[Reduction of ileocolic intussusception with hydrostatic enema under ultrasound guidance in pediatric patients: Case report]. / Reducción de intususcepción ileocólica con enema hidrostático bajo guía ecográfica en pacientes pediátricos: Reporte de casos.

Ileocolic intussusception is a pediatric emergency with initial non-surgical treatment. Ultrasound-guided hydrostatic reduction in pediatric patients is a widely used initial treatment method in the world; however, its use is not widespread in our environment. We present 4 cases of patients with ileocolic intussusception treated by ultrasound-guided hydrostatic reduction in the Instituto Nacional de Salud del Niño - San Borja (INSNSB), with therapeutic reduction and without complications.

Reducción de intususcepción ileocólica con enema hidrostático bajo guía ecográfica en pacientes pediátricos: Reporte de casos

La intususcepción ileocólica es una emergencia pediátrica con tratamiento inicial no quirúrgico a nivel mundial. La reducción hidrostática bajo guía ecográfica en pacientes pediátricos es un método de tratamiento inicial ampliamente utilizado en el mundo; sin embargo, en nuestro medio no se encuentra difundido su uso. Presentamos 4 casos de pacientes con intususcepción ileocólica tratados mediante enema hidrostático bajo guía ecográfica en el Instituto Nacional de Salud del Niño - San Borja (INSNSB), con reducción terapéutica y sin complicaciones.

Ileocolic intussusception is a pediatric emergency with initial non-surgical treatment. Ultrasound-guided hydrostatic reduction in pediatric patients is a widely used initial treatment method in the world; however, its use is not widespread in our environment. We present 4 cases of patients with ileocolic intussusception treated by ultrasound-guided hydrostatic reduction in the Instituto Nacional de Salud del Niño - San Borja (INSNSB), with therapeutic reduction and without complications.

Corrosion in artificial saliva of a Ni-Cr-based dental alloy joined by TIG welding and conventional brazing.

STATEMENT OF THE PROBLEM: Fixed prosthesis and partial dental prosthesis frameworks are usually made from welded Ni-Cr-based alloys. These structures can corrode in saliva and have to be investigated to establish their safety. PURPOSE: The purpose of this study was to evaluate the corrosion behavior of joints joined by tungsten inert gas (TIG) welding and conventional brazing in specimens made of commercial Ni-Cr alloy in Fusayama artificial saliva at 37°C (pH 2.5 and 5.5). MATERIAL AND METHODS: Eighteen Ni-Cr base metal specimens were cast and welded by brazing or tungsten inert gas methods. The specimens were divided into 3 groups (base metal, 2 welded specimens), and the composition and microstructure were qualitatively evaluated. The results of potential corrosion and corrosion current density were analyzed with a 1-way analysis of variance and the Tukey test for pairwise comparisons (α=.05). RESULTS: Base metal and tungsten inert gas welded material showed equivalent results in electrochemical corrosion tests, while the air-torched specimens exhibited low corrosion resistance. The performance was worst at pH 2.5. CONCLUSIONS: These results suggest that tungsten inert gas is a suitable welding process for use in dentistry, because the final microstructure does not reduce the corrosion resistance in artificial saliva at 37°C, even in a corrosion-testing medium that facilitates galvanic corrosion processes. Moreover, the corrosion current density of brazed Ni-Cr alloy joints was significantly higher (P<.001) than the base metal and tungsten inert gas welded joints.

Avaliação da microestrutura, microdureza e resistência à corrosão de juntas soldadas de uma liga de Ni-Cr obtidas através de diferentes processos de soldagem / Evaluation of the microstructure, hardness and corrosion resistance of welded joints of a Ni-Cr alloy obtained by different welding processes

Este trabalho avaliou o comportamento eletroquímico do metal de base (MB) de uma liga a base de níquel-cromo em relação a juntas soldadas desta liga obtidas pelos processos de brasagem (BRA) e Tungsten Inert Gas (TIG), imersos em saliva artificial com pH 2,5 e 5,5. Foram também realizados ensaios de microdureza e caracterização microestrutural, por meio de microscopia óptica e eletrônica de varredura e análise química semi-quantitativa por EDS, nos grupos MB, TIG, BRA e no cordão de solda a laser (LAS). O MB apresentou uma matriz rica em níquel e cromo, distribuída em um arranjo dendrítico típico, apresentando inclusões metálicas de silício e titânio, além de porosidades. As soldas TIG e LAS revelaram uma microestrutura mais refinada que o MB, mostrando, entretanto, uma mesma composição química e distribuição de seus elementos. A solda BRA apresentou diferenças marcantes em sua microestrutura, composição química e distribuição de seus elementos em relação ao MB. Os dados de microdureza Vickers (HV), potencial de corrosão (Ecorr) e densidade de corrente de corrosão (jcorr) foram analisados com ANOVA e teste de Tukey (p<0,05). Para determinação da influência do pH quanto a resistência à corrosão dos grupos MB, TIG e BRA, empregou-se o teste t de Student (p<0,05). O MB apresentou menor média de microdureza (256,13 ± 9,39 HV), seguido pelos grupos TIG (271,53 ± 8,07 HV), LAS (303,73 ± 13,93 HV) e BRA (551,99 ± 37,73 HV). Em pH 2,5 as médias do Ecorr (mV) para o MB, TIG e BRA foram, respectivamente, -67,9 ± 8,43, -52,78 ± 16,74, e -284,33 ± 19,04; e em pH 5,5, médias de -54,03 ± 21,15, -62,08 ± 20,16 e -278,8 ± 28,96. Os valores médios de jcorr (µA.cm-2) para o MB, TIG e BRA em pH 2,5 foram, respectivamente, 2,49 ± 0,95, 5,584 ± 1,64 e 27,45 ± 4,9; e em pH 5,5, médias de 1,929 ± 0,83, 4,267 ± 1,51 e 54,2 ± 11,96. Os grupos MB e TIG apresentaram boa resistência à corrosão, com maior módulo de impedância em relação ao grupo BRA. As diferenças no pH da ...

This study evaluated and compared the electrochemical behavior of the base metal (BM) of a nickel-chromium dental alloy with welded joints obtained by brazing processes (BRA) and Tungsten Inert Gas (TIG), when immersed in artificial saliva at pH 2.5 and 5.5. Microhardness, microstructural characterization by means of optical microscopy, scanning electron microscopy (SEM) and semi-quantitative chemical analysis by Energy Dispersive Spectroscopy (EDS), were performed in the groups BM, TIG, BRA and in joints weld by laser (LAS). The BM showed a matrix rich in nickel and chromium, distributed in a typical dendritic arrangement, with inclusions of silicon and titanium, and porosities. LAS and TIG welds reveled a microstructure more refined than the BM, however, the same chemical composition and distribution of its elements. BRA showed marked differences in their microstructure, chemical composition and distribution of the elements in relation to BM. Vickers microhardness (HV), corrosion potential (Ecorr) and corrosion current density (jcorr) were statistically analyzed with ANOVA and Tukey test (p <0.05). In order to determine the influence of pH and corrosion resistance in groups BM, TIG and BRA, Student t test, with significance level of 95% was used. BM had the lowest average microhardness (HV 256.13 ± 9.39), followed by groups TIG (271.53 ± 8.07 HV), LAS (303.73 ± 13.93 HV) and BRA (551, HV 99 ± 37.73). At pH 2.5 the average Ecorr (mV) for the MB and TIG were respectively -67.9 ± 8.43 and -52.78 ± 16.74, and at pH 5.5, averaging -54, 03 ± 21.15 and -62.08 ± 20.16. LAS group showed averages of Ecorr (mV) at pH 2.5 and 5.5, respectively, -284.33 ± 19.04 and 28.96 ± -278.8. The average values of jcorr (ìA.cm-2) to BM and TIG at pH 2.5 were respectively 2.49 ± 0.95 and 5.584 ± 1.64, and at pH 5.5, 1.929 ± 0.83 and 4.267 ± 1.51. Average jcorr for LAS group (ìA.cm-2) at pH 2.5 and 5.5 were respectively 27.45 ± 4.9 and 11.96 ± 54.2. BM and TIG ...

Degradation of polymeric restorative materials subjected to a high caries challenge.

OBJECTIVES: The aim of this study was to evaluate the degradation of different resin filling materials after a caries challenge, by high performance liquid chromatography (HPLC) and contact angle (θ) measurement. METHODS: Four different polymeric restorative materials (a resin composite, a polyacid-modified resin composite, an ormocer and a resin-modified glass ionomer cement) were tested. Five samples (30 mm × 6 mm × 2 mm) of each material were formed in a Teflon mold, following the manufacturer's instructions. After pH cycles, the solutions were injected in an HPLC. The θ was obtained, before and after pH cycle, by a goniometer at 60% air humidity and 25°C. A distilled water drop (0.006 ml) was put on the material surface, and after 6 min, 10 measures were obtained at 20s intervals. Each sample received 4 drops, one at a time, on different areas. RESULTS: HPLC results showed elution of byproducts in all materials. This was greater in the acid medium. Bis-GMA and TEGDMA were detected in TPH Spectrum and Definite residues. Analyses of the contact angle by ANOVA and Student-Neuman-Keuls's test showed that the surfaces of TPH Spectrum, Dyract AP and Definite were altered, except Vitremer (p<0.05). SIGNIFICANCE: All materials tested degraded on a caries simulated medium, suggesting that a great effort should be made to disseminate oral health information, since a high caries challenge environment (low pH) can lead to dental composite degradation, with potential toxic risks to patients.

Influência das fontes halógena e LED e modos de ativação no grau de conversão de dois compósitos / Influence of photoactivation with halogen light and LED and types of activation on degree of conversion of two composites

O objetivo do presente artigo é avaliar a influência da fotoativação com lâmpadas halógena e LED no grau de conversão dos compósitos microíbrido e nanoparticulado. Trinta amostras foram divididas em seis grupos variando tipo de resina, tipo de lâmpada e tipo de ativação. Para medir grau de conversão foi utilizada espectrofotometria por Raman. As amostras não polimerizadas e polimerizadas foram comparadas para avaliar se houve diferença no grau de conversão para Ho1: os diferentes compósitos; Ho2: as diferentes fontes luminosas e Ho3: os diferentes modos de ativação. Para análise estatística foram utilizados Anova e T de Student. Os resultados mostraram haver diferença estatística, demonstrando maior grau de conversão para resinas nanoparticuladas, o que pode estar ligado à presença de TEGDMA em sua matriz.

The objective this paper is evaluate influence of photoativation with halogen light and LED on conversion’s degree of two different composites. Thirty samples were divided in six groups considering type of composite, photoativation unit and type of polimerization used. Ramanspectrophotometry was used to measure the degree of conversion. The Non-polimerized and polimerized sampleswere compared to evaluate if there was any difference on the degree of conversion to Ho1: composites; Ho2:diferent polimerization sources and Ho3: diferent activation modes. Anova and T Student were utlilized to statisticalanalysis. Results showed difference between the degrees of conversion of the different composites expressing ahigher value for nanoparticulate resins, which could be explained by the presence of the TEGDMA on the composition of the matrix.

Utilização de dentes bovinos compossível substituto aos dentes humanos nos testes in vitro: revisão de literatura / Bovine teeth as possible substitute to human teeth in laboratory studies: current findings reviewed

Um dos desafios atuais para a pesquisa odontológica é a dificul-dade de se conseguir dentes humanos hígidos em quantidade suficiente. Além disso, outras dificuldades, como a necessidade de padronização dos substratos, redução do risco de infecção e a questão bioética, têm motivado o desenvolvimento de pesquisas científicas que visam a conseguir um substituto viável para os dentes humanos. A proposta deste estudo foi realizar uma revisão de literatura avaliando uma possível substituição do substrato humano. O esmalte bovino parece ser um substituto adequado ao esmalte humano, mas a dentina deve ser utilizada com cautela, visto que incidências e profundidades aleatórias do corte, em relação aos túbulos dentinários, podem alterar os resultados.

One of the currently challenges for dentistry research is the difficulty to obtain enough amounts of higid human teeth. Moreover, other difficulties as standardization of substrates, reduction of infection risk and bioethics question involving humans have stimulated the develop-ment of scientific research to obtain an available substitute for human teeth. The proposal of this study was to make a literature review and to evaluate a possible substitution for the human substrate. The bovine enamel seems to be an adequate substitute to the human enamel, but the dentine must be used with caution, since random incidences and depths of the slices in relation to the dentin tubules can modify the results.

Influence of two self-etching primer systems on enamel adhesion.

The aim of this study was to compare two self-etching and a total-etch adhesive systems by assessing their shear bond strength to bovine enamel and the microleakage on class V composite restorations prepared on bovine enamel. Bovine teeth selected and allocated in three groups: Group 1: Scothbond Multi-Purpose; Group 2: Clearfil Liner Bond 2V; Group 3: Etch & Prime 3.0. For the microleakage test, each group was composed of ten class V restorations on the buccal surface. Two examiners attributed scores ranging from 0 (without leakage) to 3 (maximum leakage) to determine silver nitrate penetration at enamel-composite interface. Microleakage data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests at 5% significance level. For the bond strength test, ten teeth of each group were included, had their buccal surfaces flattened in order to obtain a 3-mm-diameter area to which a resin cylinder was bonded. After one week, the specimens were tested in shear strength at a crosshead speed of 0.5 mm/min. Bond strength data were treated by ANOVA and LSD tests at 5% significance level. The debonded interfaces were examined under scanning electron microscopy. No leakage was observed along enamel margins. Means (+/- SD) in MPa were: 18.75 (+/-5.83), 22.17 (+/-4.95) and 14.93 (+/-6.7) for Groups 1, 2, and 3, respectively. According to the results of this study, the self-etching primer systems presented statistically similar behavior (p>0.05) to that of the total-etch adhesive system (used as a control), not only regarding marginal leakage at bovine enamel-composite resin interface, but also regarding the shear bond strength of the bovine enamel. However, the self-etching primer systems differed significantly (p>0.05) to each other, with better results for Clearfil Liner Bond 2V. In conclusion, the self-etching primer systems had a performance comparable to that of the total-etch adhesive system.

Influence of two self-etching primer systems on enamel adhesion

The aim of this study was to compare two self-etching and a total-etch adhesive systems by assessing their shear bond strength to bovine enamel and the microleakage on class V composite restorations prepared on bovine enamel. Bovine teeth selected and allocated in three groups: Group 1: Scothbond Multi-Purpose; Group 2: Clearfil Liner Bond 2V; Group 3: Etch & Prime 3.0. For the microleakage test, each group was composed of ten class V restorations on the buccal surface. Two examiners attributed scores ranging from 0 (without leakage) to 3 (maximum leakage) to determine silver nitrate penetration at enamel-composite interface. Microleakage data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests at 5 percent significance level. For the bond strength test, ten teeth of each group were included, had their buccal surfaces flattened in order to obtain a 3-mm-diameter area to which a resin cylinder was bonded. After one week, the specimens were tested in shear strength at a crosshead speed of 0.5 mm/min. Bond strength data were treated by ANOVA and LSD tests at 5 percent significance level. The debonded interfaces were examined under scanning electron microscopy. No leakage was observed along enamel margins. Means (± SD) in MPa were: 18.75 (±5.83), 22.17 (±4.95) and 14.93 (±6.7) for Groups 1, 2, and 3, respectively. According to the results of this study, the self-etching primer systems presented statistically similar behavior (p>0.05) to that of the total-etch adhesive system (used as a control), not only regarding marginal leakage at bovine enamel-composite resin interface, but also regarding the shear bond strength of the bovine enamel. However, the self-etching primer systems differed significantly (p>0.05) to each other, with better results for Clearfil Liner Bond 2V. In conclusion, the self-etching primer systems had a performance comparable to that of the total-etch adhesive system.

O objetivo deste estudo foi comparar um sistema adesivo que utiliza condicionamento ácido total com outros contendo primers autocondicionantes em sua composição, quando aplicados ao esmalte bovino. Para isto, foram realizados testes de microinfiltração com corante e testes de resistência de união ao cisalhamento. Os dentes bovinos foram divididos em três grupos, de acordo com o sistema adesivo empregado: Grupo 1 (controle) - Scotchbond Multi-Uso Plus (3M); Grupo 2- Clearfil Liner Bond 2V (Kuraray); e Grupo 3- Etch & Prime 3.0 (Degussa). Para microinfiltração, cada grupo foi composto de dez restaurações classe V na superfície vestibular dos dentes e restauradas com o compósito TPH (Dentisply). A avaliação foi realizada por dois avaliadores previamente calibrados, usando um sistema de escore crescente de 0 (sem infiltração) até 3 (infiltração além da parede axial), dependendo do grau de penetração de um corante a base de nitrato de prata. Para o teste de resistência ao cisalhamento, 10 dentes de cada grupo foram incluídos em um tubo de metal, usando uma resina autopolimerizável. Suas superfícies vestibulares foram desgastadas até a obtenção de uma área de adesão com diâmetro de 3 mm. Sobre estas superfícies foram construídos cilindros de resina composta TPH. Após uma semana, foram submetidos ao ensaio de cisalhamento, a uma velocidade de 0,5 mm/min. Após a ruptura, as superfícies dos cilindros de resina composta foram recolhidas para observação em microscópio eletrônico de varredura. Para os testes de microinfiltração, os resultados foram tratados estatisticamente por Kruskal-Wallis e Mann-Whitney (p>0,05). O teste de microinfiltração não revelou diferença entre os grupos. Os resultados do teste de cisalhamento foram tratados por ANOVA e teste LSD (p<0,05). As médias e desvios padrão em MPa foram: G1: 18,75 ± 5,83; G2: 22,17 ± 4,95; G3: 14,93 ± 6,7. Não houve diferença estatisticamente significante entre o grupo controle e os autocondicionantes...