In vivo comparison of two bone substitutes in the distal femur of the rabbit.
OBJECTIVE
This study aimed to microradiographically evaluate the healing of grafted defects using a surgically standardized model that was suitable for comparing the regenerative potential of different grafts.


METHODS
Two different biomaterials, bovine porous bone mineral (BPBM) and nanohydroxyapatite (NHA), were used to fill defects produced in the distal epiphyses of 10 adult male rabbits for 2 and 4 months. Three rabbits were left untreated, without defects, as controls. Evaluations were performed on microradiographs of sections of polymethyl methacrylate-embedded rabbit epiphyses. The amounts of graft material and bone were evaluated by splitting the filled hole into three portions.


RESULTS
A greater amount of BPBM granules were in contact with bone at both 2 and 4 months versus the NHA (statistically significant difference in the central portion of the defect), and a persistence of the BPBM over time was apparent. The amount of NHA decreased from the inner to the outer portion of the defect, particularly after 4 months. The bone amount increased from the inner to the outer portion, particularly for the NHA graft, which produced an early cortex. The amount of mineralized material reached about 80% in the BPBM and 40% to 60% in the NHA after 4 months.


CONCLUSIONS
Both the analyzed biomaterials performed adequately for bone regeneration. The two biomaterials are probably suitable for grafting defects related to early cortical formation or spacemaintaining clinical requirements.
University of Modena and Reggio Emilia, Modena, Italy.
Carlo
C
Bertoldi
Davide
D
Zaffe
D000818:Animals; D001857:Bone Matrix / Q000637:transplantation; D001861:Bone Regeneration; D018786:Bone Substitutes; D017886:Durapatite; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008852:Microradiography; D008903:Minerals; D049329:Nanostructures; D011817:Rabbits
C077540:Bio-Oss; D018786:Bone Substitutes; D008903:Minerals; D017886:Durapatite