Combined use of deproteinized bovine bone mineral and α-tricalcium phosphate using gelatin carriers.

Abstract

Objective: To study the effect on biomaterial degradation and bone formation of different ratios between α-tricalcium phosphate (α-TCP) and deproteinized bovine bone mineral (DBBM) using various gelatins as a carrier.

Materials and methods: Thirty-six critical-sized calvarial bone defects were randomly treated in 18 animals. Four biomaterials with different compositional relations of DBBM to α-TCP and granules to carrier were investigated: (1) 40 ± 10% DBBM/40 ± 10% α-TCP with 20 ± 10% gelatin type 1 in ratio 4:1 (B1/G1), (2) 20 ± 10% DBBM/60 ± 10% α-TCP with 20 ± 10% gelatin type 1 in ratio 4:1 (B2/G1), (3) 20 ± 10% DBBM/60 ± 10% α-TCP with 15 ± 10%/5 ± 5% gelatin type 2/ glycerine (B2/G2) and 4), 10 ± 10% DBBM/60 ± 10% α-TCP with 20 ± 10%/10 ± 10% gelatin type 2/ glycerine (B3/G2). As a positive control 50 ± 10% DBBM/50 ± 10% α-TCP without gelatin (PC, B1/G0) and as a negative control (NC) empty defects were chosen. All defects were covered with a collagen membrane. The samples were harvested 4 weeks post-surgically and examined by micro-CT and histomorphometric analysis.

Results: New bone formation was evident in all defects. The mineralized tissue volume was significantly higher in the four tested biomaterials than in the NC group, but lower compared to the PC group. Histomorphometry showed similar levels of bone formation in all groups, whereas only the PC group reached a significantly higher total augmentation area than that of the NC. The PC group showed significantly higher mineralized tissue density and residual material area compared to the B3/G2 group, and more residual DBBM than the four tested biomaterials.

Conclusions: New bone formation was not significantly affected either by different DBBM:α-TCP compositional ratios nor the presence of various gelatin carriers.

Clinical relevance: Similar levels of osteoconductivity indicates the presumptive use of combined products in alveolar ridge augmentation to support bone formation. Gelatin with or without glycerine may be considered for its use as a carrier to the biomaterials frequently applied in peri-implant surgery.