Mechanobiological Evaluation of 3D-Printed Lightweight High-Strength Mandibular Implants

Abstract

<p><strong>Objectives</strong>: The advancement of lightweight, high-strength biomedical implants is crucial for applications in maxillofacial reconstruction. Traditional implants frequently encounter challenges related to mechanical strength mismatches and inadequate shape precision. This study aims to develop a 3D-printed, metal-embedded resin composite implant that is customized to meet individual patient anatomy and strength requirements. By addressing these issues, the proposed solution seeks to fulfill the clinical demands of personalized patient care in dental reconstructive procedures.<br><strong>Methods</strong>: A new resin composite was synthesized and reinforced with titanium alloy (Ti-6Al-4V) plates, which underwent surface modifications, including sandblasting, acid etching, alkaline heating, and Al2O3 atomic layer deposition (ALD). Mechanical tests were conducted to evaluate the performance of the implants. Interfacial shear strength (IFSS) tests were performed to assess the bonding strength between the resin and both treated or untreated metal surfaces. Additionally, compressive and diametral tensile strength tests were carried out on cylindrical specimens reinforced with varying layers of metal (0, 1, 2, and 3 layers) to investigate the effects of multi-layer reinforcement. Finally, a standard mandibular model with a segmental defect was employed to compare the mechanical performance of two-layer metal-embedded specimens with that of resin-only implants.<br><strong>Results</strong>: Surface-treated metal plates exhibited a significant enhancement in interfacial bonding, with Al2O3 ALD-coated samples showing up to a 94% increase in IFSS compared to untreated metal plates. Cylindrical specimens with embedded metal layers displayed improved compressive strength and modulus, with mechanical performance correlating positively with the number of embedded layers. In the mandibular defect model, the two-layer metal-embedded implant outperformed the resin-only implant, offering superior load-bearing capacity and structural durability.<br><strong>Conclusions</strong>: The integration of surface-treated metal layers into resin composites significantly enhances their mechanical properties, presenting a promising strategy for the development of patient-specific implants. This advancement has the potential to improve clinical outcomes in maxillofacial reconstruction.</p>