Análise histológica comparativa da fixação de enxerto autógeno com parafuso e adesivo à base de cianoacrilato

Abstract

Rehabilitation of atrophic edentulous areas requires the use of a block bone graft. The most used method for fixation of the bone blocks are the titanium screws. However, the use of these fixation devices has disadvantages, including the need for removal, risk of fracture and formation of artifacts in imaginological examinations. The use of tissue adhesives based on cyanoacrylates has been suggested as an alternative to the use of screws in the fixation of autogenous bone grafts. This work aims to compare histologically the receptor bed of autogenous bone graft blocks fixed with ethyl-cyanoacrylate-based adhesives in relation to fixation with titanium screws. Twenty-four adult male rabbits were used, in which two 8mm surgical defects were performed in the parietal bone region, laterally to the median sagittal suture. The fixation of the autogenous bone blocks was performed in the posterior region of the parietal bone with screw and adhesive. Two defects were performed in each parietal, and one of the defects was directed to the screw group and the other defect to the adhesive group. The screw and adhesive groups were subdivided according to the experimental periods of 60 and 75 days, with n = 6 in each group and in each time. Histological analysis evaluated the bone-graft interface, evaluating the areas of bone and soft tissue. In the areas of bone tissue, the following criteria were evaluated: mature bone, immature bone, empty gaps, gaps filled by osteocytes, empty spaces, bone marrow, areas of necrosis, osteoclasts, osteoblasts and blood vessels. In the areas of adjacent soft tissue were evaluated: collagen fibers, fibroblasts, blood vessels, inflammatory cells, multinucleated giant cells, osteoblasts, osteoclasts, empty spaces and areas of necrosis. An increase in the volume density of immature bone (P = 0,0026) was observed in the adhesive group in relation to the screw group in the period of 75 days. And the screw group 75 days showed a decrease in the volume density of immature bone when compared to the 60-day screw Group (p = 0,0184). No differences were observed in tissue components of the soft tissues and in the adjacent inflammatory response of the receptor bed of autogenous graft fixed with titanium screws and with cyanoacrylate-based adhesives after 60 and 75 days. It was possible to conclude that the use of the screw and ethyl-cyanoacrylate were equivalent in the fixation of autogenous bone blocks. The highest presence of immature bone in the adhesive group 75 days suggests a slower bone maturation with the use of the adhesive.