Subcutaneous connective tissue response to primary root canal filling materials

This study evaluated the response of the subcutaneous connective tissue of BALB/c mice to root filling materials indicated for primary teeth: zinc oxide/eugenol cement (ZOE), Calen paste thickened with zinc oxide (Calen/ZO) and Sealapex sealer. The mice (n=102) received polyethylene tube implants with the materials, thereby forming 11 groups, as follows: I, II, III: Calen/ZO for 7, 21 and 63 days, respectively; IV, V, VI: Sealapex for 7, 21 and 63 days, respectively; VII, VIII, IX: ZOE for 7, 21 and 63 days, respectively; X and XI: empty tube for 7 and 21 days, respectively. The biopsied tissues were submitted to histological analysis (descriptive analysis and semi-quantitative analysis using a scoring system for collagen fiber formation, tissue thickness and inflammatory infiltrate). A quantitative analysis was performed by measuring the area and thickness of the granulomatous reactionary tissue (GRT). Data were analyzed by Kruskal-Wallis, ANOVA and Tukey's post-hoc tests (?=0.05). There was no significant difference (p>0.05) among the materials with respect to collagen fiber formation or GRT thickness. However, Calen/ZO produced the least severe inflammatory infiltrate (p<0.05). The area of the GRT was significantly smaller (p<0.05) for Calen/ZO and Sealapex. In conclusion, Calen/ZO presented the best tissue reaction, followed by Sealapex and ZOE.

FiltekTM Silorane and FiltekTM Supreme XT resins: tissue reaction after subcutaneous implantation in isogenic mice

The aim of this study was to evaluate the tissue compatibility of a silorane-based resin system (FiltekTM Silorane) and a methacrylate-based nanoparticle resin (FiltekTM Supreme XT) after implantation in the subcutaneous connective tissue of isogenic mice. One hundred and thirty five male isogenic BALB/c mice were randomly assigned to 12 experimental and 3 control groups, according to the implanted material and the experimental period of 7, 21 and 63 days. At the end of each period, the animals were killed and the tubes with the surrounding tissues were removed and processed for microscopic analysis. Samples were subjected to a descriptive and a semi-quantitative analyses using a 4-point scoring system (0-3) to evaluate the collagen fiber formation and inflammatory infiltrate. Data were statistically analyzed using the Kruskal Wallis test (?=0.05). The results showed that there was no significant difference between the experimental and control groups considering the three evaluation periods (p>0.05). The silorane-based and the methacrylate-based nanoparticle resins presented similar tissue response to that of the empty tube (control group) after subcutaneous implantation in isogenic mice.

Histopathological evaluation of root canal filling materials for primary teeth

This study aimed to assess the response of apical and periapical tissues of dogs' teeth after root canal filling with different materials. Forty roots from dogs' premolars were prepared biomechanically and assigned to 4 groups filled with: Group I: commercial calcium hydroxide and polyethylene glycol-based paste (Calen®) thickened with zinc oxide; Group II: paste composed of iodoform, Rifocort® and camphorated paramonochlorophenol; Group III: zinc oxide-eugenol cement; Group IV: sterile saline. After 30 days, the samples were subjected to histological processing. The histopathological findings revealed that in Groups I and IV the apical and periapical regions exhibited normal appearance, with large number of fibers and cells and no resorption of mineralized tissues. In Group II, mild inflammatory infiltrate and mild edema were observed, with discrete fibrogenesis and bone resorption. Group III showed altered periapical region and thickened periodontal ligament with presence of inflammatory cells and edema. It may be concluded that the Calen paste thickened with zinc oxide yielded the best tissue response, being the most indicated material for root canal filling of primary teeth with pulp vitality.

Subcutaneous tissue response of isogenic mice to calcium hydroxide-based pastes with chlorhexidine

This study was evaluated the response of subcutaneous connective tissue of isogenic mice to calcium hydroxide-based pastes with chlorhexidine digluconate (CHX). Seventy isogenic male BALB/c mice aged 6-8 weeks and weighing 15-20 g were randomly assigned to 8 groups. The animals received polyethylene tube implants as follows: Groups I, II, and III (n=10) - Calen® paste mixed with 0.4% CHX (experimental paste; Calen/CHX) for 7, 21, and 63 days, respectively; Groups IV, V, and VI (n=10) - UltraCal™ paste mixed with 2% CHX (experimental paste supplied by Ultradent Products Inc.; Ultracal/CHX) for 7, 21, and 63 days, respectively; and Groups VII and VIII (n=5): empty tube for 7 and 21 days, respectively. At the end of the experimental periods, the implants were removed together with the surrounding tissues (skin and subcutaneous connective tissue). The biopsied tissues were subjected to routine processing for histological analysis. Using a descriptive analysis and a four-point (0-3) scoring system, the following criteria were considered for qualitative and quantitative analysis of the tissue around the implanted materials: collagen fiber formation, tissue thickness and inflammatory infiltrate. A quantitative analysis was performed by measuring the thickness (µm), area (µm²) and perimeter (µm) of the reactionary granulomatous tissue formed at the tube ends. Data were analyzed statistically by the Kruskal-Wallis test and Dunn's post-test (α=0.05). Calen/CHX showed biocompatibility with the subcutaneous and reactionary tissues, with areas of discrete fibrosis and normal conjunctive fibrous tissue, though without statistically significant difference (p>0.05) from the control groups. In Groups I to III, there was a predominance of score 1, while in Groups IV to VI scores 2 and 3 predominated for all analyzed parameters. UltraCal/CHX, on the other hand, induced the formation of an inflammatory infiltrate and abundant exudate, suggesting a persistent residual aggression from the material, even 63 days after implant placement. In conclusion, the Calen paste mixed with 0.4% CHX allowed an adequate tissue response, whereas the UltraCal paste mixed with 2% CHX showed unsatisfactory results.

Synthesis and biocompatibility of an experimental glass ionomer cement prepared by a non-hydrolytic sol-gel method

The aims of this study were to demonstrate the synthesis of an experimental glass ionomer cement (GIC) by the non-hydrolytic sol-gel method and to evaluate its biocompatibility in comparison to a conventional glass ionomer cement (Vidrion R). Four polyethylene tubes containing the tested cements were implanted in the dorsal region of 15 rats, as follows: GI - experimental GIC and GII - conventional GIC. The external tube walls was considered the control group (CG). The rats were sacrificed 7, 21 and 42 days after implant placement for histopathological analysis. A four-point (I-IV) scoring system was used to graduate the inflammatory reaction. Regarding the experimental GIC sintherization, thermogravimetric and x-ray diffraction analysis demonstrated vitreous material formation at 110oC by the sol-gel method. For biocompatibility test, results showed a moderate chronic inflammatory reaction for GI (III), severe for GII (IV) and mild for CG (II) at 7 days. After 21 days, GI presented a mild reaction (II); GII, moderate (III) and CG, mild (II). At 42 days, GI showed a mild/absent inflammatory reaction (II to I), similar to GII (II to I). CG presented absence of chronic inflammatory reaction (I). It was concluded that the experimental GIC presented mild/absent tissue reaction after 42 days, being biocompatible when tested in the connective tissue of rats.

Immediate implants placed into infected sockets: a case report with 3-year follow-up

The esthetics and functional integrity of the periodontal tissue may be compromised by dental loss. Immediate implants became a viable option to maintain the periodontal architecture because of their anatomic compatibility with the dental socket and the possibility of eliminating local contamination. This article describes the procedure of immediate implant placement in the anterior maxilla replacing teeth with chronic periapical lesions, which were condemned due to endodontic lesions persisting after failed endodontic treatment and endodontic surgery, and discusses the relationship between the procedure and periapical lesions. Surgical removal of hopeless teeth 11, 12 and 21 was performed conservatively in such a way to preserve the anatomy and gingival esthetics. A second surgical access was gained at the apical level, allowing the debridement of the surgical chamber for elimination of the periapical lesion, visual orientation for setting of the implants and filling of the surgical chamber with xenogenous bovine bone graft. After this procedure, the bone chamber was covered with an absorbent membrane and the healing screws were positioned on the implants. Later, a provisional partial removable denture was installed and the implants were inserted after 6 months. After 3 years of rehabilitation, the implants present satisfactory functional and esthetic conditions, suggesting that immediate implant placement combined with guided bone regeneration may be indicated for replacing teeth lost due to chronic periapical lesions with endodontic failure history in the anterior maxilla.

Tissue inflammatory response to implantation of calcium hydroxide and iodoform in the back of rats

PURPOSE: This study evaluated the inflammatory reaction caused by the implantation of iodoform and calcium hydroxide in the back of rats. These drugs may be used as intracanal dressings to eliminate residual bacteria of the root canal system. METHODS: Twenty albinic rats (Rattus norvegicus, var Wistar) were divided into four groups: control group 1 (CG1) had normal skin; control group 2 (CG2) had wounded tissue without drugs; in groups 3 and 4, iodoform (IG) and calcium hydroxide (CHG) were inserted into the wounds, respectively. After 3, 5 and 11 days, slices of the implanted areas were macroscopically and microscopically observed regarding to their qualitative and quantitative aspects. RESULTS: In the macroscopical analysis, the CHG showed a large area of necrosis and swelling, which progressively decreased; in the IG the presence of iodoform surrounded by normal tissue was observed. The qualitative and quantitative histological analysis showed that IG promoted a shorter delay in the inflammatory response than the CHG. CONCLUSION: The inflammatory reaction for iodoform had a peak period five days after the drug insertion. By comparison, calcium hydroxide showed a very large area of necrosis that could only be partially eliminated after eleven days.

Parceria público x privada no desenvolvimento de pesquisa em melhoramento genético animal

O melhoramento genético animal é, normalmente, pesquisado e desenvolvido nas universidades e instituições públicas de pesquisa do Brasil. No entanto, os rebanhos de exploração zootécnica, verdadeiros objetivos desses estudos, pertencem à iniciativa privada. O melhoramento genético animal e as parcerias público-privadas constituem-se em um caso especial de grande sucesso, que é analisado no presente texto, com ênfase especial ao Grupo de Melhoramento Animal e Biotecnologia da Faculdade de Zootecnia e Engenharia de Alimentos da Universidade de São Paulo, instituição de origem dos autores. O sucesso desse grupo, medido em atividades de pesquisa e suas conseqüentes publicações, de ensino e formação de recursos humanos e de extensão de serviços à comunidade, é apresentado como incentivo aos pesquisadores das mais diversas áreas ligadas à produção animal.

Resíduos de sisal como reforço em compósitos de polipropileno virgem e reciclado

Foram estudadas as propriedades térmicas e mecânicas de compósitos de polipropileno, virgem e reciclado, reforçados com 30% em massa de fibras residuais de sisal, assim como o perfil de processamento e a morfologia da matriz polimérica. Para tanto, foram determinadas a resistência à tração, o módulo de Young, alongamento na ruptura, e energia de impacto. As amostras também foram caracterizadas por MEV, DMTA e TG. Para ambos os compósitos de polipropileno, virgem e reciclado, com a adição das fibras, o alongamento na ruptura mostrou uma queda significativa, enquanto que a resistência à tração não sofreu grandes variações. Houve um aumento significativo nos valores de tração na ruptura e de energia de impacto com a adição das fibras de sisal na matriz de polipropileno. As análises térmicas mostraram ligações secundárias, como as ligações polares, entre as fibras e a matriz, concordando com o comportamento mecânico dos compósitos. Constatou-se que a temperatura de transição vítrea não variou após a adição da fibra.

Influência de diferentes materiais de cobertura no conforto térmico de instalações para frangos de corte no oeste paulista

Este trabalho apresenta um estudo da influência de diferentes materiais de cobertura no conforto térmico de instalações destinadas à criação de frangos de corte. A pesquisa foi desenvolvida no Câmpus Experimental da UNESP de Dracena - SP. Quatro protótipos em escala real foram construídos, com área de 28 m² cada, cobertos com telha reciclada à base de embalagens longa vida, telha cerâmica, telha cerâmica pintada de branco e telha de fibrocimento. Os dados foram coletados durante o período de inverno de 2007, totalizando 90 dias. Com esses dados, foram calculados os índices de conforto térmico Carga Térmica Radiante (CTR) e a variável ambiental (Ta). Uma análise estatística por inferência e descritiva foi realizada com os valores do índice de conforto térmico e da variável ambiental. Com os resultados obtidos, é possível afirmar que a telha reciclada apresentou índices de conforto térmico semelhantes àqueles encontrados para as telhas cerâmicas. O protótipo coberto com telha de fibrocimento apresentou os maiores índices, e o coberto com telha cerâmica branca, os menores índices de conforto térmico. No entanto para o período de inverno e para os horários avaliados, todas as instalações apresentaram índices de conforto térmico fora da zona de termoneutralidade do frango de corte.

Isotermas de dessorção de filé de bonito (Sarda sarda) desidratado osmoticamente e defumado

O presente trabalho teve como objetivo a obtenção de isotermas de dessorção de filés de bonito (Sarda sarda), previamente salgados a vácuo e defumados com fumaça líquida. As isotermas foram obtidas a quatro temperaturas (5, 25, 40 e 60 ºC) em condições de dessorção, através do método gravimétrico estático, com soluções salinas saturadas. Os dados experimentais foram ajustados a quatro modelos da literatura (BET linearizado, GAB, Henderson e Oswin modificado). Os resultados mostraram que as isotermas tomaram forma sigmoidal de tipo II e que o modelo de Guggenheim-Anderson-deBoer (GAB) foi aceitável para modelar os dados experimentais. O calor isostérico de dessorção, um parâmetro necessário para simular e projetar adequadamente o secador, também foi calculado e pode ser representado através de um modelo matemático simples, em função da umidade de equilíbrio.

Albedo à superfície a partir de imagens Landsat 5 em áreas de cana-de-açúcar e cerrado

Propôs-se, neste trabalho, estimar dados de albedo à superfície terrestre usando-se o sensor Thematic Mapper (TM) do satélite LANDSAT 5 e compará-lo com dados de duas estações agrometeorológicas localizadas em região de Cerrado e a outra em cultivo da cana-de-açúcar. A região de estudo está localizada no município de Santa Rita do Passa Quatro, SP, Brasil. Para a realização do estudo obtiveram-se seis imagens orbitais do satélite Landsat 5 sensores TM, na órbita 220 e ponto 75, nas datas de 22/02, 11/04, 29/05, 01/08, 17/08 e 21/11, todas do ano de 2005, a que correspondem os dias juliano de 53, 101, 149, 213, 229 e 325, respectivamente. As correções geométricas para as imagens foram realizadas e geradas as cartas de albedo. O algoritmo SEBAL estimou satisfatoriamente os valores de albedo de superfícies sobre áreas de cerrado e de cana-de-açúcar, na região de Santa Rita do Passa Quatro, SP, consistentes com observações realizadas do albedo à superfície.

Nervo alógeno conservado em glicerol: estudo experimental em ratos

A utilização de aloenxerto de nervo conservado em glicerol é uma alternativa a auto-enxertia em casos de lesões de nervos periféricos com perda de substância que diminui a morbidade cirúrgica e provem material suficiente para a reparação neural. O objetivo deste trabalho foi comparar o grau de reparação nervosa, utilizando análises histológica e funcional, através da interposição de enxerto autógeno (grupo A), de tubo de veia conservada em glicerol (grupo B) e de interposição de nervo alógeno conservado em glicerol (grupo C) em defeitos de 5 mm no nervo fibular de ratos Wistar. A análise histológica foi feita após o sacrifício dos animais( 6 semanas) , usando o corante azul de toluidina a 1%. No grupo A (auto-enxerto) verificou-se reação tecidual perineural e escape de fibras axonais mielinizadas para fora dos limites do epineuro que foi maior se comparada ao verificado no Grupo B (Veia autógena + glicerol) e Grupo C (aloenxerto de nervo).A avaliação funcional foi feita através da análise dos padrões das pegadas das patas posteriores dos ratos ("Walking Track Analysis"), nos períodos: pré-operatório, pós-operatório imediato, na terceira e sexta semanas. Na recuperação funcional, não houve diferença estatisticamente significativa entre os três grupos em nenhum dos períodos avaliados.

Avaliação da cicatrização de feridas em dorso de ratos tratados com mitomicina C tópica e posterior reforço com injetável

Estudo experimental em animais. A mitomicina C vem sendo usada como inibidor de fibroblastos, acarretando, com isso, diminuição do processo cicatricial em feridas cirúrgicas. OBJETIVO: Este trabalho visa avaliar o uso de Mitomicina C para diminuir o processo cicatricial, através de seu uso tópico com reforços posteriores injetáveis. MATERIAL E MÉTODOS: Foi usado um modelo de feridas em dorso de ratos, com retirada circular da pele e cicatrização por segunda intenção. Foram usados 18 ratos, divididos em três grupos: controle; com uso tópico; e com reforço de mitomicina C injetável, mensalmente e por 2 meses. Após 3 meses os animais foram sacrificados e as cicatrizes retiradas cirurgicamente e submetidas a estudo histológico. RESULTADOS: Notou-se sob vários critérios que a cicatrização com o uso tópico é menos intensa, mas ao se usar o reforço injetável os parâmetros voltam a ser comparados ao do grupo controle. DISCUSSÃO: Acreditamos que a administração injetável de mitomicina C nas cicatrizes, pela sua elevada característica tóxica, acarreta destruição tecidual e neoformação cicatricial. CONCLUSÕES: A mitomicina C diminui o processo cicatricial quando usada topicamente, mas acarreta aumento da cicatrização quando nestas feridas são feitos reforços injetáveis.

An Eulerian Immersed Boundary Method for flow simulations over stationary and moving rigid bodies

The fluid flow over bodies with complex geometry has been the subject of research of many scientists and widely explored experimentally and numerically. The present study proposes an Eulerian Immersed Boundary Method for flows simulations over stationary or moving rigid bodies. The proposed method allows the use of Cartesians Meshes. Here, two-dimensional simulations of fluid flow over stationary and oscillating circular cylinders were used for verification and validation. Four different cases were explored: the flow over a stationary cylinder, the flow over a cylinder oscillating in the flow direction, the flow over a cylinder oscillating in the normal flow direction, and a cylinder with angular oscillation. The time integration was carried out by a classical 4th order Runge-Kutta scheme, with a time step of the same order of distance between two consecutive points in x direction. High-order compact finite difference schemes were used to calculate spatial derivatives. The drag and lift coefficients, the lock-in phenomenon and vorticity contour plots were used for the verification and validation of the proposed method. The extension of the current method allowing the study of a body with different geometry and three-dimensional simulations is straightforward. The results obtained show a good agreement with both numerical and experimental results, encouraging the use of the proposed method.