Comparison of bioresorbable bone substitutes, carbonate apatite and β-tricalcium phosphate, for alveolar bone augmentation with simultaneous implant placement

Aim: This study histologically compared two bioresorbable bone substitutes with different composition, carbonate apatite (CO₃Ap) and beta-tricalcium phosphate (β-TCP), through alveolar bone augmentation with simultaneous titanium implant placement in beagle dogs. Methods: Bone defects (length 7 mm, width 2 mm, and depth 6 mm) were created bilaterally at mandibular premolar sites and augmented with either CO₃Ap or β-TCP granules after titanium implant installation. The specimens with the surrounding tissue were harvested from the mandible at 4, 12, and 24 weeks postoperatively, and histological evaluation was performed. Results: Most β-TCP granules dissolved in early stages postoperatively, resulting in a lower volume of alveolar bone surrounding the titanium implant. By contrast, in the case of CO₃Ap group, the alveolar ridge was reconstructed without reducing the alveolar bone height, and almost all implant threads were covered with new bone by at least 12 weeks postoperatively. Quantitatively, the CO₃Ap group showed a significantly higher percentage of new bone formation in the alveolar ridge portion at all follow-ups. Additionally, it demonstrated a significantly higher bone-to-implant contact ratio than that of the β-TCP group at 12 and 24 weeks after implantation (70.8 ± 5.6% vs. 29.3 ± 16.4% and 54.8 ± 6.9% vs. 41.8 ± 2.2%, respectively). Conclusion: In conclusion, based on the superior outcomes noted in this study, CO₃Ap is useful for clinical use in alveolar bone augmentation with simultaneous implant placement.