TY - JOUR

T1 - Design of Reliable Remobilisation Finger Implants with Geometry Elements of a Triple Periodic Minimal Surface Structure via Additive Manufacturing of Silicon Nitride

AU - Koplin, Christof

AU - Schwarzer-Fischer, Eric

AU - Zschippang, Eveline

AU - Löw, Yannick M.

AU - Czekalla, Martin

AU - Seibel, Arthur

AU - Rörich, Anna

AU - Georgii, Joachim

AU - Güttler, Felix

AU - Yarar-Schlickewei, Sinef

AU - Kailer, Andreas

N1 - This research received no external funding. The project FingerKit is an internal project of the Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.

PY - 2023/3/18

Y1 - 2023/3/18

N2 - When finger joints become immobile due to an accident during sports or a widespread disease such as rheumatoid arthritis, customised finger joint implants are to be created. In an automated process chain, implants will be produced from ceramic or metallic materials. Artificial intelligence-supported software is used to calculate three-dimensional models of the finger bones from two-dimensional X-ray images. Then, the individual implant design is derived from the finger model and 3D printed. The 3D printing process and the structures used are evaluated via model tests and the final implant design via a reliability calculation in a way to ensure that this is also possible via an AI process in the future. Using additive manufacturing with silicon nitride-based ceramics, model specimens and implants are produced via the lithography-based ceramic vat photopolymerisation process with full geometry or elements of triple periodic minimal surfaces structure. The model specimens are tested experimentally, and the loads are matched with a characteristic strength assuming a Weibull distribution of defects in the volume to generate and match failure probabilities. Calculated fracture forces of the silicon nitride-based ceramic structure was validated by comparison of simulation and tests, and the calculation can be used as a quality index for training of artificial intelligence in the future. The proposed method for individualized finger implant design and manufacturing may allow for correction of potential malpositions of the fingers in the future.

AB - When finger joints become immobile due to an accident during sports or a widespread disease such as rheumatoid arthritis, customised finger joint implants are to be created. In an automated process chain, implants will be produced from ceramic or metallic materials. Artificial intelligence-supported software is used to calculate three-dimensional models of the finger bones from two-dimensional X-ray images. Then, the individual implant design is derived from the finger model and 3D printed. The 3D printing process and the structures used are evaluated via model tests and the final implant design via a reliability calculation in a way to ensure that this is also possible via an AI process in the future. Using additive manufacturing with silicon nitride-based ceramics, model specimens and implants are produced via the lithography-based ceramic vat photopolymerisation process with full geometry or elements of triple periodic minimal surfaces structure. The model specimens are tested experimentally, and the loads are matched with a characteristic strength assuming a Weibull distribution of defects in the volume to generate and match failure probabilities. Calculated fracture forces of the silicon nitride-based ceramic structure was validated by comparison of simulation and tests, and the calculation can be used as a quality index for training of artificial intelligence in the future. The proposed method for individualized finger implant design and manufacturing may allow for correction of potential malpositions of the fingers in the future.

KW - remobilisation

KW - additive manufacturing

KW - reliability

KW - AI-based

KW - reconstruction

KW - joint-implant

KW - crack-growth

KW - autogeneration

KW - Engineering

U2 - 10.3390/j6010014

DO - 10.3390/j6010014

M3 - Journal articles

VL - 6

SP - 180

EP - 197

JO - J - Multidisciplinary Scientific Journal

JF - J - Multidisciplinary Scientific Journal

SN - 2571-8800

IS - 1

ER -