Bone regeneration and biosorption patterns of different bone substitutes: an study in rabbit skulls.

Purpose: This study aimed to analyze the bone regeneration and biosorption patterns of different bone substitutes in a rabbit skull defect model.

Methods: Four circular 8 mm-defects were created in the cranium of 12 New Zealand white rabbits, each weighing approximately 3 kg. Each defect was randomly assigned to one of 4 treatment groups: cortical deproteinized porcine bone mineral (DPBM), cancellous DPBM, biphasic calcium phosphate (BCP) with a 6:4 ratio of hydroxyapatite (HA) to β-tricalcium phosphate (β-TCP) (TCP4), and BCP with a 2:8 ratio of HA to β-TCP (TCP8). The rabbits were euthanized at either 6 weeks (n=6) or 12 weeks (n=6) post-surgery. The harvested specimens were then analyzed both radiographically and histomorphometrically.

Results: In the micro-computed tomography analysis, no statistically significant differences were observed among the 4 groups, except in the bone graft volume/tissue volume (GV/TV) at 12 weeks. Cortical DBPM exhibited a higher GV/TV ratio than cancellous DBPM at the same time point. The histomorphometric analysis revealed increased biosorption in cancellous DBPM compared to cortical DBPM at 12 weeks. However, the percentage of newly formed bone did not significantly differ among the 4 groups.

Conclusions: All types of bone substitutes demonstrated similar patterns of bone regeneration at both 6 and 12 weeks of observation. However, cancellous DPBM exhibited a higher rate of bioabsorption compared to other bone substitutes, suggesting that it may have different indications or applications in guided bone regeneration protocols.