3-D Printed BCP Blocks with Different Pore Sizes for Regeneration in Rabbit Calvarial Defects

Abstract Background Alveolar ridge augmentation is frequently performed in the deficient alveolar ridge to facilitate the placement of dental implants. Severe resorption of the bony ridge may occur because of aging or periodontal and periapical pathologies. When faced with this situation, a block bone graft might be indicated, since the block bone provides structural stability to the augmented site. The aim of this study was to compare three-dimensionally printed biphasic calcium phosphate (BCP) block bone substitutes with different pore sizes (0.8, 1.0 and 1.2 mm) for regeneration rabbit calvarial defects. Material & Methods Four circular defects were formed on the calvaria of ten rabbits. Each defect was randomly allocated to the following study groups: 1) Control group, 2) 0.8 mm group, 3) 1.0 mm group, and 4) 1.2 mm group. All specimens were harvested at 2 and 8 weeks postoperatively, and the samples were analyzed radiographically and histomorphometrically. Results Histologically, the BCP blocks remained unresorbed up to 8 weeks, and new bone formation occurred within the porous structure of the blocks. At the early healing period of 2 weeks, histomorphometric analysis revealed significantly greater new bone formation in the BCP groups compared to the control (p < 0.05). However, there were no significant differences between the groups with different pore sizes (p > 0.05). At 8 weeks, only the 1.0 mm group (3.42 ± 0.48 mm2) showed a significantly greater area of new bone compared to the control group (2.26 ± 0.59 mm2) (p < 0.05). Among the BCP block groups, 1.0 mm and 1.2 mm groups exhibited significantly greater area of new bone compared to the 0.8 mm group (3.42 ± 0.48 and 3.04 ± 0.66 vs 1.60 ± 0.70 mm2, respectively). Conclusions Within the limitations of this study, 1.0 mm pore diameter of the BCP block bone substitute was the most optimal size for bone regeneration. The BCP block bone substitutes can be applied in bone defects for successful bone regeneration, and further study should be performed in more challenging defect configurations prior to the clinical application.