3D-Printed Metal-Polymer Multiphase Implant for Mandibular Reconstruction

Abstract

<p><strong>Objectives</strong>: Repair of large-volume segmental bone defects is clinically challenging due to the specific biomechanical, biocompatible, and esthetic requirements. This study aims to develop a 3D printable, photosensitive, high-strength resin-based composite, create a robust bond with a 3D printed Ti alloy plate through surface modifications, and ultimately integrate these methodologies to produce personalized oral maxillofacial prostheses.<br><strong>Methods</strong>: (1) To optimize resin composite strength, five different formulations are tested. (2) To enhance the bond between Ti alloy (Ti-6Al-4V) and composite resin, SLS (selective laser sintering) 3D metal-printed Ti alloy plates accept surface modifications, including sandblasting, chemical etching (acid etching and alkaline heating), Al₂O₃ ALD coating (~10 nm thickness), and silane coupling agent coating. Interfacial shear strength (IFSS) between Ti alloy and polymer composite, with and without Al₂O₃ coating, is evaluated, and SEM images capture the surface changes. (3) Different layers (0, 2, 4) of surface-modified Ti alloy plates are incorporated into SLA composite fabrication. Compressive and diametral strength of standard cylinder metal-composite specimens are evaluated. (4) The finite elements analysis is used to verify the consistency of simulated and experiment results in the cylinder model first. Then establish mandible anatomical structure to simulate the stress distribution of the mandible implant.<br><strong>Results</strong>: The ideal resin formulation, offering both mechanical and biocompatible properties, consisted of 80 wt% methacrylate monomers and 20 wt% nano-fillers (nano-hydroxyapatites and nano-silica particulates). IFSS values increased by up to 50% with Al₂O₃ coating compared to without the coating, and a more irregular and rough morphology is observed on Al₂O₃ coated Ti alloy. The FEA results are consistent with experiment results and the personalized mandible implant can be optimized.<br><strong>Conclusions</strong>: This study provides a novel 3D-printed multiphase bone implant with excellent mechanical strength, anatomical precision, and biocompatibility, making it ideal for oral and maxillofacial reconstruction in load-bearing areas.<br></p>