Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods. oft tissue prostheses are widely used in maxillofacial rehabilitation. Patient numbers is ever increasing due to the advancements in medicine, surgical techniques and in particular cancer survival rates 1 . However, the high fabrication cost of traditional prostheses prompted the researchers to explore alternatives to reduce the cost and time of fabrication. Three-dimensional (3D) printing or rapid prototyping (RP) is a layered manufacturing method that can be used to fabricate complex structures. It is an additive manufacturing (AM) process, fundamentally different from the conventional subtractive manufacturing processes. Using 3D printing a physical object can be fabricated from a 3D computer-aided design (CAD) model layer by layer, more conveniently and more rapidly than other manufacturing means. Additionally, it is easy to customize a product according to personal requirement, consequently a wide variety of applications of 3D printing technology in soft matter fabrication have emerged recently [2] [3] [4] [5] [6] [7] [8] . The use of 3D printing can help in the development of omnibearing biodevices 4 . Such as described in the report by Wang et al., 5 , who used hydrogel and cells to fabricate models that mimic complex soft organs in vitro with the help of 3D printing. Also, Landers et al., printed a hydrogel scaffolds using 3D plotter to attain a designed external shape and a well-defined internal pore structure 6 . Many reports also discussed the fabrication of soft tissues for implant, and scaffolds with cell-seeded hydrogel or collagen matrix for clinical application were developed [9] [10] [11] [12] . High-fidelity ears with collagen type I hydrogel scaffolds were fabricated by injection. Even following an extended period after implantation, they continue to effectively mimic the native auricle both biomechanically and histologically . To improve the mechanical properties of the fibrous collagen matrix, composite ear scaffolds with wire frameworks were used to ensure a 3D shape after implantation 11 . Mannoor, M. S., et al 12 printed bionic ears able to gather inductively-coupled signals from cochlea-shaped electrodes, demonstrating the merging capabilities of biological and nanoelectronic functionalities. However, because scaffolds or soft tissues based on tissue engineering are designed to acquire real tissues after implanting, further clinical study and a thorough ethics evaluation are still needed. Furthermore, in 2003 Cheah et al., 13,14 integrated CAD/CAM techniques for developing facial prostheses and described a complete fabrication process using the selective laser sintering (SLS) 3D printing technology. It is worth noting, they and Eggbeer et al. 15 also discussed the difference between indirect mold production via silicone rubber molding and direct mold production via RP fabrication. In addition, a template-based framework was proposed to rebuild the nasal 3D model with the data from 3D and computed tomography (CT) scans 16 . The results showed that this method had advantages over other rebuilding methods in terms of accuracy, speed, safety and cost. E. Bassoli et al., 17 reported a combined 3D printing/indirect replication method to fabricate 3D vascularlike structures of soft tissue 17 ; using the ProJetH HD 3000 3D printer from 3D Systems Inc. to print the negative mold of the vascular structure.
Additive manufacturing is also used in medical applications such as printing customised airway stents and soft prostheses [8] REF .
Fabrication of low cost soft tissue prostheses with the desktop 3D printer
Scientific Reports
Scientific Reports
Materials Science Medicine