OBJECTIVES: This study aims to analyze the biomechanics of three kinds of rigid internal fixation methods for condylar head fractures. METHODS: A three dimensional finite element model of the normal mandible was constructed. It was then used to prepare condylar head fracture finite element model and three kinds of rigid internal fixation finite element model (unilateral tension screw, bilateral tension screw, tension screw+titanium plate). The mechanical characteristics and changes of the mandible condyle under the same mechanical conditions were compared among the three different rigid internal fixation methods. RESULTS: The maximum equivalent stress and displacement of the non-free end of condyle under the rigid internal fixation method of unilateral tension screw were 71.03 MPa and 4.72 mm, respectively. The maximum equivalent stress and displacement of the free end of condyle were 78.45 MPa and 4.50 mm, respectively. The maximum stress of fracture suture was 3.27 MPa. The maximum equivalent stress and displacement of the non-free end of condyle under the rigid internal fixation method of bilateral tension screw were 70.52 MPa and 4.00 mm, respectively. The maximum equivalent stress and displacement of the free end of condyle were 72.49 MPa and 3.85 mm, respectively. The maximum stress of fracture suture was 2.33 MPa. The maximum equivalent stress and maximum displacement of the non-free end of condyle under the rigid internal fixation method of tension screw+titanium plate were 67.26 MPa and 2.66 mm, respectively. The maximum equivalent stress and maximum displacement of the free end of condyle were 69.66 MPa and 2.50 mm, respectively. The maximum stress of fracture suture was 2.18 MPa. CONCLUSIONS The tension screw+titanium plate rigid internal fixation method is the most conducive to biomechanical distribution for condylar head fractures.
Fracture Fixation, Internal/instrumentation* ; Mandibular Condyle/surgery* ; Biomechanical Phenomena ; Bone Screws ; Finite Element Analysis ; Humans ; Mandibular Fractures/surgery* ; Bone Plates ; Titanium ; Stress, Mechanical

OBJECTIVES: This study aimed to compare the osteogenic performance differences of titanium surface coatings modified by dopamine or silanized graphene oxide, and to provide a more suitable modification scheme for titanium surface graphene oxide coatings. METHODS: Titanium was subjected to alkali-heat treatment and then modified with dopamine and silanization, respectively, followed by coating with graphene oxide. Control and experimental groups were designed as follows: pure titanium (Ti) group; titanium after alkali-heat treatment (Ti-NaOH) group; titanium after alkali-heat treatment and silanization modification (Ti-APTES) group; titanium after alkali-heat treatment and dopamine modification (Ti-DOPA) group; titanium with silanization-modified surface decorated with graphene oxide (Ti-APTES/GO) group; titanium with dopamine-modified surface decorated with graphene oxide (Ti-DOPA/GO) group. The physical and chemical properties of the material surfaces were analyzed using scanning electron microscopy (SEM), contact angle goniometer, X-ray photoelectron spectroscopy (XPS), and Raman spectrometer. The proliferation and adhesion morphology of mouse embryonic osteoblast precursor cells MC3T3-E1 on the material surfaces were observed by cell viability detection and immunofluorescence staining followed by laser confocal microscopy. The effects on the osteogenic differentiation of MC3T3-E1 cells were studied by alkaline phosphatase (ALP) staining, alizarin red staining and quantification, and real-time quantitative polymerase chain reaction. RESULTS: After modification with graphene oxide coating, a thin-film-like structure was observed on the surface under SEM. The hydrophilicity of all experimental groups was improved, among which the Ti-DOPA/GO group had the best hydrophilicity. XPS and Raman spectroscopy analysis showed that the modified materials exhibited typical D and G peaks, and XPS revealed the presence of a large number of oxygen-containing functional groups on the surface. CCK8 assay showed that all groups of materials had no cytotoxicity, and the proliferation level of the Ti-APTES/GO group was higher than that of the Ti-DOPA/GO group. Under the laser confocal microscope, the cells in the Ti-DOPA/GO and Ti-APTES/GO groups spread more fully. The Ti-DOPA/GO and Ti-APTES/GO groups had the deepest ALP staining, and the Ti-APTES/GO group had the most alizarin red-stained mineralized nodules and the highest quantitative result of alizarin red staining. In the Ti-DOPA/GO and Ti-APTES/GO groups, the expression of the early osteogenic-related gene RUNX2 reached a relatively high level, while in the expression of the late osteogenic-related genes OPN and OCN, the Ti-APTES/GO group performed better than the Ti-DOPA/GO group. CONCLUSIONS Ti-APTES/GO significantly outperformed Ti-DOPA/GO in promoting the adhesion, proliferation, and in vitro osteogenic differentiation of MC3T3-E1 cells.
Titanium/chemistry* ; Graphite/chemistry* ; Dopamine/chemistry* ; Animals ; Mice ; Osteogenesis ; Osteoblasts/cytology* ; Surface Properties ; Cell Proliferation ; Silanes/chemistry* ; Cell Adhesion ; Coated Materials, Biocompatible/chemistry* ; Cell Differentiation ; Alkaline Phosphatase/metabolism* ; Microscopy, Electron, Scanning

OBJECTIVES: To evaluate the osteogenic efficacy of three-dimensional printing individualized titanium mesh (3D-PITM) as a scaffold material in guided bone regeneration (GBR). METHODS: 1) Patients undergoing GBR for alveolar bone defects were enrolled as study subjects, and postoperative healing complications were recorded. 2) Postoperative cone beam computed tomography (CBCT) scans acquired at least 6 months post-surgery were used to calculate the percentage of actual bone formation volume. 3) Alveolar bone specimens were collected during the first-stage implant surgery for histomorphometric analysis. This analysis quantitatively measured the proportions of newly formed bone and newly formed unmineralized bone within the specimens. Specimens were categorized into three groups based on healing complications (good healing group, wound dehiscence group, 3D-PITM exposure group) to compare differences in the proportions of newly formed bone and newly formed unmineralized bone. RESULTS: 1) Twelve patients were included. Guided bone regeneration failed in one patient, and 3D-PITM exposure occurred in three patients (exposure rate: 25%). 2) The mean percentage of actual bone formation volume in the 11 successful guided bone regeneration cases was 95.23%±28.85%. 3) Histomorphometric analysis revealed that newly formed bone constituted 40.35% of the alveolar bone specimens, with newly formed unmineralized bone accounting for 13.84% of the newly formed bone. Intergroup comparisons showed no statistically significant differences (P>0.05) in the proportions of newly formed bone or newly formed unmineralized bone between the good healing group and the wound dehiscence group or the 3D-PITM exposure group. CONCLUSIONS 3D-PITM enables effective bone augmentation. Radiographic assessment demonstrated favorable bone formation volume, while histological analysis confirmed substantial formation of newly formed mineralized bone within the surgical site.
Humans ; Printing, Three-Dimensional ; Titanium ; Cone-Beam Computed Tomography ; Bone Regeneration ; Osteogenesis ; Surgical Mesh ; Tissue Scaffolds ; Alveolar Process/surgery* ; Adult ; Male ; Middle Aged ; Female ; Wound Healing ; Guided Tissue Regeneration, Periodontal/methods* ; Alveolar Bone Loss/surgery*

In this paper, a preliminary stress/strain analysis of the design structure of a nickel-titanium alloy patent foramen ovale occluder is conducted with the finite element simulation analysis method. In the analysis, solid structure modeling is carried out on three different specifications of domestic patent foramen ovale occluders. Referring to the test method of fatigue performance in inspection standard YY/T 1553-2017, an initial installation deformation is applied to the model, and then the fatigue displacement of 2 mm is applied to the sample to make the model fatigue deformation. The fatigue safety factors of each type of occluder are obtained by strain simulation analysis. The results indicate that the minimum fatigue safety factors of the three specifications of domestic patent foramen ovale occluders are 2.09, 2.35 and 2.06 respectively, which all meet the design of fatigue safety factor greater than 1. Among them, 1818 and 3030 specifications of patent foramen ovale occluders have close values in minimum fatigue safety factors, and both are lower than that of 1825 model. Therefore, it is recommended to carry out physical fatigue tests on both 1818 and 3030 specifications to further verify the fatigue performance of the products.
Finite Element Analysis ; Titanium ; Nickel ; Alloys ; Foramen Ovale, Patent ; Materials Testing ; Septal Occluder Device ; Stress, Mechanical

OBJECTIVES

To determine and group the anthropometric norms of the zygomaticomaxillary (ZM) fixation points as a basis for optimizing the design of maxillary L-plates, from a sample population aged 19 to 59, in a tertiary government hospital in Central Luzon, Philippines.

Design: Retrospective Review of CT scans

Setting: Tertiary Government Training Hospital

Participants: CT scan images of 110 surgical patients from the Department of ORL-HNS, obtained between January 2023 and December 2024 were measured

A total of 169 maxillae were analyzed, comprising 85 right and 84 left sides. The maxillary width (MW) of males (30.59 ± 2.86 mm) was found to be wider than the MW of females (29.68 ± 2.69 mm) by 0.91 mm. The zygomatic width (ZW) and its inclination angle (IA), on the other hand, were not significantly different. There were also no significant differences in the MW, ZW, and IA between the right and left sides; with the MW mean at 30.17 ± 2.81 mm and a range of 24.40 36.80 mm, the ZW mean at 20.22 ± 2.47 mm and a range of 15.40–28.30 mm, and the IA mean at 111.13 ± 11.29 degrees and a range of 78.50–131.70 degrees. To capture the range of maxillary sizes among patients, a quartile-based grouping was introduced. The MW, ZW, and IA of the L-plates were classified into small (27.80 mm, 18.30 mm, 104.15 degrees), medium (29.80 mm, 19.90 mm, 110.70 degrees), and large (32.35 mm, 22.05 mm, 120.20 degrees) sizes, respectively.

This study established reference values for the MW, ZW and IA to optimize the maxillary L-plate design for ZM fractures. The novel quartile-based grouping provided options for future L-plate measurements – potentially creating a better fit for patients, streamlining design in implant production, and improving the efficiency and outcomes of maxillofacial surgeons.

The evaluation of blood compatibility of biomaterials is crucial for ensuring the clinical safety of implantable medical devices. To address the limitations of traditional testing methods in real-time monitoring and electrical property analysis, this study developed a portable electrical impedance tomography (EIT) system. The system uses a 16-electrode design, operates within a frequency range of 1 to 500 kHz, achieves a signal to noise ratio (SNR) of 69.54 dB at 50 kHz, and has a data collection speed of 20 frames per second. Experimental results show that the EIT system developed in this study is highly consistent with a microplate reader ( R ²=0.97) in detecting the hemolytic behavior of industrial-grade titanium (TA3) and titanium alloy-titanium 6 aluminum 4 vanadium (TC4) in anticoagulated bovine blood. Additionally, with the support of a multimodal image fusion Gauss-Newton one-step iterative algorithm, the system can accurately locate and monitor in real-time the dynamic changes in blood permeation and coagulation caused by TC4 in vivo. In conclusion, the EIT system developed in this study provides a new and effective method for evaluating the blood compatibility of biomaterials.
Electric Impedance ; Animals ; Tomography/instrumentation* ; Biocompatible Materials ; Materials Testing/instrumentation* ; Cattle ; Titanium ; Alloys ; Prostheses and Implants

This article aims to compare and analyze the biomechanical differences between wing-shaped titanium plates and traditional titanium plates in fixing acetabular anterior column and posterior hemi-transverse (ACPHT) fracture under multiple working conditions using the finite element method. Firstly, four sets of internal fixation models for acetabular ACPHT fractures were established, and the hip joint stress under standing, sitting, forward extension, and abduction conditions was calculated through analysis software. Then, the stress of screws and titanium plates, as well as the stress and displacement of the fracture end face, were analyzed. Research has found that when using wing-shaped titanium plates to fix acetabular ACPHT fractures, the peak stress of screws decreases under all working conditions, while the peak stress of wing-shaped titanium plates decreases under standing and sitting conditions and increases under forward and outward extension conditions. The relative displacement and mean stress of the fracture end face decrease under all working conditions, but the values are higher under forward and outward extension conditions. Wing-shaped titanium plates can reduce the probability of screw fatigue failure when fixing acetabular ACPHT fractures and can bear greater loads under forward and outward extension conditions, improving the mechanical stability of the pelvis. Moreover, the stress on the fracture end surface is more conducive to stimulating fracture healing and promoting bone tissue growth. However, premature forward and outward extension rehabilitation exercises should not be performed.
Titanium ; Bone Plates ; Humans ; Acetabulum/surgery* ; Fracture Fixation, Internal/methods* ; Biomechanical Phenomena ; Finite Element Analysis ; Bone Screws ; Fractures, Bone/surgery* ; Stress, Mechanical ; Working Conditions

This paper aims to explore the effect of electrical stimulation of triboelectric nanogenerators (TENGs) on the osteogenic and other biological behaviors of mouse embryonic osteoblast precursor cells (MC3T3-E1 cells) on titanium surfaces. First, an origami-type TENG was fabricated, and its electrical output performance was tested. The optimal current of the generator and the feasibility of the experiment were verified by the CCK-8 assay and scratch assay. At the optimal current, the osteogenic conditions of the cells in each group were determined by quantitative analysis of the total protein content, alkaline phosphatase (ALP) activity, and alizarin red staining (ARS) on the titanium surface. Finally, the adhesion and spreading of cells on the titanium surface after electrical stimulation were observed. The results showed that the TENG had good electrical output performance, with an open-circuit voltage of 65 V and a short-circuit current of 42 μA. Compared with the rest of the current, a current strength of 30 μA significantly improved cell proliferation and migration, osteogenesis, and adhesion and spreading capabilities. The above results confirm the safety and operability of TENG in biomedical applications, laying the foundation for future TENG applications in reducing the time of bone integration around titanium implants after surgery.
Titanium/chemistry* ; Osteogenesis ; Animals ; Mice ; Osteoblasts/cytology* ; Electric Stimulation/instrumentation* ; Cell Adhesion ; Cell Proliferation ; Surface Properties ; Cell Differentiation ; Nanotechnology

OBJECTIVE: To investigate the effectiveness of nickel-titanium shape memory staples in treating multiple metatarsal fractures. METHODS: The clinical data of 27 patients with multiple metatarsal fractures who were treated between January 2022 and June 2023 and met the selection criteria were retrospectively analysed. The cohort consisted of 16 males and 11 females, aged 33-65 years (mean, 47.44 years). The causes of injury included heavy object impact in 11 cases, traffic accidents in 9 cases, and crush in 7 cases. Simultaneous fractures of 2, 3, 4, and 5 bones occurred in 6, 6, 4, and 8 cases, respectively, with tarsometatarsal joint injury in 3 cases. Fixation was performed using staples for 16, 22, and 9 fractures in the metatarsal neck, shaft, and the base, respectively, and 5 tarsometatarsal joint injuries. Preoperative soft tissue injuries were identified in 8 cases and classified according to the Tscherne-Oestern closed soft tissue injury classification as type Ⅰ in 5 cases and type Ⅱ in 3 cases. One case of type Ⅱexhibited preoperative skin necrosis. The patients were treated with fixation using nickel-titanium shape memory staples. Complications and fracture healing were documented. At last follow-up, the American Orthopaedic Foot and Ankle Society (AOFAS) forefoot score was used to evaluate the function, and the visual analogue scale (VAS) score was used to evaluate the pain. RESULTS: The 27 patients were followed up 9-19 months (mean, 12.4 months). Postoperative X-ray films revealed no loss of fracture reduction, and all fractures achieved bony union. No internal fixator loosening, breakage, or other mechanical failures was observed. The mean fracture healing time was 3.13 months (range, 3-4 months). Postoperatively, 4 cases (2 of Tscherne-Oestern type Ⅰ, 2 of type Ⅱ) developed superficial skin necrosis, which resolved with dressing changes. No infection was observed in the remaining patients, and all wounds healed. At last follow-up, the AOFAS forefoot score ranged from 70 to 95, with an average of 86.6, of which 19 cases were excellent, 6 cases were good, and 2 cases were fair, with an excellent and good rate of 92.6%; the VAS score ranged from 0 to 3, with an average of 0.9, of which 24 cases were excellent, and 3 cases were good, with an excellent and good rate of 100%. CONCLUSION The use of nickel-titanium shape memory staples in the treatment of multiple metatarsal fractures can effectively protect local skin and soft tissues and minimize secondary damage associated with internal fixator insertion. It is a viable surgical option for management of multiple metatarsal fractures.
Humans ; Male ; Female ; Middle Aged ; Adult ; Titanium ; Nickel ; Retrospective Studies ; Fracture Fixation, Internal/instrumentation* ; Aged ; Metatarsal Bones/surgery* ; Fractures, Bone/surgery* ; Treatment Outcome ; Sutures ; Fractures, Multiple/surgery*

OBJECTIVE: To analyze the effectiveness of single three-dimensional (3D)-printed microporous titanium prostheses and flap combined prostheses implantation in the treatment of large segmental infectious bone defects in limbs. METHODS: A retrospective analysis was conducted on the clinical data of 76 patients with large segmental infectious bone defects in limbs who were treated between January 2019 and February 2024 and met the selection criteria. Among them, 51 were male and 25 were female, with an age of (47.7±9.4) years. Of the 76 patients, 51 had no soft tissue defects (single prostheses group), while 25 had associated soft tissue defects (flap combined group). The single prostheses group included 28 cases of tibial bone defects, 11 cases of femoral defects, 5 cases of humeral defects, 4 cases of radial bone defects, and 3 cases of metacarpal, or carpal bone defects, with bone defect length ranging from 3.5 to 28.0 cm. The flap combined group included 3 cases of extensive dorsum of foot soft tissue defects combined with large segmental metatarsal bone defects, 19 cases of lower leg soft tissue defects combined with large segmental tibial bone defects, and 3 cases of hand and forearm soft tissue defects combined with metacarpal, carpal, or radial bone defects, with bone defect length ranging from 3.8 to 32.0 cm and soft tissue defect areas ranging from 8 cm×5 cm to 33 cm×10 cm. In the first stage, vancomycin-loaded bone cement was used to control infection, and flap repair was performed in the flap combined group. In the second stage, 3D-printed microporous titanium prostheses were implanted. Postoperative assessments were performed to evaluate infection control and bone integration, and pain release was evaluated using the visual analogue scale (VAS) score. RESULTS: All patients were followed up postoperatively, with an average follow-up time of (35.2±13.4) months. In the 61 lower limb injury patients, the time of standing, walk with crutches, and fully bear weight were (2.2±0.6), (3.9±1.1), and (5.4±1.1) months, respectively. The VAS score at 1 year postoperatively was significantly lower than preoperative one ( t=-10.678, P<0.001). At 1 year postoperatively, 69 patients (90.8%) showed no complication such as infection, fracture, prosthesis displacement, or breakage, and X-ray films indicated good integration at the prosthesis-bone interface. According to the Paley scoring system for the healing of infectious bone defects, the results were excellent in 37 cases, good in 29 cases, fair in 3 cases, and poor in 7 cases. In the single prostheses group, during the follow-up, there was 1 case each of femoral prostheses fracture, femoral infection, and tibial infection, with a treatment success rate of 94.1% (48/51). In lower limb injury patients, the time of fully bear weight was (5.0±1.0) months. In the flap combined group, during the follow-up, 1 case of tibial fixation prostheses screw fracture occurred, along with 2 cases of recurrent foot infection in diabetic patients and 1 case of tibial infection. The treatment success rate was 84.0% (21/25). The time of fully bear weight in lower limb injury patients was (5.8±1.2) months. The overall infection eradication rate for all patients was 93.4% (71/76). CONCLUSION The use of 3D-printed microporous titanium prostheses, either alone or in combination with flaps, for the treatment of large segmental infectious bone defects in the limbs results in good effectiveness with a low incidence of complications. It is a feasible strategy for the reconstruction of infectious bone defects.
Humans ; Male ; Female ; Middle Aged ; Printing, Three-Dimensional ; Titanium ; Retrospective Studies ; Surgical Flaps ; Adult ; Prosthesis Implantation/methods* ; Plastic Surgery Procedures/methods* ; Treatment Outcome ; Prostheses and Implants ; Bone Diseases, Infectious/surgery* ; Extremities/surgery* ; Prosthesis Design