Evaluation of 3D-Printed Polylactic Acid as a Bone Substitute: An Animal Study in a Rat Model

Bone repair and regeneration are important processes for treating bone defects and injuries. However, traditional bone grafts like autografts and allografts have limitations, such as complications at the donor site and immune rejection. As a result, there is growing interest in using polylactic acid (PLA), a biodegradable and biocompatible material, as a synthetic bone substitute. This study aims to evaluate the effectiveness of 3D-printed PLA scaffolds as bone substitutes using a rat model.

PLA scaffolds with dimensions of 2 × 2 × 4 mm and 2 × 2 × 8 mm were fabricated using the CUBEX-TRIO 3D printer. Twelve male Wistar rats were divided into four groups based on defect size (4 and 8 mm) and observation period (4 weeks and 8 weeks). The surgical procedures involved creating discontinuity defects in the rats' zygoma and implanting PLA scaffolds that were stabilized with a bio-membrane. Bone regeneration was assessed through radiographic analysis and histological examination.

Radiographic analysis confirmed the formation of bone in the grafted regions. Histological analysis revealed connective tissue formation at the defect edges and scaffold surface at both 4 and 8 weeks. In the 4 mm defect group, the transformation of connective tissue into chondrocytes and endochondral ossification was observed at 8 weeks, indicating successful bone regeneration. However, in the 8 mm defect group, bone formation was not as evident, suggesting limitations in the osteoinductive potential of PLA scaffolds for larger defects.

The 3D-printed PLA scaffolds show promise as bone substitutes for small to moderate-sized defects due to their effective biocompatibility and osteoinductive potential. Further studies are needed to optimize their performance for larger defects, potentially enhancing their clinical application in bone repair and regeneration.