Utilization of Ethyl Cyanoacrylate and 2-Octyl Cyanoacrylate Adhesives for Autogenous Bone Graft Fixation: Histomorphometric Study in Rats
The present study analyzes the repair process of autogenous bone graft in a block fixed with ethyl cyanoacrylate and 2-octyl cyanoacrylate adhesives in rat calvaria. Forty-eight rats, divided into 3 groups, received round osteotomies at the right parietal bone for the attainment of autogenous bone graft fragment, which was fixed at the opposite side to the donor site with ethyl cyanoacrylate (ethyl group) and 2-octyl cyanoacrylate (octyl group) adhesives. In the control group, bone fragment was only juxtaposed at the parietal bone surface without any fixation material. The animals were euthanized after 10 and 60 postoperative days. The calvariae were processed in a laboratory for the attainment of slides stained through the hematoxylin and eosin technique for histological and histometric analysis. The qualitative analysis showed a discrete inflammatory infiltrate in the control group and moderate inflammatory infiltrate in the ethyl and octyl groups at the 10-day period, which remained at the 60-day period, mainly in the octyl group. The bone fragment remained bonded to the recipient site through the adhesive, but graft incorporation was not observed in any of the specimens. Resorption was higher in the octyl group followed by the ethyl and control groups, both at the 10- and 60-day periods, but with no statistical significance (P < .05). Although promoting graft fixation and its maintenance at the recipient site, both studied adhesives did not allow the graft incorporation, producing a localized and discrete inflammatory reaction, which persisted at 60 days, being more intense in the octyl cyanoacrylate group.
Figure 1. Group I: 10 days: Superficially, corrugated periosteal tissue with fibers parallel to graft surface. Bone graft fragment (BG) with osteocyte lacunae. Interface area filled by fibrous connective tissue (hematoxylin and eosin, original ×125). Figure 2. Group I: 10 days: Graft peripheral area, where it is possible to observe areas of bone new formation (asterisks) from the graft fragment (BG) and from the parietal bone (OP) (hematoxylin and eosin, original ×160). Figure 3. Group II: 10 days: Bone graft (BG) peripheral area. Direct contact of the adhesive (AD) with fibrous connective tissue which is presented with moderate inflammatory infiltrate (hematoxylin and eosin, original ×160). Figure 4. Group III: 10 days: Thick periosteal tissue with moderate inflammatory infiltrate. Underneath, bone graft (BG) with osteocyte lacunae and intratrabecular spaces filled by connective tissue. 2-octyl cyanoacrylate adhesive (AD) filling the entire interface area of graft-recipient site (hematoxylin and eosin, original ×125). Figure 5. Group III: 10 days: Graft margins: contact between adhesive and fibrous connective tissue with moderate inflammatory infiltrate. Migration of connective tissue with inflammatory cells through the interface area (arrows) (hematoxylin and eosin, original ×160). Figure 6. Group I: 60 days: Union between bone graft and recipient site through mature bone (hematoxylin and eosin, original ×125).
Figure 7. Group II: 60 days: Adhesive (AD) permanence at the interface between graft and recipient site. Graft has few signs of bone remodeling, mainly at the area near to the adhesive (hematoxylin and eosin, original ×160). Figure 8. Group II: 60 days: Interface peripheral area. Presence of fibrous connective tissue with moderate inflammatory infiltrate and multinucleated giant cells (arrow) in contact with the adhesive (hematoxylin and eosin, original ×250). Figure 9. Group III: 60 days: Bone graft fragment (BG) extensively resorbed surrounded by connective tissue presenting moderate inflammatory infiltrate, also at the parietal bone (PB). Adhesive persistence filling the entire area of graft-recipient site interface (hematoxylin and eosin, original ×125). Figure 10. Group III: 60 days: Fibrous connective tissue surrounding the graft, separating it from the adhesive, infiltrated by inflammatory (hematoxylin and eosin, original ×250). Figure 11. Mean (in pixels) of the bone grafts area at 10 and 60 days in control, ethyl and octyl groups.
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