The regenerative effect of various thickness of barriers with and without bone grafting in critical size defects in rabbit calvaria. A Multi Centre Randomized Controlled In Vivo Study

Aim To investigate the regenerative effects of various thickness and types of barrier materials with and without bone grafting in a rabbit calvaria model. Materials and Methods One hundred male rabbits were partitioned into two groups, one without and one with bone grafting. The groups were further divided into 5 subgroups n = 10 each: control C, no membrane single layered collagen [1], double layered collagen DC, 0.5 mm cortical collagenated bone barrier L1, and 1.0 mm cortical collagenated bone barrier L2. In all experimental groups, each distinct type of barriers 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. Results The utilization of cortical bone barriers increased bone formation in all experimental groups. For Group NB, percentage scores significantly differed among subgroups (p < 0.00). L1 and L2 subgroups had more favorable histological scores than the control groups (p < 0.00). Furthermore, the L2 subgroup had a higher score than the SC subgroup p = 0.001. In Group BG, percentage scores significantly differed among subgroups (p < 0.00). DC, L1, and L2 subgroups had higher scores than the controls (p = 0.02), (p < 0.00) , and (p = 0.00) , respectively. The L2 subgroup had a higher score than the SC subgroup (p = 0.01). The BG group had significantly higher scores overall compared to the NB group based on barriers (p < 0.05). Conclusions This study found that 1 mm-thick cortical bone barriers achieved superior histologic scores for tissue quality and bone maturation compared to 0.5 mm cortical bone barriers and single or double-layered collagen membranes. These findings suggest that 1 mm cortical bone barriers enhance bone regeneration, with barrier-membrane thickness and biological properties playing a key role in surgical outcomes.