# The Regenerative Effect of Various Barrier Membranes With and Without Bone Grafting in Critical Size Defects in Rabbit Calvaria

## TL;DR

This study tests how different types and thicknesses of barrier membranes, with and without bone grafts, affect bone regeneration in rabbits.

## Contribution

The study introduces a rabbit model to evaluate how barrier membrane architecture influences bone regeneration outcomes.

## Key findings

- The 1.0 mm cortical lamina barrier showed the best regenerative performance in bone defects.
- Thicker cortical barriers outperformed thinner collagen membranes in promoting tissue maturation.
- Bone grafting enhanced overall histological scores compared to non-grafted groups.

## Abstract

This multicentre randomized controlled clinical trial aims to investigate the regenerative effects of various thicknesses and types of barrier materials with and without bone grafting in a rabbit calvaria model.

One hundred male rabbits were partitioned into two groups: one without bone graft (NB) and one with bone grafting (BG). The groups were further divided into five subgroups, n = 10 each: C (control); SC (0.3 mm single‐layered collagen); DC (0.6 mm double‐layered collagen); L1 (0.5 mm cortical collagenated bone barrier); and L2 (1.0 mm cortical collagenated bone barrier). In all experimental groups, each distinct type of barrier was applied following the creation of a 10 mm circular defect in the calvaria of each rabbit. After 24 weeks, the calvariae were examined by histologic and histomorphometric analyses.

The utilization of cortical bone barriers increased bone formation in all experimental groups. For Group NB, the histological score significantly differed among subgroups (p < 0.001). L1 and L2 subgroups had more favorable histological scores than the control groups (p < 0.001). Furthermore, the L2 subgroup had a higher histological score than the SC subgroup (p < 0.001). In Group BG, histological score significantly differed among subgroups (p < 0.001). DC, L1, and L2 subgroups had higher histological scores than the controls (p < 0.02), (p < 0.001), and (p < 0.001), respectively. The L2 subgroup had a higher histological score than the SC subgroup (p < 0.01). The BG group had significantly higher histological scores overall compared to the NB group based on barriers (p < 0.05).

Within the limits of this model, the 1.0 mm cortical lamina barrier demonstrated the most favorable regenerative performance, consistently achieving higher histologic scores and more advanced tissue maturation than thinner cortical lamina or collagen membranes. These findings indicate that barrier architecture, particularly thickness and mechanical stability, plays an important role in promoting predictable bone regeneration.