Preclinical evaluation of a 3D-printed hydroxyapatite/poly(lactic-co-glycolic acid) scaffold for ridge augmentation

Background/Purpose: Supracrestal ridge augmentation (SRA) is a major challenge for clinicians. This study investigated the efficacy of a 3D-printed (3DP) hydroxyapatite/poly(lacticco-glycolic acid) (HA/PLGA) scaffold as a potential biologic for SRA. Methods: Scaffolds that were 5 mm in diameter and 2.5-mm thick with a 1.2-mm diameter through-and-through central hole composed of 90% HA and 10% PLGA were printed using an extrusion-based bioprinter. The HA/ PLGA scaffold was fixed with a 1.2-mm titanium mini implant on the buccal surface of rat mandible (Ti-HPS), and the outcome of SRA were compared with sites treated with a titanium mini-implant alone (control) and a titanium mini-implant covered with deproteinized bovine bone-derived matrix (Ti-DBBM) at 4 and 8 weeks by micro computed tomography (micro-CT), back-scattered SEM, and histology assessments. Results: The HA/PLGA scaffolds were 2.486 +/- 0.082 mm thick with an outer diameter of 4.543 +/- 0.057 mm and an inner diameter of 1.089 +/- 0.045 mm, and the pore dimensions were 0.48-0.52 mm. There was significantly more mineralized tissue in the Ti-DBBM and Ti-HPS groups than in the control group at both time points. Newly formed bone (NB) was well integrated with the DBBM and HA/PLGA scaffolds. The framework of the 3DP-HA/PLGA scaffold remained in place, and NB-implant contact (NBIC) was advanced to the middle level in the TiHPS group until 8 weeks, whereas dispersion of DBBM with a lower level NBIC was noted in the Ti-DBBM group at both time points. Conclusion: The 3DP HA/PLGA scaffold maintains supracrestal space and demonstrates osteoconductivity to facilitate SRA.