Tissue response to the composite 50% hydroxyapatite: 50% polyhydroxybutyrate for bone substitution in rabbits

E.C. Carlo A.P.B. Borges M.I.V. Vargas M.M. Martinez R.B. Eleotério A.R. Dias M.C.D. Rodrigues About the authors

The biocompatibility, osseointegration, osseoconductivity, and biodegradation of a 50-50% hydroxyapatite (HAP-91®)-polyhydroxybutyrate were evaluated. The composite was implanted in bone defects of 12 rabbits (experimental group), being compared to unfilled defects (control group, 12 animals). The clinical parameters of pain, lameness, infection, dehiscence, and edema were evaluated during the first eight days and on the 45th and 90th days after surgery. Radiographs were taken in four animals per group at 8, 45, and 90 days after surgery, when animals were euthanized to collect samples for histology and histomorphometry. Significant differences between groups for all clinical parameters were not observed. Radiographs showed a similar radiopacity of the composite and bone and their direct contact. More bone than connective tissue was found within the defect at 8, 45, and 90 days and at the interface on the 45th and 90th days. Projections of bone and connective tissue were seen inside the composite. Biodegradation signs became evident, with absence of inflammatory infiltrate. Data support that such composite is biocompatible, osseoconductive, biodegradable, and integrate to bone.

rabbit; biomaterials; bone substitute; composite

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