Dimension elite

When printing the gear models, a Stratasys Dimension Elite thermoplastic printer (Stratasys, Ltd., MN) was used in this study. This printer, shown in Figure 9, has an enclosed heated environment with an 8 × 8 × 12 build volume, which allows it to use ABS thermoplastic. The machine has the precision to print layers between 0.007 in. and 0.01 in. thick. Each part was printed from red ABS thermoplastic at approximately a 20 to 30 percent infill density with layers of approximately 0.01 in. thickness. The plastic was extruded at a temperature between 260 and 280 degrees Celsius, while the temperature of the build chamber was maintained at approximately 75 degrees Celsius. The print speed was 0.000173 cubic in./sec., and the total time of print was 5 : 30 hours for the gear and support structure.

The portable turbidimeter was developed using a smartphone (Nokia Lumia 1020) and a custom-made opto-mechanical attachment coupled to the rear camera of the smartphone (Fig. 1a). This attachment unit consists of two white LEDs, two coin-size batteries (Product No. B008XBL34A, Amazon), an external lens (Product No. 63–471, Edmund Optics), paper diffusers (Product No. SG 3201, Sphere Optics, Herrsching, Germany), and optical fibers (Product No. ESKA CK-30, Mitsubishi Chemical Corporation, Japan) (Fig. 1b). The LEDs are placed on top of the disposable cuvette (Product No. 60965D-1, Lab Genome, (Houston, TX, USA)). There are four optical fibers (i.e., the transmittance fibers) that are integrated into the unit at the bottom of the sample to capture the transmittance of light and another four optical fibers (i.e. the nephelometric fibers) on the sides of the sample to capture the side-scattered light (Fig. 1c). These fibers are bundled at the other end, facing the external lens of the attachment unit.
The opto-mechanical attachment unit was designed using Autodesk Inventor software and printed using a 3D printer (Stratasys, Dimension Elite). The printed parts were assembled and integrated with the optical components to have the final design (Fig. 1).

The Oli-Up System was engineered as a reusable system, avoiding the necessity for component replacement. Individual components were crafted utilizing commercial CAD software (Solid Edge 2023, Siemens PLM Software, Plano, TX, USA). Initial design prototypes were fabricated employing an FDM-3D Printer (Dimension Elite, Stratasys, Rechovot, Israel). Following a comprehensive reassessment of dimensions and configurations, *.dxf files were generated for CNC-cutting, with subsequent preparation of G-Code facilitated through VCarve Pro (Vectric Ltd, Alcester, UK). This G-Code was subsequently utilized for the precise cutting of molding blanks composed of PEEK (GM GmbH, Munich, Germany) on a CNC machine (PFK 1607 PX, BZT Maschinenbau GmbH, Leopoldshöhe, Germany).

For the tests, a 3D-printed replica of human facial anatomy (“maxillofacial phantom”) was designed and produced. Starting from real computed tomography datasets, the cranial, maxillary and mandibular bones were extracted with a semiautomatic segmentation pipeline [34 (link)] and a complete 3D virtual model of the skull was obtained (Figure 2). From the virtual model, a tangible phantom made of acrylonitrile butadiene styrene (ABS) was produced via 3D printing (3D printer Dimension Elite, Stratasys, Eden Prairie, MN, United States). The primary muscles of mastication (i.e., temporalis, medial pterygoid, lateral pterygoid and masseter) were added to the skull virtual model using Blender software, together with facial soft tissues (soft palate, tongue, gums), functional to the realistic simulation of the surgical procedure (Figure 2). To obtain the physical replicas of the muscles and soft tissues, ad hoc molds were designed, and 3D printed, then silicone casting was made using these molds. Finally, to achieve further realism, and to help keep the jaws in position, facial skin was also designed and produced using the silicone casting technique described above (Figure 2). The resulting maxillofacial phantom is depicted in Figure 3.