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ACS Applied Bio Materials Sep 2023Contact lenses are one of the most successful applications of biomaterials. The chemical structure of the polymers used in contact lenses plays an important role in... (Review)
Review
Contact lenses are one of the most successful applications of biomaterials. The chemical structure of the polymers used in contact lenses plays an important role in determining the function of contact lenses. Different types of contact lenses have been developed based on the chemical structure of polymers. When designing contact lenses, materials scientists consider factors such as mechanical properties, processing properties, optical properties, histocompatibility, and antifouling properties, to ensure long-term wear with minimal discomfort. Advances in contact lens materials have addressed traditional issues such as oxygen permeability and biocompatibility, improving overall comfort, and duration of use. For example, silicone hydrogel contact lenses with high oxygen permeability were developed to extend the duration of use. In addition, controlling the surface properties of contact lenses in direct contact with the cornea tissue through surface polymer modification mimics the surface morphology of corneal tissue while maintaining the essential properties of the contact lens, a significant improvement for long-term use and reuse of contact lenses. This review presents the material science elements required for advanced contact lenses of the future and summarizes the chemical methods for achieving these goals.
Topics: Silicones; Hydrogels; Biomimetics; Contact Lenses; Oxygen; Polymers
PubMed: 37616500
DOI: 10.1021/acsabm.3c00296 -
Laeknabladid Apr 2023For decades, breast implants have been available for breast reconstructions and breast augmentations to improve the patients' health-related quality of life. Silicone... (Review)
Review
For decades, breast implants have been available for breast reconstructions and breast augmentations to improve the patients' health-related quality of life. Silicone implants (SI) have been used since the middle of the last century for breast reconstruction, for example after breast cancer, for birth defects, gender confirmation procedures, or for breast augmentation. Every year, several hundred SI are performed in Iceland for these purposes, but no central register is maintained. It can be estimated that at least 1000 - 3000 women have SI in Iceland and that around 300 Icelandic patients get SI every year. This informal review article discusses the so-called ASIA syndrome, the immunological effects of silicone and the possible relationship of SI to autoimmune diseases, symptoms, and diagnosis. In the methodology, this paper does not rely on the strict conditions of systematic reviews, but the authors relied only on peer-reviewed sources through PubMed, UpToDate and Scopus. The keywords used are silicon, silicon implant, silicon particles, immune response, autoimmunity, autoinflammation, Autoimmune/inflammatory syndrome induced by aduvants, ASIA, ASIA syndrome, breast implant illness. The paper reviews known facts about the disease, its characteristics, and statistical aspects.
Topics: Humans; Female; Silicon; Quality of Life; Systematic Reviews as Topic; Breast Implants; Autoimmune Diseases; Silicones; Syndrome
PubMed: 36988131
DOI: 10.17992/lbl.2023.04.739 -
International Journal of Environmental... Feb 2022Humans are exposed to numerous potentially harmful chemicals throughout their lifetime. Although many studies have addressed this issue, the data on chronic exposure is... (Review)
Review
Humans are exposed to numerous potentially harmful chemicals throughout their lifetime. Although many studies have addressed this issue, the data on chronic exposure is still lacking. Hence, there is a growing interest in methods and tools allowing to longitudinally track personal exposure to multiple chemicals via different routes. Since the seminal work, silicone wristbands (WBs) have been increasingly used to facilitate human exposure assessment, as using WBs as a wearable sampler offers new insights into measuring chemical risks involved in many ambient and occupational scenarios. However, the literature lacks a detailed overview regarding methodologies being used; a comprehensive comparison with other approaches of personal exposure assessment is needed as well. Therefore, the aim of this review is fourfold. First, we summarize hitherto conducted research that employed silicone WBs as personal passive samplers. Second, all pre-analytical and analytical steps used to obtain exposure data are discussed. Third, we compare main characteristics of WBs with key features of selected matrices used in exposure assessment, namely urine, blood, hand wipes, active air sampling, and settled dust. Finally, we discuss future needs of research employing silicone WBs. Our work shows a variety of possibilities, advantages, and caveats associated with employment of silicone WBs as personal passive samplers. Although further research is necessary, silicone WBs have already been proven valuable as a tool for longitudinal assessment of personal exposure.
Topics: Dust; Environmental Monitoring; Humans; Silicones
PubMed: 35206121
DOI: 10.3390/ijerph19041935 -
Contact Lens & Anterior Eye : the... Jun 2020Daily disposable (DD) contact lenses first came to the market approximately 25 years ago and eye care professionals (ECPs) started prescribing silicone hydrogel (SiH)... (Review)
Review
Daily disposable (DD) contact lenses first came to the market approximately 25 years ago and eye care professionals (ECPs) started prescribing silicone hydrogel (SiH) contact lenses, primarily for extended or continuous wear, approximately 20 years ago. It has now been over ten years since SiH DD contact lenses have been available, and while SiH materials are routinely prescribed by ECPs for reusable daily wear, hydrogel materials are still frequently selected for the DD modality of contact lens wear. This article reviews the evidence to support the benefits of both a DD modality and SiH materials and how patients' needs may be met with SiH DD contact lenses, with respect to clinical performance, health outcomes, satisfaction, compliance and convenience. Factors which may enable or constrain ECPs from prescribing SiH DD contact lenses, as opposed to hydrogel DD and reusable contact lenses, for more of their patients are discussed with the objective of providing ECPs with a greater understanding of the advantages that can be afforded by prescribing SiH DD contact lenses to both their new and existing contact lens wearers.
Topics: Contact Lenses, Hydrophilic; Disposable Equipment; Humans; Hydrogels; Patient Compliance; Refractive Errors; Silicones; Surveys and Questionnaires
PubMed: 32098715
DOI: 10.1016/j.clae.2020.02.001 -
Medicine Oct 2020To investigate the efficacy and complications that might be associated with pyrocarbon compared with silicone in patients undergoing joint replacement surgery. (Comparative Study)
Comparative Study Meta-Analysis
OBJECTIVE
To investigate the efficacy and complications that might be associated with pyrocarbon compared with silicone in patients undergoing joint replacement surgery.
METHODS
The full-text papers about the clinical efficacy of pyrocarbon and silicone were retrieved from multiple databases. Review Manager version 5.0 was adopted for meta-analysis and analyses of sensitivity and bias.
RESULTS
Ultimately, we studied 232 patients across eight studies that met the eligibility criteria. The meta-analysis suggested a significant difference between the pyrocarbon and silicone groups in terms of the Disabilities of the Arm, Shoulder, and Hand (DASH) score (standard mean difference (SMD) = 1.48; 95% CI [0.97, 1.99]; P = .009; P for Heterogeneity <0.00001; I = 63%); Visual Analogue Score (VAS) (SMD = 1.68; 95% CI [1.36, 1.99]; P < .00001; P for heterogeneity = 0.01; I = 61%), and the abnormal radiolucent line (RR = 6.66; 95% CI [3.19, 13.89]; P < .00001; P for heterogeneity = 0.87, I = 0%); and ossification development (RR = 0.90; 95% CI [0.56, 1.44], P = .66; P for heterogeneity = 0.94, I = 0%).
CONCLUSION
This study showed that pyrocarbon might be an efficient material compared with silicone for joint replacement surgery, but resulted in poorer functional and pain outcomes compared with silicone.
Topics: Arthroplasty, Replacement; Biocompatible Materials; Carbon; Disability Evaluation; Humans; Joint Prosthesis; Pain Measurement; Prosthesis Design; Silicones
PubMed: 33031299
DOI: 10.1097/MD.0000000000022548 -
JAMA Network Open Sep 2021
Topics: Breast Implants; Humans; Silicones
PubMed: 34542621
DOI: 10.1001/jamanetworkopen.2021.28947 -
Macromolecular Rapid Communications Mar 2016Silicone elastomers are promising materials for dielectric elastomer transducers (DETs) due to their superior properties such as high efficiency, reliability and fast... (Review)
Review
Silicone elastomers are promising materials for dielectric elastomer transducers (DETs) due to their superior properties such as high efficiency, reliability and fast response times. DETs consist of thin elastomer films sandwiched between compliant electrodes, and they constitute an interesting class of transducer due to their inherent lightweight and potentially large strains. For the field to progress towards industrial implementation, a leap in material development is required, specifically targeting longer lifetime and higher energy densities to provide more efficient transduction at lower driving voltages. In this review, the current state of silicone elastomers for DETs is summarised and critically discussed, including commercial elastomers, composites, polymer blends, grafted elastomers and complex network structures. For future developments in the field it is essential that all aspects of the elastomer are taken into account, namely dielectric losses, lifetime and the very often ignored polymer network integrity and stability.
Topics: Dimethylpolysiloxanes; Electric Conductivity; Electric Power Supplies; Electrodes; Silicone Elastomers
PubMed: 26773231
DOI: 10.1002/marc.201500576 -
Medicine Jan 2019Male-to-female transgender (MtF TG) individuals often report using illegal subcutaneous silicone injections for body feminisation. It leads to silicone dissemination and...
Male-to-female transgender (MtF TG) individuals often report using illegal subcutaneous silicone injections for body feminisation. It leads to silicone dissemination and various dermatologic complications.We report the long-term complications of these feminisation procedures with blood smear examination and dermatologic examination.Between July 2015 and December 2015, 77 MtF TG consulting at Bichat Hospital (Paris, France) were included in this cross-sectional study. Blood smear examinations were performed by a trained haematologist to quantify the presence of silicone vacuoles in monocytes.All patients reported a history of massive amounts of silicone injections (mean 4 L, range 0.5-15 L). Most patients were South American (75/77, 97%). Fifty-nine (59/75, 79%) were HIV-seropositive, mostly with undetectable HIV RNA plasma levels (46/58, 80%). Clinical examinations reported dermatologic complications for all patients: lymphatic or subcutaneous migration of silicone (59%), inflammation (50%), varicose veins (39%), post-inflammatory pigmentation (20%), infection (14%) and abscesses (4%). Blood smear examination showed intracytoplasmic vacuoles containing silicone in monocytes in all patients.We did not chemically prove the silicone nature of the vacuoles. The design of this study does not allow evaluation of short-term complications that should not be minimized.Illicit massive silicone injections always induced chronic and definitive silicone blood diffusion with dermatologic complications. This study highlights the dangers and the inefficiency of clandestine esthetic surgery. There is a need for targeted information campaigns with transgender populations about silicone injections. Otherwise, these practices may persist.
Topics: Adult; Aged; Criminal Behavior; Cross-Sectional Studies; Diffusion; Female; Hematologic Tests; Humans; Injections, Subcutaneous; Male; Middle Aged; Silicones; Skin Diseases; Transsexualism; Young Adult
PubMed: 30681578
DOI: 10.1097/MD.0000000000014143 -
Journal of Cancer Research and... 2022Surgical ablation of a large tumor creates a defect which is technically difficult to reconstruct. Radiated tissue bed poses a challenge to reconstruction and is...
Surgical ablation of a large tumor creates a defect which is technically difficult to reconstruct. Radiated tissue bed poses a challenge to reconstruction and is complicated in presence of osteoradionecrosis. This report describes a case of a 62 year old gentleman with oral cancer who underwent surgery and radiotherapy twice. He developed an orocutaneous defect (OCD) following surgery and radiotherapy. Prosthetic rehabilitation of OCD was done. Full facial impression with irreversible hydrocolloid was made and wax sculpture made on the model obtained. Standard laboratory steps were followed for mould fabrication and maxillofacial silicone was used to fabricate the prosthesis. It was retained to the spectacle with silicone adhesives. The silicone facial prosthesis provided to the patient was easy to use, covered the defect and improved the quality of life of the patient.
Topics: Face; Humans; Male; Maxillofacial Prosthesis; Middle Aged; Prosthesis Design; Quality of Life; Silicones
PubMed: 35900575
DOI: 10.4103/jcrt.JCRT_1141_20 -
Prilozi (Makedonska Akademija Na... Sep 2017A quality-made dental impression is a prerequisite for successful fixed-prosthodontic fabrication and is directly dependent on the dimensional stability, accuracy and... (Review)
Review
A quality-made dental impression is a prerequisite for successful fixed-prosthodontic fabrication and is directly dependent on the dimensional stability, accuracy and flexibility of the elastomeric impression materials, as well as on the appropriately used impression techniques. The purpose of this paper is to provide a literature review of relevant scientific papers which discuss the use of various silicone impression materials, different impression techniques and to evaluate their impact on the dimensional stability and accuracy of the obtained impressions. Scientific papers and studies were selected according to the materials used, the sample size, impression technique, storage time, type of measurements and use of spacer for the period between 2002 and 2016. In the reviewed literature several factors that influence the dimensional stability and accuracy of silicone impression molds, including the choice of the type of viscosity, impression material thickness, impression technique, retention of the impression material on the tray, storage time before the casting, number of castings, hydrophilicity of the material, release of byproducts, contraction after polymerization, thermal contraction and incomplete elastic recovery were presented. The literature review confirmed the lack of standardization of methodologies applied in the research and their great diversity. All findings point to the superiority of the addition silicone compared to the condensation silicone.
Topics: Dental Casting Technique; Dental Impression Materials; Dental Impression Technique; Humans; Models, Dental; Polymerization; Silicones; Surface Properties; Viscosity
PubMed: 28991761
DOI: 10.1515/prilozi-2017-0031