Journal Article

Finite Element Simulation and Additive Manufacturing of Stiffness-Matched NiTi Fixation Hardware for Mandibular Reconstruction Surgery

Amerinatanzi, Amirhesam, Jahadakbar, Ahmadreza, Karaca, Haluk, Dean, David, Shayesteh Moghaddam, Narges, Elahinia, Mohammad

2016

Overview

Process parameters and post-processing heat treatment techniques have been developed to produce both shape memory and superelastic NiTi using Additive Manufacturing. By introducing engineered porosity, the stiffness of NiTi can be tuned to the level closely matching cortical bone. Using additively manufactured porous superelastic NiTi, we have proposed the use of patient-specific, stiffness-matched fixation hardware, for mandible skeletal reconstructive surgery. Currently, Ti-6Al-4V is the most commonly used material for skeletal fixation devices. Although this material offers more than sufficient strength for immobilization during the bone healing process, the high stiffness of Ti-6Al-4V implants can cause stress shielding. In this paper, we present a study of mandibular reconstruction that uses a dry cadaver mandible to validate our geometric and biomechanical design and fabrication (i.e., 3D printing) of NiTi skeletal fixation hardware. Based on the reference-dried mandible, we have developed a Finite Element model to evaluate the performance of the proposed fixation. Our results show a closer-to-normal stress distribution and an enhanced contact pressure at the bone graft interface than would be in the case with Ti-6Al-4V off-the-shelf fixation hardware. The porous fixation plates used in this study were fabricated by selective laser melting.

• Publisher: MDPI AG,MDPI
• Subject: 3-D printers / Additive manufacturing / additive manufacturing (AM) / Alloys / Biocompatibility / Bioengineering / Biomechanical engineering / Biomechanics / Bone density / Bone grafts / Bone healing / Bone implants / CAD / Computer aided design / Computer simulation / Contact pressure / Contact stresses / Cortical bone / finite element analysis / Finite element method / Fixation / Grafting / Hardware / Heat treatment / Immobilization / Intermetallic compounds / Laser beam melting / Laser sintering / Mandible / mandibular reconstructive surgery / Mathematical models / Medical equipment / Medical imaging / Nickel titanides / Plastic surgery / Porosity / Post-production processing / Rapid prototyping / Reconstruction / Reconstructive surgery / Shape memory alloys / Software / Stiffness / stiffness matching / Stress concentration / Stress distribution / superelastic NiTi / Surgery / Surgical implants / Titanium base alloys / Titanium compounds / Transplants & implants