3D-Printed Ceramic Bone Scaffolds with Variable Pore Architectures

Abstract

This study evaluated the mechanical properties and bone regeneration ability of 3D-printed pure hydroxyapatite (HA)/tricalcium phosphate (TCP) pure ceramic scaffolds with variable pore architectures. A digital light processing (DLP) 3D printer was used to construct block-type scaffolds containing only HA and TCP after the polymer binder was completely removed by heat treatment. The compressive strength and porosity of the blocks with various structures were measured; scaffolds with different pore sizes were implanted in rabbit calvarial models. The animals were observed for eight weeks, and six animals were euthanized in the fourth and eighth weeks. Then, the specimens were evaluated using radiological and histological analyses. Larger scaffold pore sizes resulted in enhanced bone formation after four weeks (p < 0.05). However, in the eighth week, a correlation between pore size and bone formation was not observed (p > 0.05). The findings showed that various pore architectures of HA/TCP scaffolds can be achieved using DLP 3D printing, which can be a valuable tool for optimizing bone-scaffold properties for specific clinical treatments. As the pore size only influenced bone regeneration in the initial stage, further studies are required for pore-size optimization to balance the initial bone regeneration and mechanical strength of the scaffold.

Alloplastic Bone Substitutes for Periodontal and Bone Regeneration in Dentistry: Current Status and Prospects

“…Thus, there is great demand for 3D printing technology; many studies have been published concerning 3D printing technology. Although the evidence regarding 3D-printed alloplastic block bone grafts for ridge augmentation is currently limited to animal studies, the concept is very promising [ 68 , 69 , 70 ].…”

Current Application of Beta-Tricalcium Phosphate in Bone Repair and Its Mechanism to Regulate Osteogenesis

“…The presence of micropores increase in the surface area of biomaterials while micropore structures have been demonstrated to enhance material resorption and boost osteoinduction (Davison et al, 2014;Rustom et al, 2019). Open and interconnected macropores are not only useful for cell migration and blood vessel formation, but also essential for the diffusion of nutrients, waste and pro-osteogenic factors (Loh and Choong, 2013;Lim et al, 2020). Therefore, porosity not only allows biomaterials to absorb growth factors, but also controls the complex interaction between bone materials and pro-osteogenic factors (e.g., bone morphogenetic proteins).…”

Novel Inorganic Nanomaterial-Based Therapy for Bone Tissue Regeneration

“…As for the pore size, the HA-based 3D printed scaffolds with 1.4 mm and 1.2 mm pore sizes can promote bone regeneration at 4 weeks in rabbit calvarial defects while decreasing the mechanical strength, compared with those scaffolds with 0.8 mm and 1.0 mm pore sizes. However, the effect of pore size on bone regeneration was diminished as time went on to 8 weeks ( Figure 3 c) [ 35 ]. Future research is required to explore better methods to accurately determine the topography of nHA-based 3D printing scaffolds.…”

“…( b ) Radiographic analysis showed that 3D hydroxyapatite/extracellular matrix (HA/ECM) composites promoted bone regeneration in rat calvarial defects after 12 weeks [ 34 ]. ( c ) Both radiographic and histological evaluations exhibited more new bone formation for 3D printed nHA-based scaffolds with higher pore size only at 4 weeks [ 35 ]. *: p < 0.05, **: p < 0.01, ***: p < 0.001.…”