Reacción biológica de la cobertura de poliuretano en los implantes de gel de silicona. Trabajo experimental en ratas / Biological reaction of the polyurethane coating on silicone gel implants. Experimental work in rats

Los implantes de silicona recubiertos con poliuretano vulcanizado han reducido signifi cativamente la incidencia de contractura capsular. La FDA suspendió la venta temporalmente en EE.UU. de estos implantes por estudios que sugerían que el 2,4-TDA, metabolito del poliuretano, podría ser cancerígeno. En el año 1995, y por falta de evidencia que sustentara lo anterior, la FDA autorizó nuevamente su uso, pero aún genera controversias. Es nuestro objetivo demostrar cuál es el grado de reabsorción que sufre el poliuretano en relación con el tiempo de colocado el implante en forma experimental con ratas de laboratorio. Material y métodos. Trabajo prospectivo, experimental y a triple ciego. Se colocó en 18 ratas de laboratorio implantes de gel de silicona recubierto con poliuretano de 2 cc marca Silimed. Se realizó la extracción del implante en bloque a los 3, 6, 12, 18 y 24 meses. Se evaluó el nivel de contractura capsular, el espesor macroscópico de la cápsula y el análisis microscópico de la misma. Resultados. En ninguna de las ratas se objetivó contractura capsular. El espesor promedio de la cápsula fue de 1.88 mm (rango 1,8 a 1,92 mm, n: 18, p<0,5) siendo no signifi cativa en comparación con los 2 mm de recubierta original. A nivel microscópico se objetivó una reacción infl amatoria prolongada, reacción de células gigantes y macrófagos próximos a la cubierta, lo que forma una contractura no lineal. También se observo partículas de poliuretano grandes, rodeadas y ancladas a los macrófagos. Este hallazgo muestra que el poliuretano pasa a formar parte de la cápsula y que no se degrada en forma signifi cativa al menos a los 24 meses de haber sido implantados en ratas. Conclusión. Los hallazgos macroscópicos y microscópicos demuestran que el poliuretano pasa a formar parte de la cápsula y no a degradarse y volcarse a la circulación general como así también la formación de una capsula blanda, cuya correlación clínica, es el menor índice de contractura capsular de este tipo de implante

Polyurethane-covered silicone implants have signifi cantly reduced the incidence of capsular contracture. FDA temporarily suspended this product in EE UU due to studies that suggested 2,4-TDA, polyurethane`s metabolite, may be carcinogenic. In 1995, for lack of evidence to support this, its use was authorize by the FDA again, but still generates controversy. It is our objective to demonstrate wich is the degree of resorption of polyurethane cover, regarding the time the implant is placed, in an experimental laboratory rats. Material and methods: Prospective, experimental and triple blind study. It was placed on 18 laboratory rats 2 cc Polyurethane-covered silicone implants manufactured by Silimed. Implants removal was performed in block at 3, 6, 12, 18 and 24 months. It was evaluated the grade of capsular contracture, the macroscopic thickness of the capsule and the microscopic analysis of it. Results: None of the rats evidenced capsular contracture. The average thickness of the capsule was 1.88 mm (range 1.8 to 1.92 mm, n = 18, p <0.5) being not signifi cant compared to the original 2mm coated. The microscopic study evidenced a large infl ammatory reaction, giant cells reaction and macrophages near the coat which makes a nonlinear contracture. Large Polyurethane particles was also observed, surrounded and anchored to macrophages. These fi ndings show that the polyurethane becomes part of the capsule and does not is degraded signifi cantly at least 24 months after being implanted in rats. Conclusion: Macroscopic and microscopic fi ndings demonstrate that the polyurethane coat becomes part of the capsule and is not degraded to go to the general circulation, as well as the formation of a soft capsule, nonlineal, whose clinical correlation, is a lower rate of capsular contracture of this implant

Pectus excavatum ­ Correção cirúrgica utilizando tala externa de poliuretano fabricada com tecnologia de impressão 3D / Pectus excavatum ­ Surgical correction, using polyurethane external splint made with 3D printing technology

Objetivou-se relatar o emprego de uma tala externa confeccionada com material de poliuretano e cobertura interna de neopreme na reparação cirúrgica do pectus excavatum em um felino jovem. O felino apresentava deformidade anatômica congênita na região do externo e sinais clínicos respiratórios. Imagens avançadas de tomografia foram utilizadas para moldar a tala impressa com tecnologia tridimensional. Esta alternativa possibilitou melhor planejamento cirúrgico e, com isso, conforto para o paciente, além da qualidade própria do material de poliuretano que é levemente maleável, o que permitiu melhor moldagem e expansão torácica durante a respiração. A tala se provou resistente o suficiente para suportar a tração ocasionada pelos fios de sutura e possibilitou o reposicionamento adequado do osso esterno ao mesmo tempo que se mostrou confortável e acarretou mínimas lesões ao paciente.

The aim of this paper was to report the use of an external splint made of polyurethane material and internal neopreme covering in the surgical repair of a pectus excavatum in a young feline. The feline exhibited a congenital anatomical deformity in the external region and clinical respiratory signs. Advanced CT images were used to shape the 3D-printed splint. This alternative allowed better surgical planning and, therefore, comfort for the patient, this because to the quality of the polyurethane material, which is slightly malleable, and allowed for better molding and chest expansion during breathing. The splint proved to be strong enough to withstand the traction caused by the suture threads and allowed the proper repositioning of the sternum, at the same time it was comfortable and caused minimal injuries to the patient.

Selective Separation and Preconcentration of Caffeine from Natural and Pharmaceutical Products using New Polyurethane Foams

Abstract Two polyurethane foam-based sorbents (PUF) were synthesized by imprinting and grafting techniques and examined for selective separation and preconcentration of caffeine (CAF) in some pharmaceutical products and in black tea. Molecularly imprinted PUF was synthesized based on hydrogen-bonding interactions between CAF and alizarin yellow G (AYG) and subsequent polymerization into PUF. The static experiments indicated optimum sorption conditions at pH=6.5 and 5.5 for imprinted PUF (AY-IPUF) and grafted PUF (AY-GPUF), respectively. In the online experiments, the suitable preconcentration time was found to be 40 and 20s for (AY-IPUF) and (AY-GPUF), respectively, at a flow rate of 1.75 mL.min-1. Desorption of CAF has been affected by passing 500 µL of 0.05, 0.01 mol.L−1 HCl eluent onto (AY-IPUF) and (AY-GPUF), respectively. The online methods have provided satisfactory enrichment factors of 8.4 and 10.5 for (AY-IPUF) and (AY-GPUF), respectively. The time consumed for preconcentartion, elution and determination steps was 1.48 and 1.05 min, thus, the throughput was 42 and 57 h-1, for (AY-IPUF) and (AY-GPUF), respectively. The developed sorbents were studied for the determination of CAF in pharmaceutical samples which will be helpful to minimize caffeinism. Finally, in silico bioactivity, ADMET and drug-likeness predictive computational studies of caffeine were also carried out

Linfoma anaplásico de células grandes asociado a implante mamario. Reporte de un caso y revisión de la literatura. / Breast Implant Associated-Anaplastic Large Cell Lymphoma (BIA-ALCL) - Argentinian case

El linfoma anaplásico de células grandes asociado a implantes mamarios LACG-AI o BIA-ALCL, abreviatura en inglés de "Breast Implant Associated-Anaplastic Large Cell Lymphoma", es una nueva entidad reconocida por la OMS desde el 2016, de rara incidencia y que aún plantea muchos interrogantes. Desde su primera mención en 1997 (J. Keech - B. Creech) su incidencia ha ido en aumento. En julio de 2020, 953 casos en el mundo según el Registro de la Sociedad Americana de Cirujanos Plásticos (PROFILE), y las publicaciones se multiplican exponensialmente año a año demostrando el interés que suscita. Se ha descripto una fuerte asociación con las superficies texturizadas de los implantes mamarios y con el tipo de material (mayor textura "grado 4" y cubierta de poliuretano mayor riesgo) llegando a describirse tasas tan altas omo 1/2830 en Australia/Nueva Zelanda. Su presentación clínica en casi el 75% es bajo la forma de un seroma tardío y el tiempo de exposición promedio ronda entre los 7 a 11 años. El diagnóstico histo-patológico integra el examen morfológico con la caracterización molecular, visualizándose grandes célular anaplásicas CD30 (+), ALK (-). El tratamiento quirúrgico, capsulectomía bilateral en estadios tempranos es el gold standard. Su pronóstico es excelente con exérsis completas. Objetivo: actualizar la información sobre esta novel enfermedad y comentar un caso propio que presenta todas las características descriptas en la literatura, siendo el 14° registrado en Argentina

The anaplastic large cell lymphoma associated with breast implants, LACCG-AI o BIA-ALCL abbreviation in English, is an entity recognized by the WHO since 2016 of rare incidence and that still raises many questions. Since its firts mention in 1997 (J. Keech - B. Creech) its incidence has been increasing, In july 2020, 953 cases in the world according to the Registry of the America Society of Plastic Surgeons (PROFILE), and the publications multiply exponentially year after year, demonstrating the interest it arouses, A strong association has been described with the textured surfaces of breast implants and with the type of material (greater texture "grade 4" and higher risk polyurethane cover), reaching rates as high as 1/2830 in Australia / New Zealand. Its clinical presentation in almost 75% is in the form of a late seroma and the average exposure time is between 7 to 11 years. The pathological anatomical diagnosis integrates the morphological examination with the molecular characterization, visualizing large anaplastic CD30 (+), ALK (-) cells. Surgical treatment, bilateral capsulectomy in early stages, is the gold standard. Her prognosis is excellent with complete exeresis. Objetive: to update the information on this novel disease and comment on an own case that presents all the characteristics described in the literature, the 14th being registered in Argentina

Craft Brewery Wastewater Treatment: a Fixed-Bed Single-Batch Reactor with Intermittent Aeration to Remove COD and TN

Abstract This study evaluated an intermittently aerated, fixed-bed, single-batch reactor, with mini BioBob© as biofilm media support, as an alternative treatment of craft brewery wastewater. In order to remove chemical oxygen demand (COD) and total nitrogen (TN), seven conditions were performed in a central composite experimental design (CCD) with different aeration times (1, 2 and 3 h in a 4 h cycle) and hydraulic retention times (HRT) (12, 16 and 20 h). The results showed that the removal of COD and TN were positively affected by increased aeration time and HRT. The condition that presented the best quality effluent was Condition No. 1 (20 h HRT and 3 h aeration), with 209 ± 28 mg COD L-1; 3.00 ± 0.15 mg TKN L-1 ; and 0.67 ± 0.11 mg NO3-N L-1. Kinetic assays showed that the highest values for the substrate removal rate constant, kCOD = 0.1774 h-1 were obtained with the longest aeration time (3 h). The most probable number (MPN) test showed a higher concentration of denitrifying bacteria (heterotrophic), 3.3 x 106, than for AOB and NOB bacteria (autotrophic), which were 4.9 x 103 and 2.7 x 103, respectively. Moreover, it was possible to verify that correcting the influent alkalinity with 7.14 mg CaCO3 for each 1 mg of TKN resulted in better process efficiency. It was concluded that COD and TN can be removed from craft brewery wastewater using an intermittently aerated, fixed-bed, single-batch reactor with mini Biobob© as biofilm media support.

A castor oil plant (Ricinus communis)-derived implant improves the biomechanical properties of noncritical bone defects

ABSTRACT Purpose The biomechanical properties of the polyurethanes implant material derived from castor oil plant (Ricinus communis) were evaluated in a noncritical bone defect model in rat tibia. Methods After three weeks of the implant application, the tibias were tested by means of the biomechanical three-point flexion test and resistance, rigidity, energy at maximum load and maximum energy were evaluated. Nonparametric statistical analysis was performed. Results It was found that the group that received the implant behaved the same as the intact control group and also showed a significant increase in maximum load compared to the spontaneous repair group. Conclusions Our results indicate that the tibias with the implant material in a noncritical bone defect recover normal biomechanical parameters in less time than spontaneously.

Avaliação da deformação do preparo de superfície de implantes dentários submetidos a diferentes intensidades de torque / Deformation analysis of the surface preparation in dental implants submitted to different torque intensities

Introdução: o aprimoramento do processo de osseointegração faz com que os investimentos em pesquisa e o desenvolvimento de novos materiais e tratamentos de superfície sejam despendidos para promover a relação entre osso e implante. Uma das condições para o sucesso é a ausência de micromovimentos ou estabilidade primária da peça implantada, fato esse que leva alguns cirurgiões a aplicar torques excessivos sobre o implante, podendo resultar em danos ao tratamento aplicado à superfície externa do mesmo. Objetivo: o presente trabalho investigou possíveis níveis de deformação do preparo de superfície conforme diferentes valores de torque foram aplicados à dois sistemas de implantes para avaliar os possíveis danos causados. Metodologia: foram instalados 5 implantes do sistema Dérig e 5 implantes do sistema Straumann em um bloco de poliuretano, para posterior remoção com contra-torque e avaliação da superfície sob o Microscópio Eletrônico de Varredura (MEV). Resultados: nos resultados obtidos, no grupo de implantes Dérig não foi possível constatar evidências que comprovem que a elevação dos valores de torque aplicados aos implantes até 95 Ncm danifiquem ou alterem a estrutura do preparo de superfície externa dos implantes, contudo, no grupo Straumann, verificamos danos e alterações no preparo de superfície com torque progressivo a partir de 50 Ncm. Conclusão: possíveis alterações e danos ao preparo de superfície de implantes que apresentem rugosidade de superfície aumentada por jateamento podem ocorrer em torques acima de 50 Ncm empregados com o objetivo de aumentar sua estabilidade primária.

Introduction: improving the osseointegration process means that investments in research and development of new materials and surface treatments are expended to promote the relationship between bone and implant. One of the conditions for success is the absence of micromovements or primary stability of the implanted part. This fact causes some surgeons to apply excessive torque to the implant, which may result in damage to the treatment applied to the external surface of the implant. Objective: The present work investigated possible surface preparation deformation levels as different torque values were applied to two implant systems to evaluate the possible damage caused. Methodology: ive Dérig system implants and five Straumann system implants were installed in a polyurethane block for subsequent counter-torque removal and surface evaluation under the Scanning Electron Microscope (SEM). Results: Iin the obtained results, in the Dérig implant group it was not possible to verify evidences that the increase of the torque values applied to the implants up to 95 Ncm could damage or alter the structure of the external surface preparation of the implants, however, in the Straumann group we verified damage and changes in surface preparation with progressive torque from 50 Ncm. Conclusion: possible alterations and damages to the surface preparation of implants that present increased surface roughness by blasting can occur in torques above 50 Ncm employed in order to increase their primary stability.

The Role of Pedicle Screw Surface on Insertion Torque and Pullout Strength / Influência da superfície dos parafusos pediculares no torque de inserção e resistência ao arrancamento

Abstract Objective Compare by mechanical tests the pullout resistance and the insertion torque of rough and smooth pedicle screws. Methods Pedicle screws with rough surface and smooth surface, with diameters of 4.8; 5.5 and 6.5 mm, were inserted in polyurethane blocks with density of 10 PCF (0.16 g/cm3). Insertion torque and pullout strength were assessed. Results The pullout strength of the rough surface and smooth surface screws did not differ, except in the group of 4.8 mm diameter screws. In this group, the rough surface screws showed greater resistance to pullout. Conclusion Pedicle screws with a rough surface did not show increased pullout resistance in the acute phase of their insertion in polyurethane blocks compared to smooth surface screws. The rough surface screws had a higher insertion torque than the smooth surface screws, depending on the diameter of the screw and the preparation of the pilot hole.

Resumo Objetivo Comparar por testes mecânicos a resistência ao arrancamento e o torque de inserção do parafuso pedicularjateado e liso. Métodos Parafusos pediculares de superfície áspera e de superfície lisa com diâmetros de 4,8; 5,5 e 6,5 mm foram inseridos em blocos de poliuretano com densidade de 10 PCF (0,16 g/cm3). O torque de inserção e a força de arrancamento foram avaliados. Resultados A força de arrancamento dos parafusos de superfície áspera e de superfície lisa não diferiu, exceto no grupo de parafusos com 4,8 mm de diâmetro. Nesse grupo, os parafusos de superfície áspera apresentaram maior resistência ao arrancamento. Conclusão Os parafusos pediculares de superfície áspera não apresentaram aumento da resistência ao arrancamento na fase aguda de sua inserção em blocos de poliuretano em relação aos parafusos de superfície lisa. Os parafusos de superfície áspera apresentaram maior torque de inserção que os parafusos de superfície lisa, dependendo do diâmetro do parafuso e da preparação do furo piloto.

Influence of an alternative implant design and surgical protocol on primary stability

Abstract The purpose of thisin vitrostudy was to evaluate the influence of a new proposal of implant design and surgical protocol on primary stability in different bone densities. Four groups were tested (n=9): G1 - tapered, cone morse, Ø 4.3 mm x 10 mm in length (Alvim CM); G2 - experimental tapered; G3 - cylindrical, cone morse, Ø 4.0 mm x 11 mm in length (Titamax CM) and G4 - experimental cylindrical. The experimental implants were obtained from a design change in the respective commercial models. The insertion was performed in polyurethane (PU) blocks 0.24 g/cm3(20 pcf) and 0.64 g/cm3(40 pcf), according to different surgical protocols. The primary stability was measured by means of insertion torque (IT) and pullout test. Data were analyzed by ANOVA, Tukey's test (α=0.05) and Pearson's correlation. For IT and pullout, conventional and experimental implants showed no difference between them when inserted in the 20 pcf PU (p>0.05). In the 40 pcf PU, the modified implants exhibited greater IT (p<0.05) and lower pullout (p<0.05) compared to the respective conventional models. The implant design tested associated with the surgical protocol, positively influenced primary stability in higher density bones.

Resumo O objetivo deste estudo in vitro foi avaliar a influência de uma nova proposta de design de implante e protocolo cirúrgico na estabilidade primária em diferentes densidades ósseas. Foram testados quatro grupos (n=9): G1 - cônico, cone morse, Ø 4,3 mm x 10 mm de comprimento (Alvim CM); G2 - experimental cônico; G3 - cilíndrico, cone morse, Ø 4,0 mm x 11 mm de comprimento (Titamax CM) e G4 - experimental cilíndrico. Os implantes experimentais foram obtidos a partir de uma mudança no design dos respectivos modelos comerciais. A inserção foi realizada em blocos de poliuretano (PU) 0,24 g/cm3 (20 pcf) e 0,64 g/cm3 (40 pcf), de acordo com diferentes protocolos cirúrgicos. A estabilidade primária foi aferida por meio do torque de inserção (TI) e ensaio de arrancamento. Os dados foram analisados por ANOVA, teste de Tukey (α=0,05) e correlação de Pearson. Para TI e arrancamento, os implantes convencionais e experimentais não mostraram diferença entre si quando inseridos na PU de 20 pcf (p>0,05). Na PU de 40 pcf, os implantes modificados exibiram maior TI (p <0,05) e menor arrancamento (p <0,05) em relação aos respectivos modelos convencionais. O design do implante testado associado ao protocolo cirúrgico, influenciou positivamente a estabilidade primária em ossos de maior densidade.

Composite-derived monomers affect cell viability and cytokine expression in human leukocytes stimulated with Porphyromonas gingivalis

Abstract Objectives: Dental composites release unreacted resin monomers into the oral environment, even after polymerization. Periodontal cells are, therefore, exposed to substances that potentially elicit the immune inflammatory response. The underlying molecular mechanisms associated with the interaction between resin monomers and human immune cells found in the gingival crevicular fluid are not fully understood yet. This study investigated the ability of bisphenol A-glycidyl methacrylate (BISGMA), urethane dimethacrylate (UDMA) and triethylene glycol dimethacrylate (TEGDMA) to induce apoptosis and cytokine release by human leukocytes stimulated with a periodontal pathogen. Methodology: Peripheral blood mononuclear cells (PBMC) from 16 healthy individuals were included in this study. To determine the toxicity, the PBMC were incubated for 20 hours, with monomers, for the analysis of cell viability using MTT assay. To evaluate cell death in the populations of monocytes and lymphocytes, they were exposed to sub-lethal doses of each monomer and of heat-inactivated Porphyromonas gingivalis (P. gingivalis) for 5 hours. Secretions of IL-1β, IL-6, IL-10 and TNF-α were determined by ELISA after 20 hours. Results: UDMA and TEGDMA induced apoptosis after a short-time exposure. Bacterial challenge induced significant production of IL-1β and TNF-α (p<0.05). TEGDMA reduced the bacterial-induced release of IL-1β and TNF-α, whereas UDMA reduced IL-1β release (p<0.05). These monomers did not affect IL-10 and IL-6 secretion. BISGMA did not significantly interfere in cytokine release. Conclusions: These results show that resin monomers are toxic to PBMC in a dose-dependent manner, and may influence the local immune inflammatory response and tissue damage mechanisms via regulation of bacterial-induced IL-1β and TNF-α secretion by PBMC.

Influência do número de roscas e da densidade dos blocos de poliuretano na estabilidade primária de implantes do sistema intraoss / The influence of implant thread number and polyurethane block density on primary stability values of the Intraoss implant system

Objetivo: avaliar e comparar a estabilidade primária dos implantes cilíndricos de 3,75 mm x 11 mm Titaoss e Titaoss dupla rosca, do Sistema Intraoss, instalados em blocos de poliuretano com baixa densidade. Material e métodos: foram realizadas 32 cavidades em dois blocos de poliuretano, simulando as densidades de ossos tipo III e IV. As estabilidades dos implantes foram mensuradas por meio do torque de inserção e frequência de ressonância. Resultados: os implantes Titaoss instalados no osso tipo III apresentaram valores de torque de inserção de 43,1 ± 14,87 Ncm, enquanto os valores dos implantes Titaoss dupla rosca foram 46,9 ± 5,3 Ncm. No osso tipo IV, os implantes Titaoss apresentaram valores de 30 ± 0,0 Ncm e os dupla rosca de 29,4 ± 1,77 Ncm. Não houve diferença significante na estabilidade primária entre os grupos dos implantes (p > 0,05) instalados no mesmo tipo de osso. Os implantes Titaoss instalados no osso tipo III apresentaram valores de ISQ de 57,3 ± 4,69, ao passo que os valores para os implantes Titaoss dupla rosca foram 54,9 ± 3,98. No osso tipo IV, os implantes Titaoss apresentaram valores de 48,4 ± 4,07 ISQ e os dupla rosca de 50,8 ± 3,98 ISQ. As estabilidades primárias dos implantes foram maiores no osso tipo III quando comparado ao IV (p < 0,05). Conclusão: os dois desenhos de implantes permitem a obtenção da estabilidade primária para a técnica da carga mediata. No entanto, para submeter esses tipos de implante à carga imediata, indica-se a técnica da subfresagem.

Objectives: this in vitro study aimed to evaluate and compare the primary stability of the cylindrical implants (3.75 mm x 11 mm) Titaoss and Titaoss double thread from Titaoss System placed in cavities made of low-density polyurethane blocks. Material and methods: 32 cavities were made in two types of polyurethane blocks simulating the type III and IV bone densities. The implant stability values were measured using the final insertion torque and resonance frequency analysis. Results: the Titaoss implants placed in type III bone achieved 43.1 ± 14.87 Ncm, while the double-thread values were 46.9 ± 5.3 Ncm. For bone type IV, the Titaoss implants reached 30Ncm and the double thread 29.4± 1.77 Ncm. No statistically significant differences on implant stability were seen for both groups (p > 0.05) for the same bone type. the Titaoss implants in bone type III had 57.3 ± 4.69 and the double thread 54.9 ± 3.98 ISQ values. In type IV bone, Titaoss reached 48.4 ± 4.07 and the double thread 50.8 ± 3.98 ISQ units. The primary stability values were greater at type III than type IV bone (p < 0.05). Conclusion: both implant designs allow for primary stability. However, the use of an underpreparation technique is recommended in cases of immediate loading protocols.

Influence of a hydrophobic monomer on the physical and mechanical properties of experimental surface sealants

Abstract This study evaluated the effect of adding the hydrophobic monomer 1,12 dodecanediol dimethacrylate (DDDMA) to experimental sealants with and without thermocycling on degree of conversion (DC), water sorption (WS), water solubility (WSB), color stability (ΔE), and micro-shear bond strength (μSBS). Five experimental and one commercially available sealant (Bisco - BIS) were tested. The experimental sealants were formulated by mixing different percentages of DDDMA monomers and urethane dimethacrylate (UDMA). The photoinitiator system was composed by camphorquinone (CQ) and tertiary amine 4-ethyl benzoate dimetilamiono (EDBA). Ethanol was used as a solvent. The experimental groups were named sequentially according to the monomeric content (DDDMA/UDMA): S40/40 (40/40), S50/30 (50/30), S60/20 (60/20), S70/10 (70/10) and S80/0 (80/0). Data were analyzed separately by one-way ANOVA, followed by Tukey's test (p<0.05). The values of DC ranged from 94.59% (S40/40) to 54.02% (S80/10). BIS showed the highest WS value (p<0.05) and S40/40, S50/30, S60/20 and S80/0 showed the lowest WS values of all tested sealants. WSB values ranged from 7.88 µg/mm3 (BIS) to 13.27 µg/mm3 (S70/10). The highest ΔE value was 11.05±2.88 for BIS and the highest μSBS value was found for S60/20. No significant difference was observed in bond strength between sealants and bovine enamel after thermocycling. Adding DDDMA to the composition of surface sealants can improve its performance, once the monomer increased the degree of conversion and the color stability.

Effect of cavity preparation design and ceramic type on the stress distribution, strain and fracture resistance of CAD/CAM onlays in molars

Abstract Objective This study aimed to evaluate the effect of the cavity preparation and ceramic type on the stress distribution, tooth strain, fracture resistance and fracture mode of human molar teeth restored with onlays. Material and Methods Forty-eight molars were divided into four groups (n=12) with assorted combinations of two study factors: BL- conventional onlay preparation with boxes made from leucite ceramic (IPS-Empress CAD, Ivoclar Vivadent); NBL- conservative onlay preparation without boxes made from leucite ceramic; BD- conventional onlay preparation with boxes made from lithium disilicate glass ceramic (IPS e.max CAD, Ivoclar Vivadent); NBL- conservative onlay preparation with boxes made from lithium disilicate glass ceramic cuspal deformation (µS) was measured at 100 N and at maximum fracture load using strain gauge. Fracture resistance (N) was measured using a compression test, and the fracture mode was recorded. Finite element analysis was used to evaluate the stress distribution by modified von Mises stress criteria. The tooth strain and fracture resistance data were analyzed using the Tukey test and two-way ANOVA, and the fracture mode was analyzed by the chi-square test (α=0.05). Results The leucite ceramic resulted in higher tooth deformation at 100 N and lower tooth deformation at the maximum fracture load than the lithium disilicate ceramic (P<0.001). The lithium disilicate ceramic exhibited higher fracture resistance than the leucite ceramic (P<0.001). The conservative onlay resulted in higher fracture strength for lithium disilicate ceramic. Finite element analysis results showed the conventional cavity preparation resulted in higher stress concentration in the ceramic restoration and remaining tooth than the conservative onlay preparation. The conservative onlays exhibited increased fracture resistance, reduced stress concentration and more favorable fracture modes. Conclusion Molars restored with lithium disilicate CAD-CAM ceramic onlays exhibited higher fracture resistance than molars restored with leucite CAD-CAM ceramic onlays.

Mechanical analysis of transversal iliac fracture stabilization using dynamic compression plate or screws and PMM in polyurethane bone model / Avaliação mecânica de estabilização de fratura ilíaca transversa com placa de compressão dinâmica ou polimetilmecatrilato associado à parafusos utilizando modelo de osso sintético de poliuretano

Pelvic fractures correspond to 20 to 30 % of the fractures observed in dogs. Complete fractures, especially with bone axis deviation should be surgically treated. The mechanical study of surgical techniques is of utmost importance to assess the best way of treating these injuries. This study compared, biomechanically, the use of a dynamic compression plate (DCP) and screws (group 1) or screws and polymethylmethacrylate (PMMA) (group 2) to stabilize an iliac fracture using a static test. Sixteen canine synthetic hemi-pelvises (test specimens) with a transverse iliac osteotomy were used. After fixation with implants, a load was applied to the acetabulum until failure. Group 1 maximal compressive load was 133.9±18.60 N, displacement at yield 21.10±3.59mm and stiffness 125.22±12.25N/mm. Group 2 maximal compressive load was 183.50±27.38N, displacement at yield 16.66±5.42mm and stiffness 215.68±33.34N/mm. The stabilization with polymethylmethacrylate was stronger than dynamic compression plate since it resisted a greater load in all test specimens.(AU)

As fraturas da pelve são frequentes em cães, correspondendo a 20-30% das fraturas encontradas na espécie. A grande maioria delas é tratada cirurgicamente, principalmente aquelas que apresentam desvio ósseo. O estudo mecânico das técnicas cirúrgicas é de extrema importância para avaliação da melhor maneira de tratamento destas lesões. O objetivo deste estudo foi comparar, do ponto de vista biomecânico, a fixação das fraturas do ílio utilizando uma placa de compressão dinâmica ou parafusos associados ao polimetilmetacrilato, por meio de um teste estático. Foram utilizadas 16 hemipelves caninas de origem sintética, nas quais uma osteotomia transversa foi realizada no corpo do ílio. As fixações foram divididas em dois grupos: fixação com placa de compressão dinâmica e parafusos (grupo1) ou parafusos associados ao polimetilmetacrilato (grupo 2). Posteriormente à fixação dos implantes foi aplicada uma carga no acetábulo de cada corpo de prova até a falha. O grupo 2 apresentou força máxima de aplicação de carga a média de 133.9±18.60N, deflexão 21.10±3.59mm e rigidez 125.22±12.25N/mm. O grupo 2 apresentou força máxima de aplicação de carga a média de 183.50±27.38N, deflexão 16.66±5.42mm e rigidez 215.68±33.34N/mm. A estabilização com o polimetilmetacrilato mostrou ser mais resistente, pois resistiu a uma maior quantidade de carga em relação à placa de compressão dinâmica, em todos os corpos de prova.(AU)

Partitioning of the diffuse attenuation coefficient for photosynthetically available irradiance in a deep dendritic tropical lake

ABSTRACT We studied the effects of particulate and dissolved optically active components on the attenuation of photosynthetic active radiation (PAR) in a tropical lake. The temporal and spatial distribution of tripton, Chl-a and aCDOM(440) and their relative contribution to the diffuse PAR attenuation coefficient (Kd) was investigated at 21 sites (dry and wet seasons and two intermediate periods) and at monthly interval at 1 pelagic site. Higher values of ​​ Kd were observed during the mixing period, characterized by a higher concentration of tripton and Chl-a compared to the stratified rainy season. In the spatial sampling PAR attenuation was dominated by tripton absorption/scattering (average relative contribution of 79%), followed by Chl-a (average 11.6%). In the monthly sampling tripton and Chl-a accounted for most of the Kd with relative contributions of 47.8% and 35.6%, respectively. Multiple linear regression analysis showed that Chl-a and tripton in combination explained 97% of the monthly variation in Kd (p<0.001), but Chl-a had more influence (higher regression coefficient). Thus, although most of light attenuation was due to tripton, seasonal variations in phytoplankton abundance were responsible for most of the temporal fluctuations in Kd.

Clinical outcome and patient satisfaction using biodegradable (NasoPore) and non-biodegradable packing, a double-blind, prospective, randomized study / Desfecho clínico e satisfação do paciente com o uso de tampão biodegradável (NasoPore) e não biodegradável: estudo prospectivo, duplo-cego e randomizado

Abstract Introduction Nasal packing after endoscopic sinus surgery is used as a standard procedure. The optimum solution to minimize or eliminate all disadvantages of this procedure may be accomplished using biodegradable packs. Objective The aim of this study was to compare patient satisfaction and clinical outcome associated with absorbable and non-absorbable packing after FESS. Methods In total, 50 patients were included in a prospective, double-blind, randomized trial. One side was packed with polyurethane foam, while the opposite side was packed with gauze packing. On the 2nd, 10th, and 30th postoperative day, the patients were questioned with the aid of a visual analog scale. The standardized questionnaires for bleeding, nasal breathing, feeling of pressure, and headache were used. The presence of synechiae, infection, or granulation was noted and recorded with the video-endoscopy. Results A significant difference according to lower pressure was found in the NasoPore group compared to the controls on day ten after surgery. The NasoPore packing had lower scores with respect to postoperative nose blockage on the 2nd and 10th days. Mucosal healing was better for the NasoPore group, both at day ten and 30 compared with the control group. Conclusion The overall patient comfort is higher when using NasoPore compared to non-resorbable traditional impregnated gauze packing. Intensive saline douches applied three to four times per day are mandatory after the operation to prevent synechiae formation and fluid resorption by the packing.

Resumo Introdução O tamponamento nasal após cirurgia sinusal endoscópica é procedimento de rotina. A solução ideal para minimizar ou eliminar as desvantagens desse procedimento pode ser alcançada com o uso de tampões biodegradáveis. Objetivo Comparar a satisfação do paciente e o desfecho clínico associados ao uso de tampões absorvíveis e não absorvíveis após a cirurgia funcional dos seios paranasais (FESS- Functional Endoscopic Sinus Surgery). Método Foram incluídos 50 pacientes neste estudo prospectivo, duplo-cego e randomizado. Um dos lados foi tamponado com espuma de poliuretano, enquanto no outro lado foi feito um tamponamento com gaze. Nos 2º, 10º e 30º dias após a operação, os pacientes foram perguntados com a ajuda de uma escala analógica visual. Foram empregados questionários padronizados para sangramento, respiração nasal, sensação de pressão e cefaleia. A presença de sinequias, infecção ou granulação foi registrada por videoendoscopia. Resultados Foi observada diferença significante, da sensação de pressão, menor no lado tratado com NasoPore vs. controles no 10º dia após a cirurgia. O tamponamento com NasoPore obteve escores mais baixos com respeito ao bloqueio nasal pós-operatório no 2º e 10º dias. A cicatrização da mucosa foi melhor no lado do NasoPore, mas no 10º e 30º dias os resultados foram comparáveis com os do lado de controle. Conclusão O conforto geral do paciente é maior com o uso de NasoPore vs. tamponamento tradicional com gaze besuntada não reabsorvível. O uso vigoroso de jatos de solução salina aplicados 3-4 vezes ao dia é um procedimento obrigatório após a cirurgia, para evitar a formação de sinequias e para uma absorção natural do tampão.

Aplicação de resina poliuretânica derivada do óleo de mamona em formas farmacêuticas gastrorretentivas de liberação controlada / Application of polyurethane resin from castor oil in controlled release gastroretentive dosage forms

Polímeros naturais têm sido amplamente utilizados como excipientes farmacêuticos, principalmente por serem biocompatíveis e renováveis. O objetivo deste estudo foi investigar a aplicação da resina poliuretânica derivada do óleo de mamona (RPDOM) em formas farmacêuticas gastrorretentivas de liberação controlada. O trabalho aqui apresentado está dividido em quatro capítulos. O capítulo 1 trata-se de uma visão geral sobre a aplicação dos poliuretanos como sistemas de liberação de fármacos, enfatizando os estudos contendo poliuretanos do óleo de mamona. O capítulo 2 trata-se de uma revisão sistemática sobre sistemas gastrorretentivos de liberação de fármacos. O capítulo 3 trata do desenvolvimento e da caracterização da RPDOM contendo fármaco na sua matriz. Domperidona e cloridrato de verapamil foram escolhidos como fármacos modelos devido ao potencial uso desses em formulações gastrorretentivas. Os estudos físico-químicos mostraram que parte da domperidona interagiu quimicamente com a RPDOM. Visto que não é possível a quebra dessa ligação química durante o estudo de dissolução, parte do fármaco ficou indisponível para liberação. Por outro lado, o verapamil foi incorporado com sucesso na RPDOM pelo método de evaporação do solvente. O verapamil interagiu através de forças intermoleculares com o polímero e esse sistema mostrou um promissor perfil de dissolução. O capítulo 4 trata do desenvolvimento de matrizes monolíticas flutuantes, contendo verapamil como fármaco modelo, espuma de polipropileno como excipiente de baixa densidade e um blend da RPDOM e da celulose microcristalina como sistema matricial. A capacidade de flutuação in vitro das matrizes e o controle da liberação do fármaco foram demonstrados. Por fim, a RPDOM mostrou-se um polímero promissor para o uso em sistemas de liberação controlada de fármacos devido a sua hidrofobicidade e para o uso em sistemas gastrorretentivos flutuantes devido à sua baixa densidade

Natural polymers have been extensively used as pharmaceutical excipients mainly due to their biocompatibility and renewability. The aim of this study was to investigate the application of polyurethane resin from castor oil (PU) in controlled release gastroretentive dosage forms. The work presented herein is divided in four chapters. Chapter 1 is an overview of the application of polyurethanes as drug delivery systems, emphasizing studies containing castor oil-based polyurethanes. Chapter 2 is a systematic review of gastroretentive drug delivery systems. Chapter 3 is about the development and characterization of the PU containing drug in its matrix. Domperidone and verapamil hydrochloride were chosen as model drugs due to their potential use in gastroretentive formulations. Physicochemical studies showed that part of domperidone interacted chemically with PU. Since it is not possible a cleavage of the chemical bond between domperidone and the polyurethane during the dissolution study, part of the drug was not available for release. On the other hand, verapamil was successfully incorporated into PU by solvent evaporation method. Verapamil interacted by intermolecular forces with the polymer and this system showed a promising drug dissolution profile. Chapter 4 shows the development of floating monolithic matrices, containing verapamil as model drug, polypropylene foam as low-density excipient and a blend of PU and microcrystalline cellulose as matrix-forming polymers. The in vitro buoyancy capability of the matrices and the ability to control drug release were demonstrated. Finally, PU proved to be a potential polymer to be used in controlled drug delivery systems due to its hydrophobicity and in gastroretentive floating systems due to its low density

Survival of sealants in molars affected by molar-incisor hypomineralization: 18-month follow-up

Abstract The objective of this study was to evaluate the clinical survival of sealants applied in first permanent molars (FPMs) affected by molar-incisor hypomineralization (MIH), at 18 months of follow-up. Forty-one first permanent molars were selected from 21 children, 6–8 years of age. MIH was classified by one calibrated examiner (kappa = 0.80) according to EAPD criteria. The inclusion criteria were fully erupted FPMs with MIH or sound FPMs (without MIH) for which sealant treatment was indicated. The FPMs were assigned to two groups: CG (control group) and HG (MIH group). Both groups were treated with sealant (FluroShield). Clinical follow-up was performed from baseline to 18 months to assess anatomical form, marginal adaptation, retention and presence of caries, according to criteria set by the United States Public Health Service-Modified, and was conducted by a blinded examiner (kappa = 0.80). The actuarial method was used to evaluate the survival of the sealants. The survival rates for the groups were compared using Fisher’s exact test (α = 5%). The cumulative survival rates were 81% at 1 month, 68.8% at 6 months, 68.8% at 12 months, and 62.6% at 18 months for CG, and 88% at 1 month, 84% at 6 months, 76% at 12 months, and 72% at 18 months for HG. No significant difference was found between the groups. The sealants in molars affected by MIH presented a survival rate similar to the sealants in the control, suggesting that sealants may be an adequate approach for preventing carious lesions in MIH-affected molars.

Surface, thermal and hemocompatible properties of novel single stage electrospun nanocomposites comprising polyurethane blended with bio oilTM

ABSTRACT In this work, the physicochemical and blood compatibility properties of prepared PU/Bio oil nanocomposites were investigated. Scanning electron microscope (SEM) studies revealed the reduction of mean fiber diameter (709 ± 211 nm) compared to the pristine PU (969 nm ± 217 nm). Fourier transform infrared spectroscopy (FTIR) analysis exposed the characteristic peaks of pristine PU. Composite peak intensities were decreased insinuating the interaction of the bio oilTM with the PU. Contact angle analysis portrayed the hydrophobic nature of the fabricated patch compared to pristine PU. Thermal gravimetric analysis (TGA) depicted the better thermal stability of the novel nanocomposite patch and its different thermal behavior in contrast with the pristine PU. Atomic force microscopy (AFM) analysis revealed the increase in the surface roughness of the composite patch. Activated partial thromboplastin time (APTT) and prothrombin time (PT) signified the novel nanocomposite patch ability in reducing the thrombogenicity and promoting the anticoagulant nature. Finally the hemolytic percentage of the fabricated composite was in the acceptable range revealing its safety and compatibility with the red blood cells. To reinstate, the fabricated patch renders promising physicochemical and blood compatible nature making it a new putative candidate for wound healing application.

Hydrocortisone release from tablets based on bioresorbable poly(ether-ester-urethane)s

Abstract Bioresorbable linear poly(ether-ester-urethane)s with different hydrophilic characteristics were synthesized from triblock copolymers of poly(ε-caprolactone)-poly(ethylene oxide)-poly(ε-caprolactone) (PCL-PEO) as macrodiols, and L-lysine diisocyanate (LDI) or hexamethylenediisocyanate (HDI) were used as the required diisocyanates. Macrodiols were obtained by ring-opening polymerization (ROP) of ε-caprolactone (CL). Polyurethanes were synthesized by the reaction of the triblock copolymers with LDI or HDI in solution using stannous 2-ethylhexanoate as catalyst. Polyurethane tablets were fabricated and investigated as prospective drug delivery systems. The effect of the PEO content on the polymers' performance as drug carriers was evaluated. It was found that water provoked more swelling and erosion of polymers with higher contents of PEO. The hydrocortisone release profiles were analyzed using the Ritger-Peppas approximation. An anomalous release behaviour (values of n higher than 0.5) was found for most of the analyzed samples.