The aim of this study is to synthesize Titania nanotubes (TNTs) on the 3D-printed Ti-6Al-4V surface and investigate the loading of antibacterial vancomycin drug dose of 200 ppm for local drug treatment application for 24 h. The antibacterial drug release from synthesized nanotubes evaluated via the chemical surface measurement and the linear fitting of Korsmeyer–Peppas model was also assessed. The TNTs were synthesized on the Ti-6Al-4V surface through the anodization process at different anodization time. The TNTs morphology was characterized using field emission scanning electron microscope (FESEM). The wettability and the chemical composition of the Ti-6Al-4V surface and the TNTs were assessed using the contact angle meter, Fourier transform infrared spectrophotometer (FTIR) and the X-ray photoelectron spectroscopy (XPS). The vancomycin of 200 ppm release behavior under controlled atmosphere was measured by the high-performance liquid chromatography (HPLC) and hence, the position for retention time at 2.5 min was ascertained. The FESEM analysis confirmed the formation of nanostructured TNTs with vertically oriented, closely packed, smooth and unperforated walls. The maximum cumulative vancomycin release of 34.7% (69.5 ppm) was recorded at 24 h. The wetting angle of both Ti-6Al-4V implant and the TNTs were found below 90 degrees. This confirmed their excellent wettability.

The aim of this study is to assess the stress distribution on the bone tissue and bone-implant interface of a customized anatomic root-analog dental implant (RAI) by means of finite element analysis (FEA) for different types of bone density. A mandibular right second premolar was selected from the CBCT database. A DICOM file was converted to an STL file to create a CAD model in FEA software. The bone boundary model was created, while bone density types I–IV were determined. Von Mises stress was measured at bone tissues and bone-implant interfaces. To validate the models, the RAI was 3D printed through a laser powder-bed fusion (L-PBF) approach. The results revealed that all RAI designs could not cause plastic deformation or fracture resulting in lower stress than the ultimate tensile stress of natural bone and implant. Compared to a conventional screw-type implant, RAIs possess a more favorable stress distribution pattern around the bone tissue and the bone-implant interface. The presence of a porous structure was found to reduce the stress at cancellous bone in type IV bone density.

Background: Midshaft clavicular fractures are common fractures and generally treated conservatively. Among the surgical options, plate fixation is the most popular and has been biomechanically and clinically proven in numerous studies. However, implant failures caused by plate deformations or breakage still occur in up to 16.7% of cases, and recent studies showed that screw holes above fracture zone (SHFZ) might be the at-risk location. Using finite element analysis, this study aimed to test the biomechanical property of the superior clavicle locking plate (SCLP) with and without SHFZ in comminuted midshaft clavicular fracture. Methods: Finite element models of comminuted midshaft clavicular fracture fixed with standard 8-hole titanium SCLP with screw holes (SHFZ plate) and without screw holes above fracture zone (No-SHFZ plate) were built. Both groups were tested under three different loading models (100-N cantilever bending, 100-N axial compression, and 1-Nm torsion). The average peak stress on medial clavicle, fracture zone, and lateral clavicle, and the peak stress on each screw hole (or the same position in the No-SHFZ plate) were measured and compared. Results: The highest average peak stress on the fracture zone was higher than those on medial and lateral clavicles under all loading conditions in both plates. However, the No-SHFZ plate significantly reduced the average peak stress value on the fracture zone, compared to the SHFZ plate (45.0% reduction in cantilever bending, 52.2% reduction in axial compression, and 54.9% reduction in axial torsion). The peak stress value on the maximal stress point in the SHFZ and No-SHFZ plates with cantilever bending, axial compression, and torsion loads were 1257.10 MPa vs. 647.21 MPa, 186.42 MPa vs. 131.63 MPa, and 111.86 MPa vs. 82.41 MPa, respectively. Conclusion: The weakest link of the SCLP construct in comminuted midshaft clavicular fracture fixation is the SHFZ, especially in the cantilever bending load. Additionally, the biomechanical property of the SCLP without SHFZ model (No-SHFZ plate) is superior to the standard SCLP model (SHFZ plate), with a significantly lower peak stress on the SHFZ location in all loading conditions. We recommend a new SCLP design with SHFZ to prevent implant failure and improve surgical outcomes.

This study aims to evaluate the mechanical performance of custom 3D-printed titanium plates in the treatment of distal humerus fractures. Rigidity of four plating configurations were investigated by finite element analysis. The results reveal that implementation of custom designs with minimal screw holes, lateral-medial linking screw and lateral brim could significantly improve stiffness and consequently leads to better biomechanical stability as compared to standard osteosynthesis design. Biomechanical testing was also performed to validate practical usability. The results confirm that newly designed custom plates fabricated by selective laser melting is a possible alternative for the treatment of distal humerus fracture.