Deproteinized bovine bone block for horizontal ridge augmentation: A clinical split-mouth prospective study – part II, histologic and microtomographic evaluation

Objectives: To evaluate the micro architectural and histological patterns of new bone formation in areas grafted with deproteinized bovine bone block (DBBM) compared to autogenous graft from mandibular ramus (AB). Materials and methods: Twelve patients with edentulous atrophic maxillary ridges were submitted to maxillary ridge reconstruction surgery. Each side of maxilla received a type of graft, according to randomization: AB or DBBM. Nine months after, cylindrical bone biopsies were obtained using a trephine bur, and then submitted to micro CT to evaluate tissue volume, surface, Bone volume and surface, bone volume percent, bone surface density, specific bone density; trabecular number, separation, thickness and pattern, porosity and connectivity. From each group, six samples were randomly selected for histological analysis. Histological images were qualitatively evaluated for tissue pattern and osteocytes infiltration. Furthermore the areas of new bone formation, vital bone, soft tissue, residual biomaterial, and necrotic bone were defined. Results: specific bone density was larger for DBBM than for AB (14.69 ± 2.66 vs 12.01 ± 2.16), but trabecular thickness was larger in AB (0.55 ± 0.33 mm) than in DBBM (0.28 ± 0.04 mm). At the histologic analysis, area of mineralized tissue was larger in the AB than in DBBM (55.29 % ± 11.24 vs 37.04 % ± 9.04). All other evaluated criteria did not differ between groups. Conclusion: DBBM presented suitable incorporation to the grafted site, allied to new bone formation, bone volume, bone density, and soft tissue areas similar to AB.