Comparison of a synthetic bone substitute composed of carbonated apatite with an anorganic bovine xenograft in particulate forms in a canine maxillary augmentation model.

Objective: To evaluate the effect of a porous geometry in particulate bone on new bone formation by comparison of anorganic bovine carbonate apatite (ABCA) with synthetic carbonated apatite (SCA), which have similar properties but different micro-structures.

Material And Methods: Porous structures and anorganic components of ABCA and SCA were evaluated using scanning electron microscope and Fourier transform infrared. They were implanted in maxillary augmentation models with the mouth split design in a total of 15 Beagle dogs. The animals were sacrificed 4, 8 and 16 weeks after surgery, and the histomorphometrical results were statistically analyzed for the material's geometrical relationship and new bone formation in relation to the available space and contact surface for osteoconduction.

Results: Both materials showed a typical infrared pattern of CO(3)(2-) -substituted hydroxyapatite (HA). Porous structures and a bridging effect of osteoconductive bone material were relatively better observed in SCA. The ratio of the material area to the total area was higher (P<0.01) for ABCA (28.03±6.09) than for SCA (20.26±4.23). The ratio of the number of particles possessing a pore structure to the total number and the interparticular space was greater (P<0.001 and 0.01) for SCA (18.12±9.44 and 79.74±4.23) compared with ABCA (1.45±1.74 and 71.63±5.85). The new bone areas and the bone-material contact lengths were greater in SCA than in ABCA (P<0.05).

Conclusions: The present study showed that porous structures may have an influence on new bone formation in osteoconductive bone substitutes.