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

Abstract

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-coglycolic 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 mm 2. 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.

The Role of Alcohol, LPS Toxicity, and ALDH2 in Dental Bony Defects

“…Since ALDH2 plays a crucial role in the clearance of toxic acetaldehyde derived from alcohol drinking and the ALDH2 mutation may cause severe bony defects, therefore, we provided drinking water with 10% alcohol to all animals in this study. Porphyromonas gingivalis is a well-known periodontal pathogen and is one of the predominant species in the gingival pockets of patients with advanced and severe periodontal disease [ 22 , 23 ]. It is mostly found in the deep periodontal pockets and active sites [ 34 , 35 ].…”

“…Micro-CT imaging protocol was as described in our previous study [ 22 ]. To obtain micro-CT images, upon animal sacrifice, samples of upper jaws of all mice were collected, trimmed, and fixed in 10% formalin solution for at least three days.…”

Degradable RGD-Functionalized 3D-Printed Scaffold Promotes Osteogenesis

“…1A). It was then sliced and outputted by a extrusion-based bioprinter, with ink composed of 90 wt% hydroxyapatite and 10 wt% 82:18 poly(lactic-co-glycolic acid), as described previously (Chang et al 2020). The dimensions, interconnectivity, and porosity of the scaffold were measured from the top view and cross-sectional view of scanning electron microscopic images with image processing software.…”

“…Images were then reconstructed and oriented to identify a 4-mm-diameter and 0.5-mm-thickness region as the radiographic region of interest, with the region covered by the lid compartment of the scaffold excluded. The following paramters within the radiographic region of interest (TV) were assessed by CT Analyzer software as previously described (Chang et al 2020): bone volume (BV; newly formed bone [NB] only) and mineralized tissue volume (MV; residual scaffold and NB).…”

“…By using biodegradable polyesters, such as polycaprolactone or poly(lactic-co-glycolic acid), as binders to bond hydroxyapatite, a direct 3D-printing technology for preparing hydroxyapatite scaffold was developed without the need for sintering or additional chemical reaction (Jakus et al 2016). The resultant scaffolds were flexible to adapt the physiologic environment with acceptable dimensional stability and demonstrated a higher level of defect fill and osteogenesis in preclinical critical-sized osseous defects (Chang et al 2020).…”