Regeneration of critical‐sized mandibular defect using a 3D‐printed hydroxyapatite‐based scaffold: An exploratory study

Background Three‐dimensional (3D) printing has become an available technology to fabricate customized tissue engineering scaffolds with delicate architecture. This exploratory study aimed to evaluate the potential of a 3D‐printed hydroxyapatite‐based scaffold as a biomaterial for obtaining guided bone regeneration (GBR) in vivo. Methods Scaffolds composed of 90% hydroxyapatite and 10% poly(lactic‐co‐glycolic acid) were printed using a microextrusion process to fit 4 mm diameter and 0.5 mm thick through‐and‐through osseous defects on the mandibular ramus of rats, with unfilled defects serving as controls. Specimens were analyzed for regeneration‐associated gene expression on day 7, and micro‐computed tomography (micro‐CT) and histology assessments were carried out on day 28. Results The scaffolds were 3.56 ± 0.43 mm (x‐axis) and 4.02 ± 0.44 mm (y‐axis) in diameter and 0.542 ± 0.035 mm thick (z‐axis), with a mean pore size of 0.420 ± 0.028 × 0.328 ± 0.005 mm2. Most scaffolds fit the defects well. Type I collagen, VEGF, and Cbfa1 were upregulated in the scaffold‐treated defects by day 7. By day 28, de novo osteogenesis and scaffold–tissue integration were evident in the scaffold‐treated defects, and entire mineralized tissue, as well as newly formed bone, was significantly promoted, as seen in the micro‐CT and histologic analyses. Conclusion The 3D‐printed hydroxyapatite‐based scaffold showed acceptable dimensional stability and demonstrated favorable osteoregenerative capability that fulfilled the need for GBR.