Novas tecnologias e inovações em cirurgia mamária / New technologies and innovations in breast surgery

Introdução: A cirurgia de mama, especialmente as associadas aos implantes de silicone, teve uma crescente popularização, tornando-se a cirurgia plástica mais realizada no mundo. Junto com esta proliferação, observa-se um aumento da preocupação com a segurança dos implantes mamários de silicone, pelas intercorrências relacionadas. Objetivo: Revisar métodos existentes para minimizar as complicações relacionadas com implante mamário de silicone, bem como as tecnologias existentes e tendências tecnológicas para implantes mamários de silicone. Métodos: Foi realizada revisão de artigos científicos relacionados com novas tecnologias e tendências para redução das complicações relacionadas com implantes mamários de silicone, bem como as patentes e fabricantes de implante de silicone mamário. Resultados: Identificamos inicialmente 78 referências, sendo reduzido para 40 para publicação, todos com linhas de pesquisas que buscam melhores resultados e redução das complicações relacionadas com implantes de silicone, seja esta cirurgia com objetivo estético ou reconstrutivo. Conclusão: A busca por um implante mamário que reduza as possíveis e frequentes complicações, principalmente a formação do biofilme, processos infecciosos e resposta imune, é o foco da maioria das pesquisas encontradas. Com o mesmo objetivo, porém surgindo mais recentemente como alternativas, existem as pesquisas para o uso de matriz dérmica acelular e a lipoenxertia, com boas expectativas.

Introduction: Breast surgery with silicone implants is gaining popularity and has become the most performed plastic surgery worldwide. However, there is increasing concern about the safety of silicone breast implants due to associated complications. Objective: To review existing technologies, technological trends, and existing methods to minimize complications related to silicone breast implants. Methods: We conducted a literature review of articles describing new technologies and trends to reduce complications related to silicone breast implants, along with information on patents and manufacturers of silicone breast implants. Results: We initially identified 78 articles, out of which 40 were shortlisted for publication . All articles had a common aim of obtaining better results and reducing complications related to silicone implants, either in aesthetic or reconstructive surgeries. Conclusion: The search for a breast implant that reduces possible and frequent complications, especially biofilm formation, infectious processes, and abnormal immune response, was the focus of most articles studied. Acellular dermal matrix and fat grafting have been reported in the literature as promising alternatives.

Randomized controlled clinical study on the accuracy of two-stage putty-and-wash impression materials.

PURPOSE: The accuracy of dental impression taking is one major factor influencing the fit of crowns and fixed partial dentures. The aim of this study was to determine the accuracy of three-dimensional (3-D) tooth surface and subgingival tooth surface reproduction using three different silicone materials and the two-stage putty-and-wash technique. MATERIALS AND METHODS: From 24 probands, three impressions each were taken with Express STD Putty/Wash (3M ESPE), Optosil/Xantopren L (Heraeus Kulzer), and an experimental ultralight body/putty material (3M ESPE) in a randomized order. The preliminary impression was cut according to established procedures for the two-stage putty-and-wash technique. Master casts were manufactured with a standardized procedure and optically digitized. The 3-D accuracy was analyzed with a computer-aided procedure. The Express STD putty-and-wash impressions were used as a reference. Linear models were used for the statistical analysis. RESULTS: Mean deviations of 27.0 microm and -23.6 microm were found for Optosil/Xantopren L and 26.5 microm and -22.6 microm for the experimental material when analyzing 3-D surface reproduction. The tooth surface (buccal/oral) significantly influenced the accuracy of the surface reproduction. Optosil/Xantopren L showed a more complete reproduction of the subgingival tooth surface than either the experimental or reference materials. CONCLUSION: The accuracy of the 3-D tooth surface reproduction as well as the reproduction of the subgingival tooth surface was not favorably influenced when the ultralight wash material was used with established cutting procedures for the preliminary impression.

Dimensional accuracy of 3 silicone dental impression materials.

This study was carried out to measure the dimensional changes in silicone impression material, which can affect the fitness of the prosthesis. Using both single and double mix techniques, 20 impression samples for each of 3 different proprietary silicones, Xantopren-H, President and Fulldent, were made. Selected measurements were made on the stone casts made from each impression. In all 3 cases, the single mix gave more accurate casts than the double mix technique. The Xantopren-H impressions had the most accurate dimensions.

[Do silicone gel breast implants must be changed?]. / Faut-il changer les prothèses mammaires en gel de silicone?

Since silicone gel breast implants have been rehabilitated in 2001, we advised our patients to change prosthesis after 10 years. Our study including 150 patients shows clearly the rupture rate is very high (60%) for the textured prosthesis after 10 years, whereas it is much low for the double lumen implants (18%) after 14 years. This study and literature lead us to be very careful and change prosthesis every 12 or 13 years.

Effect of folding on the multifocal silicone intraocular lens: scanning electron microscopic study.

PURPOSE: To evaluate whether the surface of the refractive zonal multifocal silicone intraocular lens (IOL) is altered by different folding and implantation instruments and is more sensitive to manipulation during folding than the surface of a monofocal IOL. SETTING: Department of Ophthalmology, University Hospital, Kiel, Germany. METHODS: Evaluated were the refractive multifocal silicone IOL (SA-40N, Array) and an otherwise identical monofocal IOL (SI-40NB) from the same manufacturer (Allergan Inc.). Different folding devices (folding blocks, folding and implantation forceps, and an injector system) were used. The IOLs were kept folded for 60 seconds; 24 hours later, scanning electron microscopy (SEM) was performed. In addition, the cartridges of the injector system were examined by SEM. RESULTS: Overall, regardless of the folding and implantation instruments used, both the multifocal and monofocal IOLs had discrete surface alterations. The cartridges of the injector system had a rough surface at the tip, while the proximal portion appeared smooth. CONCLUSION: There were no signs of lesions particularly affecting the surface of multifocal IOLs.

In vitro study of the number of surface defects in monophase and two-phase addition silicone impressions.

STATEMENT OF PROBLEM: Monophase addition-cured silicone impression materials in stock trays are considered to be alternatives to two-phase systems used with custom trays. PURPOSE: This study compared the number of surface defects in addition-cured silicone impressions recorded with monophase materials in stock trays and two-phase impressions in custom trays. METHODS: The number of voids visible on the surface of impressions recorded in vitro were counted. Two monophase impression materials. (President Monobody system 75, Bayer Cutter) in stock trays were compared with impressions recorded with two-phase addition silicone materials (President Plus light-body/regular-body and Zhermack Elite light-body/medium-body) in custom trays. A total of 200 automixed impressions, 50 with each material, were recorded of 50 dentoform molar teeth prepared for full veneer crowns. Impressions were examined for surface voids anywhere on the prepared part of the tooth by a trained examiner. RESULTS: Mean number of voids observed for the monophase impressions were 3.0 +/- 2.2 for President Monobody system and 3.4 +/- 2.0 for Bayer Cutter system. Mean number of voids for the two-phase materials were 0.8 +/- 1.0 for President Plus, and 1.0 +/- 1.1 for Zhermack Elite. No significant differences were observed for number of voids between the monophase materials or between the two-phase systems (ANOVA and Neuman-Keuls p > 0.05). However, both two-phase materials in custom trays had significantly fewer surface voids than the two-monophase materials (ANOVA and Neuman-Keuls, p < 0.001) used in stock trays. CONCLUSION: Monophase addition-cured impression materials in stock trays carries an increased risk of void formation on the surface of the impression when compared with two-phase addition silicone materials in custom trays.

[The disinfection of impressions to prevent hospital infections. Sodium hypochlorite as a disinfecting agent]. / Obezzarazhivanie ottiskov s tsel'iu profilaktiki vnutribol'nichnykh infektsii. Gipokhlorit natriia kak dezinfitsiruiushchee sredstvo.

Effect of sodium hypochlorite disinfection of impressions on the size and quality of plaster models is studied. Twenty-minute submerging of silicone impressions in 0.5% sodium hypochlorite solution did not change their size and did not deteriorate the quality of surface and hardness of plaster models. Stomalgin impressions cannot be disinfected by sodium hypochlorite solution because of expressed destructive effect of this disinfectant on the impressions.

Intraocular lens materials and styles: a review.

Biomaterial science has lead to the development of a variety of foldable intraocular lens (IOL) biomaterials. This literature review examines these lenses from both a basic science and a clinical perspective. By most parameters, hydrogel, soft acrylic and silicone IOL are better than polymethylmethacrylate (PMMA) lenses. Plate haptic silicone IOL have the lowest incidence of cystoid macula oedema and posterior capsule opacification, but these lenses require an intact anterior capsularhexis and posterior capsule. Yttrium aluminium garnet (YAG) laser capsulotomy must be delayed at least 3 months to avoid posterior lens dislocation. Silicone has the lowest threshold for YAG laser damage of all IOL materials and also adheres irreversibly to silicone oil with subsequent optical impairment. Three piece silicone IOL with polypropylene haptics have a higher incidence of decentration, pigment adherence and capsule opacification compared with PMMA haptics. Hydrogel lenses are very biocompatible and resistant to YAG laser damage, but pigment adheres to the surface more readily than PMMA. Soft acrylic IOL unfold slowly, resulting in controlled insertion, but it is possible to crack the lens and some lenses develop glistenings due to water accumulation. There are significant socioeconomic implications to the large differences in posterior capsule opacification rates between the various biomaterials and the lens styles.

[Implantation of elastic intraocular lenses in traumatic cataracts]. / Implantatsiia 'elasticheckikh intraokuliarnykh linz pri travmaticheskikh kataraktakh.

The results of implantations of 73 elastic silicone and 59 rigid intraocular lenses (IOL) to patients with traumatic cataracts are analyzed. Mathematical estimations of static and dynamic effects of IOLs of different specific weight on ocular tissues are presented. Implantation of elastic IOLs brings about a high rehabilitation effect and causes little complications, which is due to a low specific weight and the minimal injury inflicted to the tissues of the eye by such lenses.

The effect of the type and technique used for impression making on the accuracy of elastomeric impression materials.

The effect of the technique used for impression making on the accuracy of three types impression materials, (vinyl silicons, condensation silicons and polyether elastomers) was evaluated. Three main impression making techniques were used. Impressions were made for stainless steel master model. The impressions were poured after thirty minutes with improved stone into stone casts. Accuracy was assessed by comparing seven measurements of the master model to their corresponding on the stone case produced. A travelling microscope of 0.001 mm accuracy was used for measurements. The results of the study have shown that all elastomeric impression materials produced accurate impression but with significant difference among them. The polyether was more accurate than silicon impressions. The technique used for making the impression had more effect on the relative accuracy than the type of the material. Reference for the best technique for each type was concluded.

Effect of loading and syringing on void formation in automixed addition silicone elastomers.

The effect of loading and syringing on void formation in five automixed addition silicones was evaluated by determining the voids created in the first and second halves of material loaded and dispensed from a metal syringe. Impressions were made of a model with six stainless-steel cylinders. The voids were counted at a predetermined site on 3 separate days using a binocular microscope at x 7 magnification. Automixed addition silicones did not confirm the 'last out-fewer bubbles' phenomenon and specific loading and syringing technique did not appear to have a consistent effect on void formation in automixed elastomers.

Injectable soft tissue substitutes.

Historical and modern advances in the development of an injectable soft tissue substitute are reviewed. Nonbiologic alloplastic and biologic injectables are described. The authors' experiences, as well as those of others, employing presently available materials in terms of specific indications and special techniques are delineated. The search for a safe, effective, easy-to-use, and long-lasting soft tissue substitute continues.

Hemocompatibility of diamond-like carbon coating.

The new prosthetic heart valve that has been designed by FII Company and Pr. Baudet involves a new "composite" material: titanium alloy T16A14V coated with Diamond-like Carbon. The purpose of this study was to evaluate the in vitro hemocompatibility of this new material in terms of protein adsorption and platelet retention. The static protein adsorption test gave interesting results, particularly for the albumin assay (237%) compared to the results obtained with a silicone elastomer chosen as a reference; the fibrinogen quantity, adsorbed on the surface of the material was slightly higher than that adsorbed on the silicone surface. Platelets adhere quite twice as much as they do on the reference surface. Such investigations showed good hemocompatibility results and should initiate further studies.

Medical-purpose elastic materials based on siloxane rubbers and items made from them.

Vulcanization of the unsaturated siloxane rubbers with silicon hydrides of various structure (organohydrosiloxanes, organohydrosilazanes, organohydrosilanes) was investigated for the purpose of creating biologically-compatible materials with a high complex of medical and engineering properties. The effect of the silicon hydride structure on the vulcanization process and properties of the produced rubbers was identified. The basis sanitary and hygienic indices of rubbers were studied. A wide range of medical-purpose items was manufactured using the developed compounds.

Refining the qualification process for medical materials.

This article examines the history of the use of silicone elastomers in medical devices and explains the importance of understanding a material's physical and chemical properties. Related issues of biocompatibility testing, materials biodurability, process controls, regulation, cost, FDA master files, and expedited approval also are addressed.

Effect of three plastic catheters on survival and growth of Pseudomonas aeruginosa.

The effect of polyvinylchloride (PVC), polyurethane (PU) and siliconized latex (SL) catheters on the survival and growth of six non-mucoid and three mucoid strains of Pseudomonas aeruginosa was evaluated. Pseudomonas aeruginosa (1 x 10(8)) was incubated in PBS alone (control) or with 30 1-cm length segments of each catheter and the number of viable microorganisms was determined after 8 h, 1, 2, 5, 7 and 10 days. The presence of PVC catheters significantly favoured the survival and growth of non-mucoid strains in comparison to the control (P less than 0.05 at 5 days, P less than 0.01 at 7 days and thereafter); a similar result was observed with SL catheters (P less than 0.05 at 2 days, P less than 0.01 at 5 days and thereafter). No differences were observed with PU catheters. The number of mucoid microorganisms decreased with time in all controls and suspensions containing segments of catheter, but non-mucoid revertants appeared and quickly increased in the presence of PVC and SL (but not PU) catheters. Eluates of PBS previously containing PVC or SL segments induced a 100- to 500-fold increase in the growth of a non-mucoid strain in comparison with PBS alone. It is concluded that some plastic catheters can release substance(s) that favour the viability of P. aeruginosa.

In situ replication techniques: II. Quantitative methodologies for replicate materials.

Because replicate materials have requirements different from those of recording or impression materials, quantitative methodologies were sought using commercial impression materials. Two satisfactory objective techniques resulted, a laser-scattering and a capillary flow test. Using high-resolution gratings to stimulate tooth detail (less than 1 micron), the reproduction quality of 36 two-stage replicas was determined in diffraction, reflection, and in an unblazed state. Using precision bore glass tubes (0.25, 0.5, 1, and 2 mm diameters) to simulate the high-energy surface of enamel, the flow characteristics of nine elastomers (the first stage replicates) and four epoxies (the second stage replicates) were determined at isobaric conditions. Because the laser spot size was relatively large (0.6 mm) and the pressure differential was small (25 mm Hg), both the global resolution and the low shear rate characteristics could be measured. Of the commercial materials tested, Reprosil Light had the best combination of fluidity and resolution, regardless of which positive material was used. Although Permagum Low, Silene Wash, and Xantopren Blue scored high in one of the two tests, none of these materials could compare to Reprosil Light within the context described herein.