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.

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.

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.

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.

Liquid-infused polymers are recognized for their ability to repel foulants, making them promising for biomedical applications including catheter-associated urinary tract infections (CAUTIs). However, the impact of the quantity of free liquid layer covering the surface on protein and bacterial adhesion is not well understood. Here, we explore how the amount of free silicone liquid layer in infused silicone catheter materials influences the adhesion of bacteria and proteins relevant to CAUTIs. To alter the quantity of the free liquid layer, we either physically removed excess liquid from fully infused catheter materials or partially infused them. We then evaluated the impact on bacterial and host protein adhesion. Physical removal of the free liquid layer from the fully infused samples reduced the height of the liquid layer from 60 μm to below detection limits and silicone liquid loss into the environment by approximately 64% compared to controls, without significantly increasing the deposition of protein fibrinogen or the adhesion of the common uropathogen Enterococcus faecalis. Partially infused samples showed even greater reductions in liquid loss: samples infused to 70%-80% of their maximum capacity exhibited about an 85% decrease in liquid loss compared to fully infused controls. Notably, samples with more than 70% infusion did not show significant increases in fibrinogen or E. faecalis adhesion. These findings suggest that adjusting the levels of the free liquid layer in infused polymers can influence protein and bacterial adhesion on their surfaces. Moreover, removing the free liquid layer can effectively reduce liquid loss from these polymers while maintaining their functionality.

BACKGROUND: A straight silicone stent can be used to treat proximal benign tracheal stenosis in non-surgical candidates. However, stent migration is a common complication when placed at a particular location and can lead to major complications. This case series of laryngotracheal stenosis reports a fixation method for straight silicone stents in the subglottic trachea (Stage 3 of the McCaffrey classification).
METHODS: The medical charts of these patients scheduled for straight silicone stent placement with suture fixation between 2014 and 2020 at the CHU UCL Namur Hospital (Belgium) were retrospectively reviewed. The procedure was performed using a rigid bronchoscope. Details of the procedure were obtained from medical records.
RESULTS: This case series included six patients (males: 4, females: 2). The median patient age was 59 years. Two suture fixations were placed following previous silicone stent migration episodes, whereas the others were placed proactively to avoid this risk. All fixations were performed by the device Freka® Pexact II ENFIt®, originally developed for gastropexy in endoscopic gastrostomy. The sutures were subcutaneously buried.
CONCLUSIONS: During the 6-month follow-up period, complications such as fixation issues and stent migration were reported despite the off-label use of the treatment. The straight silicone stent fixation technique used in this case series was simple and effective for securing the stent in upper benign tracheal stenosis.

BACKGROUND: The elastomechanical properties of nanocarriers have recently been discussed as important for the efficient delivery of various therapeutics. Some data indicate that optimal nanocarriers\' elasticity can modulate in vivo nanocarrier stability, interaction with phagocytes, and uptake by target cells. Here, we presented a study to extensively analyze the in vivo behavior of LIP-SS liposomes that were modified by forming the silicone network within the lipid bilayers to improve their elastomechanical properties. We verified liposome pharmacokinetic profiles and biodistribution, including retention in tumors on a mouse model of breast cancer, while biocompatibility was analyzed on healthy mice.
RESULTS: We showed that fluorescently labeled LIP-SS and control LIP-CAT liposomes had similar pharmacokinetic profiles, biodistribution, and retention in tumors, indicating that modified elasticity did not improve nanocarrier in vivo performance. Interestingly, biocompatibility studies revealed no changes in blood morphology, liver, spleen, and kidney function but indicated prolonged activation of immune response manifesting in increased concentration of proinflammatory cytokines in sera of animals exposed to all tested liposomes.
CONCLUSIONS: Incorporating the silicone layer into the liposome structure did not change nanocarriers\' characteristics in vivo. Further modification of the LIP-SS surface, including decoration with hydrophilic stealth polymers, should be performed to improve their pharmacokinetics and retention in tumors significantly. Activation of the immune response by LIP-SS and LIP-CAT, resulting in elevated inflammatory cytokine production, requires detailed studies to elucidate its mechanism.

BACKGROUND: Incontinence-associated dermatitis (IAD) is a tough problem in clinical settings, not only increasing the risk of complications like catheter-related urinary tract infections and pressure ulcers in elderly and critically ill patients, but also prolonging hospital stays, raising hospital costs, and possibly leading to medical disputes. This study is aimed to evaluate the therapeutic effect of silicone dressing combined with topical oxygen therapy on IAD in a rat model.
METHODS: An IAD rat model induced by synthetic urine with trypsin was established. Hematoxylin & eosin staining was carried out to examine skin histology. Using immunofluorescence, the microvessel density in the affected skin tissues was determined. ELISA was performed to measure the concentrations of inflammatory cytokines and angiogenic factors in serum. The mRNA expression of EGF, PDGF, and VEGF was detected via qRT-PCR. Western blotting was employed to determine NF-κB p65/STAT1 pathway-related protein levels.
RESULTS: Compared to single therapy, silicone dressing combined with topical oxygen therapy could significantly reduce the severity of IAD, improve skin histology, inhibit inflammation, and promote angiogenesis in IAD rat models. Additionally, the results showed that relatively speaking, the combined therapy suppressed the NF-κB p65/STAT1 signaling pathway more effectively.
CONCLUSIONS: These findings indicated that silicone dressing combined with topical oxygen therapy can alleviate IAD through promoting wound healing and inhibiting inflammation via NF-κB p65/STAT1 signaling pathway in a rat model, which provided a theoretical basis for the prevention and treatment of IAD in clinic.