Cytoskeleton adaptation to stretchable surface relaxation improves adherent cryopreservation of human mesenchymal stem cells.

Adherent cell systems are usually dissociated before being cryopreserved, as standard protocols are established for cells in suspension. The application of standard procedures to more complex systems, sensitive to dissociation, such as adherent monolayers, especially comprising mature cell types, or tissues, remains unsatisfactory. Uncontrolled cell detachment due to intracellular tensile stress, membrane ruptures and damages of adhesion proteins are common during freezing and thawing of cell monolayers. However, many therapeutically relevant cell systems grow adherently to develop their native morphology and functionality, but lose their integrity after dissociation. The hypothesis is that cells on stretchable substrates have a more adaptable cytoskeleton and membrane, reducing cryopreservation-induced stress. Our studies investigate the influence of stretchable surfaces on the cryopreservation of adherent cells to avoid harmful dissociation and expedite post-thawing cultivation of functional cells. A stretching apparatus for defined radial stretching, consisting of silicone vessels and films with specific surface textures for cell culture, were developed. Adherent human umbilical cord mesenchymal stem cells (hUC-MSCs) were cultivated on a stretched silicone film within the vessel, forming a monolayer that were compressed by relaxation, while remaining attached to the relaxed film. Compressed hUC-MSCs, which were cryopreserved adherently showed higher viability and less detachment after thawing compared to control cells without compression. Within three to seven days post-thawing, the hUC-MSCs recovered, and the monolayer reformed. These experiments support the hypothesis that cryopreservation success of adherent cell systems is enhanced by improved adaptability of the cytoskeleton and cell membrane, opening up new approaches in cryobiotechnology.

Multi-layered silicone-based breast tissue phantom for multi-modal optical spectroscopy.

The heterogeneity, non-uniform nature, and ethical concerns in sourcing biological tissues pose several challenges to designing, calibrating, standardizing, and evaluating the performance of spectroscopy-based diagnostic methods. A synthetic phantom module that can resemble a multi-layered tissue structure while including multiple tissue biomarkers with long-shelf life and stability is vital to overcome these challenges. This work uses a multi-layered silicone phantom to incorporate multiple biomarkers suitable for multi-modal spectroscopy testing and calibration. The phantom mimics the microcalcification distribution in the breast tissues using hydroxyapatite and the endogenous fluorescence seen in the tissues using Flavin Adenine Dinucleotide (FAD) and Nicotinamide Adenine Dinucleotide (NADH). The utility of this phantom for tumor margin analysis is analyzed using Diffuse reflectance, fluorescence, and Raman spectroscopy. The observed relative differences in intensity with changes in the silicone tumor layer depth and thickness are suitable for instrument calibration and fiber-optic probe design for tumor margin analysis. .

Development and validation of a realistic type III esophageal atresia simulator for the training of pediatric surgeons.

BACKGROUND: The technical complexity and limited casuistry of neonatal surgical pathology limit the possibilities of developing the necessary technical competencies by specialists in training. Esophageal atresia constitutes the paradigm of this problem. The use of synthetic 3D models for training is a promising line of research, although the literature is limited. METHODS: We conceptualized, designed, and produced an anatomically realistic model for the open correction of type III oesophageal atresia. We validated it with two groups of participants (experts and non-experts) through face, construct, and content-validity questionnaires. RESULTS: The model was validated by nine experts and nine non-experts. The mean procedure time for the experts and non-experts groups was 34.0 and 38.4 min, respectively. Two non-experts did not complete the procedure at the designed time (45 min). Regarding the face validity questionnaire, the mean rating of the model was 3.2 out of 4. Regarding the construct validity, we found statistically significant differences between groups for the equidistance between sutures, 100% correct in the expert group vs. 42.9% correct in the non-expert group (p = 0.02), and for the item "Confirms that tracheoesophageal fistula closure is watertight before continuing the procedure", correctly assessed by 66.7% of the experts vs. by 11.1% of non-experts (p = 0.05). Concerning content validity, the mean score was 3.3 out of 4 for the experts and 3.4 out of 4 for the non-experts. CONCLUSIONS: The present model is a cost-effective, simple-to-produce, and validated option for training open correction of type III esophageal atresia. However, future studies with larger sample sizes and blinded validators are needed before drawing definitive conclusions.

A simple, novel technique to create silicone vessels for microsurgical training.

Background and objectives: Effective microsurgical training necessitates dedicated practice, prompting the development of simulation models that mitigate the hygiene risks, regulatory challenges, and storage difficulties associated with conventional biological models. This study aims to evaluate the preferences of microsurgeons and medical students regarding self-made silicone simulation vessels, comparing them to standard biological models. Methods: A three-part jig, comprising of a two-part metal clamp component and a transparent acrylic block with 4x4 channels, was designed. This assembly produced 16 vessels with a 1 â€‹mm inner diameter. Liquid silicone (Ecoflex 00-30), readily accessible from online distributors, was injected into the channels using a syringe. After tightening the clamp component and inserting 16 1 â€‹mm k-wires, the vessels were left to set for approximately 24 â€‹h 20 medical students with no prior microsurgical experience and 10 microsurgery-trained surgeons then evaluated these silicone vessels against a commonly used biological model (chicken brachial artery for surgeons or chicken aorta for students). Participants were then surveyed about their preference for a specific model for frequent practice using a 10-point Likert scale. Results and conclusion: In assessing ideal microsurgical training models, all participants highlighted the importance of realism. Surgeons' main practical considerations were hygiene, availability, and setup and storage ease, while medical students were primarily concerned with cost-effectiveness. Both surgeons and medical students perceived the biological model as more realistic, yet less hygienic and harder to set up and store. Conversely, the silicone model, though deemed less realistic, offered advantages in hygiene, availability, cost-effectiveness, and setup and storage simplicity. The silicone model emerged as the overall favorite amongst all participants for frequent practice. Silicone vessels may serve as a complementary adjunct to biological models, allowing surgeons-in-training to practice their skills outside of the operating room and lab settings.

The Effect of Chemical Disinfectants on Maxillofacial Silicone With the Addition of Silver Nanoparticles: An Original Research.

Background and objective Silicone has emerged as the most widely accepted material for facial prosthesis fabrication. However, silicone materials have certain limitations. Several techniques have been investigated to lessen the degradation of the polymer, such as the use of nanoparticles and nano-oxides, etc. In this study, we aimed to evaluate the effect of various chemical disinfectants on color stability, hardness, and surface roughness of maxillofacial silicone, after the addition of silver nanoparticles. Materials and methods This was an in vitro study carried out in the Department of Prosthodontics, Sharad Pawar Dental College and Hospital; 80 samples of maxillofacial silicone incorporated with silver nanoparticles (in a concentration of 20 ppm) were fabricated in a mold of 3 x 10 mm dimension disc. The samples were then tested for surface roughness (using a digital roughness tester), Shore A hardness (using a durometer), and color stability (using a spectrophotometer). The samples were then classified into four groups according to various disinfectants used: sodium hypochlorite (1% w/w), chlorhexidine gluconate (0.2%), and neutral soap, and distal water was deemed the control group. After 48 hours, the samples underwent retesting to assess for changes in readings under the same parameters (i.e., surface roughness, Shore A hardness, and color stability) to obtain results, i.e., the samples were tested after fabrication, before immersion, and 48 hours after immersion in disinfectants. Results When taking into account the surface roughness, the maximum roughness value was observed in the sodium hypochlorite group and the least roughness value in distilled water (mean % change of 38.359 to negligible change in the distilled water group). As for the Shore A hardness, the maximum hardness value was seen in the sodium hypochlorite group and the least hardness value in distilled water (mean % change of 15.780 to 2.125 in distilled water). Regarding color stability, the maximum increase in color values was seen in the sodium hypochlorite group (mean: 2.4) followed by the neutral soap group (mean: 1.653); the chlorhexidine gluconate group (mean: -0.287) showed the maximum decrease in color value from the initial to the final phase. Conclusions Based on our findings, surface roughness altered the most when samples were immersed in 1% sodium hypochlorite disinfectant and the least when samples were immersed in neutral soap disinfectant. Shore A hardness altered the most when samples were immersed in 1% sodium hypochlorite disinfectant, but altered the least when samples were immersed in neutral soap disinfectant. Color stability altered the most when samples were immersed in neutral soap disinfectant, but altered the least when samples were immersed in 0.2% chlorhexidine gluconate. Disinfection with neutral soap seems to lead to fewer changes in physical properties (i.e., surface roughness and Shore A hardness) and hence is recommended as a disinfectant for silicone prosthesis. However, our study also showed that 0.2% chlorhexidine gluconate had the least effect on the parameter of color stability, and hence it could be the disinfectant of choice for prostheses with high esthetic requirements.

Troubleshooting Vaginal Stents: A Critical Review of Common Problems and Solutions.

This review aims to examine the use of vaginal stents in clinical practice, specifically for treating vaginal agenesis and related complications and problem associated with vaginal stents. Vaginal agenesis, also known as Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, is a congenital disorder characterized by the uterus not developing or developing only partially. Vaginal stents are medical devices that preserve the structural integrity and patency of the vaginal canal after trauma or surgery. They play an important part in gynecological treatments such as post-radiation therapy, reconstructive surgery, and vaginal stenosis management. The review also discusses the primary applications of vaginal stents, such as preventing adhesions, healing mucosa, and maintaining patency. It also investigates frequent concerns associated with stent use, such as complications and the need for better designs. Vaginal stents are essential in a variety of therapeutic settings, providing major benefits in maintaining vaginal tissue and function. However, their use is fraught with complications, including the risk of infection, discomfort, and the possibility of inappropriate placement.

Capsular contracture in breast reconstruction: A systematic review and meta-analysis.

BACKGROUND: Capsular contracture after implant-based breast reconstruction is not an uncommon problem and affects reconstruction outcomes. It can be influenced by various factors, such as the plane of implant placement, implant surface and implant type. This systematic review and meta-analysis aimed to evaluate how the abovementioned risk factors can affect capsular contracture rates. METHODS: A systematic review and meta-analysis was performed. PubMed MEDLINE, EMBASE (OvidSP) and Cochrane Library were searched. Comparison groups included subpectoral versus prepectoral implant placement, smooth versus textured implants and saline versus silicone implants. Odds ratios (ORs) were calculated for capsular contracture for each group. The level of evidence was evaluated using the Oxford Centre for Evidence-Based Medicine. RESULTS: Twenty-three studies met the inclusion criteria. Sixteen studies compared subpectoral versus prepectoral implant placement, with no statistically significant differences in capsular contracture rates [OR, 1.21; 95% confidence interval (95% CI), 0.75-1.95; P = 0.44]. Five studies compared smooth versus textured implants, with no statistically significant differences in capsular contracture rates (OR, 0.99; 95% CI, 0.50-1.93; P = 0.97). Two studies compared saline versus silicone implants for capsular contracture. Patients receiving saline implants had significantly lower capsular contracture rates than silicone implants (OR, 0.19; 95% CI, 0.08-0.43; P < 0.0001). CONCLUSIONS: Implant-based breast reconstruction using saline implants demonstrated reduced capsular contracture rates compared to silicone implants. However, no significant differences were observed in capsular contracture rates between subpectoral versus prepectoral implant placement and smooth versus textured implants.

Randomized Controlled Trial on Silicone Intubation in Endoscopic Mechanical Dacryocystorhinostomy (SEND): An 11-year Outcome Report.

PURPOSE: To compare the long-term outcomes of mucosal-sparing mechanical endoscopic dacryocystorhinostomy (MMED) for primary acquired nasolacrimal duct obstruction (PANDO) with or without silicone intubation. METHODS: An 11-year follow-up study of the Silicone intubation in Endoscopic Dacryocystorhinostomy (SEND) randomized controlled trial (RCT) was conducted at a university-affiliated dacryology clinic from December 2019 to March 2023. Questionnaires on symptoms, anterior segment examination, endoscopic examination with functional endoscopic dye test (FEDT) and FICI grading, and ostial size measurements using Image J software were performed by a masked ophthalmologist. The primary outcome was surgical success, defined by Munk's score ≤1 and a positive fluorescein endoscopic dye test. Secondary outcomes included risk factors for failure and outcomes of revision surgeries. RESULTS: Fifty-three of the original 118 patients were evaluated at 155 ± 21 (136-218) months postoperatively. Seventy-seven percent (46/60) ostia remained successful, including 70% (19/27) of unstented and 82% (27/33) of stented ostia (p = .3). Stented ostia had larger size (p = .003), but this did not confer higher success (p = .14). Successful ostia had higher FICI scores and better ostial dynamicity (p < .05). Ostium movement was the only parameter associated with surgical success on multivariate analysis (OR 13.1, p = .01). Four (1 stented) underwent revision MMED, intraoperative mitomycin-C, and 12-week intubation. All revision ostia were functional after 141 ± 43 months. CONCLUSIONS: Surgical success of MMED after 11-years was 77%, a notable reduction compared to 96% success at 1-year. Statistical advantage of silicone intubation for primary MMED was not demonstrated, though clinically, stented ostia had a higher success (82% vs 70%). The presence of a dynamic internal common opening was highly associated with long-term surgical success.

Silicone Wristbands as a Personal Passive Sampler to Evaluate Indoor Exposure to Volatile and Non-volatile PFASs.

Exposure to per- and polyfluoroalkyl substances (PFASs) primarily occurs via consumption of contaminated drinking water and food; however, individuals can also be exposed dermally and via inhalation indoors. This study developed an analytical method for measuring volatile PFASs in silicone wristbands and used them to assess personal exposure in a Midwestern community (n = 87). Paired samples of blood and wristbands were analyzed for PFASs using LC-MS/MS and GC-HRMS to monitor both non-volatile and volatile PFASs. The most frequently detected PFASs in wristbands were: 6:2 diPAP, 6:2 FTOH, MeFOSE and EtFOSE. Females had a 4-fold higher exposure to 6:2 diPAP compared to males and age-dependent differences in exposure to 6:2 FTOH, MeFOSE and EtFOSE were observed. Exposure to MeFOSE and EtFOSE differed based on the average time spent in the home. Frequently detected PFASs in blood were: PFOA, PFOS, PFHxS, PFHpS, and N-MeFOSAA. A strong correlation was found between MeFOSE in the wristbands and N-MeFOSAA in serum (rs = 0.90, p-value <0.001), suggesting exposure to this PFAS was primarily via inhalation and dermal exposure. These results demonstrate that wristbands can provide individual level data on exposure to some polyfluoroalkyl precursors present indoors that reflect serum levels of their suspected biotransformation products.

Electrostatic Dissipation in 3D-Printable Silicone.

In this report, we describe the incorporation of single-walled carbon nanotubes (CNTs) into 3D printable siloxane elastomers for electrostatic dissipation. The composite was characterized, focusing on how rheological and mechanical properties of the siloxane are affected at various CNT loading levels. Electrical properties were also characterized to develop materials with effective electrostatic dissipation. We demonstrate that low loadings (<1 wt %) of CNTs can be sufficiently dispersed into silicone resins that can be 3D printed, and the resulting material shows a significant improvement in electrostatic dissipation through the reduction in electrical resistivity with minimal effect on its mechanical properties.

Injectable and 3D Extrusion Printable Hydrophilic Silicone-Based Hydrogels for Controlled Ocular Delivery of Ophthalmic Drugs.

While silicone elastomers have found widespread use in the biomedical industry, 3D printing them has proven to be difficult due to the material's slow drying time, low viscosity, and hydrophobicity. Herein, we arrested the hydrophilic silicone (HS) macrochains into a semi-interpenetrating polymer network (semi-IPN) via an in situ photogelation-assisted 3D microextrusion printing technique. The flow behavior of the pregel solutions and the mechanical properties of the printed HS hydrogels were tested, showing a high elastic modulus (approximately 15 kPa), a low tan δ, high elasticity, and delayed network rupturing. The uniaxial compression tests demonstrated a nearly negligible permanent deformation, suggesting that the printed hybrid hydrogel maintained its elastic properties. Drug loading and diffusion in the microporous hydrogel are shown via the non-Fickian anomalous transport mechanism, leading to highly tunable loading/releasing profiles (approximately 20% cumulative release) depending on the HS concentration. The drug encapsulation exhibits exceptional stability, remaining intact without any degradation even after a storage period of 1 month. As far as we know, this is the first soft biomaterial based on HS that functions as an exceptional controlled drug delivery device.

The Effect of Cigarettes Smoke on the Color and Properties of a Silicone for Maxillofacial Prostheses.

Although deterioration of silicone maxillofacial prostheses is severely accentuated in smoking patients, the phenomenon has not been systematically studied. To address a gap in the literature concerning the stability of maxillofacial prostheses during service, in this contribution, the effect of cigarette smoke on the aspect and physical properties of M511 silicone elastomer was evaluated. The aspect, surface, and overall properties of the silicone material, pigmented or not, were followed by AFM, color measurements, FTIR, water contact angle measurements, TGA-DTG and DSC, hardness and compression stress-strain measurements. The types of the contaminants adsorbed were assessed by XRF, ESI-MS, MALDI-MS, and NMR spectral analyses. Important modifications in color, contact angle, surface roughness, local mechanical properties, and thermal properties were found in the silicone material for maxillofacial prostheses after exposure to cigarettes smoke. The presence of lead, nicotine, and several other organic compounds adsorbed into the silicone material was emphasized. Slight decrease in hardness and increase in Young's modulus was found. The combined data show important impact of cigarette smoke on the silicone physical properties and could indicate chemical transformations by secondary cross-linking. To our knowledge, this is the first study making use of complementary physical methods to assess the effect of cigarette smoke on the aspect and integrity of silicone materials for maxillofacial prostheses.

Silicone tags as an effective method of monitoring environmental contaminant exposures in a geographically diverse sample of dogs from the Dog Aging Project.

Introduction: Companion animals offer a unique opportunity to investigate risk factors and exposures in our shared environment. Passive sampling techniques have proven effective in capturing environmental exposures in dogs and humans. Methods: In a pilot study, we deployed silicone monitoring devices (tags) on the collars of a sample of 15 dogs from the Dog Aging Project Pack cohort for a period of 120 h (5 days). We extracted and analyzed the tags via gas chromatography-mass spectrometry for 119 chemical compounds in and around participants' homes. Results: Analytes belonging to the following chemical classes were detected: brominated flame retardants (BFRs), organophosphate esters (OPEs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides, phthalates, and personal care products. The types and amounts of analytes detected varied substantially among participants. Discussion: Data from this pilot study indicate that silicone dog tags are an effective means to detect and measure chemical exposure in and around pet dogs' households. Having created a sound methodological infrastructure, we will deploy tags to a geographically diverse and larger sample size of Dog Aging Project participants with a goal of further assessing geographic variation in exposures.

Selective bronchial occlusion for acquired bronchobiliary fistula caused by treatment of hepatocellular carcinoma: A case series.

Acquired bronchobiliary fistula (ABBF) is very rare among the complications that occur in patients with hepatocellular carcinoma (HCC) after treatment. Although surgery and drainage have been the main methods for treating ABBF for a long time, they are not entirely suitable for patients with refractory ABBF resulting from HCC therapy. In this study, we present four cases of ABBF caused by HCC treatment, who were treated using selective bronchial occlusion (SBO). Among the 4 patients with ABBF treated with SBO, 3 cases successfully blocked ABBF with SBO, and the treatment success rate was 75%. All successfully treated patients reported disappearance of symptoms of bilioptysis and cough was alleviated. No life-threatening adverse reactions were reported following SBO intervention, and no deaths occurred. We believe that the use of video bronchoscopy to place a self-made silicone plug in the bronchus to treat refractory ABBF is a feasible palliative treatment, which can significantly improve the condition of ABBF patients.

Electroretinograms Recorded with Skin Electrodes from Post-Vitrectomy Silicone Oil Filled Eyes with Proliferative Diabetic Retinopathy.

Purpose: To determine the physiological status of the retina by electroretinography (ERG) using skin electrodes and the RETevalTM system in eyes that had undergone pars plana vitrectomy (PPV) with silicone oil (SO) tamponade. The vitrectomy was performed for a retinal detachment and proliferative diabetic retinopathy (PDR). Design: Retrospective case series. Methods: ERGs were recorded with the RETevalTM system (LKC Technologies Inc. Gaithersburg, MD; Welch Allyn, Inc. Skaneateles Falls, NY) from eight eyes with PDR before and after the SO removal. The amplitudes and implicit times of the a- and b-waves of the ERGs before the SO removal were compared to that after the SO removal. Results: ERGs were recordable in four eyes before and after the SO removal and the a- and b-amplitudes improved in three eyes and worsened in one eye after the SO removal. In the remaining four eyes, ERGs were non-recordable both before and after the SO removal. Conclusion: These results indicate that ERGs picked up by skin electrodes can be used to assess the physiology of the retina in eyes with a SO tamponade. The flat ERGs in the SO-filled eye indicated the presence of diffuse retinal damage which was confirmed by the flat ERGs after the SO removal.

There has been an increasing number of reports on evaluating the retinal function using electroretinography (ERG) with skin electrodes. The main advantage of this system is the ability to record ERGs with a skin electrode that does not touch the cornea and ocular surface. This reduces the risk of infection especially in the postoperative period and in clinical situations where infection is suspected. In addition, there have been only a few reports evaluating the function of the retina by ERG in SO-filled eyes. We recorded ERGs with the RETeval (LKC Technologies Inc. Gaithersburg, MD; Welch Allyn Inc. Skaneateles Falls, NY) device, a relatively new ERG recording system that uses skin electrodes and is less invasive. We recorded ERGs from eight SO-filled eyes with proliferative diabetic retinopathy (PDR). In 4 SO filled eyes, the amplitudes increased in three eyes after the SO removal. In the other four eyes, ERGs were non-recordable before and after the SO removal. These results suggest that the RETeval system that uses skin electrodes can be used to assess the retinal function in PDR eyes with a SO tamponade. We suggest that the absence of ERGs in the SO filled eyes was not due to the electrical non-conductive effects of SO but may indicate the presence of diffuse retinal damage which was confirmed after the SO removal.

The elasticity of silicone-stabilized liposomes has no impact on their in vivo behavior.

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. CONCLUSION: 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.

Comparison of the Marginal and Internal Fit of Ceramic Laminate Veneers Fabricated with Four Different Computer-Aided Manufacturing Techniques.

Purpose: The improvement of computer-aided design and computer-aided manufacturing (CAD/CAM) has changed the methods of fabricating laminate veneers. The objectives of this study were to evaluate the marginal and internal fit of ceramic veneers manufactured with different CAD/CAM techniques. Materials and methods: A metal die was made by copying a prepared plastic maxillary central right incisor and scanned for designing a laminate veneer. One hundred laminate veneers were made with four different CAD/CAM techniques (n=25), including milled lithium disilicate (MLD), heat-pressed lithium disilicate with 3-dimensional (3D) printed wax patterns (PLD), milled zirconia (MZ), and 3Dprinted zirconia (PZ). The virtual marginal and internal fit of fabricated veneers was evaluated with digital crown fitting software. The actual marginal and internal fit was measured with the silicone replica method under a digital microscope. The measured data were analyzed using the one-way analysis of variance and the Turkey test. Results: There were significant differences in marginal and internal fit (P < 0.001) among manufacturing techniques. Both the virtual and actual marginal and internal gaps were higher in the PLD and PZ groups compared to the MLD and MZ groups. Conclusion: All four CAD/CAM techniques of manufacturing veneers, that is, milled lithium disilicate, heat-pressed lithium disilicate with 3D-printed wax patterns, milled zirconia, and 3D-printed zirconia, have clinically acceptable marginal and internal fit. Milled zirconia and lithium disilicate veneers demonstrated superior marginal and internal fit compared to 3D-printed zirconia and heat-pressed lithium disilicate veneers with 3D-printed wax patterns.

A Volume-Adjustable Artificial Womb for Extremely Preterm Infants.

More than 13 million children are born preterm annually. Prematurity-related mortality accounts for 0.9 million deaths worldwide. The majority of those affected are Extremely Preterm Infants (gestational age less than 28 weeks). Immaturity causes organ failure and specific morbidities like germinal matrix hemorrhage, bronchopulmonary dysplasia, and necrotizing enterocolitis. Artificial womb and placenta technologies address these issues. As a bridge-to-life technology, they provide a liquid environment to allow organ maturation under more physiological conditions. The proposed artificial womb can adapt to fetal growth. Volume adjustment is achieved by removing fluid from the interspace between an inner and outer chamber. Results of the in vitro tests showed a temperature constancy of 36.8°C ± 0.3°C without pressure loss over 7 days. The volume of the inner sac was variable between 3.6 and 7.0 L. We designed a filtration and disinfection system for this particular purpose. This system has proven strong disinfection capabilities, effective filtering of metabolic waste, and the ability to avoid phospholipid washout. The presented artificial womb has sufficient volume variability to adapt to the physiologic growth of an extremely preterm neonate over a 4-week period. We regard this as an important step in the development of this bridge-to-life technology.

Retinal redetachment after silicone oil removal: a risk factor analysis.

PURPOSE: To report the rate of retinal redetachment after silicone oil removal following rhegmatogenous retinal detachment surgery and to determine potential risk factors. METHODS: Retrospective observational case series of 161 eyes who underwent rhegmatogenous retinal detachment surgery and subsequent silicone oil removal. Pre- and intraoperative risk factors were evaluated using univariate and multivariate logistic regression. We also evaluated the effect of tamponade duration on anatomical outcomes. RESULTS: The median tamponade duration was 5.9 [4.3;7.6] months. Seventeen (10.6%) eyes underwent silicone oil removal within 3 months of surgery, with a median delay of 2.3 [2.0;2.8] months. The rate of retinal detachment after silicone oil removal was 14.9%. A history of previous unsuccessful surgery was the only significant risk factor for retinal redetachment after silicone oil removal (OR 4.8, 95%CI [1.5;19.0], p = 0.02). The use of 360° laser retinopexy and concomitant air or gas tamponade during silicone oil removal were not found to affect the redetachment rate. Eyes with silicone oil tamponade ≤ 3 months showed an increased, albeit not significant, risk of developing recurrent rhegmatogenous retinal detachment after silicone oil removal (35.3% versus 12.5%, p = 0.06). CONCLUSION: A retinal redetachment occurred in 14.9% of eyes undergoing silicone oil removal following rhegmatogenous retinal detachment surgery. Previous failed surgery was associated with a 4.8-fold increased risk of developing recurrent rhegmatogenous retinal detachment after silicone oil removal. Eyes with silicone oil tamponade ≤ 3 months tended to have a higher redetachment rate. TRIAL REGISTRATION NUMBER: ID NCT05647928 (12th April 2022).

Success Rate of External Dacryocystorhinostomy With and Without Stent.

Dacryocystorhinostomy (DCR) is a procedure that bypasses an obstruction in the nasolacrimal duct system. DCR can be categorized into two primary techniques: external and endoscopic. This review aims to assess the success rate of external DCR procedures, both with and without the use of a stent. This study compared the outcomes of primary DCR with and without silicone intubation in multiple studies. The reviewed studies consistently showed that silicone intubation significantly improves the success rates of DCR, with success rates ranging from 80% to 95%. The involved studies suggest that silicone intubation offers specific advantages in complex cases involving distant and common canaliculus blockages and recurrent DCR surgeries. This review emphasizes that multiple studies have documented higher success rates of external dacryocystorhinostomy (DCR) when silicone tubes are utilized as stents. Furthermore, external DCR has been identified as the preferred procedure among medical professionals.