BACKGROUND: To treat stenosed coronary arteries, percutaneous transluminal coronary angioplasty (PTCA) balloon catheters must combine pushability, trackability, crossability, and rewrap behavior. The existing anatomic track model (ASTM F2394) for catheter testing lacks 3D morphology, vessel tortuosity, and compliance, making evaluating performance characteristics difficult. This study aimed to develop a three-dimensional patient-specific phantom (3DPSP) for device testing and safe training for interventional cardiologists.
METHODS: A range of silicone materials with different shore hardnesses (00-30-45 A) and wall thicknesses (0.5 mm, 1 mm, 2 mm) were tested to determine compliance for creating coronary vessel phantoms. Compliance was assessed using optical coherence tomography (OCT) and compared to values in the literature. Stenosis was induced using multilayer casting and brushing methods, with gypsum added for calcification. The radial tensile properties of the samples were investigated, and the relationship between Young\'s modulus and compliance was determined. Various methods have been introduced to approximate the friction between silicone and real coronary vessel walls. Computerized tomography (CT) scans were used to obtain patient-specific anatomy from the femoral artery to the coronary arteries. Artery lumens were segmented from the CT scans to create dissolvable 3D-printed core models.
RESULTS: A 15A shore hardness silicone yielded an experimental compliance of 12.3-22.4 m m 2 mmHg · 10 3 for stenosed tubes and 14.7-57.9 m m 2 mmHg · 10 3 for uniform tubes, aligning closely with the literature data (6.28-40.88 m m 2 mmHg · 10 3 ). The Young\'s modulus ranged from 43.2 to 75.5 kPa and 56.6-67.9 kPa for the uniform and calcified materials, respectively. The dependency of the compliance on the wall thickness, Young\'s modulus, and inner diameter could be shown. Introducing a lubricant reduced the silicone friction coefficient from 0.52 to 0.13. The 3DPSP was successfully fabricated, and comparative analyses were conducted among eight commercially available catheters.
CONCLUSIONS: This study presents a novel method for crafting 3DPSPs with realistic mechanical and frictional properties. The proposed approach enables the creation of comprehensive and anatomically precise setups spanning the right femoral artery to the coronary arteries, highlighting the importance of such realistic environments for advancing medical device development and fostering safe training conditions.

UNASSIGNED: There is limited literature available comparing the accuracy of intraradicular impressions made with a novel hybrid impression material using the indirect and direct technique at three different locations.
UNASSIGNED: For this comparative in vitro analysis, postspace was prepared in 15 recently extracted teeth and impressions made with vinyl polysiloxane, polyether (PE), vinyl polyether silicone (VPES), and pattern resin. Postpatterns obtained were re-seated on the teeth and longitudinally sectioned. A binocular microscope was used to measure apical and lateral discrepancies at three locations (L1, L2, and L3). L1 at the postcore junction, L2 at the middle of the post space, and L3, 2 mm short of the apical end. The data obtained were statistically analyzed using the Statistical Package for the Social Sciences (SPSS) software. One-way analysis of variance (ANOVA) (intergroup) followed by Tukey\'s post hoc test with P ≤ 0.05 was used.
UNASSIGNED: The one-way ANOVA noted a highly significant difference at the apical location. Pattern resin had the highest apical discrepancy (151.93 ± 8.59 µm), whereas the lowest was with vinyl PE silicone (140.31 ± 11.46 µm). At L1, the highest discrepancy was seen with pattern resin (32.09 ± 2.31 µm), whereas the lowest was with the addition silicone (31.94 ± 2.54 µm). At L2, addition silicone (32.88 ± 2.81 µm) showed the highest discrepancy, whereas the lowest was with vinyl PE silicone (30.5 ± 8.79 µm). The PE group had the highest mean at the L3 location (31.38 ± 3.46 µm) and the lowest was with vinyl PE silicone (30.93 ± 2.25 µm). At all lateral locations, no significant difference was noted. Tukey\'s post hoc comparison showed a significant difference between pattern resin and VPES (11.62 µm) followed by pattern resin and addition silicone (11.47 µm) apically.
UNASSIGNED: The indirect technique using VPES or addition silicone is more accurate than the direct technique at the apical location.

As the global population ages, ischemic stroke has risen to become the second leading cause of disability and mortality worldwide, placing an immense burden on both society and families. Although treatments such as intravenous thrombolysis and endovascular interventions can substantially improve the outcomes for patients with acute ischemic stroke, only a small percentage of individuals benefit from these therapies. To advance our understanding of the disease and to discover more effective treatments, researchers are continuously developing and refining animal models. Among these, the middle cerebral artery occlusion (MCAO) model stands out as the most commonly used model in cerebrovascular disease research. The filament used in this model is crucial for its development. This protocol outlines a method for creating filaments with consistent diameters and varying lengths of silicone coating. The MCAO model produced using this method in C57 mice has demonstrated high success and consistency, offering a valuable tool for tailored investigations into ischemic cerebrovascular diseases.

BACKGROUND: Digitally fabricated dentures may require relining due to continual alveolar ridge resorption. However, studies evaluating the tensile bond strength (TBS) of digitally fabricated dentures bonded to denture liners are lacking. This study aimed to evaluate the TBS of autopolymerized, heat-polymerized, milled, and 3D printed denture base materials bonded to 2 acrylic-based and 2 silicone-based denture liners, both before and after thermocycling. Additionally, the impact of thermocycling on the TBS were also evaluated.
METHODS: The TBS of 4 different denture base materials (Palapress (PL), Vertex Rapid Simplified (VR), Smile CAM total prosthesis (SC), and NextDent denture 3D+ (ND)) bonded to 2 acrylic-based (GC Soft-Liner (GC) and Tokuyama Rebase II (RB)) and 2 silicone-based (Ufi Gel P (UP) and Sofreliner Tough M (ST)) denture liners were tested. Specimens (n = 8) were divided into non-thermocycling and thermocycling groups. Non-thermocycling specimens were tested after 24-hours water immersion, while thermocycling specimens were underwent 5000 cycle and were immediately tested. Mode of failure was examined under a stereomicroscope. Data were analyzed using 2-way ANOVA and Tukey HSD tests (α = 0.05), and independent samples t test (α = 0.05) for TBS between non-thermocycling and thermocycling groups.
RESULTS: For the non-thermocycling groups, within the same denture liner material, no significant differences were found between denture base materials, except the ND + RB group, which had significantly lower TBS. For the thermocycling groups, within the same denture liner material, the TBS in the PL group exhibited the highest and the ND group exhibited the lowest. Within the same denture base material, in both non-thermocycling and thermocycling groups, the TBS in the ST group exhibited the highest; in contrast, that in the GC group exhibited the lowest. No significant differences were observed in TBS between non-thermocycling and thermocycling groups, except for denture base materials bonded to the ST group, SC + UP, and ND + UP groups.
CONCLUSIONS: Milled denture base can be relined with acrylic-based or silicone-based denture liner. However, cautions should be exercised when relining 3D printed denture base. Thermocycling did not affect TBS between acrylic-based denture liners and denture bases. In contrast, it affected the bond between silicone-based denture liner and denture base.

The aim of this study was to assess the perceptibility and acceptability thresholds of maxillofacial silicones for light and dark skin colors and to evaluate the effect of gender and professional experience on these thresholds. Two different sets of specimens (as light and dark) each, consisting of 14 (25 × 25 × 6-mm3) silicone skin replications, were produced. Four specimens of each set were produced from the same silicon mixture of the relevant set and polymerized simultaneously to provide standardized fabrication conditions. These 4 light/dark specimens were assigned as \"baseline color specimens (BCs)\" in each set, while the other 10 specimens were produced with a color difference level that increased gradually from BC. These stepped levels were obtained by controlled increasing of the pigment concentration in the relevant baseline silicon mixture. Color difference levels of specimens were calculated by using the CIELAB and CIEDE2000 formulas. Observers comprised of 3 different professional experiences as first-year dental students, interns, and dentists (n = 30/group, gender-balanced) were included. Combinations consisting of 5 specimens with 4 BCs and 1 different color were shown to the observers to assess whether the color difference was perceptible or acceptable. Perceptibility and acceptability percentages were regressed with color difference levels to estimate the best fit curve and confidence intervals were calculated (α = 0.05). The highest estimation of the coefficient of determination (R2) was found in the cubic curve for all parameters. A significant difference was found between the light and dark colors. The perceptibility thresholds (ΔE*ab/ΔE00) were 0.8/0.59 and 2.63/1.75 for light and dark colors, respectively. The acceptability thresholds (ΔE*ab/ΔE00) were 3.35/2.25, 10.07/7.04 for light and dark colors, respectively. No significant differences were found between gender and among experience groups concerning visual thresholds. Regardless of gender and experience, observers could perceive color differences more easily in light skin colors.

OBJECTIVE: To describe a 41-gauge silicone fine-needle aspiration biopsy (S-FNAB) technique and assess its value in diagnosing primary vitreoretinal lymphoma (PVRL).
METHODS: Retrospective review of seven consecutive patients who underwent vitreous biopsy (VB) and 41-gauge S-FNAB of retinal/subretinal lesions in a single tertiary center between January 2012 and March 2023.
RESULTS: Of seven patients, S-FNAB confirmed the diagnosis of PVRL in six patients. In five of those patients, both VB and retinal/subretinal S-FNAB (performed at the same procedure) yielded positive results, with the retinal thickness at the biopsy site as small as 231 µm. Four of these five patients had one or more previous negative VB. In one patient, S-FNAB yielded positive results despite a negative VB. Silicone fine-needle aspiration biopsy failed to confirm positive VB for PVRL in the remaining patient. The time from symptom onset to diagnosis of PVRL ranged from 18 days to 26 months. There were no severe complications associated with the procedure.
CONCLUSIONS: Silicone fine-needle aspiration biopsy might be a valuable method for obtaining a sufficient sample of viable cells to diagnose PVRL. It can be performed as a primary procedure along with VB. Further studies are warranted to determine where this technique could be most advantageous.

It is unusual to see complications with the preparation of ear mold in order to get hearing aids for children who are in need. However, we came across 2 cases who had a foreign body retained in the middle ear after a long period of time from taking silicon mold impression for hearing aid fitting. One patient presented after 2 years, and the other patient presented after 10 years of hearing aid fitting. We are reporting 2 cases with silicon impression material left in the middle ear for a long period of time after taking an impression for hearing aid fitting and found unexpectedly during exploratory tympanotomy. These reported cases are among the few cases reported worldwide without clear known incidence. This necessitates proper examination by otolaryngologists and the audiologists who are responsible for taking the impression to prevent such complications.

BACKGROUND: Battlefield trauma necessitates prompt hemostatic intervention to mitigate fatalities resulting from critical blood loss. Insights from Operation Enduring Freedom and Operation Iraqi Freedom emphasize the limitations of conventional methods, such as tourniquets, especially in noncompressible torso hemorrhage. Despite advancements in hemostatic agents, the evolving dynamics of multidomain operations necessitate novel, lightweight strategies for hemorrhage control. This study investigates the Silicone-Based Polymer (SBP) Universal Combat Matrix (UCM) by SiOxMed, a multimodal matrix exhibiting efficacy in lethal hemorrhage models. The study evaluates UCM\'s multiday hemostatic capabilities in a noncompressible torso hemorrhage model, offering pivotal insights for potential deployment in battlefield trauma.
METHODS: This research was performed under Institutional Animal Care and Use Committee approval and was designed to replicate austere conditions in an off-site enclosed facility. Yorkshire Hampshire swine underwent baseline assessments and anesthesia induction (n = 3). A Grade IV liver injury was made by incising X-shaped lesions, each measuring 4 cm × 2.5 cm, into the diaphragmatic surface of the left and right middle lobes using a scalpel blade, resulting in a lesion region of approximately 3 cm × 6 cm × 3 cm, followed by 30 seconds of uncontrolled bleeding. The injuries were then treated with SBP. Intensive care unit monitoring for 1 hour ensured sustained hemostasis, followed by 48 hours of postanesthesia monitoring and then a return to the operating table to visualize sustained hemostasis. Posteuthanasia, liver tissue underwent histological assessments to evaluate the hemorrhagic interface and liver tissue reactivity.
RESULTS: The average time to hemostatic control was 247.3 ± 71.3 seconds. Stable heart rate (81.3 ± 10.0) and respiratory rate (31.7 ± 16.5) were maintained during intensive care unit monitoring. All swine survived the 1-hour anesthesia monitoring period and the subsequent 48-hour monitoring (average survival time, 48.0 hours ± 0.0, n = 3). Visualization of the abdominal cavity at 48 hours revealed no hemorrhage. Histological assessment demonstrated aligned red blood cells and stratified layers of fibrin at the hemorrhagic interface. Masson\'s Trichrome analysis demonstrated a reactive and regenerative scenario 48 hours postinjury, with a collagen membrane demarcating uninjured and exposed liver regions, along with a comprehensive stromal response.
CONCLUSIONS: In conclusion, our investigation into the SBP UCM hemostatic efficacy in a grade IV liver laceration model demonstrates its rapid and reliable action in controlling bleeding, showcasing practicality with an average mass of 4.0 ± 1.0 g. Silicone-Based Polymer sustained hemostasis without adverse physiological effects, as evidenced by stable parameters and the survival of all swine during and after anesthesia. Macroscopic examination at 48 hours revealed durable adherence with no indications of hemorrhage. Histological evaluations highlighted SBP\'s role in stable clot formation, fibrinogenesis, and tissue regeneration, indicating its potential as a multimodal wound dressing. Although promising, the study has limitations, emphasizing the need for future research with larger samples and controls. This work sets the stage for exploring SBP\'s clinical implications, particularly in scenarios where lightweight, multimodal technologies are crucial for addressing traumatic injuries and enhancing military medical capabilities.

Accurate transverse deformation measurements are required for the estimation of the Poisson function and volume ratio. In this study, pure silicone and soft composite specimens were subjected to uniaxial tension, and the digital image correlation method was used to measure longitudinal and in- and out-of-plane transverse stretches. To minimize the effects of measurement errors on parameter estimation, the measured transverse stretches were defined in terms of the longitudinal stretch using a new formulation based on Poisson\'s ratios and two stretch-dependent parameters. From this formulation, Poisson functions and volume ratio for soft materials under large deformations were obtained. The results showed that pure silicone can be considered isotropic and nearly incompressible under large deformations, as expected. In contrast, Poisson\'s ratio of silicone reinforced with extensible fabric can exceed classical bounds, including negative value (auxetic behavior). The incompressibility assumption can be employed for describing the stress-stretch curve of pure silicone, while volume ratios are required for soft composites. Data of human skin, aortic wall, and annulus fibrosus from the literature were selected and analyzed. Except for the aortic wall, which can be considered nearly incompressible, the studied soft tissues must be regarded as compressible. All tissues presented anisotropic behavior.

The characteristics of dopamine self-polymerization were used to cover the nano-titanium dioxide (TiO2) surface and produce nano-titanium dioxide-polydopamine (TiO2-PDA). The reducing nature of dopamine was then used to reduce silver nitrate to silver elemental particles on the modified nano-titanium dioxide: The resulting TiO2-PDA-Ag nanoparticles were used as antimicrobial agents. Finally, the antibacterial agent was mixed with silicone to obtain an antibacterial silicone composite material. The composition and structure of antibacterial agents were analyzed by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron energy spectroscopy, and X-ray diffraction. Microscopy and the antibacterial properties of the silicone antibacterial composites were studied as well. The TiO2-PDA-Ag antimicrobial agent had good dispersion versus nano-TiO2. The three were strongly combined with obvious characteristic peaks. The antibacterial agents were evenly dispersed in silicone, and the silicone composite has excellent antibacterial properties. Bacillus subtilis (B. subtilis) adhesion was reduced from 246 × 104 cfu/cm2 to 2 × 104 cfu/cm2, and colibacillus (E. coli) reduced from 228 × 104 cfu/cm2 leading to bacteria-free adhesion.