Purpose: To analyze, radiographically and histologically, the influence of anorganic bovine bone matrix (ABBM) particle size on bone repair.

Materials and methods: Four calvarial defects were prepared in 18 adult New Zealand rabbits. The defects were filled with particulate autogenous bone (control group); ABBM of large, medium and small size granules. The animals were sacrificed at 15, 30, and 60 days postoperatively. The samples were radiographically examined before histological processing and compared with images of adjacent cranial bone.

Results: Autogenous bone showed a slight radiopacity initially, increasing to become similar to the adjacent bone at 60 days. The large and medium ABBM particles maintained the same radiographic behavior, showing a radiolucent area in the central portion of the defect at 60 days. ABBM of small granules showed slight radiolucency at the initial period, increasing in subsequent evaluations. Histological analysis showed more intense bone formation within the control group. All three particle sizes resulted in inflammatory infiltration at 15 and 30 days. Defects filled with ABBM of medium or large size granules presented a large amount of remaining particles and fibrous connective tissue in the defect at the final evaluation. In contrast, ABBM of small size granules lead to a greater amount of osteoid tissue, and the particles were almost totally reabsorbed within 60 days of grafting.

Conclusions:

• (1)

  Autogenous bone graft lead to the best result in terms of bone defect repair;

• (2)

  ABBM of large and medium size granules are not totally reabsorbed at the observed timeframe;

• (3)

  ABBM of small size granules was more intensively reabsorbed and lead to a greater osteoid tissue formation when compared to the medium and large granules.

Conflict of interest: None declared.