921 resultados para Dent Texture


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The long-term impact of irrigation on a Mediterranean sandy soil irrigated with Treated wastewater (TWW) since 1980 was evaluated. The main soil properties (CEC, pH, size distribution, exchangeable cations and chloride, hydraulic conductivity) as well as the organic matter and Cu, Cr and Pb speciation in an irrigated soil and a non-irrigated control soil at various soil depths were monitored and compared during a 2 years experiment. In this first part, the evolution of the physico-chemical soil properties was described. The irrigation with TWW was beneficial with regard to water and nutrient supplying. All the exchangeable cations other than K(+) were higher in the irrigated soil than in the reference one. A part of the exchangeable cations was not fixed on the exchange complex but stored as labile salts or in concentrated soil solution. Despite the very sandy soil texture, both saturated and unsaturated hydraulic conductivity exhibited a significant diminution in the irrigated soil, but remained high enough to allow water percolation during rainy periods and subsequent leaching of accumulated salts, preventing soil salinization. In the irrigated soil, exchangeable sodium percentage (ESP) exhibited high values (20% on average) and the soil organic C was lower than in the reference. No significant effect was noticed on soil mineralogical composition due to irrigation. (C) 2010 Published by Elsevier Ltd.

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Iowa DOT research in 1986, demonstrated that carbide tooth milling can produce an acceptable surface texture. Based upon that research, specifications were developed for "Pavement Surface Repair (Milling)". This specification was applied to reprofile a nine-mile section of badly faulted portland cement concrete (pcc) pavement on route 163 just east of Des Moines. The Profile Index (measured with a 25-foot California Profilograph) was improved from an average of 55.2 inches per mile prior to milling to 10.6 inches per mile after milling. The bid price was $0.75 per square yard for pcc containing limestone coarse aggregate and $1.21 for pcc containing gravel coarse aggregate. Carbide tooth milling should be considered as an acceptable alternate method of reprofiling even though there is some spalling of joints.

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There are many miles of portland cement concrete pavement in Iowa that due to normal wear, and in some cases accelerated wear from studded tires, the surface has become polished resulting in less than desirable friction values. Retexturing the surface may be an economical way to re-establish desirable friction values. Retexturing by grinding with diamond blades and transverse grooving with diamond blades are two methods of rehabilitating p.c.c. surfaces. MU Inc. of Lebanan, Tennessee proposed to provide without charge to the Iowa Department of Transportation, one 1500 ft x 12 ft section each of three methods of texturing. They are longitudinal grinding, transverse grooving and longitudinal grinding followed by transverse grooving. A section of 1500 feet is needed to properly evaluate a texturing method. It was decided by Iowa DOT personnel that due to possible differential friction it would be undesirable to texture only one lane. The decision was made to do test sections of 1500 ft x 24 ft with the cost of the additional texturing paid by the Iowa DOT. Iowa also has areas where the p.c.c. pavement has faulted at the joints and cracks which results in poor riding quality. Methods of correcting the faulting are to underseal the pavement where needed and/or grinding the surface to eliminate the faulted areas. It was decided to include in this research project a section for profiling by grinding.

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Seven experimental texture sections were constructed on the Polk-Jasper RP-163-1(50)--16--77 project just east of Des Moines. The experimental sections included two groove depths for a longitudinal tine texture and 13 mm (1/2 in.), 19 mm (1 in.) and variable spaced transverse tine textures. An artificial turf textured section was also included. Friction values and a rating of objectionable noise were determined for all sections. All transverse tine textures generated a high level of objectionable noise. The longitudinal tine texture was rated very good in regard to objectionable noise. At this time, all tined textures are providing satisfactory friction values.

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Para demostrar que los parámetros periodontales no se alteran por la fenestración con colgajo de reposición apical de los caninos incluidos, se seleccionaron 12 pacientes con canino incluido por vestibular y el canino contralateral correctamente erupcionado. El tratamiento fue ortodóncico-quirúrgico, con colgajo de reposición apical (9 casos) o de reposición apical lateral (3 casos). Tres años después de finalizar el tratamiento ortodóncico, se valoró el estado periodontal de los caninos mediante: índice de plata, índice gingival, sangrado al sondaje, profundidad de sondaje y anchura de encía queratinizada. No se hallaron diferencias estadísticamente significativas entre el grupo experimental (caninos fenestrados) y el control (caninos contralaterales).

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Se presenta el caso de una mujer de 23 años de edad que presentaba los molares inferiores permanentes segundo y tercero impactados verticalmente en la rama ascendente de la mandíbula. Las superficies oclusales de ambos dientes se encontraban en contacto. Tras un diagnóstico preciso, que incluyó una tomografía computarizada, se decidió extraer ambos dientes. El conducto del nervio dentario inferior, que en las radiografías se consideró que se encontraba bajo riesgo, no sufrió ningún daño, gracias a una técnica quirúrgica cuidadosa.

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En el presente trabajo se ha realizado una revisión bibliográfica de la relación existente entre la erupción de los terceros molares y la posibilidad de que aparezca un apiñamiento anterior (normalmente inferior). El apiñamiento es una malposición dental muy frecuente en la población, por lo que si realmente se puede relacionar con la erupción del tercer molar, el tratamiento precoz en dichos casos evitaría la aparición de esta malposición dental. Conoceremos las posturas de los diferentes autores al respecto, los distintos tratamientos que se pueden realizar y otros aspectos relacionados con el tema.

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Se presenta el caso de un paciente varón que tenía el canino temporal inferior derecho no exfoliado a los 15 años de edad; a la exploración se descubrió que existía el canino permanente totalmente incluído, con la particularidad de que estaba asociado a un quiste folicular y que la posible causa de inclusión era la presencia de un premolar supernumerario también retenido; otra rareza a destacar es que se hizo un abordaje quirúrgico mixto, vestibular para el premolar supernumerario y lingual para el canino permanente siendo esta última eventualidad realmente excepcional. Se discuten los aspectos referentes al diagnóstico y a la estrategia quirúrgica adoptadas en este caso poco habitual.

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La correcta identificación anatómica del conducto dentario inferior, por el que circula el nervio dentario inferior, con respecto al tercer molar es esencial cuando es preciso practicar la exéresis de los cordales inferiores incluidos, puesto que la proximidad de ambas estructuras condiciona la posibilidad de lesionar dicho nervio. En este artículo, se revisa el estudio radiológico del conducto dentario inferior y se comentan las diferentes técnicas de diagnóstico por la imagen (ortopantomografía, radiografías periapicales y oclusales y tomografía axial computadorizada), así como sus diversas indicaciones y los signos radiológicos útiles para determinar la situación y trayecto del conducto dentario inferior con respecto a los ápices.

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Se describe un paciente que presentaba dos mesiodens molariformes en posición palatina con formación radicular casi completa que impedían la erupción total de los incisivos centrales superiores permanentes con desplazamiento vestibular.

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El caso estudiado corresponde a una niña de 13 años y 1 mes, que acude a la consulta de ortodoncia por una ligera protrusión de incisivos superiores. Presenta una oclusión de clase I, molar y canina, y clase I esquelética. Con una discrepancia inferior de 4 mm, un patrón de crecimiento dólico, y un perfil recto con el surco supramentoniano borrado. Ante una paciente de estas características se nos plantean diversas posibilidades de tratamiento, con o sin extracciones, e incluso la posibilidad de no tratar.

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Se presenta el caso de un paciente con un objeto inanimado en fosa nasal izquierda, que acudió a la Clínica Odontológica de Bellvitge, por la ausencia de los incisivos laterales permanentes en el maxilar superior. Al confirmar la presencia de los incisivos, a partir de una radiografía oclusal, descubrimos, de forma casual, un objeto radiopaco al que acompañaba una específica sintomatología. Después de la intervención del otorrinolaringólogo, dicha sintomatología desapareció. Referimos el manejo de los cuerpos extraños en fosas nasales y aprovechamos la ocasión para revisar las pautas generales de orientación diagnóstico-terapéuticas frente a esta patología.

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La extracción del tercer molar inferior incluido provoca efectos secundarios como dolor, inflamación y trismo. Presentamos un estudio cuyo objetivo fue relacionar la edad, el sexo, el tabaco y la higiene oral con el postoperatorio de 100 de terceros molares inferiores incluidos. La edad, el sexo y el consumo de tabaco no influyeron significativamente en el postoperatorio. Sólo hallamos una correlación estadísticamente significativa entre la higiene oral y el dolor a las 6 horas de la exodoncia.

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The origin and evolution of CO2 inclusions and calcite veins in peridotite xenoliths of the Pannonian Basin, Hungary, were investigated by means of petrographic investigation and stable isotope analyses. The fluid inclusions recovered in paragenetic olivine and clinopyroxene belong to distinct populations: type A (texturally early) inclusions with regular shapes (often with negative crystal forms) forming intragranular trails, type B (texturally late) inclusions defining randomly oriented trails that reach grain boundaries Type B inclusions are often associated with silicate melt (type C) inclusions Stable carbon isotope compositions in inclusion-hosted CO2 were obtained by vacuum crushing followed by conventional dual inlet as well as continuous flow mass spectrometry in order to eliminate possible lab artifacts. Olivines, clino- and orthopyroxenes of the host peridotite have oxygen isotope compositions from 5.3 to 6.0 parts per thousand (relative to V-SMOW). without any relationship with xenolith texture. Some of the xenoliths contained calcite in various forms veins and infillings in silicate globules in veins, secondary carbonate veins filling cracks and metasomatic veins with diffuse margins The former two carbonate types have delta C-13 values around -13 parts per thousand (relative to V-PDB) and low Sr contents (<05 wt %), whereas the third type,veins with high-temperature metasomatic features have a delta C-13 value of -5 0 parts per thousand and high Sr contents up to 34 wt.% In spite of the mantle-like delta C-13 value and the unusually high Sr content typical for mantle-derived carbonate, trace element compositions have proven a crustal origin. This observation supports the conclusions of earlier studies that the carbonate melt droplets found on peridotite xenoliths in the alkaline basalts represent mobilized sedimentary carbonate. The large delta C-13 range and the C-12-enrichment in the carbonates can be attributed to devolanlization of the migrating carbonate or infiltration of surficial fluids containing C-12-rich dissolved carbon Carbon isotope compositions of inclusion-hosted CO2 range from -17 8 to -4.8 parts per thousand (relative to V-PDB) with no relation to the amount of CO2 released by vacuum crushing. Low-delta C-13 values measured by stepwise heating under vacuum suggest that the carbon component is pristine and not related to surficial contamination, and that primary mantle fluids with delta C-13 values around -5 parts per thousand were at least partly preserved in the xenoliths Tectonic reworking and heating by the basaltic magma resulted in partial CO2 release and local C-13-depletion. (C) 2010 Elsevier B V All rights reserved

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BACKGROUND: The potential effects of ionizing radiation are of particular concern in children. The model-based iterative reconstruction VEO(TM) is a technique commercialized to improve image quality and reduce noise compared with the filtered back-projection (FBP) method. OBJECTIVE: To evaluate the potential of VEO(TM) on diagnostic image quality and dose reduction in pediatric chest CT examinations. MATERIALS AND METHODS: Twenty children (mean 11.4 years) with cystic fibrosis underwent either a standard CT or a moderately reduced-dose CT plus a minimum-dose CT performed at 100 kVp. Reduced-dose CT examinations consisted of two consecutive acquisitions: one moderately reduced-dose CT with increased noise index (NI = 70) and one minimum-dose CT at CTDIvol 0.14 mGy. Standard CTs were reconstructed using the FBP method while low-dose CTs were reconstructed using FBP and VEO. Two senior radiologists evaluated diagnostic image quality independently by scoring anatomical structures using a four-point scale (1 = excellent, 2 = clear, 3 = diminished, 4 = non-diagnostic). Standard deviation (SD) and signal-to-noise ratio (SNR) were also computed. RESULTS: At moderately reduced doses, VEO images had significantly lower SD (P < 0.001) and higher SNR (P < 0.05) in comparison to filtered back-projection images. Further improvements were obtained at minimum-dose CT. The best diagnostic image quality was obtained with VEO at minimum-dose CT for the small structures (subpleural vessels and lung fissures) (P < 0.001). The potential for dose reduction was dependent on the diagnostic task because of the modification of the image texture produced by this reconstruction. CONCLUSIONS: At minimum-dose CT, VEO enables important dose reduction depending on the clinical indication and makes visible certain small structures that were not perceptible with filtered back-projection.