The primary goal of this study is to develop and analyze 3D printed structures based on a well-known composite known as β-Tricalcium Phosphate (TCP)– polylactic acid (PLA). There are some interesting aspects of this study. First, we developed 3D printable TCP–PLA composite filaments in-house, with high reproducibility, by a one-step process method using a single screw extruder. Second, we explored the physicochemical properties of the developed TCP–PLA composite filaments. Third, we investigated the effect of an FDM-based nozzle temperature of 190 °C, 200 °C, 210 °C, and 220 °C on the composite’s crystallinity and rheological and mechanical properties. Results confirmed the successful development of constant-diameter TCP–PLA composite filaments with a homogeneous distribution of TCP particles in the PLA matrix. We observed that a higher nozzle temperature in the FDM process increased the crystallinity of the printed PLA and TCP–PLA structures. As a result, it also helped to enhance the mechanical properties of the printed structures. The rheological studies were performed in the same temperature range used in the actual FDM process, and results showed an improvement in rheological properties at higher nozzle temperatures. The bare polymer and the composite polymer-ceramic melts exhibited lower viscosity and less rigidity at higher nozzle temperatures, which resulted in enhancing the polymer melt flowability and interlayer bonding between the printed layers. Overall, our results confirmed that 3D printable TCP–PLA filaments could be made in-house, and optimization of the nozzle temperature is essential to developing 3D printed composite parts with favorable mechanical properties.

This review paper is related to the biomechanics of additively manufactured (AM) metallic scaffolds, in particular titanium alloy Ti6Al4V scaffolds. This is because Ti6Al4V has been identified as an ideal candidate for AM metallic scaffolds. The factors that affect the scaffold technology are the design, the material used to build the scaffold, and the fabrication process. This review paper includes thus a discussion on the design of Ti6A4V scaffolds in relation to how their behavior is affected by their cell shapes and porosities. This is followed by a discussion on the post treatment and mechanical characterization including in-vitro and in-vivo biomechanical studies. A review and discussion are also presented on the ongoing efforts to develop predictive tools to derive the relationships between structure, processing, properties and performance of powder-bed additive manufacturing of metals. This is a challenge when developing process computational models because the problem involves multi-physics and is of multi-scale in nature. Advantages, limitations, and future trends in AM scaffolds are finally discussed. AM is considered at the forefront of Industry 4.0, the fourth industrial revolution. The market of scaffold technology will continue to boom because of the high demand for human tissue repair.

This study aims to explore the application of Fused Deposition Modeling (FDM) as a 3D printing technique for developing endosseous Polyetheretherketone (PEEK) dental implants. Specifically, the primary aim of the study is to systematically investigate the effects of key FDM processing parameters, including thermal conditions, print speed, layer height, build orientation, and post-processing heat treatments, on the mechanical and thermal properties of PEEK implants. By conducting an in-depth analysis, this study aims to establish optimized processing guidelines for the reliable manufacturing of high-performance, clinically viable PEEK dental implants. PEEK dental implants were fabricated using FDM with variations in thermal conditions (nozzle, bedplate, and chamber temperatures), print speed, layer height, build orientation, and post-print heat treatments. Mechanical testing (compression and fatigue), detailed thermal characterization using Differential Scanning Calorimetry (DSC), and fractographic analysis were performed. Finite Element Analysis (FEA) was also conducted to understand the implant's load-bearing performance. Nozzle temperature dictates implant resolution, while chamber temperature is a key determinant of implant crystallinity. Interestingly, for PEEK dental implants, all the FDM thermal processing conditions play a crucial role in influencing the part's thermal properties. Moreover, print speed plays an essential role in developing dimensionally accurate high-strength implants. Notably, the fractographic analysis of the failed implants revealed interesting multimodal fracture behavior specific to 3D-printed threaded implants. FEA demonstrates that the implants tend to buckle under load and break at the implant-abutment interface, consistent with experimental results. Furthermore, fatigue testing reveals that PEEK implants, fabricated at a specific build orientation with respect to the bedplate, suffice the Food and Drug Administration durability requirements. These findings underscore the clinical potential of FDM-developed PEEK as a customizable, lightweight, and durable alternative to conventional metallic implants, paving the way for next-generation patient-specific lightweight dental implant solutions.

Volumetric muscle loss (VML) is a devastating injury in which extensive skeletal muscle loss overwhelms endogenous healing. Despite their therapeutic efficacy, acellular constructs fail to provide a comprehensive set of bioactive cues required for muscle development. Notably, very few constructs provide bioelectrical cues necessary for muscle development. To address that need, this study aimed to develop a myogenic platform that provides a comprehensive set of bioactive cues, including bioelectrical cues that can be delivered wirelessly, to promote skeletal muscle development. To achieve this, we engineered a microchanneled, piezoelectric, 3D-printed platform based on a unique interpenetrating hydrogel network of gelatin methacrylate and poly(acrylic acid) that incorporates barium titanate nanoparticles. Rheological studies showed stable gel-like viscoelasticity and shear-thinning behavior of the hydrogels, indicating their suitability for extrusion-3D printing. Physicochemical characterization demonstrated the platform’s structural fidelity, precise microchannel definition, pronounced flexibility, and self-adhesiveness. While the platform’s stiffness was comparable to that of skeletal muscle, it also generated a surface potential of ∼90 mV when deformed by ultrasound (US), highlighting its piezoelectric nature and ability to harness electromechanically triggered bioelectrical cues. FE-SEM and immunofluorescence analyses revealed that microchannels and US-induced piezoelectricity from the platform can synergistically help form dense, compact, and aligned myotubes. Notably, we demonstrate that the US-induced piezoelectric platforms can promote early-stage myotube development, enhance myogenic progression, and help form mature, elongated, thick myotubes over time. Finally, we observe that the piezoelectric platforms exhibit increased FAK and MAPK activation in adherent cells over time, suggesting that these pathways can contribute to transducing electromechanical cues that promote myotube maturation. Overall, this is the first-of-its-kind comprehensive study to engineer a platform that delivers a comprehensive set of bioactive cues, specifically wirelessly delivered bioelectrical cues, resulting in a spatiotemporally bioinstructive microenvironment for skeletal muscle development. We believe this unique platform could be a promising regenerative therapy for VML.