Microleakage evaluation of pit and fissure sealants done with different procedures, materials, and laser after invasive technique

This study evaluated the microleakage of pit and fissure sealants after different surface preparation (invasive technique and laser irradiation) and the use of different materials (fluoride resin-filled sealant, resin-modified glass ionomer cement and adhesive system). Eighty-four pre molars were used in this study, which were divided into seven groups. After the accomplishment of the different treatments, these were submitted to thermocycling process and assess for microleakage by examination under an epifluorescent microscope and scored zero to seven. Two specimens of each group were observed under scanning electron microscope (SEM). The results showed that laser irradiation did not lessen microleakage in pit and fissures when using a filled-resin sealant with fluoride or a resin-modified glass ionomer cement. The use of laser irradiation and adhesive system, followed by a resin-filled sealant with fluoride, showed the lowest microleakage scores in pit and fissures. Comparing this group to the resin-modified glass ionomer cement group, there was statistical significance. The use of a adhesive system decreased microleakage when using a fluoride resin-filled sealant with or without previous laser irradiation; although it was not statistically significant.

Shear bond strength of orthodontic brackets bonded using halogen light and light-emitting diode at different debond times

The aim of this in vitro study was to compare the photoactivation effects of QTH (Quartz-Tungsten-Halogen) and LED (Light-Emitting Diode) on the SBS (Shear Bond Strength) of orthodontic brackets at different debond times. Seventy-two bovine lower incisors were randomly divided into two groups according to the photoactivation system used (QTH or LED). The enamel surfaces were conditioned with Transbond self-etching primer, and APC (Adhesive Pre-Coated) brackets were used in all specimens. Group I was cured with QTH for 20 s and Group II with LED for 10 s. Both groups were subdivided according to the different experimental times after bonding (immediately, 24 h and 7 days). The specimens were tested for SBS and the enamel surfaces were analyzed according to the Adhesive Remnant Index (ARI). The statistical analysis included the Tukey's test to evaluate the main effects of photoactivation and debond time on SBS. The Chi-square test was used to compare the ARI values found for each group, and no statistically significant difference was observed. The debond time of 7 days for QTH photoactivation showed statistically greater values of SBS when compared to the immediate and 24 h periods. There was no statistically significant difference between the QTH and LED groups immediately and after the 24 h period. In conclusion, bonding orthodontic brackets with LED photoactivation for 10 s is suggested because it requires a reduced clinical chair time.

Clinical evaluation of two packable resin-based composite restorations: A three-year report

This randomized clinical trial sought to evaluate the performance of two packable composites over a period of 36 months. A total of 39 Class I and II restorations were placed in the permanent teeth of 20 patients. Using United States Public Health Services criteria, two investigators evaluated the restorations immediately after placement and again after 12 and 36 months, examining color match, marginal discoloration, marginal integrity, recurrent caries, proximal contact, anatomical shape, surface texture, and postoperative sensitivity. It was concluded that the packable composites evaluated showed satisfactory clinical performance after three years.

La memoria colectiva y los retos del feminismo

Incluye Bibliografía

The collective memory and challenges of feminism

Includes bibliography

Fecundidad: diferenciales geográficos y socioeconómicos de la fecundidad, 1960-1983. EDENH II y otras fuentes

Complementa la información contenida en los documentos publicados con los símbolos LC/DEM/CR/G.7, G.9 y G.12

Pollen morphology in Brazilian species of Codonanthe (Mart.) Hanst. and Nematanthus Schrader (Gesneriaceae)

Pollen morphology of 24 Brazilian species of Codonanthe and Nematanthus (Gesneriaceae) was investigated by means of light microscopy, scanning and transmission electron microscopy, in search of new characters that might contribute to taxonomic characterisation of the genera. The pollen grains are tricolpate or tricolporate, semitectate, reticulate, with simplicolumellate muri, sometimes with microreticulum and perforations, or duplicolumellate muri ring-shaped around lumina. The species studied were grouped into five pollen types on the basis of aperture characteristics and details of surface ornamentation. Sub-types were defined with reference to presence or absence of microreticulum and perforations around the lumina. Based on analysis of the morphology and measurements of pollen grains, we verified a close relationship among the genera, but can nevertheless discriminate their species. © 2013 Copyright Collegium Palynologicum Scandinavicum.

Bolivia: mortalidad en el menor de dos anos y fecundidad por condicion de migracion en la region de los Llanos: Censo 1976. Trabajo de investigacion

Incluye Bibliografía

Efecto de la migracion en las estimaciones de fecundidad por el metodo de hijos propios. La Paz (Bolivia 1976) y Bogota D.E. (Colombia 1973); trabajo final de investigacion

Incluye Bibliografía

Costa Rica: estimaciones sobre necesidades de vivienda 1985-2000

Incluye Bibliografía

Avaliação da movimentação de cães por meio de captura-recaptura fotográfica e georeferenciamento

Pós-graduação em Ciência Animal - FMVA

Costa Rica: proyeccion de jefes de hogar por sexo, edad y estado conyugal, 1985-2025

Incluye Bibliografía

Costa Rica: estimaciones y proyecciones de vivienda 1985-2025

Incluye Bibliografía

Construyendo capacidades tecnológicas en escenarios inestables: empresas manufactureras argentinas y brasileñas

Desde la década de 1970, el contexto macroeconómico en la Argentina y el Brasil se caracterizó por cambios económicos drásticos e inestabilidad. En numerosos estudios se ha documentado el efecto generalmente negativo de ese entorno en las capacidades de innovación del sector manufacturero. En este trabajo, en cambio, se analiza el posible surgimiento de nuevas capacidades de innovación en dicho período, revelándose dos fenómenos importantes. Primero, un número no menor de empresas, incluso en entornos inestables, redoblaron sus esfuerzos innovadores. Segundo, estas empresas se concentran en un grupo reducido de sectores relacionados con las ventajas estáticas de estos países o en sectores favorecidos por regímenes sectoriales específicos. Los resultados encontrados, aunque exploratorios, contribuyen a la discusión sobre la construcción de capacidades innovadoras en contextos macroeconómicos inestables y la capacidad de los sectores vinculados a las ventajas estáticas de ambos países para generar espacios de innovación y creación de valor.