Silicone plastination of nasus and lingua in large ruminants with and without use of formaldehyde / Plastinación de silicona de nasus y lengua en rumiantes mayores con y sin el uso de formaldehido

SUMMARY: Plastination is an anatomical preparate preparation technique characterized by the replacement of tissue fluids with a reactive polymer. Although more challenging and economically costly than many anatomical methods, this method is desirable because of the fact that specimens created in this method are highly similar to the natural appearance of the intended objects, and they are durable and harmless end products for human health. Our main goal was to completely leave out formaldehyde and similar carcinogenic chemicals used in a method like plastination and to allow production of formaldehyde-free plastinates to be used in anatomy training and examinations in our country. To that end, we compared nose and tongue of 10 large ruminants by subjecting them to plastination, 5 of them with formaldehyde and 5 of them without formaldehyde, and aimed to leave formaldehyde out by taking into account the difference between them. Silicone plastination is the most commonly-used and best-known technique among the plastination techniques because specimens created using this technique look aesthetically impressive. Silicone plastination consists mainly of 5 phases. First of all, we obtained the anatomical situs we wanted and made specimens ready by dissecting some of them after fixation and some of them without fixation. Then, after the implementation of a dehydration phase in acetone baths at -25 °C, a forced impregnation phase was implemented by using a mixture of S10-S3 chemical under negative pressure. In the final phase, the curing and hardening phase, the plastination process was completed by giving the specimens their final shape with the use of the S6 solution. As a result, no significant difference was observed between silicone plastination with and without formaldehyde.

RESUMEN: La plastinación es una técnica de preparados anatómicos caracterizada por la sustitución de fluidos tisulares por un polímero reactivo. A pesar de ser económicamente más costoso que muchas métodos anatómicos, este técnica es deseable debido a que las muestras creadas son muy similares a la apariencia natural de los objetos previstos y son productos finales duraderos e inofensivos para la salud humana. Nuestro objetivo principal fue dejar completamente de lado el formaldehído y las sustancias químicas cancerígenas similares utilizadas en un método como la plastinación y permitir la producción de plastinados libres de formaldehído para su uso en la formación y los exámenes de anatomía en nuestro país. Con ese fin, comparamos la nariz y la lengua de 10 rumiantes mayores sometiéndolos a plastinación, 5 de ellos con formaldehído y 5 de ellos sin formaldehído, y buscamos eliminar el formaldehído considerando la diferencia entre ellos. La plastinación con silicona es la técnica más utilizada y más conocida entre las técnicas de plastinación porque los especímenes creados con ella se ven estéticamente impresionantes. La plastinación con silicona consta principalmente de 5 fases. En primer lugar, obtuvimos el situs anatómico que queríamos y preparamos los especímenes diseccionando algunos de ellos después de la fijación y otros sin fijación. Luego, de la implementación de una fase de deshidratación en baños de acetona a -25 °C, se implementó una fase de impregnación forzada utilizando una mezcla del químico S10-S3 a presión negativa. En la fase final, la fase de curado y endurecimiento, se completó el proceso de plastinación dando a los especímenes su forma definitiva con el uso de la solución S6. Como resultado, no se observaron diferencias significativas entre la plastinación con silicona con y sin formaldehído.

Protocolo unificado de plastinación con silicona en frío y a temperatura ambiente / Unified plastination protocol with silicone at cold and room temperature

RESUMEN: En la actualidad, la técnica de plastinación es considerada una de las más novedosas formas de conservación cuerpos completos, secciones y órganos, tanto humanos como animales, para su uso en docencia de pre y postgrado, como así también investigación morfológica. En este sentido, para desarrollar las diversas técnicas de plastinación se requiere de equipamiento específico y formación especializada de académicos, que tengan la capacidad de llevar adelante la diversidad de protocolos que existen, según el material anatómico que se desee preservar. En el año 2015, desde el Laboratorio de Plastinación y Técnicas Anatómicas de la Universidad de La Frontera, se propuso por primera una nueva técnica de plastinación a temperatura ambiente, que permitió obtener preparaciones plastinadas de igual calidad que las técnicas clásicas de plastinación. En la actualidad, desde nuestro laboratorio, se propone un nuevo protocolo de plastinación con silicona que unifica las técnicas que se desarrollan en frío como así también a temperatura ambiente para la conservación de cuerpos humanos y animales completos, secciones anatómicas, regiones corporales, y órganos aislados.

SUMMARY: At present, plastination technique is considered one of the newest forms of conservation of whole bodies, sections and organs, both human and animal, for use in undergraduate and graduate teaching, as well as morphological research. In this sense, to develop the various plastination techniques requires specific equipment and specialized training of academics, who have the ability to carry out the diversity of protocols that exist, according to the anatomical material that is to be preserved. In 2015, from the Laboratory of Plastination and Anatomical Techniques of Universidad de La Frotera, a new plastination technique was proposed for the first time at room temperature, which allowed obtaining plastinated preparations of the same quality as the classic plastination techniques. At present, from our laboratory, a new protocol for plastination with silicone is proposed that unifies the techniques that are developed in cold as well as at room temperature for the conservation of complete human and animal bodies, such as as well as anatomical sections, body regions, and isolated organs.

Conceptos fundamentales del protocolo modificado de plastinación a temperatura ambiente con silicona, con posterior pigmentación, y su aplicación para la conservación de placenta humana / Fundamental concepts of the modified room temperature plastination protocol with silicone, with subsequent pigmentation, and its application for the conservation of human placenta

RESUMEN: El auge experimentado en los últimos años en la aplicación de las técnicas anatómicas para la conservación de muestras anatómicas está directamente relacionado con la necesidad de preservación de los escasos especímenes con que cuentan las instituciones universitarias en relación a aumentar el tiempo de utilización del mismo. En este sentido, la plastinación es la técnica anatómica que más se destaca y que permite preservar por tiempo indeterminado, sin toxicidad, las preparaciones anatómicas. Presentamos el protocolo modificado de plastinación a temperatura ambiente con silicona, desarrollado en el Laboratorio de Plastinación y Técnicas Anatómicas de la Universidad de La Frontera, con el objetivo de aplicarla a la conservación de una placenta humana, la cual posteriormente fue pigmentada para otorgarle un aspecto más cercano a lo real.

SUMMARY: The surge experienced in recent years in the application of anatomical techniques for the conservation of anatomical samples is directly related to the need to preserve the few specimens that university institutions have in relation to increase the time of use of the same. In this sense, the plastination is the anatomical technique that stands out and that allows to preserve indefinitely, without toxicity, the anatomical preparations. We present the modified plastination protocol at room temperature with silicone, developed in the Laboratory of Plastination and Anatomical Techniques of the University of La Frontera, with the aim of applying it to the conservation of a human placenta, which was subsequently pigmented to give it an appearance closer to the real.

Avaliação da alteração dimensional de quatro marcas comerciais de silicone por reação de adição variando o tempo de armazenagem dos moldes / Dimensional alteration assessment of four silicone brands through addition reaction varying molds storage time

O objetivo deste estudo foi mensurar e comparar a precisão dimensional de modelos de gesso confeccionados por meio de moldagem de impressão única (material pesado/fluído de uma única vez) com quatro diferentes marcas comerciais de silicone polimerizados por reação de adição (Express XT®, Futura®, Aquasil® e Virtual®). Inicialmente, foi confeccionado um modelo acrílico mestre, o qual possuía três pilares metálicos paralelos entre si e equidistantes 50 mm um do outro. Para obtenção dos moldes foram utilizadas cinco moldeiras individuais em acrílico, cujas faces externas adaptavam-se perfeitamente na base do modelo padrão, promovendo o "stop" de inserção da moldeira. Após o procedimento de moldagem e confecção dos modelos experimentais, foram medidas as distâncias entre os três cilindros e o diâmetro de cada cilindro. Essas medições foram feitas por três vezes em um mesmo ponto e, destas, criou-se uma média obtendo os resultados finais. Os valores das distâncias foram analisados estatisticamente por meio de uma análise bifatorial, e as médias comparadas pelo teste de Tukey (5%). Os dados demostraram que todas as marcas analisadas apresentaram alteração dimensional e diferiram entre si quando comparadas.

The objective of this study was to measure and compare the dimensional accuracy of plaster models made by only impression molding (heavy material/fluid at one time) of four different brands of polymerized silicone through addition reaction (Express XT®, Futura ®, Aquasil® and Virtual®). Initially, a master acrylic model was manufactured, which had three parallel metal pillars and equidistant 50 mm from each other. To obtain the impressions, we used five individual acrylic trays, whose external faces perfectly adapted to the standard model base, thus promoting the "stop" of molding insertion. Following the molding procedure and the experimental models manufacturing, distances between the three cylinders and the diameter of each cylinder were measured. These measurements were made three times at the same point, and from these average results were obtained. The distance values were statistically analyzed using a two-factor analysis and the means compared by Tukey test (5%). The data demonstrated that all the analyzed brands presented dimensional changes and differed from each other when compared.

Molecular and morphological surface analysis: effect of filling pastes and cleaning agents on root dentin

Abstract The quality of the dentin root is the most important factor for restoration resin sealing and drives the outcome of endodontic treatment. Objective This study evaluated the effect of different filling pastes and cleaning agents on the root dentin of primary teeth using Fourier-transformed Raman spectroscopy (FT-Raman), micro energy-dispersive X-ray fluorescence (µ-EDXRF) and scanning electron microscopic (SEM) analysis. Material and Methods Eighty roots of primary teeth were endodontically prepared and distributed into 4 groups and filled according to the following filling pastes: Control-no filling (CP), Calen®+zinc oxide (CZ), Calcipex II® (CII), Vitapex® (V). After seven days, filling paste groups were distributed to 4 subgroups according to cleaning agents (n=5): Control-no cleaning (C), Ethanol (E), Tergenform® (T), 35% Phosphoric acid (PA). Then, the roots were sectioned and the dentin root sections were internally evaluated by FT-Raman, µ-EDXRF and SEM. Data was submitted to two-way ANOVA and Tukey tests (α=0.05). Results Regarding filling pastes, there was no significant difference in organic content. CP provided the lowest calcium values and, calcium/phosphoric ratio (Ca/P), and the highest phosphoric values. For cleaning agents there was no difference in organic content when compared to the C; however, T showed significantly higher calcium and Ca/P than PA. All groups showed similar results for phosphorus. The dentin smear layer was present after use of the cleaning agents, except PA. Conclusion The filling pastes changed the inorganic content, however they did not change the organic content. Cleaning agents did not alter the inorganic and organic content. PA cleaned and opened dentin tubules.

Evaluation of the physicochemical properties of silicone- and epoxy resin-based root canal sealers

Abstract To assess the physicochemical properties of AH Plus, GuttaFlow 2, GuttaFlow BioSeal, and MM Seal, five samples of each root canal sealer were evaluated to determine their setting time (ST), dimensional change (DC), solubility (SL), flow (FL), and radiopacity (RD) according to American National Standards Institute/American Dental Association (ANSI/ADA) Specification 57. The distilled and deionized water obtained from the SL test were subjected to atomic absorption spectrometry to observe the presence of Ca2+, K+, and Na+ ions. Statistical analysis was performed by using one-way ANOVA and Tukey-Kramer tests (p < 0.05). The following results were obtained: ST (min) (AH Plus 463.6 ± 13.22; GuttaFlow 2 24.35 ± 2.78; GuttaFlow Bioseal 17.4 ± 0.55; MM Seal 47.60 ± 4.39), DC (%) (AH Plus 0.06 ± 0.12; GuttaFlow 2 −26.06 ± 1.24; GuttaFlow Bioseal 2.10 ± 1.47; MM Seal 8.47 ± 2.41), SL (%) (AH Plus 0.41 ± 0.21; GuttaFlow 2 5.13 ± 4.11; GuttaFlow Bioseal 3.03 ± 1.05; MM Seal 0.94 ± 0.17), FL (mm) (AH Plus 36.42 ± 0.40; GuttaFlow 2 36.44 ± 0.05; GuttaFlow Bioseal 35.4 ± 0.03; MM Seal 52.75 ± 0.60), and RD (mmAl) (AH Plus 7.52 ± 1.59; GuttaFlow 2 6.85 ± 0.14; GuttaFlow Bioseal 7.02 ± 0.18; MM Seal 3.32 ± 0.90). ST, DC, SL, FL, and RD showed statistical differences among the root canal sealers (p < 0.05). As AH Plus showed the lowest DC and SL values (p < 0.05), the findings indicate that this sample is the only sealer conforming to ANSI/ADA standards.

In vitro antibacterial activity of a silicone-based endodontic sealer and two conventional sealers

Abstract The aim of this study was to evaluate whether the modification in the silver component is capable of providing GuttaFlow 2 with antibacterial activity against Enterococcus faecalis compared with epoxy resin-based (AH Plus) and zinc oxide and eugenol-based (Endofill) sealers. The antibacterial activity was evaluated using a reference strain of E. faecalis (ATCC 29212). Freshly mixed sealers were subjected to the agar diffusion test (ADT), while the direct contact test (DCT) was performed after materials setting. ADT results were obtained through measurements, in millimeters, of the inhibition zones promoted by the materials, using a digital caliper. In DCT, values of CFU/mL promoted by the three sealers were compared in three experimental periods (1 min, 1 h, and 24 h). The data were analyzed using Kruskal-Wallis and Dunn post-hoc tests (p < 0.05). In both ADT and DCT, GuttaFlow 2 presented no effect against E. faecalis, while Endofill and AH Plus showed similar inhibition zones. Endofill was the only material capable of reducing bacterial growth in DCT. In conclusion, modifications in the silver particle of GuttaFlow 2 did not result in a sealer with antibacterial effect against E. faecalis.

Sequela de injeção de silicone em lábio inferior: correção cirúrgica pela técnica do biquíni modificada / Sequelae of inferior lip silicone injection: surgical correction using the modified "bikini" technique

Pacientes portadores de sequelas devido a injeções de substâncias inabsorvíveis tem se tornado cada vez mais frequentes. O silicone injetável ou polidimetilsiloxano fluido é um polímero manufaturado que contém silicone elementar. As complicações consequentes ao uso desta substância podem ser precoces ou tardias. Apresentamos um relato de caso onde uma deformidade por injeção de silicone em lábios foi tratada cirurgicamente usando a técnica do biquíni modificada obtendo um bom resultado funcional e estético.

Increasing numbers of patients have sequelae due to the injection of non-absorbable substances. Injectable silicone or polydimethylsiloxane fluid is a manufactured polymer containing elemental silicon. The complications associated with the use of this substance can present early or late. Here we present a case report in which a deformity due to a silicone injection in the lips was surgically treated using the modified "bikini" technique that produced a functionally and aesthetically favorable result.

Candida albicans biofilms and MMA surface treatment influence the adhesion of soft denture liners to PMMA resin

The effect of Candida albicans biofilms and methyl methacrylate (MMA) pretreatment on the bond strength between soft denture liners and polymethyl methacrylate (PMMA) resin was analyzed. Specimens were prepared and randomly divided with respect to PMMA pretreatment, soft liner type (silicone-based or PMMA-based), and presence or absence of a C. albicans biofilm. Samples were composed of a soft denture liner bonded between two PMMA bars. Specimens (n = 10) were incubated to produce a C. albicans biofilm or stored in sterile PBS for 12 days. The tensile bond strength test was performed and failure type was determined using a stereomicroscope. Surface roughness (SR) and scanning electron microscopy (SEM) analysis were performed on denture liners (n = 8). Highest bond strength was observed in samples containing a silicone-based soft liner and stored in PBS, regardless of pretreatment (p < 0.01). Silicone-based specimens mostly underwent adhesive failures, while samples containing PMMA-based liners predominantly underwent cohesive failures. The silicone-based specimens SR decreased after 12 days of biofilm accumulation or PBS storage, while the SR of PMMA-based soft liners increased (p < 0.01). The PMMA-based soft liners surfaces presented sharp valleys and depressions, while silicone-based specimens surfaces exhibited more gentle features. In vitro exposure to C. albicans biofilms reduced the adhesion of denture liners to PMMA resin, and MMA pretreatment is recommended during relining procedures.

Mastoplastia redutora associada a implante de silicone: quando indico? / Reduction mastoplasty with silicone implants: When is it indicated?

Introdução: Insatisfação dos pacientes com resultado de mamoplastia redutora pode ser identificado em alguns casos, especialmente quando apresentam ptose acompanhada de flacidez excessive, estrias, e ainda, componente mamário mais gorduroso que glandular. Nesses tipos de pacientes, é muito difícil conseguir bons resultados por longo período. Implantes mamários de pequeno volume, podem ser colocados no mesmo tempo da mamoplastia redutora com o objetivo de se obter melhor forma, contorno e projeção das mamas, com maior satisfação a longo prazo. Método: No período de 1997 a 2012, duzentos e sessenta e quatro pacientes com idade entre 27e 55 anos (idade média de 38), foram submetidas à mamoplastia redutora com imediata colocação de implante mamário. Resultados: Foram obtidos resultados satisfatórios, com adequado preenchimento do pólo superior, mamas firmes e reduzida estatística de ptose pós-operatória. Foram identificados dois casos de carcinoma in sito, como achados no anátomo-patológico. Conclusão: Mastoplastia redutora associada a implantes de silicone é um procedimento seguro para casos selecionados.

INTRODUCTION: Patient dissatisfaction with reduction mammoplasty outcomes can occur, especially in cases of ptosis accompanied by excessive flaccidity, striations, and a higher fat than glandular content. In such cases, achieving long-lasting results is very difficult. Small-volume breast implants can be placed during the reduction mammoplasty with the purpose of obtaining better breast shape, contour, and projection as well as greater long-term satisfaction. METHOD: Between 1997 and 2012, 264 patients aged 27-55 years (mean, 38) underwent reduction mammoplasty with immediate placement of breast implants. RESULTS: Satisfactory results were obtained, with adequate filling of the upper pole, increased breast firmness, and statistical reduction in postoperative ptosis. Two cases of carcinoma in situ were identified in the pathological exam. CONCLUSION: Reduction mastoplasty associated with silicone implants is safe for selected cases.

Fenômeno de Marcus Gunn recidivado: relato de caso e revisão bibliográfica / Surgical treatment of relapsed Marcus Gunn syndrome: a case report and literature review

INTRODUÇÃO: O fenômeno de Marcus Gunn é uma ptose congênita rara e pouco conhecida, de origem neurogênica, de fisiopatogenia ainda não esclarecida. Os autores relatam um caso de ptose acentuada e recidivada após quatro correções cirúrgicas, e fazem uma breve revisão bibliográfica. RELATO DE CASO: Adulto jovem de 19 anos, sexo masculino, foi submetido a quatro tentativas de correção de ptose palpebral a direita em outros serviços, sem diagnóstico da origem da ptose congênita. O paciente apresentava abertura palpebral do olho direito ao abrir a boca, ao lateralizar o olhar para o lado ipse-lateral, e ao fechamento do olho contra-lateral. A última cirurgia foi realizada 2 anos antes, com posicionamento e fixação de fitas de silicone. O paciente não apresentava nenhum déficit neurológico ou visual. Foi submetido à cirurgia para remoção das fitas de silicone anteriormente posicionadas, confecção de enxertos em fita de técido fibroconectivo da fáscia lata do membro inferior direito, miectomia do musculo elevador da pálpebra ptosada, fixação dos enxertos da fáscia lata na borda superior do tarso com tração e fixação ao musculo frontal ipsilateral. Evoluiu com movimentos sincrônicos das pálpebras bilateralmente, e sem recidiva do ptose até o presente momento.

INTRODUCTION: Marcus Gunn syndrome is a rare and little known congenital ptosis of neurogenic origin. Its physiopathological mechanism has not been clarified. The authors report a case of pronounced ptosis that relapsed after four surgical corrections, along with a brief literature review. CASE REPORT: A 19-year-old young adult underwent four surgical corrections of the right palpebral ptosis in other services, without a definite diagnosis of the origin of the congenital ptosis. The patient showed eyelid opening in the right eye on opening the mouth, when the eye is lateralized to the ipsilateral side, and with contralateral eye closure. The last surgery was performed 2 years prior, during which silicone bands were placed and fixated. The patient did not present any visual or neurological deficit. He underwent surgery in order to remove the silicone bands that were previously placed, to prepare the strip grafts made of fibrous connective tissue from the fascia lata of the right inferior limb, and to perform myectomy of the levator muscle of the palpebral ptosis, fixation of the fascia lata grafts at the upper edge of the tarsus with traction and fixation to the ipsilateral frontal muscle. The patient progressed with synchronic movements of the eyelids bilaterally, and without relapse of the ptosis until the present date.

Comparative study on direct and indirect bracket bonding techniques regarding time length and bracket detachment

OBJECTIVE: The aim of this study was to assess the time spent for direct (DBB - direct bracket bonding) and indirect (IBB - indirect bracket bonding) bracket bonding techniques. The time length of laboratorial (IBB) and clinical steps (DBB and IBB) as well as the prevalence of loose bracket after a 24-week follow-up were evaluated. METHODS: Seventeen patients (7 men and 10 women) with a mean age of 21 years, requiring orthodontic treatment were selected for this study. A total of 304 brackets were used (151 DBB and 153 IBB). The same bracket type and bonding material were used in both groups. Data were submitted to statistical analysis by Wilcoxon non-parametric test at 5% level of significance. RESULTS: Considering the total time length, the IBB technique was more time-consuming than the DBB (p < 0.001). However, considering only the clinical phase, the IBB took less time than the DBB (p < 0.001). There was no significant difference (p = 0.910) for the time spent during laboratorial positioning of the brackets and clinical session for IBB in comparison to the clinical procedure for DBB. Additionally, no difference was found as for the prevalence of loose bracket between both groups. CONCLUSION: the IBB can be suggested as a valid clinical procedure since the clinical session was faster and the total time spent for laboratorial positioning of the brackets and clinical procedure was similar to that of DBB. In addition, both approaches resulted in similar frequency of loose bracket.

OBJETIVO: avaliar o tempo necessário para realização da colagem de braquetes pelas técnicas direta (CDB) e indireta (CIB), mensurando o tempo despendido entre a parte laboratorial (CIB) e a parte clínica (CDB e CIB), e a prevalência de descolamentos durante o período de observação de 24 semanas. MÉTODOS: dezessete pacientes (7 homens e 10 mulheres), com idade média de 21 anos, com necessidade de tratamento ortodôntico, foram selecionados para participar desse estudo. Foram utilizados um total de 304 braquetes, sendo que 151 foram colados pela técnica de CDB e 153 pela CIB, com o mesmo tipo de braquete e material de colagem. Os dados foram submetidos ao teste não paramétrico de Wilcoxon, com significância de 5%. RESULTADOS: o tempo total para realização da CIB foi maior em relação à CDB (p < 0,001). Levando em consideração apenas a fase clínica, foi observado que o tempo para CIB foi menor em relação a CDB (p < 0,001). A comparação entre o tempo despendido para o posicionamento dos braquetes em laboratório mais o tempo em clínica para CIB com o tempo em clínica para a CDB revelou que não houve diferença significativa (p = 0,910), nem tampouco quanto à prevalência de descolamento dos braquetes. CONCLUSÃO: a CIB apresenta-se como uma utilidade clínica singular, pois o tempo em clínica foi menor que o da CDB. O tempo despendido no posicionamento dos braquetes no laboratório e de execução clínica da CIB foi semelhante ao tempo gasto pela CDB, a quantidade de descolamentos foi semelhante entre as técnicas.

Influence of disinfectant solutions on test materials used for the determination of masticatory performance

Masticatory function can be evaluated objectively as the capacity of an individual to fragment solid food after a fixed number of chewing cycles, the so-called masticatory performance (MP). The objective of this study was to evaluate the reliability of four different test materials (Optosil, Optocal, Zetapuls, and Perfil) and five disinfection protocols by aspersion and immersion (no disinfection, 2% glutaraldehyde, 2% chlorhexidine, 5.25% sodium hypochlorite, and 70% alcohol) on the MP, determined at three moments (24 hours, 15 and 60 days) after storing the fragmented blocks. MP was evaluated by calculating X50 through the sieving technique and the Rosim-Ramler equation. The weight and microbiologic count (colony forming units, CFUs) of chewed blocks were measured to identify any variations that would make MP determination unfeasible. Differences in MP were observed among the materials (p < 0.01). Perfil presented the highest X50 value (worst MP determination), followed by Zetaplus (both p < 0.05), Optosil, and Optocal (both p > 0.05). The time and disinfection type had no influence on MP (p > 0.05). The number of CFUs differed between the nondisinfected group and all other disinfection groups at all time points (p < 0.01). No other significant difference in CFU count between disinfection groups was observed. In conclusion, disinfection did not alter the reliability of the test materials for the MP calculation for up to 60 days.

Comparação das alterações dimensionais lineares em modelos de gesso pedra tipo IV obtidos de moldes de siliconas de condensação e de adição em períodos diferentes de vazamento / Dimensional alteration of dental stone type IV casts acquired by condensation and addition silicone poured at different periods

Avaliou-se a estabilidade dimensional de duas marcas comerciais, sendo uma de silicona de condensação e outra de adição em função de diferentes tempos de vazamento. Um modelo padrão metálico foi elaborado com dois pilares com mesma altura, diâmetro e distância entre si. A partir desse modelo padrão foram obtidos 80 moldes através da técnica de dupla moldagem com um alívio uniforme de 1 mm em moldeiras parcial de alumínio perfurada, de estoque. Um total de 80 amostras foram confeccionadas, sendo 40 com silicona de condensação e outras 40 com silicona de adição. Os tempos de vazamento com o gesso tipo IV Durone foram de 30 minutos, 24 horas, 72 horas e uma semana para todas as condições experimentais testadas respectivamente após a moldagem. As medições foram feitas em três áreas distintas de cada pilar: diâmetro oclusal, altura e a distância entre os mesmos também foi registrada. Um aparelho de medição tridimensional (Ortho Analyzer-2010) foi empregado para as mensurações. Os resultados nos tempos de vazamento de 30 minutos e 24 horas são os melhores para obter o modelo de gesso para ambos os materiais. A silicona de condensação pode ser utilizada com segurança desde que o vazamento seja no máximo até 24horas

Dimensional stability of two silicones impression materials, condensation and addition, was assessed regarding poured periods. A metal master model was constructed with two implant abutments with same height, diameter and same distance between them. Eighty models of the master model were obtained with the two times impression technique. All partial aluminum stock trays were relieved in 1 mm. The sample was divided in two groups: 1) 40 models acquired by condensation silicone and 2) 40 models acquired by addition silicone. The dental stone type IV poured periods were: 30 minutes, 24 hours, 72 hours and one week for all experimental conditions testes after impression. The OrthoAnalyzer-2010 was used to measure three zones of each abutment: occlusal diameter, height and distance between the abutments. The data were analyzed and results were better at periods 30 minutes and 24 hours with both materials. The condensation silicone can be well utilized provided that the poured period does not exceed 24 hours

Tecnica indireta com resinas compostas para uso direto para restauraçao de dentes posteriores: estratificação, escultura dental e polimerização adicional (Parte II) / Indirect technique with composite resins for direct use in restorations of posterior teeth: stratification, dental sculpture and addition polymerization (Part II)

O desenvolvimento constante e evolução dos compósitos, juntamente das técnicas restauradoras em dentes posteriores, possibilitam melhores propriedades mecânicas e ópticas desses materiais, aumentando sua longevidade clínica. O emprego da polimerização adicional das resinas compostas realizado com calor, luz e pressão (ou associação dos métodos) resulta em melhores resultados na estabilidade dimensional, bem como da resistência diametral e à compressão. Este artigo descreve a técnica de estratificação e escultura dental em restauração de resina composta em dente posterior e destaca o uso e a importância da polimerização adicional

Constant development and evolution of the composites, along with restoration techniques in posterior teeth, allow better mechanical and optical properties of these materials, extending their clinic longevity. The usage of addition polymerization of the composite resins performed with heat, light and pressure (or a combination of these methods), presents better results for dimensional stability as well as for diametric resistance and compression. This work describes the technique of stratification and dental sculpture on composite resin restoration in posterior teeth, and highlights the use and the importance of addition polymerization

Restauração unitária de cerâmica em dente anterior: relato de caso / Unitary restoration of ceramic in anterior tooth: case report

Laminados de cerâmica são recomendados para dentes que exigem alto padrão estético, como os dentes anteriores, recobrindo com material estético, dentes com alteração de cor, forma ou função. Este trabalho tem como objetivo descrever a sequência clínica dos procedimentos para confecção de uma restauração unitária cerâmica em dente anterior. Paciente H.D.C., sexo feminino, 24 anos, apresentou-se à clínica do Curso de Odontologia da UFMA com queixa estética no elemento 21. No exame clínico, verificou-se a presença de escurecimento dental, causado por traumatismo. Em uma primeira sessão clínica, foi realizado procedimento de moldagem para confecção de restauração provisória posteriormente à execução do preparo. Realizou-se a seleção de cor, o preparo dentário para faceta de cerâmica pura, a moldagem do preparo e, em seguida, confeccionou-se a restauração provisória à base de bis-acrilato, com o auxílio de uma matriz de silicone. Foi realizado o acabamento e polimento da provisória. Em uma nova sessão clínica, foi realizado o ajuste da restauração cerâmica e os procedimentos de cimentação adesiva. O resultado final alcançado possibilitou a restituição da forma, função e estética adequadas

Ceramic laminate veneers are prostheses recommended to teeth that require a good aesthetic, as anterior teeth, covering with aesthetic material teeth with color, shape or function alteration. The aim of this paper is to describe the sequence of clinical procedures for making a unitary ceramic restoration in anterior tooth. Patient H.D.C., female, 24 years old, presented herself to the clinic of the Faculty of Dentistry - UFMA with esthetic complaint of the element 21. On clinical examination, there was the presence of tooth darkening, caused by trauma. It was proposed as initial treatment the manufacture of a ceramic laminate. In a single clinical session, it was performed molding procedure for making temporary restoration after the execution of the tooth preparation. We performed the color selection, preparation dental ceramic veneering, the molding of the tooth preparation and, subsequently, was made the provisional restoration with bis-acrylate, using the technique of the silicone matrix. It was conducted the finishing and polishing of the provisional restoration. The result achieved enabled the restoration of form, function and aesthetics appropriate

Effects of sulfur-based hemostatic agents and gingival retraction cords handled with latex gloves on the polymerization of polyvinyl siloxane impression materials

OBJECTIVES: This study investigated the possible interactions between three addition silicone materials (Express®, Aquasil Ultra® and Adsil®), three hemostatic agents (ferric sulfate, StatGel FS®; aluminum sulfate, GelCord®; and aluminum chloride, Hemostop®) and gingival retraction cords previously handled with latex gloves to determine whether direct contact with medicaments or indirect contamination by latex in conditions similar to those found in clinical practice inhibit or affect the setting of the impression materials. MATERIAL AND METHODS: A portable device for the simultaneous test of several specimens was specifically developed for this study. Polymerization inhibition was analyzed by examination of the impressions and the molded surface. Ten trials were performed for each addition silicone material used in the study, at a total of 240 study samples. RESULTS: All the samples tested (N=240) were nonreactive regardless of the type of combination used. CONCLUSIONS: Aluminum sulfate, ferric sulfate and aluminum chloride hemostatic solutions did not show any inhibitory potential on the addition silicone samples under study, and there were no changes in polymerization as a result of contact between addition silicone and retraction cords handled with latex gloves.

Transferencia de la posición tridimensional del implante / Transfer of the three-dimensional implant position

Uno de los pasos fundamentales para la obtención de un resultado protésico satisfactorio en implantología es la transferencia de la posición tridimensional del implante ya oseointegrado al modelo definitivo. Para ello generalmente se utilizan cubetas individuales de termocurado confeccionadas por el protésico dental, rígidas y con perforaciones que corresponden a la emergencia del transfer del implante y materiales de tipo elastómeros. En el siguiente trabajo se expondrán los pasos detallados para una correcta toma de impresiones, la crítica de las mismas y la justificación de los materiales utilizados. Asimismo, se expondrán las bondades que presentan las placas de fotocurado para la realización de una cubeta individual por el profesional, confeccionadas a partir de un modelo de estudio preliminar, en el consultorio.

Gran reconstrucción de dientes anteriores, con resinas compuestas; alternativa a la prótesis: reporte de un caso / Large reconstruction of anterior teeth with composite resins; an alternative to prosthodontics: a case report

La situación socioeconómica de la región hace que mucha gente tenga dificultades en acceder a tratamientos de prótesis complejos. La disponibilidad de sistemas adhesivos eficaces y las recientemente lanzadas resinas compuestas de nanopartículas posibilitan ofrecer alterantivas conservadoras a los tratamientos complejos de prótesis.

Visual evaluation of color stability after accelerated aging of pigmented and nonpigmented silicones to be used in facial prostheses.

OBJECTIVES: The objective of this study was to evaluate by a visual method of comparison the color stability of nonpigmented and pigmented facial silicones after accelerated aging. MATERIALS AND METHODS: Two kinds of silicones were used in this study; one specifically formulated for facial prostheses and the other an acetic silicone for industrial use. Twenty-four trial bodies were made for each silicone. These were divided into colorless and intrinsically pigmented groups: ceramic, make-up, and iron oxide. The groups were submitted to accelerated aging for nonmetallic materials. An initial reading and subsequent readings were made at 163, 351, 692, and 1000 hours using a visual method of comparison. The values were annotated in a spreadsheet by two observers, according to scores elaborated for this study. RESULTS: All groups presented color stability in the visual method. According to the results obtained and analyzed in this study, we can conclude that both silicones, Silastic 732 RTV and Silastic MDX 4-4210, behaved similarly, they can therefore be indicated for use in maxillofacial prosthesis. The time factor of aging influenced negatively, independently of the pigmentation, or lack of it, and of silicones and no group had visually noticeable alterations in any of the accelerated aging time, independently of the addition or not of pigments.