was to compare the histological features of bone filled with commonly used bone grafts placed in defects in the rabbit’s tibiae and to evaluate the integration of titanium implants inserted in the treated bone. Two cylindrical defects per tibia were created in 10 rabbits, and filled with either Bio-Oss, Bioglass, Ostim-Paste or left untreated and covered with a collagen membrane. Six weeks later one ITI titanium implantwas inserted at the center of each defect. Healing was allowed for 6 weeks. The animals were sacrificed and ground sections obtained. Samples from original bone were characterized by a cortical plate of compact bone surrounding a central large marrow space. The coronal portion of the implants was integrated in mineralized bone, the central portion was in contact with marrow spaces. Occasionally, a seam of newly formed bone lined the central portion of the implants. In Bio-Osss filled bone the graft particles were either surrounded by bone marrow or mineralized bone originating from the cortical plate. Bridges of mineralized tissue connecting particles and lining the central portion of the implants could be observed. In Ostim-Paste filled bone the graft appeared either as a compact large mass of material, or as fragmented in particles of smaller and irregular sizes. In the first case, a seam of mineralized bone could be observed lining the perimeter of the graft mass, otherwise bridges of mineralized tissue connected the particles and lined the central portion of the implants. In Bioglass filled bone the graft was represented by well distinguished granules as well as ‘dusty’ material. Some particles were in contact with mineralized tissue that invested the central portion of the implants, others with bone marrow. Morphometric analysis showed a higher proportion of lamellar bone in the original bone samples, followed by Bio Oss, Ostim -Paste and Bioglass samples, respectively. The proportion of woven bone was extremely variable. Bone marrow occupied more space in the grafted samples than in the original bone samples. The proportion of grafts particles varied widely within samples from the same group. Ostims-Paste appeared to occupy more space than the other grafts. A similar degree of osteointegration (bone to implant contact, (BIC) of the titanium implants withmineralized bone was observed for all grafted groups (about 40%). On the other hand, a lower degree of BIC, amounting to 34%, could be observed in the original bone group. The statistical analysis showed no significant differences in BIC among the groups. Supported in part by the Clinical Research Foundation (CRF) for the Promotion of Oral Health, University of Berne.