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Purpose: Extrinsic trauma to the orbit may cause a blowout or orbital fracture, which often requires surgery for reconstruction of the orbit and repositioning of the eyeball with an implant. Post-operative complications, however, are high with the most frequent cause of complications being a mismatch of the position and shape of the implant and fracture. These mismatches may be reduced by computed tomography (CT) based modeling and three-dimensional (3D) printed guide. Therefore, the aim of this study is to propose and evaluate a patient-specific guide to shape an orbital implant using 3D printing. Design/methodology/approach: Using CT images of a patient, an orbital fracture can be modeled to design an implant guide for positioning and shaping of the surface and boundaries of the implant. The guide was manufactured using UV curable plastic at 0.032 mm resolution by a 3D printer. The accuracy of this method was evaluated by micro-CT scanning of the surgical guides and shaping implants. Findings: The length and depth of the 3D model, press-compressed and decompressed implants were compared. The mean differences in length were 0.67 ± 0.38 mm, 0.63 ± 0.28 mm and 0.10 ± 0.10 mm, and the mean differences in depth were 0.64 ± 0.37 mm, 1.22 ± 0.56 mm and 0.57 ± 0.23 mm, respectively. Statistical evaluation was performed with a Bland-Altman plot. Originality/value: This study suggests a patient-specific guide to shape an orbital implant using 3D printing and evaluate the guiding accuracy of the implant versus the planned model. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to systemically evaluate morphological printing errors between computer-aided design (CAD) and reference models fabricated using two different three-dimensional printing (3DP) technologies with hard and soft materials. Design/methodology/approach: The reference models were designed to ensure simpler and more accurate measurements than those obtained from actual kidney simulators. Three reference models, i.e. cube, dumbbell and simplified kidney, were manufactured using photopolymer jetting (PolyJet) with soft and hard materials and multi-jet printing (MJP) with hard materials. Each reference model was repeatably measured five times using digital calipers for each length. These values were compared with those obtained using CAD. Findings: The results demonstrate that the cube models with the hard material of MJP and hard and soft materials of PolyJet were smaller (p = 0.022, 0.015 and 0.057, respectively). The dumbbell model with the hard material of MJP was smaller (p = 0.029) and that with the soft material of PolyJet was larger (p = 0.020). However, the dumbbell with the hard material of PolyJet generated low errors (p = 0.065). Finally, the simplified kidney models with the hard material of MJP and soft materials of PolyJet were smaller (p = 0.093 and 0.021) and that with the hard material of PolyJet was opposite to the former models (p = 0.043). Originality/value: This study, to the best of authors' knowledge, is the first to determine the accuracy between CAD and reference models fabricated using two different 3DP technologies with multi-materials. Thus, it serves references for surgical applications as simulators and guides that require accuracy. [ABSTRACT FROM AUTHOR]