Comparative Evaluation of Bovine- and Porcine-Derived Xenografts in Rabbit Calvarial and Canine Mandibular Dehiscence Models

Background: This study compared two xenogeneic bone graft materials, A-Oss (bovine-derived) and The Graft (porcine-derived), using a rabbit calvarial defect model and a canine mandibular dehiscence-type defect model. Methods: Healing was evaluated at 6 and 12 weeks in rabbits and at 24 weeks in mongrel dogs. Micro-computed tomography quantified mineralized tissue fill (defect closure) in rabbits and, in dogs, the compartments classified as new bone and residual graft, together with vertical and horizontal volumetric maintenance. Hematoxylin and eosin (H&E) sections provided complementary qualitative observations. Results: In rabbits, defect closure did not differ between materials at 6 weeks (67.1 ± 12.7% vs. 70.2 ± 15.1%, p = 0.090) or 12 weeks (78.6 ± 5.9% vs. 72.3 ± 0.9%, p = 0.124). In dogs, new bone was similar between groups (43.5 ± 3.2% vs. 45.9 ± 1.1%, p = 0.208), whereas residual graft showed a numerical trend toward higher values with A-Oss (20.2 ± 3.5% vs. 13.3 ± 4.5%, p = 0.069). Vertical volume maintenance also trended higher with A-Oss (91.1 ± 1.6% vs. 87.8 ± 1.3%, p = 0.056), while horizontal maintenance was comparable (94.5 ± 1.8% vs. 91.4 ± 2.8%, p = 0.241). Histology in both models showed graft particles within the defect/augmented regions with surrounding eosinophilic matrix and intervening tissue spaces. Conclusions: Overall, both materials produced similar healing profiles across models, with small between-material differences most apparent in the canine dehiscence setting.