Repair and regeneration of large bone defects is still a challenge, especially for defects which are the irregular and complex. Three-dimension (3D) printing, as an advanced fabrication technology, has been received considerable attentions due to its high precision, customized geometry and personalization. In this study, 3D porous polylactic acid/nano hydroxyapatite (PLA/nHA) composite scaffolds with enhanced osteogenesis and osteoconductivity were successfully fabricated by desktop fused deposition modeling technology. Morphological, composition and structural analysis revealed that nHA was successfully introduced into the PLA system and homogeneously dispersed in the printed PLA/nHA scaffolds. In vitro antibacterial experiment confirmed that the printed porous PLA/nHA scaffolds have good ability for loading and releasing vancomycin and levofloxacin. Meanwhile, MG-63 cells were used to evaluate the cytocompatibility of printed porous PLA/nHA scaffolds by proliferation and cellular morphological analysis. In addition, rabbit model was established to evaluate the osteogenesis and osteoconductivity of printed PLA/nHA scaffolds. All these results suggested that the 3D printed PLA/nHA scaffolds have great potential for repairing and regeneration of large bone defects.

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In recent years, the rapid development of 3D printing technologies lead to its new applications in the area of healthcare and medicine, including dentistry, orthopedics, cardiovascular, pharmaceutics, neurosurgery, engineered tissue models, medical devices, and anatomical models. Dentistry is widely acknowledged to benefit from 3D printing technologies due to its needs for the customization and personalization of dental products. In this review, the authors discuss and summarize various 3D imaging technologies and the recent advances of 3D digital processing techniques in dentistry in an effort to give a new perspective and greater understanding of the current development of 3D printing technologies in dentistry. It is anticipated that this review will explore why 3D printing is important to dentistry, and why dentistry motivates development in 3D printing applications. Further, current challenges and further perspectives are also discussed which helps researchers to optimize the 3D printing technology in dentistry, improve 3D printing strategies, and direct future dental bioprinting and translational applications.

Organic-inorganic hybrid materials, composed of phases that interact on a nanoscale and a microstructure that mimics the extracellular matrix, can potentially provide attractive scaffolds for bone regeneration. In the present study, hybrid scaffolds of gelatin and bioactive glass (BG) with a fibrous microstructure were prepared by a combined sol-gel and electrospinning technique and evaluated in vitro. Structural and chemical analyses showed that the fibers consisted of gelatin and BG that were covalently linked by 3-glycidoxypropyltrimethoxysilane to form a homogeneous phase. Immersion of the gelatin-BG hybrid scaffolds in a simulated body fluid (SBF) at 37 C resulted in the formation of a hydroxyapatite (HA)-like material on the surface of the fibers within 12 h, showing the bioactivity of the scaffolds. After 5 days in SBF, the surface of the hybrid scaffolds was completely covered with an HA-like layer. The gelatin-BG hybrid scaffolds had a tensile strength of 4.3 6 1.2 MPa and an elongation to failure of 168 6 14%, compared to values of 0.5 6 0.2 MPa and 63 6 2% for gelatin scaffolds with a similar microstructure. The hybrid scaffolds supported the proliferation of osteoblastic MC3T3-E1 cells, alkaline phosphatase activity, and mineralization during in vitro culture, showing their biocompatibility. The results indicate that these gelatin-BG hybrid scaffolds prepared by a combination of sol-gel processing and electrospinning have potential for application in bone regeneration.

3D printing is an additive manufacturing (AM) technology that has developed rapidly in the past decades due to its advantages, such as freedom of design, mass customization, waste minimization, and the ability to manufacture complex structures, as well as fast prototyping. Various materials are used in 3D printing, including metals, polymers, ceramics, concrete, and their composites. The polymer's easy processing makes it stands out among many materials. As a thermoplastic polymer, polylactic acid (PLA) received more attention as an effective biomedical material due to its proven biodegradation and biocompatibility. Herein, the development of 3D-printing technology is summarized and various applications of 3D-printed PLA and their composites in orthopedics are introduced. Furthermore, the current limitations and future opportunities in 3D printing are also discussed to help guide the 3D-printing development and improve 3D-printing strategies in orthopedic.