Shape Accuracy and Surface Quality of Additively Manufactured, Optimized, Patient-Specific Bone Plates

Abstract

Powder-based additive manufacturing technologies such as powder bed fusion (PBF) using a laser beam (PBF-LB) and PBF using an electron beam (PBF-EB) allow the manufacturing of complex, patient-specific implants from titanium alloys at appropriate manufacturing expenses and thus production cost. To meet medical quality requirements, mechanical post-treatment (e.g., grinding and polishing) is often required. However, different medical applications require specific quality characteristics. It is therefore necessary to assess the fulfillment of the requirements for each case individually with regard to the manufacturing technologies. This study investigated the potential of the two mentioned additive manufacturing technologies for manufacturing patient-specific, topology-optimized bone plates that are used for osteosynthesis (the joining of bone segments) in the reconstruction of the mandible (lower jaw). Identical individualized implants were manufactured and subsequently treated with established industrial processes and examined according to medical quality requirements. Crucial quality requirements for this medical application are the shape accuracy (for exact bone positioning and even load transmission) as well as the surface quality (to enhance fatigue strength and prevent bone ingrowth in view of the subsequent easy removal of the plates). The machining of the implants is shown in comparison to distinguish the two manufacturing processes from established procedures.