title: Simple additive manufacturing of an osteoconductive ceramic using suspension melt extrusion.
abstract: Craniofacial bone trauma is a leading reason for surgery at most hospitals. Large pieces of destroyed or resected bone are often replaced with non-resorbable and stock implants, and these are associated with a variety of problems. This paper explores the use of a novel fatty acid/calcium phosphate suspension melt for simple additive manufacturing of ceramic tricalcium phosphate implants.
  
  
  
  A wide variety of non-aqueous liquids were tested to determine the formulation of a storable 3D printable tricalcium phosphate suspension ink, and only fatty acid-based inks were found to work. A heated stearic acid-tricalcium phosphate suspension melt was then 3D printed, carbonized and sintered, yielding implants with controllable macroporosities. Their microstructure, compressive strength and chemical purity were analyzed with electron microscopy, mechanical testing and Raman spectroscopy, respectively. Mesenchymal stem cell culture was used to assess their osteoconductivity as defined by collagen deposition, alkaline phosphatase secretion and de-novo mineralization.
  
  
  
  After a rapid sintering process, the implants retained their pre-sintering shape with open pores. They possessed clinically relevant mechanical strength and were chemically pure. They supported adhesion of mesenchymal stem cells, and these were able to deposit collagen onto the implants, secrete alkaline phosphatase and further mineralize the ceramic.
  
  
  
  The tricalcium phosphate/fatty acid ink described here and its 3D printing may be sufficiently simple and effective to enable rapid, on-demand and in-hospital fabrication of individualized ceramic implants that allow clinicians to use them for treatment of bone trauma.
authors.affiliation: The Maersk Mc-Kinney Moller Institute, Faculty of Engineering, University of Southern Denmark, Campusvej 55, DK-5000 Odense M, Denmark. Electronic address: caslo07@student.sdu.dk.
authors.forename: Casper
authors.initials: C
authors.lastname: Slots
authors.affiliation: The Maersk Mc-Kinney Moller Institute, Faculty of Engineering, University of Southern Denmark, Campusvej 55, DK-5000 Odense M, Denmark. Electronic address: maje211@student.sdu.dk.
authors.forename: Martin Bonde
authors.initials: MB
authors.lastname: Jensen
authors.affiliation: Department of Endocrinology and Metabolism, Molecular Endocrinology Laboratory (KMEB), Odense University Hospital, University of Southern Denmark, Winsløwparken 25.1, DK-5000 Odense C, Denmark. Electronic address: nditzel@health.sdu.dk.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Ditzel
authors.affiliation: Department of Chemical Engineering, Biotechnology and Environmental Technology, Faculty of Engineering, University of Southern Denmark, Campusvej 55, DK-5000 Odense M, Denmark. Electronic address: marhe@kbm.sdu.dk.
authors.forename: Martin A B
authors.initials: MA
authors.lastname: Hedegaard
authors.affiliation: Department of Technology and Innovation, Faculty of Engineering, University of Southern Denmark, Campusvej 55, DK-5000 Odense M, Denmark. Electronic address: borg@iti.sdu.dk.
authors.forename: Søren Wiatr
authors.initials: SW
authors.lastname: Borg
authors.affiliation: The Maersk Mc-Kinney Moller Institute, Faculty of Engineering, University of Southern Denmark, Campusvej 55, DK-5000 Odense M, Denmark. Electronic address: oal@mmmi.sdu.dk.
authors.forename: Ole
authors.initials: O
authors.lastname: Albrektsen
authors.affiliation: Department of Oral and Maxillofacial Surgery, Odense University Hospital, University of Southern Denmark, Sdr. Boulevard 29, DK-5000 Odense C, Denmark. Electronic address: torben.thygesen@rsyd.dk.
authors.forename: Torben
authors.initials: T
authors.lastname: Thygesen
authors.affiliation: Department of Endocrinology and Metabolism, Molecular Endocrinology Laboratory (KMEB), Odense University Hospital, University of Southern Denmark, Winsløwparken 25.1, DK-5000 Odense C, Denmark. Electronic address: mkassem@health.sdu.dk.
authors.forename: Moustapha
authors.initials: M
authors.lastname: Kassem
authors.affiliation: The Maersk Mc-Kinney Moller Institute, Faculty of Engineering, University of Southern Denmark, Campusvej 55, DK-5000 Odense M, Denmark; Department of Chemical Engineering, Biotechnology and Environmental Technology, Faculty of Engineering, University of Southern Denmark, Campusvej 55, DK-5000 Odense M, Denmark. Electronic address: moan@kbm.sdu.dk.
authors.forename: Morten Østergaard
authors.initials: MØ
authors.lastname: Andersen
mesh_terms: D001861:Bone Regeneration; D001842:Bone and Bones; D002130:Calcium Phosphates; D002516:Ceramics; D019245:Compressive Strength; D003776:Dental Porcelain; D059630:Mesenchymal Stem Cells
chemical_list: D002130:Calcium Phosphates; D003776:Dental Porcelain
keywords: 3D printing; Additive manufacturing; Bone implant; Ceramic; Implant; Tricalcium phosphate