Critical-sized bone defects pose significant challenges in orthopedic surgery. The introduction of 3D printing technology in bone grafting offers a promising solution by creating customized grafts that mimic the natural bone structure. This study aimed to reconstruct long-segment bone defects in the rabbit radius using a 3D-printed material composed of hydroxyapatite (HAP) and poly(lactide-co-glycolide) (PLGA), referred to as ALBO-OS, and to evaluate its potential to support bone healing without the use of stem cells or growth factors. Six rabbits underwent computed tomography scanning to create patient-specific 3D models of the radius. Custom-designed ALBO-OS implants were 3D-printed and used to fill segmental defects corresponding to one-third of the bone length in each rabbit, created by osteotomy. Over a 12-week observation period, graft integration, osteointegration, and overall bone regeneration were assessed through histological and histomorphometric analyses. The implanted scaffolds demonstrated encouraging bone healing, with significant bone regeneration observed within the defect areas. Histological evaluation revealed significant new bone formation and vascularization, with minimal inflammatory response. The findings demonstrated the potential of 3D-printed HAP/PLGA-based materials as a promising strategy for the reconstruction of large bone defects, eliminating the need for exogenous biological agents.

Background/Objectives: Articular cartilage and osteochondral defects have limited intrinsic healing capacity. This study evaluated the biocompatibility and in vivo regenerative potential of two novel hydroxyapatite-based hydrogels — Simplex Gel (hydroxyapatite/hydroxyethyl cellulose) and Complex Gel (additionally enriched with sodium hyaluronate and chondroitin sulfate) — compared with a commercial hyaluronic-acid control (Reviscon^® 1%). Methods: Cytotoxicity (MTT assay, MRC-5 fibroblasts) and genotoxicity (alkaline comet assay, human peripheral blood lymphocytes) were assessed in vitro. In vivo, six Vietnamese pigs received a superficial chondral or a deeper osteochondral defect on the tibial condyle of the right knee, treated with Reviscon^®, Simplex Gel, or Complex Gel. After 12 weeks, sections were stained (H&E, Mallory–Azan, Picrosirius Red, PECAM-1) and analyzed stereologically (n = 15 sections/bone). Results: Both gels were non-genotoxic and only weakly to moderately cytotoxic at the two highest concentrations (ISO 10993-5). All treatments achieved complete defect filling with regenerated cartilage and bone, without necrosis, inflammation, or other pathological changes. Complex Gel produced the most pronounced regenerative response, with the highest cell numerical densities and the most intense collagen deposition. Conclusions: Both hydrogels, particularly Complex Gel, are biocompatible and support osteochondral regeneration in a large-animal knee model, warranting further preclinical development.

Introduction/Objective. Aim was to evaluate the push-out bond strength to root canal dentine and radiopacity of three different sealers: Adseal (Meta Biomed Co., Cheongju-si, South Korea), CeraSeal (Meta Biomed Co.) and control AH Plus (Dentsply Sirona, Charlotte, NC, USA). Methods. In nine dentin discs, 1 mm thickness, three holes, 1.2 mm diameter, were drilled in with a fissure carbide bur. Discs were immersed in 0.5% NaOCl and 10% citric acid respectively, for 60 seconds rinsed and dried. Every hole was filled with different sealer. Specimens were wrapped in gauze previously immersed in Hank?s balanced salt solution at 37?C/seven days. The push-out test was performed using universal testing machine at a cross-head speed of 1 mm/min. The radiopacity was tested (ISO 6876/2012 standard). Three sealer specimens, 5 mm in diameter and 2 mm thick were prepared and radiographed using radiovisiography system (CCD sensor, Trophy Radiologie, Marne-la-Vallee, France) with graded aluminum step-wedge. Gray-scale value was assessed using Adobe Photoshop CS7 (Adobe Inc. San Jose, CA, USA). Results. Mean values of push-out bond strength were 5.21 ? 0.87 MPa (Adseal), 0.06 ? 0.02 MPa (CeraSeal), and 3.13 ? 0.38 MPa (AH Plus). A statistically significant difference in push-out bond strength was observed among all three sealer groups (p < 0.05). Adseal exhibited the strongest bond strength to root canal dentine. All sealers achieved radiopacity over 3 mm, with statistically significant difference among the groups (p < 0.05). Conclusion. The epoxy-based sealer Adseal showed higher bond strength compared to AH Plus and calcium silicate-based sealer CeraSeal, which, expectedly, showed the weakest dislocation resistance. All three sealers fulfilled the ISO standard to be distinguished on dental radiogram.