The treatment of maxillofacial defects presents significant challenges due to the complexity of facial anatomy and the diversity of affected tissues. Traditional workflows are labor-intensive, costly, and limited in customization. Recent advancements in fully digital workflows and direct 3D printing technologies offer new possibilities for improving the fit, aesthetics, and efficiency of prosthetic manufacturing. This scoping review aims to evaluate the current state of direct 3D printing for maxillofacial soft prostheses, assess material properties and biocompatibility, and identify challenges and future directions in this field. Methods: A comprehensive search of PubMed and Scopus databases, along with a manual search of relevant journals, was conducted to identify studies published up to December 2024. Articles focusing on direct 3D printing of maxillofacial soft prostheses were included, while studies involving traditional or mold-based workflows, ocular prostheses, and literature reviews were excluded. Data on materials, manufacturing techniques, and clinical outcomes were extracted and analyzed. Results: Out of 898 articles screened, 11 were included, 5 of which were in vivo studies (case reports). The additive manufacturing methods used in these case reports were Drop-on-Demand (DoD) silicone printing and PolyJet technology. Conclusions: Fully digital workflows and direct 3D printing technologies show promise for advancing maxillofacial prosthesis manufacturing. However, the absence of dedicated software, biocompatible materials, and medium- to long-term clinical evaluations highlight significant research gaps. Future research should focus on material development, workflow optimization, and clinical validation to enable widespread clinical adoption.

This study introduces a novel titanium hollow structure for mandibular reconstruction designed to optimize mechanical stability and stress distribution. A comparative evaluation with a similar polyetheretherketone (PEEK) structure is performed to assess material-specific biomechanical behavior. Methods: Finite element analysis (FEA) simulations were conducted to evaluate stress distribution, displacement, and structural stability of the symmetrical titanium and PEEK hollow structures under physiological conditions. The reconstructions were designed based on Scherk minimal surfaces, integrating fixing plates to achieve optimal mechanical performance while maintaining symmetry. Results: The FEA simulations demonstrated that the titanium hollow structure exhibited higher mechanical stability, lower displacement, and more uniform stress distribution, ensuring structural integrity under applied forces. In contrast, the PEEK structure displayed greater flexibility, which reduced stress shielding but resulted in higher deformation and lower load-bearing capacity. While titanium inherently supports osseointegration, PEEK requires surface modifications to enhance bone integration and long-term stability. Conclusions: The titanium hollow structure presents a promising advancement in metal-based mandibular reconstruction, effectively balancing strength, durability, and biological integration. Future research should focus on using more structures, enhancing surface modifications and optimizing lattice structures to further improve the biological and biomechanical performance of PEEK-based and titanium-based implants in load-bearing conditions.

This study introduces a novel titanium hollow structure for mandibular reconstruction, designed to optimize mechanical stability and stress distribution. A comparative evaluation with a similar polyetheretherketone (PEEK) structure is performed to assess material-specific biomechanical behavior; Methods: Finite element analysis (FEA) simulations were conducted to evaluate stress distribution, displacement, and structural stability of the symmetrical titanium and PEEK hollow structures under physiological conditions. The reconstructions were designed based on Scherk minimal surfaces, integrating fixing plates to achieve optimal mechanical performance while maintaining symmetry; Results: The titanium structure exhibited superior mechanical stability and more efficient stress distribution, ensuring structural integrity under applied forces. Conversely, PEEK demonstrated greater flexibility, reducing stress shielding but showing limitations under higher loading conditions. While titanium inherently supports osseointegration, PEEK requires surface modifications to enhance bone integration and long-term stability; Conclusions: The titanium hollow structure presents a promising advancement in metal-based mandibular reconstruction, effectively balancing strength, durability, and biological integration. Future research should focus on using more structures, enhancing surface modifications and optimizing lattice structures to further improve the biological and biomechanical performance of PEEK-based and titanium-based implants in load-bearing conditions.

Polyetheretherketone (PEEK) is increasingly attractive for patient-specific maxillofacial reconstruction because its elastic modulus approximates cortical bone, it is fully radiolucent, and it is compatible with additive manufacturing; its principal limitation is bioinertness, as the hydrophobic surface does not support protein adsorption or direct bone apposition. This study aimed to functionalize the surface of fused-deposition-modeling (FDM)-printed, medical-grade PEEK to increase its potential for bioactivity while preserving these bulk advantages. To this end, 3D-printed specimens of implant-grade PEEK were activated by CO₂ plasma and coated with gelatin methacryloyl (GelMA) via EDC/NHS coupling followed by UV photocrosslinking. Surfaces were characterized by attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, sessile-drop water contact angle measurement, gravimetric analysis, and scanning electron microscopy (SEM). Plasma treatment introduced oxygen-containing functional groups and reduced the water contact angle from 78.3° to 6.6°. GelMA deposition following EDC/NHS coupling, consistent with covalent immobilization, was supported by characteristic amide bands and was most pronounced for the 50 mg/mL formulation, corresponding to a deposited mass of 11.81 ± 0.47 μg/mm²; SEM revealed a relatively uniform protein film along the printed filaments. These results establish a surface-functionalization route and provide preliminary physicochemical indicators of potential bioactivity for patient-specific PEEK implants, to be confirmed through in vitro and in vivo biological validation.

Polyetheretherketone (PEEK) is increasingly attractive for patient-specific maxillofacial reconstruction because its elastic modulus approximates cortical bone, it is fully radiolucent, and it is compatible with additive manufacturing; its principal limitation is bioinertness, as the hydrophobic surface does not support protein adsorption or direct bone apposition. This study aimed to render the surface of fused-deposition-modelling (FDM)-printed, medical-grade PEEK bioactive while preserving these bulk advantages. To this aim, 3D printed specimens of implant-grade PEEK were activated by CO₂ plasma and coated with gelatin methacryloyl (GelMA) via EDC/NHS coupling followed by UV photocrosslinking. Surfaces were characterized by attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, sessile-drop water contact angle measurement, gravimetric analysis, and scanning electron microscopy (SEM). Plasma treatment introduced oxygen-containing functional groups and reduced the water contact angle from 78.3° to 6.6°. Covalent GelMA grafting was confirmed by characteristic amide bands, was most pronounced for the 50 mg/mL formulation, and corresponded to a deposited mass of 11.81 ± 0.47 µg/mm²; SEM revealed a relatively uniform protein film along the printed filaments. These results establish a reproducible route toward bioactive, patient-specific PEEK maxillofacial implants.