Comparison of crosslinked and non-crosslinked collagenated xenografts for vertical bone augmentation in rabbit calvaria

Bovine or porcine xenografts, which are readily available and possess osteoconductivity, are widely used for bone augmentation in clinical practice. Collagenation improves clinical handling and maintains graft integrity, and when appropriately crosslinked, collagen scaffolds can achieve high osteogenic potential and structural stability. However, studies on the histological changes due to the use of collagenated bovine bone for vertical bone augmentation are lacking. Therefore, this study aimed to compare the osteoconductivity and volume stability of two collagenated xenografts — deproteinized bovine bone mineral (DBBM) with crosslinked bovine collagen (DBBM-Cb; A-Oss Collagen ^® ) and non-crosslinked porcine collagen (DBBM-NCp; Bio-Oss ^® Collagen) — using rabbit calvarial models of vertical augmentation and critical-sized defects. Surface morphology of the grafts was analyzed using field emission scanning electron microscopy. In vivo bone regeneration was assessed using micro-computed tomography and histological analyses at 3, 5, 6, and 12 weeks following bone grafting in calvarial vertical-augmentation and defect models. Both grafts showed porous and interconnected microarchitecture favorable for osteoconduction. In the augmentation model, DBBM-Cb demonstrated significantly higher bone volume fraction (bone volume/total volume of bone tissue) at 3 weeks and vertical height retention at both 3 and 5 weeks ( P  < 0.05). In the defect model, DBBM-Cb led to significantly greater defect closure at 12 weeks ( P  < 0.05). Histological analyses confirmed improved graft integration and bone maturation with DBBM-Cb. DBBM-Cb exhibited superior osteoconductivity, structural stability, and graft volume maintenance compared to DBBM-NCp. These properties support its potential as a more effective biomaterial for vertical bone augmentation.